Plants Poisonous to Livestock in Montana and Wyoming

Plants Poisonous to Livestock in Montana and WyomingConsiderations for Reducing Production Losses

Natural Resources Conservation Service Plant Matrials Technical Note MT-124

Montana State University ExtensionUniversity of Wyoming Extension Bulletin B-1359

AcknowledgementsPlants Poisonous to Livestock in Montana and Wyoming represents a cooperative effort among individuals within the United States Department of Agriculture – Natural Resources Conservation Service (USDA-NRCS), Montana State University (MSU) Extension, and University of Wyoming (UW) Extension. This publication is adapted with permission from Poisonous Range Plants of Montana (Leininger et al. 1977) and Plants Poisonous to Livestock in the Western States (Panter et al. 2011). We acknowledge and thank previous authors for those documents and contributions to this field of study.

Contributors (alphabetical order)Haylee Barkley, USDA-NRCS, Pathways Program, Bozeman, MTKaren Clause, USDA-NRCS, Range Management Specialist, Pinedale, WYJane Mangold, Ph.D., MSU, Professor and Extension Invasive Plant Specialist, Bozeman, MTTed Nelson, DVM, USDA-NRCS, Supervisory District Conservationist, Livingston, MTNoelle Orloff, MSc, MSU, Associate Extension Specialist, Bozeman, MTMonica Pokorny, MSc, USDA-NRCS, Plant Materials Specialist, Bozeman, MTDerek Scasta, Ph.D., UW, Assistant Professor and Extension Rangeland Specialist, Laramie, WYBarton Stam, MSc, UW, Range Extension Educator, Thermopolis, WYSusan Tallman, MSc, USDA-NRCS, Area Agronomist, Bozeman, MTDaniel Tekiela, Ph.D., UW, Assistant Professor and Extension Specialist of Invasive Plant Ecology, Laramie, WY

We express our appreciation to the following reviewers:Daniel Cook, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Plant Physiologist, Logan, UTMarko Manoukian, MSU, Phillips County Extension Agency, Malta, MTJennifer Paddock, USDA-NRCS, District Conservationist, White Sulphur Springs, MTJ. Daniel Rodgers, Ph.D., UW, Associate Professor and Extension Rangeland Specialist (retired), Laramie, WYJoseph Scianna, USDA-NRCS, Plant Materials Center Manager, Bridger, MTClinton Stonecipher, USDA-ARS Poisonous Plant Research Laboratory, Range Technician, Logan, UTKevin Welch, Ph.D., USDA-ARS Poisonous Plant Research Laboratory, Research Toxicologist, Logan, UT

Suggested citation:USDA-NRCS, MSU, and UW. 2020. Plants Poisonous to Livestock in Montana and Wyoming, Considerations for Reducing Production Losses. USDA-NRCS Plant Materials Technical Note MT-124 and University of Wyoming Extension Bulletin B-1359. USDA-NRCS, Bozeman State Office, Bozeman, MT. 43 pg.

This publication is available electronically (free) and in hard copy from the NRCS Montana and Wyoming Plant Materials Program, Montana State University Extension, and University of Wyoming Extension websites.

Cover photos:Front top and bottom left: lupine (Lupinus sp.) and poison hemlock (Conium maculatum), M.Lavin, MSU; Front bottom center and bottom right: larkspur (Delphinium sp.) and milkvetch (Astragalus sp.), USDA-NRCS. Back top and center: poison hemlock (Conium maculatum) and foxtail barley (Hordeum jubatum), M. Lavin, MSU; Back bottom: deathcamas (Zigadenus venenosus), T. Nelson, USDA-NRCS.

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Persons with disabilities who require alternative means of communication for program information (e.g. Braille, large print, audiotape, American Sign Language, etc.) should contact the responsible Agency or USDA’s TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English.

Table of Contents

TABLE 1. Signs of poisoning and conditions under which plant species can be dangerous to livestock. Symptoms listed for each plant are those most likely to be observed. Not all symptoms will be seen in all toxicities, and signs of poisoning may vary greatly depending on dosage and the time taken to consume the dose. Also, individual animals respond differently to specific toxins. ....... 21

TABLE 2. Toxic doses for commonly diagnosed plant poisonings in Montana and Wyoming. For some plant species, signs of livestock poisoning may not be evident until a toxic threshold is reached. ....... 31

TABLE 3. The origin and habitat of plants with toxic properties in Montana and Wyoming. ...............................34

INTRODUCTION ........................................................................................................................................................4 Economic Impacts of Poisonous Plants .........................................................................................................4 Identifying Poisonous Plants .........................................................................................................................5FACTORS INFLUENCING PLANT TOXICITY FOR LIVESTOCK ...........................................................................6 Plant-related: ..................................................................................................................................................6 Dose ........................................................................................................................................................6 Season and Plant Growth Stage .............................................................................................................6 Palatability ..............................................................................................................................................7 Growing Conditions ...............................................................................................................................7 Component of Hay ..................................................................................................................................7 Animal-related: ..............................................................................................................................................8 Animal Species, Gender, Size and Age ..................................................................................................8 Animal Health ........................................................................................................................................8 Animal Response to Toxin .....................................................................................................................8CONDITIONS LEADING TO LIVESTOCK POISONING AND MANAGEMENT TO REDUCE IMPACTS ..................................................................................................................9 Grazing Rangeland and Pasture that Are in Poor Condition .......................................................................9 Hungry Animals on Infested Rangeland, Pasture or Cover Crop ................................................................9 Early Season Grazing on Rangeland .............................................................................................................9 Livestock Familiarity with the Area ............................................................................................................ 10 Improper Herding, Driving and Bedding.................................................................................................... 10 Inadequate Nutrient Supply..........................................................................................................................11 Water Quantity and Quality .........................................................................................................................11 Environmental Conditions ...........................................................................................................................11 Cultural Practices ........................................................................................................................................ 12 Grazing System ............................................................................................................................................ 12 Multi-species Grazing .................................................................................................................................. 13 Crop and Cover Crop Grazing ...................................................................................................................... 13CARE FOR IMPACTED ANIMALS .......................................................................................................................... 13CONTROL OF POISONOUS PLANTS ...................................................................................................................... 13POISONOUS SUBSTANCES AND OTHER FORAGE PROBLEMS ........................................................................ 14PRINCIPLE TOXINS ................................................................................................................................................14 Alkaloids ....................................................................................................................................................... 15 Cardiac Glycosides ....................................................................................................................................... 15 Cyanogenic Glycosides ................................................................................................................................. 16 Nitrate........................................................................................................................................................... 16 Oxalates .........................................................................................................................................................17 Saponins ....................................................................................................................................................... 18 Selenium ....................................................................................................................................................... 18OTHER FORAGE PROBLEMS AND DISORDERS ................................................................................................. 19 Bloat .............................................................................................................................................................. 19 Mechanical Injuries ..................................................................................................................................... 19 Mycotoxins ................................................................................................................................................... 19 Photosensitization ........................................................................................................................................20 Volatile Oils ..................................................................................................................................................20RESOURCES AND REFERENCES ..........................................................................................................................40GLOSSARY ..............................................................................................................................................................42

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IntroductionPoisonous plants contain or produce substances that cause sickness, metabolic disorders, death, or health concerns in animals when ingested. Each year these plants adversely affect 3 to 5% of the cattle, sheep, goats, and horses that graze western United States rangelands, pasture, and forest lands. There are many plants in Montana and Wyoming that have been suspected of being poisonous. However, these plants vary in their toxicities, the types of animals affected, and the environmental conditions when poisoning occurs. For example, a plant species might provide good forage for sheep yet be poisonous to cattle and horses. Another plant may provide excellent nourishment in small amounts or during certain seasons but be poisonous under different conditions.

Poisonous plants will always be present on rangeland, pasture, and forest lands, and may be intentionally planted as cover crops or forages on croplands. Many poisonous plants are native to Montana and Wyoming and naturally occur in plant communities. Other poisonous plants are introduced (i.e. non-native) species, and some of these introduced species are invasive and spreading across the region. Mismanagement of rangeland and pasture can allow these introduced and native poisonous plants to increase since some of them are unpalatable. Additionally, poor livestock management may increase the likelihood of poisoning. Rangeland and pasture should be regularly inspected for poisonous plants and the information used to make prudent livestock and grazing management decisions.

Wild onions (Allium sp.) are native plants that emerge in the early spring in a variety of plant communities. Livestock can exhibit poisoning effects if their diets contain large quantities (e.g. 25% diet) of onion leaves.

Black henbane (Hyoscyamus niger)1, an introduced invasive species from Europe, can increase with poor pasture management. Its foliage has a pungent odor and is not usually consumed by livestock unless desirable forage is lacking. When consumed, symptoms of poisoning include dilated pupils and convulsions.

1 Nomenclature, common and scientific names, follows USDA PLANTS Database, 2019.

This publication describes signs of poisoning and livestock affected (Table 1), toxic doses and factors influencing toxicity (Table 2), and the habitats where these poisonous plants grow in Montana and Wyoming (Table 3). The publication also describes environmental and management conditions leading to livestock poisoning along with management considerations to prevent or minimize impacts.

Economic Impacts of Poisonous PlantsPoisonous plants cause an economic loss to the livestock industry. In 1992, the economic value from direct losses of cattle and sheep in the 17 western states was $340 million dollars, which would exceed $600 million today when adjusted for inflation. In addition, there are indirect economic impacts from poisonous plants associated with increased management costs.

Direct impacts include the following effects on animals:• Death• Abortions• Birth defects• Weight loss due to illness or decreased feed intake• Lengthened calving interval• Decreased fertility• Decreased immune response• Increased organ damage (e.g. lungs, liver, nervous

system, etc.) • Loss of breeding stock due to mortality, functional

inefficiency, etc.

Photo: USDA-NRCS

Photo: USDA-NRCS

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Identifying Poisonous PlantsThere is no single rule or characteristic that can be used to determine a toxic plant from a non-toxic plant. To protect animals from poisoning, learn to identify poisonous plants that are common to the area and obtain reliable information on their poisonous properties. Some poisonous plant publications focus on plant identification; however, this publication does not because plant identification resources are readily available. We provide a list of resources to aid in identification in the Resources and References Section below.

Sudden onset of illness with no apparent cause may indicate poisoning by a toxic plant. If plant poisoning is suspected, the responsible plant(s) must be identified, which is sometimes a difficult task. Symptoms may be similar across multiple poisonous plants, all symptoms may not manifest, and some symptoms may be atypical. Sometimes poisoning is even caused by a plant not commonly recognized as toxic. Examine the rangeland or pasture for poisonous plant species.

Halogeton (Halogeton glomeratus) has red stems and fleshy leaves. It has caused hundreds of livestock deaths in a single day at one location in various western states. Livestock should not be allowed to become hungry or thirsty while grazing in areas infested with halogeton, as they will graze indiscriminately. Proper rangeland management is the best way to minimize livestock losses.

The maintenance of regular, detailed livestock management records can be a useful tool when diagnosing plant poisoning for an animal displaying symptoms. For example, information about the date animals entered a pasture, where they moved from, their general health prior to symptom onset, and utilization of suspected plants can all be important. If the animal is alive, careful observations and notes about its behavior should be made. If the animal has recently died, an inspection in the digestive tract (or a complete necropsy) for identifiable plant parts is recommended, along with an examination for abnormal-appearing organs. Contact a veterinarian or other qualified individual for help making a diagnosis. Whether or not an animal is treated for plant poisoning may be decided by behavioral observations, noted above, and by correct identification of the suspected poisonous plant. Ultimately, correct identification of the plant is essential for any long-term proactive corrective action and should be considered an important starting point if problems occur.

When the presumed causal plant is identified, it should be collected for verification by someone with plant identification expertise. Collect the entire plant or, if too large, representative parts of the plant (roots, stems, leaves, flowers, fruits, and unique attributes). Record information regarding date, location, habitat, plant size, and plant growth characteristics. Photographs of the plant and its habitat are also useful. Soon after collection, press the specimen between two pieces of newspaper or cardboard to air dry. Alternatively, place the plant in a bag in a refrigerator for short term storage if needed. If mailing the specimen for verification, place the pressed sample or bag in a padded envelope or box. Use caution when handling specimens as some plants are toxic to humans too!

Submit samples to one of the following:• Local Extension or USDA-NRCS offices • Montana State University Schutter

Diagnostic Laboratory (http://diagnostics.montana.edu/)

• University of Wyoming Herbarium (http://rmh.uwyo.edu/data/search.php)

• USDA-ARS Poisonous Plant Research Laboratory (https://www.ars.usda.gov/pacific-west-area/logan-ut/poisonous-plant-research/)

Indirect losses include the following management costs:• Building and maintaining fences• Increased feed requirements• Increased medical treatments• Altered grazing programs• Decreased forage availability• Decreased land values• Increased stress on livestock managers

Photo: M. Lavin, MSU

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Factors Influencing Plant Toxicity to LivestockPlant-relatedDoseThe dose (i.e. amount consumed) needed for a plant to cause undesirable effects to livestock depends on factors like the amount and concentration of a toxin and how rapidly it is consumed. In plants, the dose is influenced by growing season, growth stage, palatability, and growing conditions. Some plants are lethal after one exposure or a short duration of time, other plants may require ingestion of large amounts before affecting livestock, and other plants cause poisoning weeks or months after ingestion. Acute poisoning occurs when animals are exposed to a toxic dose on one occasion or for a short time and symptoms are relatively instantaneous. For example, cattle or sheep consuming small amounts of poison hemlock will exhibit symptoms of poisoning within an hour. Chronic poisoning is long-term, repeated, or continuous exposure to a toxin. The toxins accumulate in the animal’s body over time, symptoms are delayed, and damage is usually irreversible. For example, cows consuming lupine during their early gestation period may show no evidence of poisoning until they give birth to calves with cleft palates and skeletal defects (i.e. crooked calf syndrome).

Information on what constitutes a toxic dose is only available for commonly problematic species in Montana and Wyoming (Table 2), and, in many cases, is based on limited scientific research. The toxic dose is dependent on plant-related factors discussed below, as well as animal-related factors such as animal health, species, and age.

Season and Plant Growth StagePoisonous plants vary in their toxicities and palatability with season and growth stage. Rangeland and pasture should be examined for the kinds, quantities, and distribution of poisonous plants before livestock are allowed to graze. Some areas should be avoided during the most dangerous season if dense stands of poisonous plants grow there. For example, some plants are most palatable during their early growth stages, making spring the most dangerous period for poisoning.

Chokecherry (Prunus virginiana) leaves have finely toothed margins and a short, pointed tip. The toxic substance in chokecherry, hydrogen cyanide, is found principally in the leaves. Leaves become less toxic as the growing season progresses.

Poison hemlock (Conium maculatum) is 2 to 20 feet tall with white flowers, finely dissected leaves, and purple spots on the stem. Livestock poisoning is most common in the early spring when tender, succulent, highly toxic new leaves begin growth.

Lupines (Lupinus spp.) have palmately compound leaves which radiate from a central point. Lupine poisoning can be reduced by keeping hungry animals away from lupine in early growth stages and in late summer when the plant contains seeds that are very toxic.

Photo: A. Oomen, bugwood.orgPhoto: USDA-NRCS Photo: T. Nelson, USDA-NRCS


Some poisonous plants are most toxic when they are immature, others when mature, and still others are equally toxic at all growth stages (see Tables 1 and 2). Toxic substances are often concentrated in certain plant tissues, and negative impacts may only be apparent

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Arrowgrass (Triglochin maritima) has fleshy, dark-green, grass-like leaves and a slender flower stalk. Arrowgrass plants quickly become toxic when stressed or damaged from drought, frost, or cutting. Foliage that re-grows following harvest is also toxic.

Shadscale saltbush (Atriplex confertifolia) has grayish bark, alternate leaves, and fruits with four conspicuous wings. It accumulates high levels of selenium when growing in selenium-rich soils and can cause chronic selenium poisoning when consumed by livestock .

Photo: K. Clause, NRCS


Component of HayPlant toxicity may increase, decrease, or remain static when foliage dries. This factor and the plant’s stage of development when harvested, is important in determining toxicity of hay containing poisonous plants. When poisonous plants are mixed with non-poisonous plants and fed together in hay, livestock are unable to discriminate between them as readily as when grazing in a field and are consequently more vulnerable to poisoning. Areas containing substantial amounts of poisonous plants should not be hayed, and hay containing poisonous plants should not be fed to livestock without consulting with the local Extension agent, NRCS employee, or another qualified person.

Growing ConditionsPlants growing during stressful conditions (e.g. drought, freezing) commonly have increased toxicity levels. For example, arrowgrass grown with adequate moisture does not cause hydrogen cyanide poisoning, but when growth is stressed or stunted from inadequate moisture, arrowgrass quickly becomes toxic. This

problem can be exacerbated by a lack of palatable forage during drought which can cause livestock to eat any plant available, even species with toxic properties.

The concentration of different elements in soil can influence several species of poisonous plants. For example, certain species of saltbush and milkvetch growing in soils high in selenium accumulate toxic quantities of this element, whereas the same saltbush species may provide good forage on soils low in selenium.

When certain species grow in the same vicinity and are grazed in combination, toxic effects can vary. For example, sheep feeding on horsebrush just following or in conjunction with black sage and then exposed to bright sunlight may develop a characteristic swelling of the head called bighead (i.e. photosensitization). Sheep grazing horsebrush alone may experience toxic impacts without developing bighead.

PalatabilityPalatability is important because it determines livestock utilization of poisonous plants. Many poisonous plants are not very palatable, so animals will usually select more palatable, non-poisonous species. If an area does not offer enough palatable non-toxic forage, however, animals are more likely to consume toxic quantities of poisonous plants. In addition, palatability is highly variable and can change over the growing season or in response to recent climatic events (e.g. frost) or vegetation management. For example, many species, including poisonous plants, are more palatable for a few weeks following herbicide or fertilizer application.

when consumed at the time of year when these tissues are available. For example, plants with toxins most concentrated in seeds should not be grazed during seed development and ripening.

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Ponderosa pine (Pinus ponderosa) can cause abortions during the last trimester of pregnancy if cattle graze approximately 5 to 6 pounds of needles. The needles are generally grazed during the winter when forage is lacking or snow-covered. Prevent poisoning by limiting access to ponderosa pine during the last trimester.

Milkvetch species (Astragalus spp.) have pea-shaped flowers and grow in a variety of native habitats. Many milkvetch species can cause acute or chronic poisoning of livestock. Cattle will readily eat some toxic milkvetch species even when other forage is available. To reduce livestock losses, prevent animals from grazing these plants for extended periods, feed protein supplements, and avoid stressing cattle that have grazed toxic milkvetch species.

Horsetail species (Equisetum spp.) have hollow, jointed stems, and grow in moist to wet meadows and pastures. Horsetail can have whorls of branches at the joints (left photo) or a single, unbranched stem (right photo). It is often cut and incorporated in hay where it retains toxic properties when dry. Cattle or horses fed hay containing more than 20% horsetail can experience gastrointestinal and nervous system poisoning effects.

Photo: T. Nelson, USDA-NRCS Photo: USDA-NRCS

Photo: USDA-NRCS

Photo: M. Lavin, MSU Photo: M. Lavin, MSU

Animal Response to ToxinSome toxins quickly change to harmless substances upon ingestion or are rapidly eliminated after entering the body and are therefore usually of little danger to an animal. Alternatively, toxins rapidly absorbed into the animal’s circulatory system following ingestion are very dangerous.

Animal HealthAnimals within the same livestock class or breed may vary in their susceptibility to plant toxicity. For example, in a study that dosed Angus steers with larkspur and then imposed the steers to stressful conditions, 40% were considered resistant and the remaining 60% were too sensitive to even impose the stress without risk of death. Livestock in poor condition or subjected to adverse conditions or stress (e.g. temperature, exertion, etc.) are usually more susceptible to poisoning than non-stressed animals in good condition. Hungry animals may ingest higher quantities of a poisonous plant, while satiated animals are more selective and tend to consume lower doses of a toxic plant. In general, an animal will consume less poisonous plant tissue when it can graze selectively.

Animal-related Animal Species, Gender, Size, and AgeSome poisonous plants have a more negative effect on one specific class of livestock, while other plants are equally toxic across all classes. Different classes of livestock preferentially graze certain types of plants. For example, cows and horses prefer grasses, while sheep prefer forbs and shrubs. Rangeland and pasture should be inspected for the kinds and quantities of poisonous plants before grazing. This information can be used to decide what class of livestock should be grazed. Livestock losses may be prevented by grazing those animals that will not be harmed by the poisonous plants present. Also, skin color can determine susceptibility of animals to photosensitivity after eating certain poisonous plants. For example, light- to white-skinned individuals (Hereford cows, white-faced horses) are more photosensitive and will suffer sunburned faces or udders.

Toxicity to some poisonous plants is gender-specific, particularly as it pertains to animal reproduction. For

example, ingestion of ponderosa pine needles by male cattle appears harmless while it may cause abortions in pregnant females. Additionally, the size of animals within a class of livestock may be proportional to the quantity of toxin required to cause poisoning. As animal size increases, the amount of poisonous plant needed to be consumed to cause toxicity symptoms also increases. Younger animals are usually more susceptible to poisoning than older animals. It has been shown that yearling steers may be more susceptible to larkspur poisoning than two-year-old steers.

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Many invasive plants have poisonous properties including houndstongue, blueweed, field bindweed, hoary alyssum and more (see Table 3). Houndstongue (Cynoglossum officinale) is an invasive biennial forb that is sometimes harvested in hay where it can cause poisoning. Animals may graze pasture containing poisonous invasive plants without ill effects if ample good forage is available.

Conditions Leading to Livestock Poisoning and Management to Reduce ImpactsThe most effective way to prevent livestock loss from poisonous plants is to properly manage rangeland, pasture, forest, and livestock. Develop a grazing plan that improves or maintains rangeland or pasture condition and prevents poisoning. Plans should consider poisonous plants in the area, allowing animals to avoid them or graze them at the most appropriate time. Poisoning typically occurs when livestock are enticed by hunger or other stressful conditions, although there are exceptions where animals may show an unexplained preference for a poisonous plant. Livestock managers should know what poisonous plants are present and how to prevent animal intake. Hundreds of plants are poisonous to livestock at certain doses. Many are always toxic, whereas others are toxic only under certain conditions. In some situations, a poisonous plant may even form an important part of livestock diets without negative effects on the animals (e.g. greasewood).

Grazing Rangeland and Pasture that Are in Poor ConditionA common condition under which plant poisoning occurs is grazing rangeland and pasture that are in poor condition. Generally, as vegetation is overgrazed,

palatable species are reduced in abundance and less palatable species, including invasive and/or poisonous plants, increase. As pasture condition continues to decline, animals have to consume increasing quantities of less palatable and possibly poisonous plants to meet their nutritional requirements. The association between scarcity of forage and increased consumption of poisonous plants cannot be ignored when trying to mitigate toxicity issues. Livestock managers should use good grazing management, graze during the correct season, and use appropriate animal stocking rates.

Hungry Animals on Infested Rangeland, Pasture or Cover CropHungry animals graze less selectively than satiated animals and tend to eat whatever is within close proximity. Hungry animals should never be exposed to areas with large concentrated populations of poisonous plants. Poisoning often occurs when animals consume too much or eat too rapidly, behavior typical of hungry animals.

Early Season Grazing on RangelandWhen native rangeland or pastures are grazed too early in the growing season, the earliest growing

Photo: M. Lavin, MSUPhoto: USDA-NRCS

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species must carry the grazing load. If palatable, non-poisonous plants are unavailable, livestock will eat whatever is available, including poisonous plants. Several poisonous plants (e.g. low larkspur, lupine, deathcamas) are among the first to emerge in the spring and are in their most succulent stages. Livestock should not be released onto rangeland or pasture until adequate desirable forage is available to support grazing.

Livestock Familiarity with the AreaAnimals new to an area, especially previously confined animals, tend to graze less selectively and may consume a greater diversity of plants (including poisonous plants) than animals which are familiar with the area. In other words, they are naïve to toxic plants in a new pasture. Where livestock are grazed in unfamiliar areas, handlers should watch animals carefully. Be especially careful when grazing newly acquired livestock that are in unfamiliar rangeland or pasture. Once an animal becomes familiar with an area and its toxic plants, it may be safe to graze the pasture. For example, on rangelands where locoweed is abundant, it is safe to graze only those animals which are acquainted with locoweed but do not seek it out for consumption.

Improper Herding, Driving and BeddingCrowded animals need time to scatter across an area large enough to allow selective grazing. When animals are crowded, they may be forced to eat whatever vegetation is available. Livestock managers can minimize poisonous plant consumption by using open or loose herding methods with slow movement.

Animals often become nervous when they are driven or trailed. When being moved, animals are also unable to quickly satisfy their hunger like they would under normal pasture conditions, and they become less selective in their plant consumption. Animals that are both hungry and driven quickly are even more susceptible to poisonous plants. To minimize losses, animals should be satiated and driven slowly through areas with poisonous plants.

Livestock prefer to graze late in the evening and in the morning after leaving their bedding grounds. They are less selective in their grazing habits during these times and are more likely to consume toxic quantities of poisonous plants. The risk of plant poisoning increases when animals are bedded down in the same area for several nights.

High-use areas are subject to overgrazing of palatable plants, resulting in an increase of unpalatable plants, many of which are poisonous. Livestock managers can

Meadow deathcamas (Zigadenus venenosus), a perennial with long linear leaves, is one of the first plants to begin growth in early spring. Without enough other forage, deathcamas species may be heavily grazed and will cause livestock losses.

Greasewood (Sarcobatus vermiculatus) is adapted to saline soil where it uptakes and accumulates soluble sodium and potassium oxalates in the fleshy leaves. It can be safely eaten by livestock in moderate amounts with other forage. However, poisonings can occur when livestock eat large amounts of greasewood leaves or buds in a short period of time.

Locoweed species (Oxytropis spp.) are poisonous at all stages of growth throughout the year including when dried. Livestock that have never grazed locoweed will usually avoid it; however, once consumed, an animal can become habituated to grazing locoweed. Livestock owners can reduce losses by removing locoweed-eating animals from the herd.

Photo: USDA-NRCS Photo: M. Lavin, MSU Photo: USDA-NRCS

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reduce losses by selecting new trails and bedding grounds when possible.

Inadequate Nutrient SupplyAnimals with nutrient deficiencies often seek plants that contain high levels of the nutrient that the animal is lacking. For example, salt-deficient animals may seek out and excessively consume salt-accumulating plants like greasewood. To minimize losses, place salt and phosphorous supplements in several locations in the pasture and throughout the entire period of use of the pasture. Salt and phosphorous supplements can also be used to improve livestock distribution and lure them away from areas supporting poisonous plants. Do not place salt and other supplements in an area where poisonous plants are growing.

Water Quantity and QualityAnimals tend to graze indiscriminately when they have been without water for more than two days and are finally given the opportunity to drink. Therefore, do not place or develop water in areas where toxic plants are present. Always provide animals with an adequate supply of water.

Water quality is an important aspect of livestock management and animal performance. If water sources become contaminated with fertilizers or manure, blue-green algae can proliferate and lead to poisoning. Pesticide drift may also contaminate water sources and endanger livestock. Additionally, elevated levels of nitrates, metals (e.g. copper, lead, zinc), and other elements (e.g. selenium, arsenic, boron) in soil can lead to unsafe levels in surface and groundwater. Have water sources tested annually, determine if results are within recommended water quality standards, and take steps to determine the source of any problem.

Environmental ConditionsLate spring and early fall snowstorms may cover shorter, more desirable species, leaving taller statured poisonous plants like tall larkspur, deathcamas, and lupine as the only vegetation available to livestock. Poisoning potential may be compounded in the fall if fruiting (podded) plants extend above the snow, and those fruits are highly toxic. To minimize losses, either move or feed supplements to livestock subjected to these conditions.

Following heavy rain, some poisonous plants become more palatable or toxic because the rain stimulates new plant growth. This is especially problematic if other vegetation becomes matted and entangled, making it

Many plant species with poisonous properties, including tall larkspur, water and poison hemlock, iris, and buttercup, grow near livestock water sources such as seeps, springs, or wet meadows (see Table 3). Livestock should be moved from areas where poisonous plants surround water developments, especially during the species’ toxic window. Tall larkspur (Delphinium occidentale) poses a risk of poisoning during flower and early seedpod growth stages.

difficult for livestock to graze as discriminately as under drier conditions. When this situation arises, consider moving livestock to other areas or feeding supplements to reduce consumption of poisonous plants.

Drought can lead to early maturation of many palatable plants. In contrast, several poisonous plants remain green during drought (e.g. deep-rooted lupines or locoweed; evergreen yew or laurel). As a result, these poisonous plants may become more attractive to livestock, receive more use, and increase the risk of poisoning. The adverse effects of drought are worsened

Photo: T. Nelson, USDA-NRCS

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on overgrazed rangeland and pasture where more palatable non-poisonous plants were already stressed. These areas are also susceptible to an increase of poisonous plants when wet years follow drought.

Well-managed rangeland and pasture leaves some forage to carry-over for use during drought. During extended droughts, livestock numbers may need to be reduced or supplemental feeding initiated.

Cultural PracticesCultural practices, such as spraying herbicides or spreading fertilizer, may increase the palatability of poisonous plants for a short time after application. Certain herbicides (e.g. glyphosate, 2,4-D) will increase the plant sugar content and sweetness, making it more palatable to livestock. Salt-based herbicides can also make poisonous plants more attractive. All animals should be kept off rangeland or pasture supporting poisonous plants for at least two weeks following applications of herbicides or fertilizers, and always follow grazing restrictions on the product label.

Grazing System Grazing systems vary by timing, frequency, duration, and intensity of livestock use and can be manipulated to help manage poisonous plants. Timing refers to the season grazing occurs, and frequency is how often a pasture is grazed. Duration is how long a pasture is grazed. Intensity involves stocking density (i.e.

number of animals per acre) and is the cumulative effect grazing animals have on forage during a time period. For example, an intensive grazing management system does not necessarily lead to high grazing intensity (utilization) but it does require management that optimizes stocking density and duration to achieve utilization objectives.

Timing can be manipulated to avoid grazing when plants are most toxic. Intensity can be manipulated in some situations to alter the selectivity or amount of a plant that is consumed by each animal. For example, high intensity grazing systems (i.e. a higher density of animals for a shorter amount of time in a pasture) result in lower forage selectivity. While this could lead to increased consumption of poisonous plants, and must be carefully managed, this approach may also limit the amount of exposure any single animal has to a poisonous plant, thus limiting dose. High intensity grazing systems are most effective when there is adequate non-toxic forage and fewer poisonous plants.

It is important to note that pastures that are grazed with high frequency and long duration can expose livestock to higher risk of consuming a toxic dosage of a poisonous plant as the livestock exhaust preferred forages. However, when livestock are moved more frequently to new pastures with adequate high-quality forage, the risk of consuming poisonous plants decreases.

Because some poisonous plants are more palatable or available at certain times of the year, seasonal grazing can be a consideration for avoiding poisonous plants at toxic doses. In the example of tall larkspur, infested pastures could be grazed early or late, ultimately avoiding the toxic window (or the time when toxicity is greatest) that occurs for about five weeks at the start of the flowering stage and ends in the pod stage. However, a grazing system

that relies on grazing a pasture every year during the same season can also result in decreases in palatable, non-poisonous plants and increases in less palatable and poisonous plants, particularly in a rangeland setting.

Locoweed species (Oxytropis sericea pictured here) grow in a variety of habitats, have pea-shaped flowers that can be white, yellow, blue or purple, and can remain green when other vegetation is dormant. Livestock owners can reduce locoweed losses by keeping animals off pastures until good forage is available.


Photo: USDA-NRCS

- 13 -

Larkspur (Delphinium spp.) is highly palatable to cattle, and losses occur when cattle graze larkspur-infested areas when it is abundant or growing in large patches. Low larkspur (Delphinium bicolor), with its characteristic blue-purple spurred flowers, completes its lifecycle in the early spring. Livestock losses can be prevented by deferring grazing until plants lose their flowers and pods when it rapidly senesces.

Cover crops usually palatable and nutritious to livestock can pose a poisoning risk during periods of environmental stress or as a result of crop management, harvest, or storage.

Multi-species GrazingThe use of different livestock species in a multi-species grazing approach is a strategy to mitigate toxicity. For example, sheep can tolerate larkspur at doses four times greater than cattle, so larkspur poisoning of sheep is rare. A strategy of grazing sheep prior to grazing cattle could reduce larkspur abundance and decrease the risk of cattle consuming larkspur later.

Crop and Cover Crop GrazingCrop and cover crop management, harvesting, and storage may influence the risk of livestock poisoning. Most toxicity risks with grazing cover crops are associated with nitrates in small grains, hydrogen cyanide (HCN, also known as prussic acid) from sorghum and sorghum-sudangrass, and mycotoxins such as fusarium and ergot from various grass species. In general, monocultures or low diversity cover crops on highly fertilized land pose the highest risk of accumulating nitrates and affecting livestock if grazing is too heavy. Similarly, appreciable quantities of HCN can accumulate in new growth of cover crop species following clipping, drought, frost, hail damage, or grazing. Risks of poisoning from crops can be reduced by waiting to graze until plants have reached the proper height, maintaining a six-inch stubble height, grazing during daylight only, and waiting to graze until one

week after a killing frost. In addition, when selecting species for a cover crop mix that will be grazed, plant a diverse cover crop mix, use certified seed, and select varieties low in HCN to minimize the risk of poisoning. A cover crop sample should be tested for nitrates prior to grazing.

Care for Impacted AnimalsPreventing livestock poisoning is usually easier than curing a poisoned animal. There is often no antidote available for a plant toxin, and rangeland or pasture conditions may make treatment difficult. When a poisoned animal is found alive, if possible and without causing stress, it should be placed in a cool, shaded area with proper food and water. However, care should be taken when moving animals. Moving animals impacted from consuming a poisonous plant (e.g. larkspur) can exacerbate the problem. Contact a veterinarian as soon as possible to diagnose and treat the animal.

Help with poisonous plant problems may also be obtained from local veterinarians:• Wyoming State Veterinary Laboratory

(http://www.uwyo.edu/wyovet/)

• Montana Veterinary Diagnostic Laboratory (http://liv.mt.gov/Diagnostic-Lab)



Photo: M. Henning, USDA-NRCS

- 14 -

Control of Poisonous Plants

Leafy spurge (Euphorbia esula) can form dense infestations that can cause skin and gastrointestinal issues for cattle but can be managed by sheep grazing. Control methods for poisonous plants will depend on the species, site condition, and size of the infestation.

Poisonous Substances and Other Forage Problems

invasive properties, and some are listed on county or state noxious weed lists (e.g. leafy spurge, common tansy; Table 3). Be aware that some herbicides (e.g. 2,4-D) may increase palatability of the toxic plants. Also, herbicides may impact desirable non-target plants and reduce diversity and quality of the vegetation. If chemical control is necessary, obtain management information from your local Extension, Montana Weed District, or Wyoming Weed and Pest office.

Many poisonous plants in Montana and Wyoming are native species and a natural part of plant communities. Most native poisonous plants do not naturally dominate the plant communities where they occur, or their presence is the result of disturbance. Generally, control of native poisonous plant species is not needed. Instead, good grazing management strategies should be implemented to allow desired species to outcompete poisonous ones. Proper stocking rates and the initiation of a good grazing system may reduce the abundance of poisonous species through competition with desired non-poisonous species. In addition, several poisonous native plant species have beneficial forage attributes which offset their poisonous properties. For example, greasewood is poisonous when eaten nearly exclusively but is valuable forage when consumed with a moderate amount of other desirable forage plants. If small scale management of native poisonous plants is necessary, mechanical (mowing, digging), cultural (exclusion fence, proper land management), biological (selective grazing, insects), herbicides, and/or revegetation can be used.

In contrast, many introduced (i.e. non-native) plant species with toxic properties can form dense infestations. Many of these species have weedy or

Poisonous plants contain at least one of the following:

• Substances that are directly poisonous to livestock. Alkaloids contained in certain lupine species and oxalates contained in halogeton are common examples.

• Substances that are themselves harmless, but become toxic as they decompose slightly before or upon ingestion by the animal. Chokecherry leaves, for example, contain the glycosides amygdalin and prunnasin which, upon hydrolysis (mixing with rumen microbes), forms highly toxic hydrogen cyanide (also known as prussic acid or hydrocyanic acid).

• Substances absorbed from soil and accumulated to toxic levels by the plant. For example, several milkvetch species can accumulate selenium.

• Substances which make parts of the affected animal hypersensitive. An example is the pigment hypericin (contained in St. Johnswort) that causes white-skinned animals to be hypersensitive to sunlight.

• Miscellaneous substances such as toxic elements or metals (fluorine, arsenic, etc.) that can accumulate on or in plants found near industrial developments, toxic products formed by fungi in moldy hay or silage, contact irritants, and poor water quality caused by blue-green algae blooms.

Photo: USDA-NRCS

- 15 -

in a progressive decrease in electrical conductivity through the heart and blocks cardiac activity. While low doses of cardiac glycosides can be beneficial by slowing heart rate, increasing the contraction force and increasing cardiac output, animals consuming toxic doses develop heart and digestive disturbances leading to death. Additional signs of poisoning include rapid breathing, cold extremities, and a rapid, weak, irregular pulse caused by cardiac arrhythmias and heart block. Death typically occurs within 24 hours of the onset of symptoms.

Plants containing cardiac glycosides: Milkweeds and dogbanes can cause cardiac glycoside poisoning. However, cases of cardiac glycoside problems are rare, especially for dogbane.

Nightshade species (Solanum nigrum pictured here) have tomato-like, star-shaped flowers with five petals. They are not usually palatable to livestock but cause issues when harvested with hay or grain crops then fed to livestock. Losses can be minimized through pasture management and weed control.

Milkweed species (Asclepias speciosa pictured here) can have broad or linear leaves arranged alternately or in whorls. It is most dangerous when actively growing, but toxicity decreases with drying. Livestock tend to consume milkweed when other forage is limited, after a frost, or when it is incorporated in hay.

Principal ToxinsThe most common toxic substances in Montana and Wyoming plants are described below. Less common toxic substances are described in the Glossary.

Alkaloids Alkaloids are generally present in plants as an organic acid. There are over 40 different types of alkaloids that cause poisoning, and some plants may contain more than one. Alkaloids are always present and well-distributed throughout plant tissues. The relative toxicity and concentration of individual alkaloids varies among plant species and populations. Common human-consumed alkaloids include caffeine and nicotine. Types of toxic alkaloids include steroidal, pyrrolizidine, indolizidine, piperidine, diterpenoid, quinolizidine, and tropane.

Symptoms: Alkaloids ingested by livestock cause a strong physiological reaction. Alkaloids, such as those found in larkspur, induce muscular paralysis. Swainsonine, associated with locoweed, causes significant poisoning issues referred to as “locoism.” Signs of locoism may include depression, circling, staggering, reproductive failure, heart failure, and weight loss. In addition, a compromised immune system stemming from locoism may lead to other ailments such as foot rot, pneumonia, warts, and other infections. Alkaloid symptoms of the extremities (i.e. feet and ears) include vasoconstriction and reduced blood flow. Teratogenic species, including locoweed, groundsel, false hellebore, lupines, and poison hemlock, harm the developing fetus if plants are consumed at certain stages of gestation.

Plants containing alkaloids include but are not limited to: tall and low larkspur, monkshood, poison hemlock, deathcamas, nightshades, black henbane, locoweed, lupines, tansy ragwort, houndstongue, milkvetch, yew, false hellebore, and others.

Cardiac Glycosides Cardiac glycosides have direct effects on cardiac func-tion. Cardiac glycosides are present throughout the plant, especially the leaves, and retain reduced toxic-ity when dried. Small quantities of ingested plants can cause symptoms.

Symptoms: Cardiac glycosides directly impact the gastrointestinal tract causing hemorrhagic enteritis, abdominal pain, and diarrhea. Cardiac glycosides also inhibit the cellular membrane sodium-potassium pump which results

Photo: USDA-NRCS

Photo: USDA-NRCS

- 16 -

Cyanogenic Glycosides Cyanogenic glycosides are indirectly toxic in that they hydrolyze to produce hydrogen cyanide (HCN, also known as prussic acid) in the presence of certain enzymes and when acted upon by microorganisms in the plant or rumen. Hydrogen cyanide is a highly toxic, rapidly acting poison that inhibits oxygen utilization by cells. Some plants naturally have high levels of cyanogenic glycosides, especially in early growth stages, rapidly growing plant parts, and seeds. In other plants, the level of cyanogenic glycosides is influenced by climatic conditions, soil factors, and other factors that slow growth. Enzymatic conversion to HCN is enhanced when plant cells are damaged from drought, wilting, freezing, or crushing, or when stressed from low soil moisture, high nitrogen, low phosphorous, or herbicide applications. Avoid grazing plants high in cyanogenic glycosides while these conditions exist and wait at least a week after a severe drought or frost before grazing. Hydrogen cyanide deteriorates with time; therefore, dried hay is safe to consume.

Symptoms: Nitrate Nitrate poisoning is caused by excessive consumption of nitrate (NO3) or nitrite (NO2). Under normal conditions, nitrates are converted during digestion to nitrite; the nitrite then becomes ammonia which in turn is converted to protein. When high levels of nitrates are consumed, nitrite will accumulate in the rumen. Since nitrite is up to ten times more toxic than nitrate, poisoning can occur. Nitrate poisoning is a problem for ruminants (cattle, sheep) but is unlikely in monogastric animals (horses) because monogastric animals can’t readily convert nitrate to nitrite in their digestive systems.

Nitrates are most concentrated in plant stems and stalks, and to a lesser degree leaves; they do not accumulate in flowers or seeds. Nitrate levels are highest in young plants and decrease with maturity. Nitrates decrease only slightly with drying, so feeding nitrate-rich hay can be a problem.

Symptoms: Nitrite is absorbed into the bloodstream and converts hemoglobin to methemoglobin which interferes with the ability to carry oxygen from the lungs to the tissues. Signs of nitrate poisoning are related to the lack of oxygen in blood including: blue to chocolate brown mucous membranes

Serviceberry (Amelanchier alnifolia) grows up to 13 feet tall and produces clusters of white flowers in early spring. The upper ½ to ¾ edge of the leaf is toothed which distinguishes it from chokecherry whose leaves are toothed along the entire edge. Like chokecherry, serviceberry produces hydrogen cyanide and foliage is especially poisonous in the early flowering stage.

Hydrogen cyanide rapidly inactivates cellular respiration leading to a characteristic cherry-red venous blood from the failure of oxygen releasing at the tissues. The heart and brain are affected by a lack of oxygen, causing death to occur within one to two hours or several minutes in acute cases. Signs of poisoning prior to death include difficulty breathing, frothing at the mouth, irregular pulse, dilated pupils, staggering, muscle tremors, bright red mucous membranes, and convulsions. Chronic ingestion of low levels of cyanogenic glycosides can cause various neuropathies, musculoskeletal deformities, and goiter. Cattle and sheep (ruminants) are more susceptible to HCN poisoning than horses (monogastrics). Fetuses are also extremely sensitive to HCN poisoning.

Plants containing cyanogenic glycosides: Hydrogen cyanide poisoning is most commonly associated with Johnsongrass, sudangrass, sor-ghum-sudan grass, chokecherry, serviceberry, and arrowgrass.



- 17 -

Russian thistle (Salsola tragus), a highly branched herbaceous weed with spine-tipped leaves, can accumulate nitrate. Many plants, including crop and weed species, can accumulate nitrate. Plants containing between 0.5% to 1.5% nitrates can have sublethal effects on livestock, while plants with more than 1.5% nitrates may be lethal to livestock.

Kochia (Bassia scoparia) has green or reddish stems, linear leaves, and is often covered with silver or rusty hairs. Kochia and other members of the goosefoot family (Chenopodiaceae) have been associated with oxalate and nitrate poisoning, although occurrences are uncommon.

or blood, difficulty breathing, rapid pulse, salivation, staggering, coma, and death. Sublethal or chronic nitrate poisoning can cause abortion during any stage of gestation due to lack of oxygen.

Plants containing nitrates: Rangeland and pasture plants known to accumulate nitrates include redroot pigweed, lambsquarters, kochia, curly dock, Russian thistle, nightshades, and Johnsongrass. Grazed crop or cover crop species known to accumulate nitrates include barley, oats, millet, rye, sorghum-sudangrass, wheat, corn, alfalfa, sugar beet, rape, radish, and turnip.

Contact your local Extension or Department of Agriculture office for assistance testing forage for nitrate content. In Montana, MSU Extension offers an in-office test to rapidly assess the presence of high forage nitrates. In Wyoming, the Department of Agriculture offers feed and forage analyses for nutrients and toxic constituents.

Oxalates Oxalates cause problems when livestock are not accustomed to grazing oxalate-containing plants. Animals can tolerate grazing oxalate-containing plants if they have other plants in their diet to dilute oxalate in the rumen. For example, cattle can graze sites dominated by greasewood if there is ample grass. However, if there is very little grass and greasewood leaves have dropped to the ground, cattle intake of greasewood may increase along with the risk of oxalate poisoning. Also, gradually introducing ruminants to oxalate-containing plants can increase rumen microflora that degrade oxalate and minimize impacts. Supplementing livestock’s diet with dicalcium phosphate before and during high-risk oxalate exposure, can effectively reduce losses.

Symptoms: Oxalates occurs in two forms: insoluble calcium oxalate and soluble oxalates. Insoluble calcium oxalate, a needle-like crystal, causes severe damage to kidney tubules. This chronic form of oxalate poisoning leads to renal failure and death. Soluble oxalates rapidly combine with and decrease serum calcium and magnesium, thus impairing normal cell membrane function. This acute oxalate poisoning causes muscle tremors, weakness, collapse, and death.

Plants containing oxalates include halogeton, redroot pigweed, lambsquarter, kochia, sorrel, curly dock, greasewood, and purslane.




- 18 -

Saponins Saponins are naturally occurring glycosides in plants that have soap-like compounds. Saponins increase the permeability of membranes and may cause hemolysis of red blood-cells, thus releasing hemoglobin.

Symptoms: Plants containing saponins may act as a diuretic causing diarrhea. Other symptoms include biliary obstruction, bloat in ruminants, photosensitivity, salivation, acute hepatopathy, and death. Some saponin containing plants (e.g. oats) are beneficial when consumed, increasing and accelerating the ability to absorb compounds such as calcium and silicon that assist in digestion.

Plants containing saponins include snakeweed, puncturevine, kochia, and bouncingbet.

Selenium Selenium is an essential nutrient for animals, but it accumulates in certain plants to levels that are toxic to livestock when those plants are growing in selenium-rich soils. For example, some species of saltbush provide good forage on soils with low selenium levels but are poisonous when growing on soil high in selenium. Selenium-rich soils are derived from cretaceous shales and glacial deposits and are generally found in semi-arid areas. Plant uptake is variable and depends on the chemical form of selenium, soil pH, temperature, moisture, plant species, and stage of plant growth.

Symptoms: Selenium intoxication can occur as acute or chronic poisoning. Signs of acute selenium poisoning, occurring when animals ingest more than 50 parts per million (ppm), include abnormal posture, unsteady gait, abdominal pain, increased pulse and respiration rate, and sudden death. Chronic selenium poisoning is more common, with symptoms including rough coat (bob-tail, roached-mane), hair loss, hoof lesions, lameness, defective hoof growth, and reduction in fertility.

Plants containing selenium: Plants with more than 5 ppm selenium are potentially toxic. Primary selenium accumulator or indicator plants may accumulate up to several thousand ppm selenium. Obligate accumulator species, including milkvetch and princesplume, can cause acute poisoning but are rarely consumed due to poor palatability. Secondary selenium accumulator plants may contain up to several hundred ppm selenium, but lesser amounts are much more common. This group includes aster species, milkvetch, saltbush, Indian paintbrush, curlycup gumweed, and snakeweed. The low-accumulator group, including alfalfa, corn, and grains, rarely accumulate more than 50 ppm selenium and usually only 5 to 12 ppm. However, it is the low-accumulator plants that cause the most toxicity problems because they are commonly grazed by livestock and can lead to chronic selenium poisoning.

Milkvetch species (Astragalus spp.) have pinnately compound leaves and pea-shaped flowers and are primary selenium accumulators. To prevent animals from eating excessive amounts of selenium, identify areas of high selenium soil and develop a grazing or forage-production plan.

Photo: USDA-NRCS

Photo: USDA-NRCS

- 19 -

Alfalfa (Medicago sativa) is an important forage species with trifoliate leaves and purple or blue, occasionally yellow, flowers. Risk of poisoning from alfalfa and other forage legumes depends on the amount and rate of consumption, composition of the animal’s diet, the plant’s accumulation of toxic chemicals (e.g. selenium, nitrate), and how the crop was managed, harvested, or stored.

Some plant species, although not poisonous, can cause injury to animals resulting in discomfort, inflammation, or poor condition. Mechanical injuries can be caused by native or non-native species with long awns such as foxtail barley (Hordeum jubatum), needle-and-thread, or cheatgrass.

Other Forage Problems and DisordersBloat Bloat is caused by the entrapment of fermentation gases in the rumen. Bloat usually occurs when livestock consume lush legumes such as alfalfa or white clover. Soluble proteins in forages and other small particles within the cells of the plant are rapidly released once they reach the rumen. These proteins and particles are attacked by slime-producing rumen microbes, which cause a buildup of stable foam. The foam, often due to the presence of saponins, decreases the animal’s ability to expel rumen gases that are created from fermentation of plant material. These gases begin to accumulate, causing pressure on the diaphragm, leading to bloat.

Symptoms: Livestock suffering from bloat will begin to swell rapidly on the left side. Kicking at their sides or stomping their feet are other signs the animal is experiencing discomfort. Breathing may be labored, and urination and defecation frequent. In severe cases, the rumen can become distended, and death may occur.

Plants causing bloat include alfalfa, clovers, brassi-cas, cultivated grains, and sweetclovers.

Symptoms: The injury may result in sores and inflammation on the tongue, gums, eyes, nose, and skin. Sores can lead to localized skin infections or a general infection from bacteria entering the circulatory system. Additional injuries include plant fibers that may lodge in the stomach or intestines and fibers imbedded in eyelids causing lesions to the eyeball. Animals suffering mechanical injury may stop eating and develop a poor condition.

Plants causing mechanical injuries include bristle-grass, cheatgrass, needlegrasses, foxtail barley, rye, wild oats, burdock, and cactus.

Mycotoxins Mycotoxins are toxins produced by mold (fungi). The host plant itself may not be toxic (e.g. alsike clover, sweetclover), but toxicity problems can occur with improper feed (seeds, hay, silage) harvest and storage. Some fungi cause toxicity problems in specific plant species (e.g. perennial ryegrass, tall fescue, lupine). Major classes of mycotoxins include aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin, and ergot alkaloids (e.g. endophyte-infested fescue, swainsonine).

Symptoms: Symptoms will vary depending on the mold involved. Mycotoxins in lupine can cause severe liver, kidney and muscle disease. Ergot alkaloids in tall fescue cause vasoconstriction at the extremities, elevated respiration

Mechanical InjuriesMechanical injuries are physical issues caused by spines, sharp seeds, burs, and awns. The plant may not be poisonous, but the injuries can cause symptoms that resemble a toxin effect.


Photo: USDA-NRCS

- 20 -

rate, convulsions, lameness and tenderness of the legs, poor hair condition, loss of extremities (hooves, ears, tails), decrease in milk production, difficult births, and abortion.

Plants commonly containing mycotoxins include alsike clover, red clover, corn, sweetclovers, perennial ryegrass, tall fescue, and lupine.

Photosensitization Photosensitization can be caused from consuming plant species containing light-sensitive compounds that, once absorbed in the gastrointestinal tract, circulate in the blood. In primary photosensitization, photodynamic compounds accumulate in blood vessels at the skin surface, particularly in non-pigmented skin, and ultraviolet light transforms compounds into toxins. As a result, skin becomes abnormally sensitive to sunlight causing severe inflammation and damage. Secondary photosensitization, which is more common than primary photosensitization, is caused by a variety of plant toxins that cause liver damage or liver disease. The damaged liver cannot excrete phylloerythrin (a bacterial breakdown of chlorophyll), and it accumulates in the bloodstream. As phylloerythrin circulates and is exposed to ultraviolet light, it causes oxidative injury to blood vessels and skin tissue. Animals do not readily eat plants containing liver-damaging substances (e.g. pyrrolizidine alkaloids) unless they lack quality forage or are exposed to plants in hay. Since ingesting damaging substances is cumulative, liver disease and associated photosensitization may take many months to appear.

Symptoms: Signs of primary photosensitization include severe skin irritation, photophobia (e.g. seeking shade), rubbing and shaking the head, excessive eye tearing and discharge, redness of non-pigmented skin, increased sensitivity of skin, and swelling around ears, eyelids, lips, and nose. Skin can ooze serum, form crusts, lose hair, and slough white skin. Lameness can occur from impacts to hooves. Secondary photosensitization, in addition to symptoms of primary photosensitization, includes signs of liver failure such as weight loss, neurologic signs (e.g. yawning, drowsiness, aimless wandering, head pressing, increased licking, and coma), jaundice, abdominal distention, and diarrhea.

St. Johnswort (Hypericum perforatum), identified by the five-petaled yellow flowers with black glands on the petal margins, can form dense patches in mountains, foothills, rangelands and disturbed areas. Animals that eat St. Johnswort and are exposed to direct sunlight develop photosensitization in the white areas of the body. Affected animals should be moved out of direct sunlight and provided free access to fresh water and feed.

Plants causing photosensitization: Plants associated with primary photosensitization are buckwheat, St. Johnswort, and cow parsnip. Plants associated with liver damage leading to photosensitization include horsebrush, tansy ragwort, groundsel, fiddleneck, houndstongue, and blueweed. In addition, moldy plants and blue-green algae can cause liver damage from photosensitization.

Volatile Oils Volatile oils are organic compounds that readily vaporize or evaporate. They are responsible for a plant’s odor and a bitter taste, and, in some plants, are part of the plant’s defense to herbivory and insects. Toxicity varies with plant species.

Symptoms: Livestock exposed to plants with volatile oils may have dermatitis or skin and mucous membrane irritation. When ingested, volatile oils may cause digestive tract irritation, vomiting, reduced rumen activity, damage to the mucous lining of the digestive tract, nervousness, altered milk taste, and diarrhea.

Plants containing volatile oils include sagebrush, sagewort, buttercup, and horseweed.



- 21 -

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lal

lni

trate

, cya

noge

nic

glyc

osid

e (H

CN

)al

l sys

tem

sSu

dden

dea

th, i

ncre

ased

sal

ivat

ion,

hea

vy b

reat

hing

Blac

k he

nban

e(H

yosc

yam

us n

iger

)X

Xal

lno

dat

aal

kalo

idga

stro

inte

stin

al,

mus

culo

skel

etal

, ne

rvou

s

Inte

stin

al s

tasi

s, c

onvu

lsio

ns, a

taxi

a, c

olic

, blo

at, d

iarr

hea,

de

crea

sed

saliv

atio

n, d

ilate

d pu

pils

, inc

reas

ed h

eart

rate

Blue

wee

d(E

chiu

m v

ulga

re)

XX

all

no d

ata

alka

loid

, ph

otos

ensi

tizat

ion

inte

gum

enta

ry, l

iver

, m

uscu

losk

elet

al,

nerv

ous,

ocu

lar

Seve

re w

eigh

t los

s, m

uscl

e at

roph

y, p

hoto

sens

itivi

ty, j

aund

ice,

in

coor

dina

tion,

dep

ress

ion,

aim

less

wan

derin

g, h

ead

pres

sing

, ey

e te

arin

gBo

unci

ngbe

t(S

apon

aria

offi

cina

lis)

XX

Xse

eds

sum

mer

, fa

llsa

poni

nga

stro

inte

stin

al, l

iver

Dec

reas

ed ru

men

act

ivity

, col

ic, a

nore

xia,

exc

essi

ve s

aliv

atio

n,

diar

rhea

, liv

er to

xici

tyBr

acke

nfer

n*(P

terid

ium

aqu

ilinu

m)

XX

Xal

lsu

mm

er,

fall,

and

in

hay

glyc

osid

e,

thia

min

ase

card

iova

scul

ar,

nerv

ous,

ocu

lar,

rena

l

Dea

th, b

lindn

ess,

hem

orrh

ages

, dep

ress

ion,

nas

al a

nd re

ctal

bl

eedi

ng, b

lood

y ur

ine,

ane

mia

, hig

h fe

ver,

loss

of a

ppet

ite,

diffi

culty

bre

athi

ng, e

xces

sive

sal

ivat

ion

(cat

tle, s

heep

); co

nvul

sion

s, s

eizu

res,

wei

ght l

oss,

inco

ordi

natio

n, fa

st p

ulse

, cr

ouch

ing

stan

ce, w

eakn

ess

(hor

ses)

Tabl

e 1.

Sig

ns o

f poi

soni

ng a

nd c

ondi

tion

s un

der

whi

ch p

lant

spe

cies

can

be

dang

erou

s to

live

stoc

k. S

ympt

oms

liste

d fo

r ea

ch p

lant

are

thos

e m

ost l

ikel

y to

be

obse

rved

. N

ot a

ll sy

mpt

oms

will

be

seen

in a

ll to

xici

ties

, and

sig

ns o

f poi

soni

ng m

ay v

ary

grea

tly

depe

ndin

g on

dos

age

and

the

tim

e ta

ken

to c

onsu

me

the

dose

. Als

o, in

divi

dual

an

imal

s re

spon

d di

ffere

ntly

to s

peci

fic to

xins

.

- 22 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Bras

sica

s –

cano

la, k

ale,

ra

dish

, tur

nip

(Bra

ssic

a sp

p.),

radi

sh (R

apha

nus

sativ

us)

XX

Xal

l; to

psfa

llbl

oat,

nitra

te,

cyan

ogen

ic

glyc

osid

e (H

CN

), m

ycot

oxin

card

iova

scul

ar,

gast

roin

test

inal

, m

uscu

losk

elet

al,

nerv

ous,

resp

irato

ry

Dea

th, b

loat

, goi

ter,

cong

estio

n of

rum

en a

nd a

bom

asum

, hy

poth

yroi

dism

, blin

dnes

s, d

iarr

hea,

red-

colo

red

urin

e, a

nd

hem

olyt

ic a

nem

ia, p

ulm

onar

y em

phys

ema,

blin

dnes

s, s

tagg

erin

g,

depr

essi

on, r

educ

ed w

eigh

t gai

nBu

ckth

orn

(Rha

mnu

s ca

thar

tica)

SX

fruit,

le

aves

sprin

g,

sum

mer

, fa

ll

glyc

osid

ega

stro

inte

stin

alN

ause

a, s

tom

ach

cram

ps, v

omiti

ng, d

iarr

hea

Buck

whe

at

(Fag

opyr

um e

scul

entu

m)

XX

XX

all

sum

mer

, fa

ll, a

nd

in h

ay

frago

pyrin

, ph

otos

ensi

tizat

ion

inte

gum

enta

ry,

ocul

arPh

otos

ensi

tivity

, tea

ring

Butte

rcup

(Ran

uncu

lus

spp.

an

d C

erat

ocep

hala

te

stic

ulat

a)

XX

Xal

lal

lgl

ycos

ide,

vo

latil

e oi

lsga

stro

inte

stin

alA

bdom

inal

pai

n, ir

ritat

ion

of d

iges

tive

tract

, red

deni

ng o

f ora

l m

ucou

s m

embr

anes

, dia

rrhe

a, e

xces

sive

sal

ivat

ion

Cho

kech

erry

*(P

runu

s vi

rgin

iana

) an

d P

in c

herr

y (P

. pe

nsyl

vani

ca)

XX

XR

all;

youn

g st

ems

& le

aves

, se

eds

sprin

g,

sum

mer

cyan

ogen

ic

glyc

osid

e (H

CN

)ga

stro

inte

stin

al,

card

iova

scul

ar,

resp

irato

ry, a

ll or

gans

Sudd

en d

eath

, com

a, c

onvu

lsio

ns, m

uscu

lar s

pasm

s, d

ifficu

lty

brea

thin

g, b

loat

, muc

ous

mem

bran

es a

ppea

r pin

k/re

d, v

enou

s bl

ood

is c

herr

y re

d, n

ervo

usne

ss, w

eakn

ess,

sta

gger

ing,

ex

cess

ive

saliv

atio

nC

love

r, al

sike

(T

rifol

ium

hyb

ridum

)X

XX

Xal

lal

lbl

oat,

myc

otox

in,

nitra

te,

phot

osen

sitiz

atio

n

inte

gum

enta

ry, l

iver

, ne

rvou

sBl

oat (

rum

inan

ts),

enla

rged

live

r, w

eigh

t los

s, p

hoto

sens

itivi

ty,

jaun

dice

, dep

ress

ion,

aim

less

wan

derin

g, w

alki

ng in

circ

les,

hea

d pr

essi

ng, y

awni

ngC

love

r, re

d(T

rifol

ium

pra

tens

e)X

XX

Xal

lal

lal

kalo

id, b

loat

, m

ycot

oxin

, nitr

ate,

ph

otos

ensi

tizat

ion

gast

roin

test

inal

, in

tegu

men

tary

, re

prod

uctiv

e

Bloa

t (ru

min

ants

), ex

cess

ive

saliv

atio

n, d

ehyd

ratio

n,

phot

osen

sitiv

ity, r

epro

duct

ion

prob

lem

s

Clo

ver,

whi

te(T

rifol

ium

repe

ns)

XX

XR

all

all

bloa

t, gl

ycos

ide,

ni

trate

, ph

otos

ensi

tizat

ion

gast

roin

test

inal

, in

tegu

men

tary

, m

uscu

losk

elet

al,

repr

oduc

tive,

re

spira

tory

Bloa

t (ru

min

ants

), m

uscu

lar t

rem

ors,

incr

ease

d re

spira

tory

rate

, st

agge

ring,

recu

mbe

ncy,

pho

tose

nsiti

vity

, dro

wsi

ness

, wea

knes

s,

repr

oduc

tion

prob

lem

s

Coc

kleb

ur*

(Xan

thiu

m s

trum

ariu

m,

X. s

pino

sum

)

XX

XX

spro

uts,

se

eds

sprin

g,

sum

mer

glyc

osid

ega

stro

inte

stin

al,

nerv

ous,

rena

l, liv

er

Sudd

en d

eath

, com

a, li

ver d

amag

e, c

onvu

lsio

ns, a

taxi

a,

inco

ordi

natio

n, v

omiti

ng, a

bdom

inal

pai

n, lo

ss o

f app

etite

, de

pres

sion

, wea

knes

s C

orn*

(Zea

may

s)X

XX

Rst

ems

sum

mer

, fa

llm

ycot

oxin

, nitr

ate,

se

leni

umca

rdio

vasc

ular

, ga

stro

inte

stin

al,

repr

oduc

tive,

re

spira

tory

Dea

th, c

onge

stio

n of

rum

en a

nd a

bom

asum

, mud

dy c

yano

tic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g,

choc

olat

e-br

own

bloo

d, a

cido

sis,

wat

erin

g ey

es, r

educ

ed m

ilk

flow

, red

uced

wei

ght g

ain,

abo

rtion

, inf

ertil

ityC

ow p

arsn

ip

(Her

acle

um m

axim

um)

Xflo

wer

s,

seed

ssu

mm

er,

fall

fura

noco

umar

in,

phot

osen

sitiz

atio

nin

tegu

men

tary

Phot

osen

sitiv

ity

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 23 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Cur

lycu

p gu

mw

eed

(Grin

delia

squ

arro

sa)

XS

Xle

aves

no d

ata

sele

nium

inte

gum

enta

ry,

mus

culo

skel

etal

Hea

rt at

roph

y, li

ver f

ailu

re, l

amen

ess,

bon

e an

d jo

int

dege

nera

tion,

ane

mia

, red

uced

repr

oduc

tion

perfo

rman

ce, l

oss

of

long

hai

rs o

f the

mai

n an

d ta

il (h

orse

s, c

attle

); re

duct

ion

in fe

rtilit

y (s

heep

) D

eath

cam

as*

(Zig

aden

us s

pp.)

XX

XX

all;

bulb

, m

atur

e le

aves

all;

sprin

gal

kalo

idga

stro

inte

stin

al,

mus

culo

skel

etal

, ne

rvou

s

Sudd

en d

eath

, com

a, c

onvu

lsio

ns, a

taxi

a, p

rost

ratio

n, v

omiti

ng,

stag

gerin

g, lo

wer

ed te

mpe

ratu

re, e

xces

sive

sal

ivat

ion,

trem

ors,

la

bore

d br

eath

ing,

wea

knes

sD

ock,

cur

ly*

(Rum

ex c

rispu

s)X

XX

all;

leav

es,

stem

no d

ata

oxal

ate,

nitr

ate

mus

culo

skel

etal

, ga

stro

inte

stin

al,

rena

l

Sudd

en d

eath

, com

a, m

uscl

e tre

mor

s, k

idne

y fa

ilure

, abd

omin

al

pain

, inc

oord

inat

ion,

sal

ivat

ion,

dep

ress

ion,

wea

knes

s, re

luct

ance

to

mov

eD

ogba

ne*

(Apo

cynu

m c

anna

binu

m,

(A. a

ndro

saem

ifoliu

m)

XX

XX

leav

esal

l; ha

yca

rdia

c gl

ycos

ide

card

iova

scul

ar,

gast

roin

test

inal

, oc

ular

Sudd

en d

eath

, com

a, c

yano

sis,

irre

gula

r hea

rtbea

t, ra

pid

puls

e,

blue

col

orat

ion

of m

ucou

s m

embr

anes

, abd

omin

al p

ain,

vom

iting

, di

arrh

ea, w

eakn

ess,

dila

tion

of p

upils

Elde

rber

ry, r

ed*

(Sam

bucu

s ra

cem

osa)

XX

Ral

lfa

ll,

sprin

gcy

anog

enic

gl

ycos

ide

(HC

N)

card

iova

scul

ar,

nerv

ous,

re

prod

uctiv

e,

resp

irato

ry

Sudd

en d

eath

, abo

rtion

s, in

crea

sed

hear

t rat

e, in

crea

sed

resp

irato

ry ra

te, p

antin

g, o

pen

mou

th b

reat

hing

, ext

rem

e di

fficu

lty

brea

thin

g, v

enou

s bl

ood

is c

herr

y re

d, m

ucou

s m

embr

anes

brig

ht

red,

exc

item

ent

Fals

e he

llebo

re*

(Ver

atru

m s

pp.)

XX

Xal

l; le

aves

, ro

ots

sprin

g,

sum

mer

, fa

ll

alka

loid

gast

roin

test

inal

, ne

rvou

s,

repr

oduc

tive

Birth

def

ects

, abo

rtion

, com

a, c

onvu

lsio

ns, i

rreg

ular

hea

rtbea

t, pr

ostra

tion,

diffi

cult

resp

iratio

n, v

omiti

ng, e

xces

sive

sal

ivat

ion,

w

eakn

ess,

irre

gula

r gai

tFe

scue

, tal

l(S

ched

onor

us

arun

dina

ceus

)

XX

Xle

aves

, se

eds

sum

mer

, an

d in

ha

y

alka

loid

, myc

otox

in,

nitra

teca

rdio

vasc

ular

Gan

gren

e in

ext

rem

ities

(‘fe

scue

foot

’), im

paire

d re

prod

uctio

n an

d m

ilk p

rodu

ctio

n, h

eat s

tress

, fai

lure

to s

hed

win

ter c

oat (

cattl

e);

poor

repr

oduc

tion

(hor

ses)

Fidd

lene

ck*

(Am

sinc

kia

men

zies

ii,

(A. l

ycop

soid

es)

XR

RX

all

no d

ata

alka

loid

(p

yrro

lizid

ine)

, ph

otos

ensi

tizat

ion

Gas

troin

test

inal

, m

uscu

losk

elet

al,

nerv

ous,

ocu

lar,

rena

l, al

l sys

tem

s

Rec

tal p

rola

pse,

red

urin

e, e

dem

a of

the

legs

, pho

tose

nsiti

vity

, ph

otop

hobi

a, ja

undi

ce, w

eigh

t los

s, s

ever

e de

pres

sion

, aim

less

w

alki

ng, d

iarr

hea,

ince

ssan

t lic

king

of o

bjec

ts, h

ead

pres

sing

(c

attle

, hor

ses)

; wei

ght l

oss,

app

etite

loss

(she

ep, g

oats

)Fi

eld

bind

wee

d(C

onvo

lvul

us a

rven

sis)

Xal

l; se

eds

no d

ata

alka

loid

(tro

pane

)ga

stro

inte

stin

alC

olic

Fiel

d pe

nnyc

ress

(Thl

aspi

arv

ense

)X

all;

seed

sno

dat

agl

ycos

ide

gast

roin

test

inal

Dea

th, p

rofu

se s

wel

ling

of th

e fo

re s

tom

ach,

col

ic, b

lood

y di

arrh

ea, t

aint

ed m

ilkFl

ax(L

inum

spp

.)X

XX

Ral

lno

dat

acy

anog

enic

gl

ycos

ide

(HC

N)

card

iova

scul

ar,

resp

irato

ry

Sudd

en d

eath

, cya

nosi

s, c

herr

y-re

d ve

nous

blo

od, d

ifficu

lty

brea

thin

g, e

xces

sive

sal

ivat

ion,

ner

vous

ness

, wea

knes

sFl

ixw

eed

(Des

cura

inia

sop

hia)

Xal

l; yo

ung

plan

tssp

ring

unkn

own,

ph

otos

ensi

tizat

ion

gast

roin

test

inal

, in

tegu

men

tary

, m

uscu

losk

elet

al,

nerv

ous,

ocu

lar

Blin

dnes

s, s

ever

e ph

otos

ensi

tivity

, diffi

culty

che

win

g an

d sw

allo

win

g, w

eigh

t los

s, h

ead

pres

sing

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 24 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Gol

denb

anne

r(T

herm

opsi

s m

onta

na)

XS

all;

seed

po

dsal

l; ha

yal

kalo

idm

uscu

losk

elet

alD

eath

, ata

xia,

wea

knes

s, u

nabl

e to

sta

nd

Gra

ins,

cul

tivat

ed

(oat

s, b

arle

y, ry

e,

tritic

ale,

whe

at)

XX

XX

stem

ssp

ring,

fa

llbl

oat,

nitra

te,

myc

otox

in,

sele

nium

card

iova

scul

ar,

gast

roin

test

inal

, re

prod

uctiv

e,

resp

irato

ry

Dea

th, b

loat

(rum

inan

ts),

cong

estio

n of

rum

en a

nd a

bom

asum

, te

tany

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g, c

hoco

late

-br

own

bloo

d, w

ater

ing

eyes

, red

uced

wei

ght g

ain,

abo

rtion

, rap

id

puls

e, in

ferti

lity

Gre

asew

ood*

(Sar

coba

tus

verm

icul

atus

)

XX

XS

leav

es,

buds

sprin

g,

fall,

w

inte

r

oxal

ate

mus

culo

skel

etal

, re

nal

Dea

th, c

oma,

kid

ney

failu

re, r

ecum

benc

y, m

uscl

e tre

mor

s, te

tany

, lo

ss o

f app

etite

, slo

w p

ulse

, wea

knes

s, c

olla

pse,

inco

ordi

natio

n,

depr

essi

on, r

eluc

tanc

e to

mov

e, d

rool

ing

Gro

und

ivy

(Gle

chom

a he

dera

cea)

Xal

lsp

ring,

an

d in

ha

y

vola

tile

oils

resp

irato

ryS

wea

ting,

sal

ivat

ion,

labo

red

brea

thin

g, p

upil

dila

tion

Gro

undc

herr

y, lo

ngle

af(P

hysa

lis lo

ngifo

lia)

Xal

lsp

ring,

an

d in

ha

y

vola

tile

oils

resp

irato

ryS

wea

ting,

sal

ivat

ion,

labo

red

brea

thin

g, p

upil

dila

tion

Gro

unds

el*

(Sen

ecio

spp

.)X

RR

Xal

lal

lal

kalo

id

(pyr

roliz

idin

e),

phot

osen

sitiz

atio

n

All

syst

ems,

live

rD

eath

, rec

tal p

rola

pse,

hem

olys

is, r

ed u

rine,

ane

mia

, in

coor

dina

tion,

pho

tose

nsiti

vity

, sw

ellin

g an

d re

dnes

s to

ski

n ar

ound

eye

s, ja

undi

ce, d

iarr

hea,

dep

ress

ion,

circ

ling,

aim

less

w

ande

ring,

hea

d pr

essi

ng, e

xces

sive

tear

ing,

wea

knes

s, w

eigh

t an

d ap

petit

e lo

ssH

alog

eton

*(H

alog

eton

glo

mer

atus

)X

all

sprin

gte

trady

mol

, ph

otos

ensi

tizat

ion

hepa

tic,

inte

gum

enta

ry

Dea

th, a

borti

ons,

live

r sw

ellin

g an

d fa

ilure

, rap

id w

eak

puls

e, d

ifficu

lty b

reat

hing

, pro

stra

tion,

twitc

hing

, sec

onda

ry

phot

osen

sitiv

ity, r

edne

ss a

nd e

dem

a of

the

tissu

es o

f the

hea

d,

swel

ling

of h

ead

(ear

s, li

ps, f

ace)

, inc

oord

inat

ion,

ano

rexi

a,

depr

essi

on, l

aggi

ng b

ehin

d in

her

dH

emlo

ck, p

oiso

n*(C

oniu

m m

acul

atum

)X

XX

Xal

l; se

eds

all;

sprin

gal

kalo

idal

l sys

tem

sSu

dden

dea

th, a

borti

ons,

com

a, re

spira

tory

par

alys

is, b

irth

defe

cts,

ata

xia,

mus

cle

trem

ors,

cya

nosi

s, ra

pid

wea

k pu

lse,

in

coor

dina

tion,

abd

omin

al p

ain,

ner

vous

ness

, wea

knes

s,

saliv

atio

n, fr

eque

nt u

rinat

ion

and

defe

catio

n, d

ilate

d pu

pils

H

emlo

ck, w

ater

*(C

icut

a do

ugla

sii)

XX

XX

all;

root

ssp

ring

cicu

toxi

nm

uscu

losk

elet

al,

card

iova

scul

ar,

nerv

ous,

resp

irato

ry

Sudd

en d

eath

, com

a, s

ever

e co

nvul

sion

s, re

spira

tory

par

alys

is,

rapi

d pu

lse

and

brea

thin

g, m

uscl

e de

gene

ratio

n, e

xces

sive

sa

livat

ion,

vig

orou

s ch

ewin

g, te

eth

grin

ding

, dila

ted

pupi

ls

Hem

p (C

anna

bis

sativ

a)R

Xno

dat

ano

dat

aca

nnab

inoi

dga

stro

inte

stin

al,

mus

culo

skel

etal

Dea

th, c

oma,

into

xica

tion,

vom

iting

, sal

ivat

ion,

mus

cle

trem

ors,

at

axia

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 25 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Hor

sebr

ush*

(Tet

rady

mia

can

esce

ns)

Xal

lsp

ring

tetra

dym

ol,

phot

osen

sitiz

atio

nhe

patic

, in

tegu

men

tary

D

eath

, abo

rtion

s, li

ver s

wel

ling

and

failu

re, r

apid

wea

k pu

lse,

diffi

culty

bre

athi

ng, p

rost

ratio

n, tw

itchi

ng, s

econ

dary

ph

otos

ensi

tivity

, red

ness

and

ede

ma

of th

e tis

sues

of t

he h

ead,

sw

ellin

g of

hea

d (e

ars,

lips

, fac

e), i

ncoo

rdin

atio

n, a

nore

xia,

de

pres

sion

, lag

ging

beh

ind

in h

erd

Hor

seta

il*(E

quis

etum

spp

.)X

RS

Xal

lal

l; ha

yth

iam

inas

ega

stro

inte

stin

al,

nerv

ous

Dea

th, c

oma,

con

vuls

ions

, sei

zure

s, w

eakn

ess

and

inco

ordi

natio

n of

the

hind

legs

, rec

umbe

ncy,

wei

ght l

oss,

dep

ress

ion,

app

ear

blin

d an

d ha

ve d

ifficu

lty s

eein

g, d

iarr

hea

Hor

sew

eed,

Can

adia

n(C

onyz

a ca

nade

nsis

)S

Xal

lno

dat

avo

latil

e oi

ls, t

anni

c ac

id, g

allic

aci

din

tegu

men

tary

Irrita

ted

skin

, muc

ous

mem

bran

es, a

nd n

ostri

ls

Hou

ndst

ongu

e*(C

ynog

loss

um o

ffici

nale

)X

RR

Xal

lal

l; ha

yal

kalo

id

(pyr

roliz

idin

e),

phot

osen

sitiz

atio

n

inte

gum

enta

ry,

liver

, ner

vous

, m

uscu

losk

elet

al

Dea

th, r

ecta

l pro

laps

e, re

d ur

ine,

ede

ma

of le

gs, p

hoto

sens

itivi

ty,

jaun

dice

, wei

ght l

oss,

wal

king

in c

ircle

s, d

iarr

hea,

dep

ress

ion,

ex

cess

ive

yaw

ning

Huc

kleb

erry

, fal

se

(Men

zies

ia fe

rrug

inea

)X

XX

Xal

lsp

ring,

fa

llne

urot

oxic

di

terp

enoi

dca

rdio

vasc

ular

, ga

stro

inte

stin

alC

onvu

lsio

ns, r

ecum

benc

y, in

coor

dina

tion,

irre

gula

r hea

rtbea

t, hy

pote

nsio

n, c

olic

, vom

iting

, dep

ress

ion

Indi

an b

read

root

, si

lver

leaf

(Ped

iom

elum

ar

goph

yllu

m)

XX

XX

seed

sno

dat

aph

otos

ensi

tizat

ion

inte

gum

enta

ryPh

otos

ensi

tivity

Indi

an p

aint

brus

h(C

astil

leja

spp

.)R

Rst

emno

dat

ase

leni

umin

tegu

men

tary

, m

uscu

losk

elet

alLa

men

ess,

long

hai

rs o

f the

mai

n an

d ta

il br

eak

Iris,

Roc

ky M

ount

ain

(Iris

mis

sour

iens

isX

all

no d

ata

irisi

nga

stro

inte

stin

al,

inte

gum

enta

ryC

olic

, abd

omin

al p

ain,

bur

ning

sen

satio

n of

mou

th a

nd th

roat

, vo

miti

ng, d

iarr

hea,

irrit

ated

ski

nIri

s, y

ello

wfla

g(Ir

is p

seud

acor

us)

Xno

dat

ano

dat

agl

ycos

ide

gast

roin

test

inal

, in

tegu

men

tary

Abd

omin

al p

ain,

vom

iting

, dia

rrhe

a, ir

ritat

ed s

kin

Jim

sonw

eed*

(Dat

ura

stra

mon

ium

)X

XX

Xal

l; se

eds

no d

ata;

ha

yal

kalo

id (t

ropa

ne)

card

iova

scul

ar,

gast

roin

test

inal

, oc

ular

Col

ic, r

umen

sta

sis,

mus

cula

r tw

itchi

ng, p

aral

ysis

, res

pira

tory

pa

raly

sis,

inco

ordi

natio

n, e

xces

sive

thirs

t, lo

ss o

f app

etite

, blo

at

(rum

inan

ts),

incr

ease

d he

art r

ate,

dila

ted

pupi

ls, i

mpa

ired

visi

on,

subn

orm

al te

mpe

ratu

re, d

ry m

uzzl

e, d

ecre

ased

sal

ivat

ion

John

song

rass

*(S

orgh

um h

alep

ense

)X

XX

Xal

lal

l; w

ilted

, re

grow

th

cyan

ogen

ic

glyc

osid

e (H

CN

), ni

trate

all s

yste

ms

Sudd

en d

eath

, con

vuls

ions

, abo

rtion

s or

lim

b de

form

ities

, cy

anos

is, c

herr

y-re

d ve

nous

blo

od a

nd m

ucou

s m

embr

anes

, in

crea

sed

saliv

atio

n, d

ifficu

lt br

eath

ing,

ner

vous

ness

, wea

knes

s,

urin

ary

inco

ntin

ence

, ata

xia,

hin

d le

g w

eakn

ess

Kna

pwee

d, R

ussi

an*

(Acr

optil

on re

pens

)X

all;

gree

n pl

ants

no d

ata

DD

MP

gast

roin

test

inal

, re

spira

tory

, ner

vous

Dea

th fr

om s

tarv

atio

n, m

uscl

e tre

mor

s, fa

cial

par

alys

is, u

nabl

e to

take

hol

d of

and

che

w fo

od (c

hew

ing

dise

ase)

, inh

alat

ion

pneu

mon

ia, s

ever

e w

eigh

t los

s, in

coor

dina

tion,

deh

ydra

tion,

de

pres

sion

, exc

essi

ve s

aliv

atio

n1 X

= k

now

n aff

ects

, R =

rare

ly a

ffect

s, S

= s

uspe

cted

to a

ffect

2

pla

nt p

art o

r tim

e of

yea

r; m

ost s

usce

ptib

le p

lant

par

t or m

ost d

ange

rous

tim

e of

yea

r

*

toxi

c do

se in

form

atio

n av

aila

ble

for s

peci

es in

Tab

le 2

Tabl

e 1,

(con

t.)

- 26 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Koch

ia*

(Bas

sia

scop

aria

)X

XS

Xal

lal

l; ha

yni

trate

, oxa

late

, th

iam

inas

e, s

ulfa

te,

alka

loid

, sap

onin

, ph

otos

ensi

tizat

ion

all s

yste

ms;

kid

ney,

liv

erSu

dden

dea

th, b

lindn

ess,

kid

ney

failu

re, l

iver

dis

ease

, bro

wn

colo

red

muc

ous

mem

bran

es a

nd b

lood

, sev

ere

diffi

culty

br

eath

ing,

gas

troin

test

inal

infla

mm

atio

n, in

coor

dina

tion,

ph

otos

ensi

tivity

, dep

ress

ion,

dep

ress

ed a

ppet

ite, d

ehyd

ratio

n,

swol

len

eyel

ids,

cru

sty

muz

zle,

wei

ght l

oss

Labr

ador

tea

(Led

um g

land

ulos

um)

XX

XR

all

all;

win

ter

neur

otox

ic

dite

rpen

oid

gast

roin

test

inal

Con

vuls

ions

, inc

oord

inat

ion,

recu

mbe

ncy,

irre

gula

r hea

rtbea

t, hy

pote

nsio

n, c

olic

, vom

iting

, dep

ress

ion

Lam

bsqu

arte

rs*

(Che

nopo

dium

alb

um)

XX

Xal

lno

dat

ani

trate

, oxa

late

, su

lfate

repr

oduc

tive,

re

spira

tory

Sudd

en d

eath

, acu

te re

spira

tory

failu

re, a

borti

on

Lark

spur

*(D

elph

iniu

m s

pp.)

XR

Ral

l; ne

w

grow

th,

seed

s

sprin

g (lo

w),

sum

mer

(ta

ll)

alka

loid

(dite

rpen

e),

bloa

tm

uscu

losk

elet

al,

gast

roin

test

inal

, re

spira

tory

, ner

vous

Dea

th, m

uscu

lar o

r res

pira

tory

par

alys

is, t

rem

ors,

inco

ordi

natio

n,

stiff

ness

, sta

gger

ing,

fallin

g, m

uscl

e tre

mor

s, c

olla

pse,

blo

at,

wea

knes

s, n

ervo

usne

ss, r

egur

gita

tion,

vom

iting

, sal

ivat

ion

Laur

el(K

alm

ia p

olifo

lia)

XX

XX

all

sprin

g,

fall

neur

otox

ic

dite

rpen

oid

all s

yste

ms

Con

vuls

ions

, inc

oord

inat

ion,

recu

mbe

ncy,

irre

gula

r hea

rtbea

t, hy

pote

nsio

n, c

olic

, vom

iting

, dep

ress

ion

Leaf

y sp

urge

(Eup

horb

ia e

sula

)X

RR

Xsa

pno

dat

adi

terp

ene

este

rsga

stro

inte

stin

al,

inte

gum

enta

ry

Col

ic, v

omiti

ng, r

edde

ning

and

sw

ellin

g or

blis

terin

g of

the

skin

, ey

e irr

itatio

n, w

eigh

t los

s w

hen

excl

usiv

ely

fed

leaf

y sp

urge

, di

arrh

ea, e

xces

sive

sal

ivat

ion

Loco

wee

d*(O

xytro

pis

spp.

)X

XX

Xal

lal

l; ha

yal

kalo

id

(sw

ains

onin

e)ga

stro

inte

stin

al,

repr

oduc

tive,

co

ngen

ital,

nerv

ous,

ce

lls, l

iver

Birth

def

ects

, abo

rtion

s an

d fe

tal d

eath

, dec

reas

ed fe

rtilit

y,

cong

estiv

e he

art f

ailu

re, l

iver

dam

age,

inco

ordi

natio

n, s

tiff

and

irreg

ular

gai

t, ab

norm

al b

ehav

ior,

aggr

essi

vene

ss, l

oss

of

dire

ctio

n, e

xcita

bilit

y, w

eigh

t los

s, d

epre

ssio

n, w

eakn

ess,

sta

ring,

di

fficu

lty e

atin

g, e

xagg

erat

ed m

outh

mov

emen

t, du

ll co

atLu

pine

*(L

upin

us s

pp.)

XX

RS

all;

seed

sal

l; ha

yal

kalo

ids,

m

ycot

oxin

mus

culo

skel

etal

, ne

rvou

s, h

epat

ic,

repr

oduc

tive,

re

spira

tory

Dea

th, r

espi

rato

ry fa

ilure

, com

a, b

irth

defe

cts

(cro

oked

legs

, cle

ft pa

late

), ab

ortio

n, c

onvu

lsio

ns, i

ncoo

rdin

atio

n, d

ifficu

lt br

eath

ing,

m

uscl

e tw

itchi

ng, l

oss

of m

uscl

e co

ntro

l, le

thar

gy, h

ead

pres

sing

, de

pres

sion

, ner

vous

ness

, exc

essi

ve s

aliv

atio

n, d

ry c

oat

Mal

low

, com

mon

(Mal

va n

egle

cta)

Xle

aves

, se

edno

dat

aox

alat

e, n

itrat

em

uscu

losk

elet

al,

nerv

ous

Stag

gerin

g, la

men

ess

Mat

rimon

y vi

ne(L

yciu

m b

arba

rum

)X

Xno

dat

ano

dat

aal

kalo

id

(sol

anac

eous

)ga

stro

inte

stin

al,

nerv

ous

Dea

th, c

onvu

lsio

ns, v

omiti

ng, d

iarr

hea,

exc

item

ent

Milk

vetc

h*(A

stra

galu

s sp

p.)

(not

A. c

icer

)

XX

XX

all

all;

sprin

g,

sum

mer

alka

loid

(s

wai

nson

ine)

, se

leni

um, n

itrot

oxin

inte

gum

enta

ry,

mus

culo

skel

etal

, ne

rvou

s,

repr

oduc

tive

Dea

th, a

borti

ons,

birt

h de

fect

s, b

rain

hem

orrh

ages

, res

pira

tory

di

stre

ss, l

oad

brea

thin

g (ro

arin

g di

seas

e), c

olla

psed

lung

, de

crea

sed

mal

e fe

rtilit

y, b

lindn

ess,

wea

knes

s, lo

ss o

f con

trol

of h

ind

limbs

, pro

stra

tion,

col

laps

e, d

ecre

ased

bod

y co

nditi

on,

lam

enes

s, a

bnor

mal

beh

avio

r, lo

ss o

f dire

ctio

n, k

nock

ing

of h

ocks

an

d fe

et w

hen

wal

king

, bre

akin

g of

long

hai

rs o

f the

man

e an

d ta

il, s

past

ic ja

w m

ovem

ents

, dep

ress

ed, n

ervo

usne

ss1 X

= k

now

n aff

ects

, R =

rare

ly a

ffect

s, S

= s

uspe

cted

to a

ffect

2

pla

nt p

art o

r tim

e of

yea

r; m

ost s

usce

ptib

le p

lant

par

t or m

ost d

ange

rous

tim

e of

yea

r

*

toxi

c do

se in

form

atio

n av

aila

ble

for s

peci

es in

Tab

le 2

Tabl

e 1,

(con

t.)

- 27 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Milk

wee

d*(A

scle

pias

spp

.)X

XX

Xal

lal

l; ac

tivel

y gr

owin

g,

hay

card

iac

glyc

osid

e,

sele

nium

card

iova

scul

ar,

gast

roin

test

inal

, m

uscu

losk

elet

al,

nerv

ous,

resp

irato

ry

Dea

th, c

onvu

lsio

ns, s

eizu

res,

resp

irato

ry p

aral

ysis

, rec

umbe

ncy,

ra

pid

wea

k pu

lse,

diffi

cult

brea

thin

g w

ith g

runt

ing

soun

ds,

abdo

min

al p

ain,

col

ic, b

loat

(rum

inan

ts),

diar

rhea

sta

gger

ing,

w

eakn

ess,

mus

cle

trem

ors,

relu

ctan

ce to

sta

nd, i

ncoo

rdin

atio

n,

deep

dep

ress

ion,

ele

vate

d te

mpe

ratu

re, d

ilatio

n of

pup

ilsM

illet

(Pen

nise

tum

gla

ucum

)X

XX

stem

sfa

llni

trate

card

iova

scul

ar,

gast

roin

test

inal

, re

prod

uctiv

e,

resp

irato

ry

Dea

th, c

onge

stio

n of

rum

en a

nd a

bom

asum

, mud

dy c

yano

tic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g,

choc

olat

e-br

own

bloo

d, w

ater

ing

eyes

, red

uced

milk

flow

, re

duce

d w

eigh

t gai

n, a

borti

on a

nd in

ferti

lity

Mon

ksho

od*

(Aco

nitu

m c

olum

bian

um)

XX

XX

all;

seed

s,

root

ssu

mm

eral

kalo

ids

card

iova

scul

ar,

gast

roin

test

inal

, m

uscu

losk

elet

al,

resp

irato

ry

Sudd

en d

eath

, rec

umbe

ncy,

incr

ease

d re

spira

tory

rate

, diffi

culty

br

eath

ing,

mus

cle

wea

knes

s, s

tagg

erin

g ga

it, b

loat

ing,

exc

essi

ve

saliv

atio

n

Mou

ntai

n m

ahog

any,

cu

rl-le

af a

nd tr

ue

(Cer

coca

rpus

ledi

foliu

s,C

. mon

tanu

s)

Ral

lno

dat

acy

anog

enic

gl

ycos

ide

(HC

N)

all s

yste

ms

Sudd

en d

eath

, abo

rtion

s, d

ifficu

lty b

reat

hing

(ope

n-m

outh

br

eath

ing)

, res

pira

tory

failu

re, c

olla

pse,

muc

ous

mem

bran

es

cher

ry-r

ed in

col

or, v

enou

s bl

ood

cher

ry re

d, n

ervo

usne

ss,

wea

knes

s, e

xcite

men

t, ex

cess

ive

saliv

atio

nN

ight

shad

e*(S

olan

um s

pp.)

XX

XX

all;

fruit,

le

aves

all

alka

loid

, nitr

ate

all s

yste

ms

Dea

th, c

oma,

blo

at (r

umin

ants

), sh

ock,

kid

ney

failu

re, m

uscl

e tre

mor

s, ir

regu

lar h

eart

rate

, wea

k pu

lse,

inco

ordi

natio

n, c

olic

, la

bore

d br

eath

ing,

jaun

dice

, wea

knes

s, d

iarr

hea,

dro

wsi

ness

, ex

cess

sal

ivat

ion,

dep

ress

ion,

dro

wsi

ness

, dila

ted

pupi

lsO

nion

*(A

llium

spp

.)X

RR

Xle

aves

sprin

g,

sum

mer

alka

loid

, sul

fide

card

iova

scul

ar,

resp

irato

ry, r

enal

Poss

ible

dea

th, r

ecum

benc

y, fa

st w

eak

puls

e, c

olla

pse,

in

crea

sed

resp

irato

ry ra

te, a

nem

ia, r

ed-b

row

n ur

ine,

pal

e m

ucou

s m

embr

anes

, wea

knes

s, s

tagg

erin

gPe

nste

mon

(Pen

stem

on s

pp.)

RR

Rle

aves

no d

ata

sele

nium

inte

gum

enta

ry,

mus

culo

skel

etal

La

men

ess

(hor

ses)

, circ

ular

ridg

es in

all

feet

, los

s of

long

hai

rs o

f m

ane

and

tail

Phea

sant

’s e

ye*

(Ado

nis

aest

ival

is)

RR

Xle

aves

, flo

wer

sno

dat

a gl

ycos

ide

card

iova

scul

ar,

gast

roin

test

inal

Sudd

en d

eath

, err

atic

hea

rtbea

t, co

lic, d

ecre

ased

gut

mot

ility,

di

arrh

ea, v

omiti

ngPi

ne, p

onde

rosa

*(P

inus

pon

dero

sa)

XR

Rne

edle

s,

bark

all;

win

ter,

sprin

g

isoc

upre

ssic

aci

dre

nal,

repr

oduc

tive

Abo

rtion

, con

geni

tal d

efec

ts, p

ersi

sten

tly re

tain

ed p

lace

nta,

rena

l fa

ilure

, inc

oord

inat

ion,

aim

less

wan

derin

g

Prin

cesp

lum

e(S

tanl

eya

pinn

ata)

XX

XX

leav

esno

dat

ase

leni

umin

tegu

men

tary

, m

uscu

losk

elet

al

Dea

th, l

amen

ess,

slo

ughi

ng o

f the

hoo

f (ho

rses

), ci

rcul

ar ri

dges

in

all f

eet,

loss

of l

ong

hairs

of t

he m

ane

and

tail

Punc

ture

vine

(Trib

ulus

terr

estri

s)X

Xle

aves

, st

ems

no d

ata

sapo

nin,

nitr

ate,

ph

otos

ensi

tizat

ion

hepa

tic,

inte

gum

enta

ry,

mus

culo

skel

etal

Lam

enes

s, b

iliary

sta

sis,

pho

tose

nsiti

vity

, jau

ndic

e; s

wel

ling

of

the

head

(she

ep)

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 28 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Purs

lane

(Por

tula

ca o

lera

cea)

RR

Ral

lno

dat

aox

alat

em

uscu

losk

elet

al,

rena

lD

eath

, com

a, k

idne

y fa

ilure

, mus

cle

trem

ors,

teta

ny, r

ecum

benc

y,

wea

knes

s, d

epre

ssio

n, re

luct

ance

to m

ove

Red

root

pig

wee

d*(A

mar

anth

us re

trofle

xus)

XX

XX

all

all

oxal

ate,

nitr

ate

gast

roin

test

inal

, m

uscu

losk

elet

al,

rena

l

Dea

th, r

enal

failu

re, fl

uid

arou

nd k

idne

ys, a

taxi

a, b

loat

(ru

min

ants

), re

cum

benc

y, m

uscl

e w

eakn

ess

and

trem

ors,

kn

uckl

ing

at th

e fe

tlock

join

ts, d

ecre

ased

rum

en a

ctiv

ityR

eed

cana

rygr

ass

(Pha

laris

aru

ndin

acea

)X

XX

leav

esfa

llal

kalo

id, n

itrat

e,

sele

nium

mus

culo

skel

etal

, ne

rvou

s, re

spira

tory

Dea

th, w

eakn

ess,

sta

gger

, inc

reas

ed re

spira

tory

rate

, inc

reas

ed

wat

er in

take

, red

uced

ani

mal

per

form

ance

, gra

ss te

tany

, dia

rrhe

aR

yegr

ass,

per

enni

al

(Lol

ium

per

enne

)X

XX

leav

esno

dat

aal

kalo

id,

myc

otox

in, n

itrat

e,

phot

osen

sitiz

atio

n

inte

gum

enta

ry,

nerv

ous

Inco

ordi

natio

n, c

olla

pse,

mus

cle

spas

ms,

sta

gger

ing

(ryeg

rass

st

agge

rs),

head

sha

king

, pho

tose

nsiti

vity

, gra

ss te

tany

Sage

, lan

cele

af(S

alvi

a re

flexa

)R

RR

stem

hay

nitra

tega

stro

inte

stin

al,

mus

culo

skel

etal

Col

ic, m

uscl

e w

eakn

ess,

dia

rrhe

a

Sage

, san

d an

d fri

nged

(Arte

mis

ia fi

lifol

ia,

A. f

rigid

a)

Xle

aves

fall,

w

inte

rla

cton

e,

mon

oter

pene

, vo

latil

e oi

ls

gast

roin

test

inal

, ne

rvou

sAt

axia

(fro

nt fo

requ

arte

rs),

fallin

g do

wn,

abn

orm

al b

ehav

ior,

circ

ling,

exc

itabl

e, u

npre

dict

able

Sage

brus

h, b

ig*

(Arte

mis

ia tr

iden

tata

)S

leav

esal

lla

cton

e, v

olat

ile o

ilsga

stro

inte

stin

al,

nerv

ous

Dea

th, a

borti

ons

Sage

wor

t, gr

een

and

whi

te(A

rtem

isia

dra

cunc

ulus

, A

. lud

ovic

iana

)

XX

leav

esno

dat

avo

latil

e oi

lsga

stro

inte

stin

al,

inte

gum

enta

rySk

in ir

ritat

ion,

redu

ced

rum

en a

ctiv

ity, v

omiti

ng, d

iarr

hea

Saltb

ush

(Atri

plex

spp

.)X

XX

leav

esno

dat

ase

leni

umin

tegu

men

tary

, m

uscu

losk

elet

al

Lam

enes

s, c

rack

ed o

r def

orm

ed h

oove

s, lo

ss o

f lon

g ha

irs o

f the

m

ane

and

tail

Scot

ch b

room

(Cyt

isus

sco

pariu

s)X

XX

no d

ata

no d

ata

alka

loid

gast

roin

test

inal

, m

uscu

losk

elet

alC

onge

nita

l mal

form

atio

ns, m

uscl

e de

gene

ratio

n, m

uscl

e tre

mor

s,

inco

ordi

natio

n, c

olic

, ano

rexi

a, e

xces

sive

sal

ivat

ion

Scra

mbl

ed e

ggs

(Cor

ydal

is a

urea

)X

Xno

dat

ano

dat

aal

kalo

idne

rvou

sSu

dden

dea

th, c

onvu

lsio

ns, r

estle

ssne

ss, t

witc

hing

of f

acia

l m

uscl

esSe

rvic

eber

ry*

(Am

elan

chie

r aln

ifolia

)X

XX

all;

not

berr

ies

sprin

g,

sum

mer

cyan

ogen

ic

glyc

osid

e (H

CN

)al

l sys

tem

sSu

dden

dea

th, a

borti

ons,

com

a, c

onvu

lsio

ns, c

olla

pse,

st

agge

ring,

diffi

culty

bre

athi

ng, m

ucou

s m

embr

anes

app

ear

pink

/red,

ven

ous

bloo

d is

che

rry

red,

exc

essi

ve s

aliv

atio

n,

nerv

ousn

ess,

exc

item

ent

Snak

ewee

d*(G

utie

rrez

ia s

arot

hrae

)X

XX

Xal

lsp

ring

sapo

nin,

sel

eniu

mga

stro

inte

stin

al,

mus

culo

skel

etal

re

prod

uctiv

e, li

ver

Abo

rtion

s, li

ver n

ecro

sis

and

dege

nera

tion,

dec

reas

ed m

ale

ferti

lity,

slo

ughi

ng o

f nas

al m

ucos

a, w

eigh

t los

s, s

tom

ach

pain

s,

diar

rhea

follo

wed

by

cons

tipat

ion

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 29 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Snee

zew

eed*

(Hym

enox

ys h

oope

sii)

RX

Ral

lsu

mm

er,

fall,

hay

sesq

uite

rpen

e la

cton

ega

stro

inte

stin

al,

mus

culo

skel

etal

re

spira

tory

Dea

th, r

umen

sta

sis,

ata

xia,

live

r deg

ener

atio

n, in

hala

tion

pneu

mon

ia, i

rreg

ular

pul

se, b

loat

, wei

ght l

oss,

lam

bs b

ecom

e st

iff a

nd w

aste

d, m

uscl

e tre

mor

s, d

ecre

ased

app

etite

, vom

iting

, de

hydr

atio

n, d

epre

ssio

n, w

eakn

ess,

teet

h gr

indi

ng, f

roth

ing

at

mou

th, c

ough

ing

Sorg

hum

s*, f

orag

e, g

rain

, so

rghu

m-s

udan

gras

s,

suda

ngra

ss(S

orgh

um b

icol

or, S

. x

drum

mon

dii,

S. b

icol

or

var.

suda

nene

se)

XX

XR

all

sum

mer

, fa

llni

trate

, cya

noge

nic

glyc

osid

e (H

CN

)ca

rdio

vasc

ular

, ga

stro

inte

stin

al,

repr

oduc

tive,

re

spira

tory

Dea

th, a

cido

sis,

con

gest

ion

of ru

men

and

abo

mas

um, m

uddy

or

red

cyan

otic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s,

stag

gerin

g, c

hoco

late

-bro

wn

bloo

d, w

ater

ing

eyes

, red

uced

milk

flo

w, r

educ

ed w

eigh

t gai

n, a

borti

on a

nd in

ferti

lity

Sorr

el

(Oxa

lis s

pp.)

RR

RR

no d

ata

no d

ata

oxal

ate

mus

culo

skel

etal

, re

nal

Dea

th, c

oma,

kid

ney

failu

re, t

etan

y, re

cum

benc

y, m

uscl

e tre

mor

s,

wea

knes

s, d

epre

ssio

n, re

luct

ance

to m

ove

St. J

ohns

wor

t*(H

yper

icum

per

fora

tum

)X

XR

Xle

aves

, flo

wer

sal

l; sp

ring,

ha

y

hype

ricin

, ph

otos

ensi

tizat

ion

inte

gum

enta

ry

Phot

osen

sitiv

ity, r

edde

ning

and

ede

ma,

sev

ere

itchi

ng, b

liste

ring,

sl

ough

ing

of w

hite

ski

n, s

crat

chin

g he

ad; c

onvu

lsio

ns, r

apid

re

spira

tion

and

puls

e, lo

ss o

f con

ditio

n, e

leva

ted

tem

pera

ture

, cr

ouch

ing,

rest

less

ness

Suck

leya

, poi

son

(Suc

kley

a su

ckle

yana

)X

Xal

lsu

mm

ercy

anog

enic

gl

ycos

ide

(HC

N)

card

iova

scul

ar,

gast

roin

test

inal

, ne

rvou

s, re

spira

tory

re

prod

uctiv

e

Dea

th, a

borti

on, c

olla

pse,

pin

k or

red

muc

ous

mem

bran

es,

cher

ry-r

ed b

lood

, diffi

culty

bre

athi

ng, n

ervo

usne

ss, e

xcite

men

t, ex

cess

ive

saliv

atio

n, w

eakn

ess

Sunfl

ower

(H

elia

nthu

s sp

p.)

XX

Xst

ems

no d

ata

nitra

teca

rdio

vasc

ular

, ga

stro

inte

stin

al,

repr

oduc

tive,

re

spira

tory

Dea

th, c

onge

stio

n of

rum

en a

nd a

bom

asum

, mud

dy c

yano

tic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g,

choc

olat

e-br

own

bloo

d, w

ater

ing

eyes

, red

uced

milk

flow

, re

duce

d w

eigh

t gai

n, a

borti

on, i

nfer

tility

Sw

eetc

love

r, ye

llow

and

w

hite

* (M

elilo

tus

offici

nalis

)

XR

Xm

oldy

fe

edha

ydi

coum

arol

, m

ycot

oxin

, blo

atal

l sys

tem

sA

ntic

oagu

lant

effe

cts;

dea

th, b

loat

(rum

inan

ts),

lam

enes

s, in

tern

al

and

exte

rnal

hem

orrh

agin

g (e

.g. n

ose,

eye

cha

mbe

r, du

ring

birth

ing)

, lar

ge s

wel

lings

ove

r pro

tube

rant

bod

y ar

eas,

ane

mia

, bl

oody

and

bla

ck fe

ces,

wea

knes

sS

wee

tpea

(Lat

hyru

s sp

p.)

Xno

dat

ano

dat

aun

know

nm

uscu

losk

elet

alLa

men

ess

Tans

y, c

omm

on(T

anac

etum

vul

gare

)S

SS

leav

esno

dat

aal

kalo

id, v

olat

ile

oils

card

iova

scul

ar,

gast

roin

test

inal

Abo

rtion

s, c

onvu

lsio

ns, r

apid

wea

k pu

lse,

sto

mac

h pa

in,

saliv

atin

gTa

nsy

mus

tard

(Des

cura

inia

pin

nata

)X

all

sprin

g,

sum

mer

unkn

own,

ph

otos

ensi

tizat

ion

gast

roin

test

inal

, in

tegu

men

tary

, ne

rvou

s, o

cula

r

Blin

dnes

s, d

ifficu

lty e

atin

g (to

ngue

app

ears

par

alyz

ed),

seve

re

phot

osen

sitiv

ity, w

eigh

t los

s, h

ead

pres

sing

, aim

less

wan

derin

g

1 X =

kno

wn

affec

ts, R

= ra

rely

affe

cts,

S =

sus

pect

ed to

affe

ct

2 p

lant

par

t or t

ime

of y

ear;

mos

t sus

cept

ible

pla

nt p

art o

r mos

t dan

gero

us ti

me

of y

ear

* to

xic

dose

info

rmat

ion

avai

labl

e fo

r spe

cies

in T

able

2

Tabl

e 1,

(con

t.)

- 30 -

Plan

t Spe

cies

Live

stoc

k A

ffect

ed1

Plan

t Pa

rt2

Tim

e Ye

ar2

Toxi

n or

Dis

orde

rO

rgan

or S

yste

m

Affe

cted

Sym

ptom

s

Cattle

Sheep

Goat

Horse

Tans

y ra

gwor

t*(S

enec

io ja

coba

ea)

XX

XX

all

sprin

g,

sum

mer

, ha

y

alka

loid

(p

yrro

lizid

ine)

, ph

otos

ensi

tizat

ion

all s

yste

ms

Rec

tal s

train

ing,

live

r cirr

hosi

s, fl

uid

build

up in

abd

omen

, bile

duc

t pr

olife

ratio

n, re

d ur

ine,

pho

tose

nsiti

vity

, sw

ellin

g an

d re

dnes

s to

sk

in a

roun

d ey

es, d

iarr

hea,

sto

mac

h pa

in, a

imle

ss w

ande

ring,

he

ad p

ress

ing,

exc

essi

ve te

arin

g, le

thar

gy, w

eakn

ess,

ane

mia

, in

coor

dina

tion,

dra

ggin

g re

ar fe

et, w

eigh

t los

s, a

ppet

ite lo

ss,

depr

essi

onTe

ff (E

ragr

ostis

tef)

XX

Xst

ems

fall

nitra

teca

rdio

vasc

ular

, ga

stro

inte

stin

al,

repr

oduc

tive,

re

spira

tory

Dea

th, c

onge

stio

n of

rum

en a

nd a

bom

asum

, mud

dy c

yano

tic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g,

choc

olat

e-br

own

bloo

d, w

ater

ing

eyes

, red

uced

milk

flow

, re

duce

d w

eigh

t gai

n, a

borti

on a

nd in

ferti

lity

This

tle, C

anad

a(C

irsiu

m a

rven

se)

Rst

ems

no d

ata

nitra

teca

rdio

vasc

ular

, ga

stro

inte

stin

al,

repr

oduc

tive,

re

spira

tory

Dea

th, c

onge

stio

n of

rum

en a

nd a

bom

asum

, mud

dy c

yano

tic

muc

us m

embr

anes

, sho

rtnes

s of

bre

ath,

cya

nosi

s, s

tagg

erin

g,

choc

olat

e-br

own

bloo

d, w

ater

ing

eyes

, red

uced

milk

flow

, re

duce

d w

eigh

t gai

n, a

borti

on, i

nfer

tility

This

tle, R

ussi

an*

(Sal

sola

trag

us)

XS

stem

sno

dat

ani

trate

card

iova

scul

ar,

mus

culo

skel

etal

, re

prod

uctiv

e

Abo

rtion

s, fe

tal d

eath

, rec

umbe

ncy,

incr

ease

d he

art r

ate,

in

crea

sed

resp

irato

ry ra

te, d

ifficu

lty b

reat

hing

, bro

wn

colo

red

muc

ous

mem

bran

es, s

tagg

erin

g ga

it To

bacc

o, c

oyot

e*(N

icot

iana

atte

nuat

a)X

XX

Xal

l; gr

een

grow

thno

dat

aal

kalo

id (n

icot

ine)

gast

roin

test

inal

, m

uscu

losk

elet

al,

nerv

ous,

re

prod

uctiv

e

Birth

def

ects

, abo

rtion

, com

a, c

onvu

lsio

ns, p

aral

ysis

of t

he

mus

cles

of t

he re

spira

tory

and

car

diov

ascu

lar s

yste

m, m

uscl

e tre

mor

s, s

tagg

erin

g, in

coor

dina

tion,

dia

rrhe

a, e

xces

sive

sal

ivat

ion

Vetc

h, h

airy

(Vic

ia v

illos

a)X

Xal

l; se

eds

fall

nitra

te,

phot

osen

sitiz

atio

nca

rdio

vasc

ular

, ga

stro

inte

stin

al,

inte

gum

enta

ry,

nerv

ous

Dea

th, c

onvu

lsio

ns, h

yper

prot

eine

mia

, exc

essi

ve b

leed

ing,

blo

at

(cat

tle),

thic

keni

ng o

f ski

n, p

hoto

sens

itivi

ty, s

wol

len

lym

ph n

odes

, ab

norm

al b

ehav

ior,

diffi

culty

sta

ndin

g, it

chin

g an

d ru

bbin

g of

in

fect

ed a

reas

, dia

rrhe

a, p

oor a

ppet

ite, h

air l

oss

Whi

teto

p(C

arda

ria d

raba

)S

Sle

aves

, se

eds

fall

gluc

osin

olat

esen

docr

ine

Ant

i-thy

roid

sym

ptom

s

Yello

w s

tarth

istle

*(C

enta

urea

sol

stiti

alis

)X

all

all

DD

MP

gast

roin

test

inal

, re

spira

tory

, ner

vous

Dea

th fr

om s

tarv

atio

n, b

rain

nec

rosi

s, m

uscl

e tre

mor

s, fa

cial

m

uscl

es h

yper

toni

c (w

oode

n ex

pres

sion

), fa

cial

par

alys

is, u

nabl

e to

che

w fo

od o

r drin

k (c

hew

ing

dise

ase)

, mou

th h

eld

open

, to

ngue

pro

trude

s, in

hala

tion

pneu

mon

ia, s

ever

e w

eigh

t los

s,

inco

ordi

natio

n, d

ehyd

ratio

n, d

epre

ssio

n, e

xces

sive

sal

ivat

ion

Yew

*(T

axus

bre

vifo

lia)

XX

XX

all;

leav

esal

l; w

inte

ral

kalo

id (t

axin

e)ca

rdio

vasc

ular

, ga

stro

inte

stin

al,

mus

culo

skel

etal

, re

spira

tory

, ner

vous

Sudd

en d

eath

, com

a, c

ircul

ator

y fa

ilure

, con

vuls

ions

, slo

w

hear

t rat

e, g

astri

c di

stre

ss, m

uscl

e tre

mbl

ing,

vom

iting

, diffi

culty

br

eath

ing,

inco

ordi

natio

n, d

iarr

hea,

ner

vous

ness

, fat

igue

, dila

ted

pupi

ls1 X

= k

now

n aff

ects

, R =

rare

ly a

ffect

s, S

= s

uspe

cted

to a

ffect

2

pla

nt p

art o

r tim

e of

yea

r; m

ost s

usce

ptib

le p

lant

par

t or m

ost d

ange

rous

tim

e of

yea

r

*

toxi

c do

se in

form

atio

n av

aila

ble

for s

peci

es in

Tab

le 2

Tabl

e 1,

(con

t.)

- 31 -

Tabl

e 2.

Tox

ic d

oses

for

com

mon

ly d

iagn

osed

pla

nt p

oiso

ning

s in

Mon

tana

and

Wyo

min

g. S

ympt

oms

of li

vest

ock

pois

onin

g m

ay n

ot b

e ev

iden

t un

til a

toxi

c th

resh

old

is r

each

ed.

Plan

t Spe

cies

Toxi

c D

osag

e (b

w =

bod

y w

eigh

t; n/

a =

not a

pplic

able

)C

attle

Shee

p/G

oats

Hor

ses

Com

men

tsA

lfalfa

(Med

icag

o sa

tiva)

22 p

pm (s

elen

ium

) 10

,000

ppm

(nitr

ate)

10,0

00 p

pm (n

itrat

e)22

ppm

(sel

eniu

m)

Sele

nium

acc

umul

ated

in th

e le

aves

. Nitr

ate

leve

ls a

re h

ighe

r in

low

er s

talk

s an

d st

ems.

Arr

owgr

ass

(Trig

loch

in s

pp.)

0.1

- 1.5

% b

w0.

1 –

5.0%

bw

Rar

ely

affec

ted

Flow

erin

g sp

ikes

con

tain

twic

e th

e am

ount

of t

oxin

and

requ

ire h

alf t

he d

osag

e.

Plan

ts lo

se to

xici

ty w

ith d

ryin

g (e

.g. h

ay).

Plan

ts m

ore

toxi

c w

hen

stre

ssed

from

dr

ough

t or f

rost

.Br

acke

nfer

n(P

terid

ium

aqu

ilinu

m)

No

data

No

data

3 - 5

% b

wC

onsu

mpt

ion

for a

t lea

st 3

0 da

ys. L

ive

and

drie

d pl

ants

are

toxi

c. R

oots

and

yo

ung

shoo

ts w

ith h

ighe

st to

xici

ty.

Cho

kech

erry

(Pru

nus

virg

inia

na)

0.1

- 0.6

% b

w

0.1

- 0.4

% b

wR

arel

y aff

ecte

dC

onsu

mpt

ion

0.1

to 0

.6%

bw

of l

eave

s de

pend

ing

on g

row

th s

tage

or 0

.24%

bw

fres

h tw

igs

(leth

al).

Fres

h, b

ruis

ed, w

ilted

(dro

ught

or f

rost

), an

d dr

y le

aves

ar

e po

ison

ous.

You

ng le

aves

mor

e to

xic

than

mat

ure

leav

es. S

eed

ston

es a

re

pois

onou

s.C

ockl

ebur

(Xan

thiu

m s

pp.)

0.75

– 3

.0%

bw

0.75

– 3

.0%

bw

No

data

Con

sum

ptio

n of

fres

h gr

een

spro

uts

(cot

yled

on s

tage

) and

see

ds (b

urs)

. Tox

icity

is

not

pre

sent

in m

atur

e pl

ants

.C

orn

(Zea

may

s)0.

5 - 1

.5%

nitr

ate

0.5

- 1.5

% n

itrat

e0.

5 - 1

.5%

nitr

ate

Man

y fa

ctor

s aff

ect t

oxic

ity, b

ut g

ener

ally

0.0

5% b

w is

min

imum

leth

al d

ose.

Dea

thca

mas

(Zig

aden

us s

pp.)

1% b

w0.

5 - 2

.5%

bw

No

data

Con

sum

ptio

n of

gre

en p

lant

can

be

leth

al. T

oxic

risk

gre

ates

t at e

arly

veg

etat

ive

grow

th s

tage

s fo

llow

ed b

y th

e flo

wer

and

pod

sta

ges.

Doc

k, c

urly

(Rum

ex c

rispu

s)10

– 2

0 lb

s/da

yN

o da

taN

o da

taSi

gns

can

occu

r with

in 5

hou

rs o

f con

sum

ptio

n of

gre

en p

lant

, and

dea

th fo

llow

s w

ithin

a d

ay. A

ll pa

rts o

f the

pla

nt a

re to

xic.

Dog

bane

(Apo

cynu

m s

pp.)

0.03

- 0.

05%

bw

0.03

- 0.

06%

bw

0.03

- 0.

05%

bw

Toxi

c do

se d

epen

ds o

n ra

te o

f con

sum

ptio

n an

d di

gest

ion.

Dea

th m

ay o

ccur

6 to

12

hou

rs a

fter c

onsu

mpt

ion.

Drie

d pl

ants

rem

ain

toxi

c.El

derb

erry

, red

(Sam

bucu

s ra

cem

osa

0.25

% b

w0.

25%

bw

n/a

Inge

stio

n of

wilt

ed le

aves

can

cau

se d

eath

in 1

hou

r or l

ess.

New

gro

wth

and

re

-gro

wth

are

als

o to

xic.

Fals

e he

llebo

re(V

erat

rum

spp

.)N

o da

ta6

- 12

ozn/

aD

osag

e is

for l

eave

s an

d st

ems,

but

the

root

s ar

e 5

to 1

0 tim

es m

ore

pois

onou

s.

Pois

onou

s at

all

grow

th s

tage

s.Fi

ddle

neck

(Am

sinc

kia

spp.

)0.

1% b

wR

arel

y aff

ecte

d0.

1% b

wD

osag

e is

for c

onsu

mpt

ion

over

2 w

eeks

resu

lting

in li

ver d

isea

se. C

linic

al s

igns

m

ay n

ot a

ppea

r for

2 to

8 m

onth

s af

ter c

onsu

mpt

ion.

Gre

asew

ood

(Sar

coba

tus

verm

icul

atus

)1.

5 - 5

% b

w1.

5 - 5

% b

wN

o da

taTo

xic

if ea

ten

quic

kly

or w

hen

a m

ajor

com

pone

nt o

f liv

esto

ck d

iet.

Loss

es o

ccur

w

hen

eatin

g la

rge

quan

titie

s of

leav

es th

at h

ave

falle

n to

the

grou

nd in

the

fall

and

win

ter o

r new

gro

wth

in s

prin

g. In

crea

ses

in to

xici

ty a

s gr

owin

g se

ason

ad

vanc

es. C

an b

e va

luab

le fo

rage

if a

nim

als

are

adap

ted

to o

xala

te c

onta

inin

g pl

ants

and

con

sum

ed w

ith n

on-to

xic

fora

ge.

Gro

unds

el(S

enec

io s

pp.)

1 - 5

% b

w (a

cute

)20

0 –

300%

bw

(c

hron

ic)

1 - 7

% b

w (a

cute

)C

onsu

mpt

ion

of 1

– 5

% w

ithin

a fe

w d

ays

can

be le

thal

. Chr

onic

poi

soni

ng

caus

ed b

y ac

cum

ulat

ive

cons

umpt

ion

of a

tota

l int

ake

of 2

5 to

150

% b

w o

ver

seve

ral m

onth

s.

Hal

oget

on(H

alog

eton

glo

mer

atus

)0.

3 - 1

.5%

bw

0.3

- 1.5

% b

wR

arel

y aff

ecte

dBe

com

es m

ore

toxi

c as

gro

win

g se

ason

adv

ance

s. P

eak

toxi

city

at m

atur

ity.

Toxi

city

dep

ends

on

othe

r for

age

avai

labi

lity.

- 32 -

Plan

t Spe

cies

Toxi

c D

osag

e (b

w =

bod

y w

eigh

t; n/

a =

not a

pplic

able

)C

attle

Shee

p/G

oats

Hor

ses

Com

men

tsH

emlo

ck, p

oiso

n(C

oniu

m m

acul

atum

)0.

1 –

1.0%

bw

0.1

– 1.

0% b

w0.

1 –

1.0%

bw

Con

sum

ptio

n of

gre

en p

lant

(let

hal).

See

ds, e

spec

ially

whe

n im

mat

ure,

are

mor

e to

xic

than

oth

er p

lant

par

ts. R

emai

ns to

xic

whe

n dr

ied.

Hor

sebr

ush

(Tet

rady

mia

can

esce

ns)

n/a

0.5

- 1.2

5%n/

aSh

eep

are

mai

nly

affec

ted

by th

is p

lant

whe

n ea

ten

in c

onju

nctio

n w

ith b

lack

sa

gebr

ush

(Arte

mis

ia n

ova)

.H

orse

tail

(Equ

iset

um s

pp.)

Feed

con

tain

ing

>20%

hor

seta

il.R

arel

y aff

ecte

d.Fe

ed c

onta

inin

g >2

0% h

orse

tail.

Sym

ptom

s ap

pear

2 to

5 w

eeks

afte

r con

sum

ptio

n. F

resh

and

dry

pla

nts

are

toxi

c.

Hou

ndst

ongu

e(C

ynog

loss

um o

ffici

nale

)5

- 10%

bw

Rar

ely

affec

ted

2% o

f dry

mat

ter

inta

ke/d

ay

Hor

ses

that

con

sum

e ar

ound

1 p

lant

per

day

for 2

wee

ks s

how

sym

ptom

s.

Leth

al fo

r cat

tle w

hen

eatin

g 5%

or m

ore

of th

eir t

otal

dai

ly d

iet o

f mat

ure

plan

ts

for p

erio

ds e

xcee

ding

15

days

. Ji

mso

nwee

d(D

atur

a st

ram

oniu

m)

1 –

5% b

w o

f see

dsN

o da

ta0.

5% b

w o

f see

ds

for 1

0 da

ysTo

xins

pre

sent

in a

ll pl

ant p

arts

, inc

reas

ing

with

mat

urity

and

rem

ain

afte

r dr

ying

. See

ds h

ave

high

est c

once

ntra

tion.

Jo

hnso

ngra

ss(S

orgh

um h

alep

ense

)0.

25%

bw

0.25

% b

w0.

25%

bw

Inge

stio

n in

the

form

of w

ilted

leav

es c

an re

sult

in d

eath

in a

n ho

ur o

r les

s.

Kna

pwee

d, R

ussi

an(A

crop

tilon

repe

ns)

n/a

n/a

86 -

200%

bw

Con

sum

ptio

n ov

er 1

to 3

mon

ths.

Koch

ia(B

assi

a sc

opar

ia)

>50%

of d

iet

>50%

of d

iet

>50%

of d

iet

Toxi

city

var

ies

with

gro

wth

sta

ge. M

ore

prob

lem

s as

soci

ated

with

mat

ure,

dr

ough

ty p

lant

s.

Lam

bsqu

arte

rs(C

heno

podi

um a

lbum

)>1

% n

itrat

es>1

% n

itrat

esn/

aA

nim

als

impa

cted

afte

r con

sum

ing

plan

ts w

ith >

1% n

itrat

es.

Lark

spur

(Del

phin

ium

spp

.)0.

5 - 3

.5%

bw

Rar

ely

affec

ted

(3 –

21%

) bw

Rar

ely

affec

ted

Hig

hly

pala

tabl

e an

d hi

ghly

toxi

c to

cat

tle. T

oxic

ity fo

r bot

h lo

w a

nd ta

ll la

rksp

ur

is m

ost p

reva

lent

at fl

ower

ing

stag

e an

d de

crea

ses

afte

r see

d dr

op. T

oxic

ity

decl

ines

ove

r gro

win

g se

ason

. Fre

sh o

r drie

d pl

ants

toxi

c. S

eeds

rem

ain

toxi

c.Lo

cow

eed

(Oxy

tropi

s sp

p.)

30 -

50%

bw

in d

ry

wei

ght

No

data

81 lb

s in

4 -

6 w

eeks

Sym

ptom

s ap

pear

2 to

9 w

eeks

afte

r con

sum

ptio

n.

Lupi

ne(L

upin

us s

pp.)

0.1

- 1.5

% b

w

0.5

- 1.5

% b

wR

arel

y aff

ecte

dSp

ecie

s va

ry in

toxi

city

leve

ls. T

oxic

sub

stan

ces

thro

ugho

ut p

lant

and

co

ncen

trate

d in

see

ds. Y

oung

er p

lant

s m

ore

toxi

c th

an m

atur

e pl

ants

. See

d st

age

espe

cial

ly to

xic.

Sm

alle

r dos

es p

oiso

nous

if c

attle

eat

lupi

ne d

aily

for 3

to

7 da

ys.

Milk

vetc

h(A

stra

galu

s sp

p.)

(not

A. c

icer

)

0.2

- 0.8

% b

w8

ozN

o da

taTo

xic

dose

dep

ends

on

rate

of c

onsu

mpt

ion

and

dige

stio

n. A

ll pl

ant p

arts

and

gr

owth

sta

ges

are

toxi

c, fr

esh

or d

ried,

but

toxi

city

dec

reas

es a

s pl

ant m

atur

es

and

drie

s. L

ess

dang

erou

s af

ter s

eed

disp

ersa

l. M

ilkw

eed

(Asc

lepi

as s

pp.)

0.05

– 2

.0%

bw

0.05

– 2

.0%

bw

0.05

– 2

.0%

bw

Spec

ies

vary

in to

xici

ty le

vels

. Nar

row

leaf

spe

cies

are

the

mos

t tox

ic a

nd

broa

d-le

af s

peci

es re

lativ

ely

non-

toxi

c. T

oxic

ity ri

sk w

hen

plan

t is

activ

ely

grow

ing.

Ris

ks d

ecre

ase

with

dry

ing

but p

lant

rem

ains

toxi

c.

Mon

ksho

od

(Aco

nitu

m c

olum

bian

um)

No

data

No

data

0.07

5% b

w

All

parts

are

toxi

c w

ith ro

ots,

see

ds a

nd p

re-fl

ower

ing

leav

es h

ighe

st in

co

ncen

tratio

n.N

ight

shad

e(S

olan

um s

pp.)

0.1

- 0. 3

% b

w0.

1 - 0

.3%

bw

0.1

- 0.3

% b

wTo

xici

ty o

f the

leav

es a

nd fr

uit i

s pr

esen

t in

all g

row

th s

tage

s. H

ighe

r tox

icity

in

fall

than

spr

ing

and

in b

errie

s th

an le

aves

. Drie

d pl

ants

rem

ain

toxi

c.

Tabl

e 2,

(con

t.)

- 33 -

Plan

t Spe

cies

Toxi

c D

osag

e (b

w =

bod

y w

eigh

t; n/

a =

not a

pplic

able

)C

attle

Shee

p/G

oats

Hor

ses

Com

men

tsO

nion

(Alli

um s

pp.)

25%

of d

iet

Rar

ely

affec

ted

No

data

Toxi

city

incr

ease

s w

ith th

e pu

ngen

cy o

f oni

on.

Phea

sant

’s e

ye(A

doni

s ae

stiv

alis

)R

arel

y aff

ecte

d16

oz

gree

n w

eigh

tN

o da

taD

osag

e is

fata

l to

shee

p.

Pine

, pon

dero

sa

(Pin

us p

onde

rosa

)4.

8 - 6

lbs

dry

or

gree

n ne

edle

s or

ba

rk

Rar

ely

affec

ted

n/a

Cat

tle a

ppea

r to

eat n

eedl

es w

hen

stre

ssed

suc

h as

dur

ing

win

ter s

now

stor

ms

or s

horta

ge o

f for

age.

Con

sum

ptio

n pe

r day

for m

ore

than

3 d

ays

(abo

rtion

). C

attle

in la

st tr

imes

ter a

re m

ost s

usce

ptib

le.

Red

root

pig

wee

d(A

mar

anth

us re

trofle

xus)

0.5

- 1.5

% n

itrat

e0.

5 - 1

.5%

nitr

ate

0.5

- 1.5

% n

itrat

eM

any

fact

ors

affec

t tox

icity

, gen

eral

ly 0

.05%

bw

is m

inim

um le

thal

dos

e fo

r ni

trate

acc

umul

atio

n. O

xala

te le

vels

rem

ain

high

in d

ry p

lant

s.

Sage

brus

h, b

ig(A

rtem

isia

trid

enta

ta)

n/a

0.75

lbs

for 1

– 3

da

ysn/

aO

ccas

iona

lly to

xic

to s

heep

. Fou

nd to

be

leth

al in

exp

erim

ents

. For

mos

t sp

ecie

s, s

ageb

rush

is a

use

ful f

orag

e pl

ant.

Serv

iceb

erry

(Am

elan

chie

r aln

ifolia

)0.

1 - 0

.6%

bw

0.1

- 0.4

% b

wn/

aC

onsu

mpt

ion

0.1

to 0

.6%

bw

of l

eave

s de

pend

ing

on s

tage

of g

row

th o

r 0.2

4%

bw fr

esh

twig

s (le

thal

). W

ilted

leav

es m

ore

toxi

c th

an fr

esh

leav

es.

Snak

ewee

d(G

utie

rrez

ia s

arot

hrae

)10

- 20

% b

w10

- 20

% b

wN

o da

taC

onsu

mpt

ion

over

2 w

eeks

is le

thal

. Cat

tle a

bort

afte

r eat

ing

20 lb

s gr

een

wei

ght.

Gre

en a

nd d

ry p

lant

s to

xic.

Tox

icity

incr

ease

s on

san

dy s

oils

. Sn

eeze

wee

d(H

ymen

oxys

hoo

pesi

i)R

arel

y aff

ecte

d2

lbs

gree

n le

aves

Rar

ely

affec

ted

Con

sum

ptio

n da

ily fo

r 10

days

is le

thal

.

Sorg

hum

-sud

angr

ass,

and

su

dang

rass

(Sor

ghum

spp

.)

0.5

- 1.5

% n

itrat

e0.

5 - 1

.5%

nitr

ate

0.5

- 1.5

% n

itrat

eM

any

fact

ors

affec

t tox

icity

, but

gen

eral

ly 0

.05%

bw

is m

inim

um le

thal

dos

e.

St. J

ohns

wor

t(H

yper

icum

per

fora

tum

)1%

bw

4% b

wN

o da

taTo

xic

conc

entra

tions

var

y by

pla

nt p

heno

logy

and

loca

tion.

Tox

ic a

t all

grow

th

stag

es.

Sw

eetc

love

r, ye

llow

and

w

hite

(Mel

ilotu

s offi

cina

lis)

10 –

20

mg/

kg o

f fe

ed (1

00 d

ays)

; 60

– 7

0 m

g/kg

of

feed

(21

days

Rar

ely

affec

ted

10 –

20

mg/

kg o

f fe

ed (1

00 d

ays)

; 60

– 7

0 m

g/kg

of

feed

(21

days

)

Toxi

ns a

re fo

und

in m

oldy

feed

and

not

in a

pas

ture

set

ting.

Sw

eetc

love

r hay

ca

n re

mai

n to

xic

for 3

to 4

yea

rs a

nd c

an b

e us

ed if

dilu

ted

with

unc

onta

min

ated

fe

ed (1

:3).

Tans

y ra

gwor

t(D

escu

rain

ia p

inna

ta)

5 - 1

0% b

w

5% b

w3

- 7%

bw

Tota

l int

ake

of 2

5 to

50%

bw

ove

r sev

eral

mon

ths.

Hay

reta

ins

toxi

city

for

mon

ths.

This

tle, R

ussi

an(S

also

la tr

agus

)0.

5 - 1

.5%

nitr

ate

No

data

n/a

Man

y fa

ctor

s aff

ect t

oxic

ity, b

ut g

ener

ally

0.0

5% b

w is

min

imum

leth

al d

ose.

Toba

cco,

coy

ote

(Nic

otia

na a

ttenu

ata)

2% b

wN

o da

taN

o da

taC

onsu

mpt

ion

of 2

% b

w fr

esh

plan

t is

leth

al.

Yello

w s

tarth

istle

(Cen

taur

ea s

olst

itial

is)

n/a

n/a

86 -

200%

bw

Con

sum

ptio

n of

pla

nt g

reen

wei

ght o

ver s

ever

al w

eeks

cau

ses

impa

cts.

You

ng

hors

es m

ost s

usce

ptib

le.

Yew

(Tax

us b

revi

folia

)0.

5% b

w0.

5% b

w0.

1% b

wC

onsu

mpt

ion

of g

reen

or d

ry fo

liage

, bar

k, s

eeds

, and

aril

sur

roun

ding

see

ds

are

all t

oxic

. Fol

iage

is re

adily

eat

en b

y liv

esto

ck.

Tabl

e 2,

(con

t.)

- 34 -

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Alfa

lfaM

edic

ago

sativ

aFa

bace

aeF

IX

XX

Fiel

ds, r

oads

ides

Aly

ssum

, hoa

ryB

erte

roa

inca

naBr

assi

cace

aeF

IX

XX

XX

XM

eado

ws,

pas

ture

s, fi

elds

, roa

dsid

esA

rrow

gras

sTr

iglo

chin

mar

itim

a,T.

pal

ustri

sJu

ncag

inac

eae

GN

XX

XX

XD

amp,

wet

, mar

shy

area

s, ir

rigat

ed p

astu

res,

sal

ine

and

alka

line

soils

Aste

r, w

oody

Xylo

rhiz

a gl

abriu

scul

aAs

tera

ceae

FN

XX

Dry

alk

alin

e so

ils, c

lay

or b

ento

nitic

soi

l of s

tepp

e, b

adla

nds

Bane

berr

yA

ctae

a ru

bra

Ran

uncu

lace

aeF

NX

XX

XX

Moi

st s

oils

of f

ores

ts, a

long

stre

ams

Beet

, sug

arB

eta

vulg

aris

Che

nopo

diac

eae

FI

XC

ultiv

ated

Bird

sfoo

t tre

foil

Lotu

s co

rnic

ulat

usFa

bace

aeF

IX

XX

XR

oads

ides

, fiel

ds, p

astu

res

Blac

k he

nban

eH

yosc

yam

us n

iger

Sola

nace

aeF

IW

XX

XX

XX

Roa

dsid

es, fi

elds

, pas

ture

sBl

uew

eed

Ech

ium

vul

gare

Bora

gina

ceae

FI

MX

XX

XR

oads

ides

, fiel

ds, m

eado

ws,

rive

r gra

vel b

ars,

vac

ant l

otBo

unci

ngbe

t S

apon

aria

offi

cina

lisC

aryo

phyl

lace

aeF

IX

XR

oads

ides

, woo

dlan

ds, p

astu

res

Brac

kenf

ern

Pte

ridiu

m a

quili

num

Poly

podi

acea

eF

NX

XM

oist

to w

et fo

rest

, woo

dlan

ds a

nd m

eado

ws,

thic

kets

with

in

fore

sted

land

scap

es, a

long

stre

ams,

val

leys

to s

ubal

pine

Bras

sica

sB

rass

ica

spp.

, R

apha

nus

sativ

usBr

assi

cace

aeF

IX

XC

ultiv

ated

Buck

thor

nR

ham

nus

cath

artic

aR

ham

nace

aeS

IM

XX

XFi

elds

, woo

ded

area

s, v

acan

t lot

s, ri

paria

n co

rrid

ors

Buck

whe

atFa

gopy

rum

es

cule

ntum

Poly

gona

ceae

FI

XX

Cul

tivat

ed, r

epor

ted

to e

scap

e in

to d

istu

rbed

soi

ls a

nd

road

side

sBu

tterc

upR

anun

culu

s sp

p.

and

Cer

atoc

epha

la

test

icul

ata

Ran

uncu

lace

aeF

N, I

MX

XX

XX

XX

XM

oist

mea

dow

s, g

rass

land

s, ir

rigat

ed h

ay fi

elds

, alo

ng

road

s, la

wns

Che

rry,

pin

P

runu

s pe

nsyl

vani

caR

osac

eae

SN

XX

XX

Ope

n fo

rest

, woo

dlan

ds, t

hick

ets;

up

to lo

wer

sub

alpi

neC

hoke

cher

ryP

runu

s vi

rgin

iana

Ros

acea

eS

NX

XX

XX

Rip

aria

n th

icke

ts, f

ores

ts, p

ine

and

ash

woo

dlan

ds, r

ocky

sl

opes

, sto

ny s

oil o

f gra

ssla

nds

Clo

ver,

alsi

keTr

ifoliu

m h

ybrid

umFa

bace

aeF

IX

XX

XM

oist

are

as, r

oads

ides

, fiel

ds, p

astu

res

Clo

ver,

red

Trifo

lium

pra

tens

eFa

bace

aeF

IX

XX

XX

Mea

dow

s, fi

elds

, law

ns, r

oads

ides

, stre

amba

nks

Clo

ver,

whi

teTr

ifoliu

m re

pens

Faba

ceae

FI

XX

XM

eado

ws,

moi

st g

rass

land

s, ro

adsi

des,

fiel

dsC

ockl

ebur

Xant

hium

stru

mar

ium

, X

. spi

nosu

mAs

tera

ceae

FN

XX

XX

XSt

ream

bank

s, ro

adsi

des,

fiel

ds, f

arm

yard

s, p

ond

and

rese

rvoi

r edg

eC

orn

Zea

May

sPo

acea

eG

IX

Cul

tivat

ed, r

arel

y es

capi

ngC

ow p

arsn

ipH

erac

leum

max

imum

Api

acea

eF

NX

XX

XM

oist

soi

l of a

vala

nche

slo

pes,

thic

kets

, ope

n fo

rest

, w

oodl

ands

, ofte

n al

ong

stre

ams

Tabl

e 3.

Pla

nt fa

mily

, nat

ive

stat

us, n

oxio

us w

eed

desi

gnat

ion,

and

hab

itat

des

crip

tion

s fo

r po

ison

ous

plan

t spe

cies

in M

onta

na a

nd W

yom

ing.

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

- 35 -

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Cur

lycu

p gu

mw

eed

Grin

delia

squ

arro

saAs

tera

ceae

FN

XX

XX

XM

argi

ns o

f wet

land

s, s

tream

bank

s, ro

adsi

des,

dis

turb

ed

site

s, v

erna

lly m

oist

Dea

thca

mas

Ziga

denu

s sp

p.Li

liace

aeF

NX

XX

XX

XM

any

spec

ies

in M

T an

d W

Y th

at v

ary

in h

abita

t; M

eado

ws,

op

en fo

rest

, alo

ng s

tream

s, s

tony

cal

care

ous

soil,

ridg

es,

gras

slan

ds, a

nd s

ageb

rush

ste

ppe;

up

to s

ubal

pine

Doc

k, c

urly

Rum

ex c

rispu

sPo

lygo

nace

aeF

IX

XX

XX

XM

oist

to w

et, d

istu

rbed

site

s, d

itche

s, ro

ads,

stre

ams,

w

etla

nds

Dog

bane

Apo

cynu

m

cann

abin

um, A

. an

dros

aem

ifoliu

m

Apo

cyna

ceae

FN

XX

XX

XR

ocky

soi

l, al

ong

stre

ams,

fore

st o

peni

ngs,

ope

n w

oode

d ar

eas,

mea

dow

s, ro

adsi

des

Elde

rber

ryS

ambu

cus

spp.

Cap

rifol

iace

aeS

NX

XX

XM

oist

ope

n fo

rest

and

woo

dlan

ds, t

hick

ets,

ava

lanc

he

slop

es, a

long

stre

ams;

val

leys

to s

ubal

pine

Fals

e he

llebo

reVe

ratru

m s

pp.

Lilia

ceae

FN

XX

Wet

ripa

rian

mea

dow

s, th

icke

ts, m

oist

fore

st o

peni

ngs,

av

alan

che

slop

es; u

p to

sub

alpi

neFe

scue

, tal

l S

ched

onor

us

arun

dina

ceus

Poac

eae

GI

XX

XM

oist

mea

dow

s, p

astu

res,

ditc

h ba

nks

and

irrig

ated

fiel

ds

Fidd

lene

ckA

msi

ncki

a m

enzi

esii,

A. l

ycop

soid

esBo

ragi

nace

aeF

NX

XX

Dry

soi

ls, c

ultiv

ated

are

as, r

oads

ides

, law

ns, p

astu

res

Fiel

d bi

ndw

eed

Con

volv

ulus

arv

ensi

sC

onvo

lvul

acea

eF

IB

XX

XX

Fiel

ds, p

astu

res,

vac

ant l

ots,

road

side

s Fl

ax

Linu

m s

pp.

Lina

ceae

FN

, IX

XX

XX

XG

rass

land

s, s

ageb

rush

ste

ppe,

bad

land

s, w

oodl

ands

, m

eado

ws,

fellfi

elds

, roa

dsid

esFl

ixw

eed

Des

cura

inia

sop

hia

Bras

sica

ceae

FI

XX

XX

XX

Dis

turb

ed s

oils

of fi

elds

, roa

dsid

es, p

astu

res

Gol

denb

anne

rTh

erm

opsi

s m

onta

na,

T. rh

ombi

folia

Faba

ceae

FN

XX

XX

XX

Moi

st m

eado

ws,

thic

kets

, woo

dlan

ds, s

ageb

rush

ste

ppe,

fo

rest

, alo

ng s

tream

, pas

ture

sG

rain

s, c

ultiv

ated

Poac

eae

GI

XX

Cul

tivat

edG

reas

ewoo

dS

arco

batu

s ve

rmic

ulat

usC

heno

podi

acea

eS

NX

XX

Salin

e so

il of

stre

am te

rrac

es, b

adla

nds,

dry

alk

alin

e so

ils

Gro

und

ivy

Gle

chom

a he

dera

cea

Lam

iace

aeF

IX

XX

Shad

ed, m

oist

soi

l of f

arm

yard

s an

d pa

stur

es, s

tream

bank

sG

roun

dche

rry,

lo

ngle

afP

hysa

lis lo

ngifo

liaSo

lana

ceae

FN

XX

XD

ry s

oils

of g

rass

land

s, fi

elds

, roa

dsid

es

Gro

unds

elS

enec

io s

pp.

Aste

race

aeF

N, I

XX

XX

Hay

fiel

ds, r

oads

ides

, far

mya

rds,

was

te a

reas

Hal

oget

onH

alog

eton

glo

mer

atus

Che

nopo

diac

eae

FI

XX

XX

Barr

en a

reas

, sal

ine

soil

of a

rid a

reas

, dis

turb

ed s

tepp

e in

ar

id v

alle

ys, d

ry la

kebe

ds, a

band

oned

dry

farm

fiel

dsH

emlo

ck, p

oiso

nC

oniu

m m

acul

atum

Api

acea

eF

IX

XX

Moi

st, d

istu

rbed

soi

l alo

ng s

tream

s, d

itche

s, c

ool o

pen

slop

es

Tabl

e 3,

(con

t.)

- 36 -

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Hem

lock

, wat

erC

icut

a do

ugla

sii

Api

acea

eF

NX

XX

XW

et m

eado

ws,

mar

shes

, alo

ng s

tream

s, w

etla

nds

Hem

pC

anna

bis

sativ

aC

anna

bace

aeF

IX

XX

XFi

elds

, roa

dsid

esH

orse

brus

hTe

trady

mia

can

esce

nsAs

tera

ceae

SN

XX

XX

Gra

ssla

nds,

dry

sag

ebru

sh s

tepp

e an

d gr

assl

ands

Hor

seta

ilE

quis

etum

spp

.Eq

uise

tace

aeF

NX

XX

XX

Moi

st to

wet

soi

l mea

dow

s, p

astu

res,

fore

sts,

stre

amba

nks,

la

ke s

hore

s at

all

elev

atio

nsH

orse

wee

d,

Can

adia

nC

onyz

a ca

nade

nsis

Aste

race

aeF

NX

XX

Dis

turb

ed m

eado

ws,

rang

elan

ds, g

rass

land

s, ro

adsi

des

Hou

ndst

ongu

eC

ynog

loss

um o

ffici

nale

Bora

gina

ceae

FI

BX

XX

XX

XX

XD

istu

rbed

gro

und

of p

astu

res,

fiel

ds, r

oads

ides

, gra

ssla

nds,

m

eado

ws,

woo

dlan

ds, f

ores

ts, r

ipar

ian

area

sH

uckl

eber

ry, f

alse

Men

zies

ia fe

rrug

inea

Eric

acea

eS

NX

XX

Coo

l, m

oist

, upl

and

slop

es in

con

ifero

us fo

rest

s, fo

rmin

g de

nse

thic

kets

on

north

slo

pes;

val

leys

to s

ubal

pine

Indi

an b

read

root

, si

lver

leaf

Ped

iom

elum

ar

goph

yllu

mFa

bace

aeF

NX

XX

Dry

gra

ssla

nds,

sag

ebru

sh s

tepp

e, d

eser

t shr

ubla

nd,

road

side

s, a

nd w

oodl

ands

; ofte

n in

san

dy s

oils

In

dian

pai

ntbr

ush

Cas

tille

ja s

pp.

Scro

phul

aria

ceae

FN

XX

XX

XM

oist

gra

ssla

nds,

sag

ebru

sh s

tepp

e, m

oist

to w

et m

eado

ws,

th

icke

ts, f

ores

t ope

ning

s, n

ear s

tream

s; u

p to

alp

ine

Iris,

Roc

ky

Mou

ntai

nIri

s m

isso

urie

nsis

Irida

ceae

FN

XX

XX

XM

oist

to w

et m

eado

ws,

thic

kets

, woo

dlan

d m

argi

ns

Iris,

yel

low

flag

Iris

pseu

daco

rus

Irida

ceae

FI

MX

XM

arsh

es, w

et m

eado

ws,

wet

land

s, s

tream

ban

ks, i

rrig

atio

n di

tche

sJi

mso

nwee

dD

atur

a st

ram

oniu

mSo

lana

ceae

FI

XX

XD

istu

rbed

soi

ls, r

oads

ides

, rai

lroad

righ

ts-o

f-way

, far

mya

rds,

cu

ltiva

ted

area

sJo

hnso

ngra

ss

Sor

ghum

hal

epen

sePo

acea

eG

IX

XX

Moi

st s

oils

of d

istu

rbed

site

s, ro

adsi

des,

ditc

hes,

was

te

area

s, a

lluvi

al b

otto

m la

nd, c

ultiv

ated

fiel

ds, p

astu

res

Kna

pwee

d,

Rus

sian

A

crop

tilon

repe

nsAs

tera

ceae

FI

BX

XX

XX

Fiel

ds, g

rass

land

s, m

eado

ws,

road

side

s, s

tream

terr

aces

Koch

iaB

assi

a sc

opar

iaC

heno

podi

acea

eF

IX

XX

XD

istu

rbed

soi

l of r

oads

ides

, pas

ture

s, ra

ngel

and,

farm

yard

s,

culti

vate

d fie

lds,

tole

rant

of s

alin

e so

il La

brad

or te

aLe

dum

gla

ndul

osum

Eric

acea

eS

NX

XX

XM

oist

to w

et fo

rest

s an

d m

eado

ws;

val

leys

to s

ubal

pine

Lam

bsqu

arte

rsC

heno

podi

um a

lbum

Che

nopo

diac

eae

FN

, IX

XX

XX

Dis

turb

ed s

oils

of r

oads

ides

, fiel

ds, r

ange

land

, pas

ture

s

Lark

spur

, low

Del

phin

ium

bic

olor

, D.

nutta

llian

um,

D. g

eyer

i, an

d ot

hers

Ran

uncu

lace

aeF

NX

XX

XG

rass

land

s, s

ageb

rush

ste

ppe,

ope

n fo

rest

or w

oodl

and,

ro

cky

ridge

s

Lark

spur

, tal

lD

elph

iniu

m b

arbe

yi,

D. o

ccid

enta

le, D

gl

aucu

m, a

nd o

ther

s

Ran

uncu

lace

aeF

NX

XX

Dee

p, m

oist

soi

ls, m

ount

ain

mea

dow

s, a

spen

sta

nds,

alo

ng

stre

ams

or a

roun

d se

eps

and

sprin

gs

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

Tabl

e 3,

(con

t.)

- 37 -

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Laur

elK

alm

ia p

olifo

lia,

K. m

icro

phyl

laEr

icac

eae

SN

XX

Moi

st m

eado

ws

and

fore

sts,

bog

s, a

roun

d la

kes;

up

to

alpi

ne

Leaf

y sp

urge

Eup

horb

ia e

sula

Euph

orbi

acea

eF

IB

XX

XX

XX

Gra

ssla

nds,

mea

dow

s, w

oodl

ands

, rip

aria

n fo

rest

, pas

ture

s an

d pr

airie

sLo

cow

eed

Oxy

tropi

s se

ricea

, O

. lam

bert

ii, a

nd

othe

rs

Faba

ceae

FN

XX

XX

Gra

ssla

nds

with

wel

l-dra

ined

soi

l, ra

ngel

and,

sag

ebru

sh

step

pe, d

ry w

oodl

ands

, pas

ture

s, a

nd e

xpos

ed ri

dges

at a

ll el

evat

ions

Lu

pine

Lupi

nus

seric

eus,

L.

cau

datu

s,

L. le

ucop

hyllu

s,

L. a

rgen

teus

, L.

pla

ttens

is,

L. p

olyp

hyllu

s, L

. pu

sillu

s, a

nd o

ther

s

Faba

ceae

FN

XX

XX

XX

Man

y sp

ecie

s of

lupi

ne in

MT

and

WY;

not

all

are

pois

onou

s; S

peci

es li

sted

are

mos

t com

mon

ly c

ited

for

toxi

ns; v

arie

d ha

bita

t fro

m d

ry, s

andy

soi

l of g

rass

land

s,

sage

brus

h st

eppe

, stre

amba

nks,

moi

st m

eado

ws,

dry

, ope

n fo

rest

, woo

dlan

ds; a

ll el

evat

ions

Mal

low

, com

mon

Mal

va n

egle

cta

Mal

vace

aeF

IX

XX

Dis

turb

ed p

astu

res,

bar

nyar

ds, w

aste

are

asM

atrim

ony

vine

Lyci

um b

arba

rum

Sola

nace

aeS

IX

XX

Fiel

ds, r

oads

ides

, far

mst

eads

, was

te a

reas

Milk

vetc

hA

stra

galu

s sp

p.

(not

A. c

icer

)Fa

bace

aeF

NX

XX

XX

XM

any

spec

ies

in M

T an

d W

Y va

ry in

hab

itat a

nd to

xici

ty;

Ston

y, m

oist

soi

l of g

rass

land

s, s

ageb

rush

ste

ppe,

alk

alin

e m

eado

ws,

gra

vel b

ars,

thic

kets

, nea

r wet

land

s or

stre

ams,

op

en fo

rest

, lim

esto

ne-d

eriv

ed s

oil,

clay

soi

l; al

l ele

vatio

nsM

ilkw

eed

Asc

lepi

as s

pp.

Ascl

epia

dace

aeF

NX

XX

XX

Mea

dow

s, s

tream

bank

s, g

rass

land

s, b

adla

nds,

pin

e w

oodl

ands

, fiel

ds, r

oads

ides

, ditc

hes,

mar

shes

, pra

irie

poth

oles

Mill

etP

enni

setu

m g

lauc

umPo

acea

eG

IX

Cul

tivat

edM

onks

hood

Aco

nitu

m c

olum

bian

umR

anun

cula

ceae

FN

XX

XM

oist

to w

et m

eado

ws,

ope

n m

oist

fore

st, a

long

stre

ams;

up

to s

ubal

pine

Mou

ntai

n m

ahog

any,

cur

l-le

af a

nd tr

ue

Cer

coca

rpus

ledi

foliu

s,

C. m

onta

nus

Ros

acea

eS

NX

XX

Ston

y sl

opes

, cliff

s, ro

ck o

utcr

ops,

on

limes

tone

or

sand

ston

e, o

pen

pine

fore

st

Nig

htsh

ade

Sol

anum

spp

.So

lana

ceae

FN

, IX

XX

XX

Rip

aria

n fo

rest

s, w

oodl

ands

, thi

cket

s, g

rass

land

s, p

astu

res,

al

ong

stre

ams,

dis

turb

ed s

oils

, ditc

hes,

road

side

s, fe

nces

, fa

rmya

rds,

cul

tivat

ed fi

eld

edge

Oni

onA

llium

spp

.Li

liace

aeF

NX

XX

XX

XM

any

spec

ies

in M

T an

d W

Y th

at v

ary

in h

abita

t; gr

assl

ands

, sag

ebru

sh s

tepp

e, o

pen

fore

st, m

eado

ws,

w

oodl

ands

, thi

cket

s, ri

paria

n ar

eas,

rock

out

crop

s; a

ll el

evat

ions

Tabl

e 3,

(con

t.)

- 38 -

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Pens

tem

onP

enst

emon

spp

.Sc

roph

ular

iace

aeF

NX

XX

XX

XSa

ndy,

rock

y or

wel

l-dra

ined

soi

l; gr

assl

ands

, sag

ebru

sh

step

pe, r

ock

outc

rops

, ope

n fo

rest

and

woo

dlan

ds,

road

cuts

, mea

dow

s; a

ll el

evat

ions

Phea

sant

’s e

yeA

doni

s ae

stiv

alis

Ran

uncu

lace

aeF

IX

XEs

cape

d or

nam

enta

l pla

nt, w

eed

in c

ultiv

ated

fiel

ds,

past

ures

, roa

dsid

esPi

ne, p

onde

rosa

Pin

us p

onde

rosa

Pina

ceae

TN

XX

XX

Drie

r for

ests

, roc

ky e

xpos

ures

ass

ocia

ted

with

gra

ssla

nds

Prin

cesp

lum

eS

tanl

eya

pinn

ata

Bras

sica

ceae

FN

XX

XX

Cla

y so

il an

d dr

y, s

elen

ium

-ric

h so

il on

ope

n sl

opes

, bar

ren

hills

and

flat

s, s

tream

bank

s, b

adla

nds

Punc

ture

vine

Trib

ulus

terr

estri

sZy

goph

ylla

ceae

FI

XX

XD

ry, s

andy

or g

rave

lly s

oil o

f stre

amba

nks,

pas

ture

s,

road

side

s, w

aste

are

asPu

rsla

neP

ortu

laca

ole

race

aPo

rtula

cace

aeF

IX

XR

ich

dist

urbe

d so

il of

farm

yard

s, w

aste

are

as, c

ultiv

ated

fie

lds

Red

root

pig

wee

dA

mar

anth

us re

trofle

xus

Che

nopo

diac

eae

FN

XX

XX

XC

ultiv

ated

fiel

ds, r

oads

ides

, stre

amba

nks,

was

te a

reas

Ree

d ca

nary

gras

sP

hala

ris a

rund

inac

eaPo

acea

eG

IX

XX

Stre

amba

nks,

ditc

h ba

nks,

wet

land

s, m

ostly

at l

ower

to

mid

dle

elev

atio

ns.

Rye

gras

s,

pere

nnia

lLo

lium

per

enne

Poac

eae

GI

XD

istu

rbed

site

s, ro

adsi

des,

trai

l sid

es, a

nd n

ewly

pla

nted

la

wns

Sage

, lan

cele

afS

alvi

a re

flexa

Lam

iace

aeF

NX

XX

XD

istu

rbed

are

as, r

oads

ides

, fiel

ds, p

astu

res,

and

was

te

area

sSa

ge, s

and

and

fring

ed s

age

Arte

mis

ia fi

lifol

ia,

A. f

rigid

a As

tera

ceae

SN

XX

XM

any

spec

ies

in M

T an

d W

Y th

at v

ary

in h

abita

t; St

ony

or s

andy

soi

ls o

f gra

ssla

nds,

sag

ebru

sh s

tepp

e, o

pen

mea

dow

s, c

onife

rous

woo

dlan

dsSa

gebr

ush,

big

Arte

mis

ia tr

iden

tata

Aste

race

aeS

NX

XX

XX

XD

eep

soils

of s

ageb

rush

ste

ppe,

ste

ep o

pen

slop

es, d

ry

plai

ns a

nd h

illsi

des;

val

leys

to s

ubal

pine

Sa

gew

ort,

gree

n an

d w

hite

Arte

mis

ia d

racu

ncul

us,

A. l

udov

icia

naAs

tera

ceae

FN

XX

XX

XX

XG

rass

land

s, m

eado

ws,

sag

ebru

sh s

tepp

e, s

tream

bank

s,

road

side

s, ta

lus

slop

esSa

ltbus

hA

tripl

ex s

pp.

Che

nopo

diac

eae

SN

XX

XX

XU

sual

ly o

n al

kalin

e or

sal

ine

soil

of s

ageb

rush

ste

ppe,

gr

assl

ands

, bad

land

sSc

otch

bro

omC

ytis

us s

copa

rius

Faba

ceae

SI

MX

XM

oist

road

side

sSc

ram

bled

egg

sC

oryd

alis

aur

eaFu

mar

iace

aeF

NX

XX

XX

Moi

st, o

pen

fore

sts,

dis

turb

ed a

reas

; val

leys

to s

ubal

pine

Serv

iceb

erry

Am

elan

chie

r aln

ifolia

Ros

acea

eS

NX

XX

XX

XM

oist

to d

ry fo

rest

s, g

rass

land

s, m

eado

ws,

woo

dlan

ds,

stre

amba

nks,

ava

lanc

he s

lope

s; v

alle

ys to

low

er s

ubal

pine

Snak

ewee

dG

utie

rrez

ia s

arot

hrae

Aste

race

aeF

NX

XX

XX

Sage

brus

h st

eppe

, gra

ssla

nds,

juni

per w

oodl

ands

, ba

dlan

ds, p

astu

res;

val

leys

to s

ubal

pine

Tabl

e 3,

(con

t.)

- 39 -

1 G =

gra

ss /

gram

inoi

d / g

rass

-like

, F =

forb

/ br

oadl

eaf p

lant

, S =

shr

ub, T

= tr

ee

2 N

= N

ativ

e, I

= In

trodu

ced

to M

onta

na a

nd W

yom

ing

3 Sta

te-li

sted

nox

ious

wee

d in

Mon

tana

(M),

Wyo

min

g (W

), or

bot

h (B

).

Plan

t Spe

cies

Scie

ntifi

c N

ame(

s)Pl

ant F

amily

Lifeform1

Native2

Noxious3

Hab

itat

Hab

itat D

escr

iptio

n

Mountains

Foothills

Shrubland

Plains

Valleys

Wet Areas

Cropland

Disturbed

Snee

zew

eed

Hym

enox

ys h

oope

sii

Aste

race

aeF

NX

Moi

st s

lope

s an

d w

ell-d

rain

ed m

eado

ws;

up

to s

ubal

pine

Sorg

hum

s, fo

rage

, gr

ain,

sor

ghum

-su

dang

rass

, su

dang

rass

Sor

ghum

bic

olor

, S

. x d

rum

mon

dii,

S. b

icol

or v

ar.

suda

nene

se

Poac

eae

GI

XC

ultiv

ated

, rar

ely

esca

ping

Sorr

elO

xalis

spp

.O

xalid

acea

eF

N, I

XX

XX

XO

pen

fore

sts,

pra

iries

, fiel

ds, s

tream

bank

s, w

aste

are

as

St. J

ohns

wor

tH

yper

icum

per

fora

tum

Clu

siac

eae

FI

BX

XX

XG

rass

land

, ope

n fo

rest

, pas

ture

s, m

eado

ws,

road

side

s,

dist

urbe

d ar

eas

Suck

leya

, poi

son

Suc

kley

a su

ckle

yana

Che

nopo

diac

eae

FN

XX

XSp

arse

ly v

eget

ated

soi

l of r

eced

ing

lake

s an

d po

nds

or fl

ood

area

s, c

ultiv

ated

fiel

dsSu

nflow

er

Hel

iant

hus

spp.

Aste

race

aeF

N, I

XX

XX

XD

istu

rbed

soi

l of fi

elds

, gra

ssla

nds,

rang

elan

d, s

tream

bank

s,

wet

mea

dow

s, th

icke

ts, r

oads

ides

, cul

tivat

ed fi

elds

Sw

eetc

love

r, ye

llow

and

whi

teM

elilo

tus

offici

nalis

Faba

ceae

FI

XX

XX

XR

oads

ides

, fiel

ds, s

tream

bank

s, g

rass

land

s, ra

ngel

and,

op

en s

lope

s in

bad

land

sS

wee

tpea

Lath

yrus

spp

.Fa

bace

aeF

NX

XX

XX

Roa

dsid

es, fi

elds

, thi

cket

s, m

eado

ws,

moi

st a

reas

, ope

n as

pen

or p

ine

fore

stTa

nsy,

com

mon

Tana

cetu

m v

ulga

reAs

tera

ceae

FI

BX

XX

XM

oist

dis

turb

ed m

eado

ws,

alo

ng s

tream

s an

d di

tche

s Ta

nsy

mus

tard

Des

cura

inia

pin

nata

Bras

sica

ceae

FN

XX

XX

XX

Gra

ssla

nds,

cul

tivat

ed fi

elds

, roa

dsid

es, w

aste

are

asTa

nsy

ragw

ort

Sen

ecio

jaco

baea

Aste

race

aeF

IM

XX

XD

istu

rbed

soi

l of o

pen

fore

st, m

eado

ws,

pas

ture

s, o

ften

asso

ciat

ed w

ith ti

mbe

r har

vest

or fi

reTe

ffE

ragr

ostis

tef

Poac

eae

GI

XC

ultiv

ated

, rar

ely

esca

ping

This

tle, C

anad

aC

irsiu

m a

rven

seAs

tera

ceae

FI

BX

XX

XX

XX

Moi

st d

istu

rbed

soi

ls o

f fiel

ds, m

eado

ws,

thic

kets

, roa

dsid

es,

woo

dlan

ds, o

pen

fore

st, s

tream

bank

s, w

etla

nds

This

tle, R

ussi

anS

also

la tr

agus

Aste

race

aeF

IX

XX

XD

ry d

istu

rbed

soi

ls o

f roa

dsid

es, c

ultiv

ated

fiel

ds, d

ry la

ke

beds

, was

te a

reas

Toba

cco,

coy

ote

Nic

otia

na a

ttenu

ata

Sola

nace

aeF

NX

XX

XX

Sand

y or

gra

velly

soi

l of s

tream

bank

s, h

ills,

railr

oad

right

-of-

way

, was

te a

reas

Vetc

h, h

airy

Vic

ia v

illos

aFa

bace

aeF

IX

XX

Roa

dsid

es, c

ultiv

ated

fiel

ds, g

rass

land

sW

hite

top

Car

daria

dra

baBr

assi

cace

aeF

IB

XX

XX

XX

XX

Fiel

ds, r

oads

ides

, stre

amba

nks

Yello

w s

tarth

istle

C

enta

urea

sol

stiti

alis

Aste

race

aeF

IB

XX

XX

XFi

elds

, gra

ssla

nds,

road

side

s, d

istu

rbed

are

asYe

wTa

xus

brev

ifolia

Taxa

ceae

SN

XX

XX

Wet

fore

st, h

umid

env

ironm

ents

, usu

ally

on

acid

soi

ls

Tabl

e 3,

(con

t.)

Resources and ReferencesCarlson, M. and B. Anderson. 2013. Cyanide Poisoning, University of Nebraska Lincoln Extension

NebGuide G2184, Lincoln, NE. Available at: http://extensionpubs.unl.edu/

Cornell University. 2007. Brown midrib sorghum sudangrass: successfully growing a high energy grass for dairy cows. Cornell University Cooperative Extension, Agronomy Fact Sheet Series 14, Ithaca, NY. Available at: http://nmsp.cals.cornell.edu/publications/factsheets/factsheet14.pdf

Dorn, R.D. 2001. Vascular Plants of Wyoming. Mountain West Publishing, Cheyenne, WY.

Drewnoski, M., B. Anderson, P. Kononoff, and B. Reynolds. 2019. Nitrates in Livestock Feeding. University of Nebraska Extension NebGuide G1779, Lincoln, NE. Available at: http://extensionpubs.unl.edu/

Forero, L., G. Nadar, A. Craigmill, J. DiTomaso, B. Puschner, and J. Maas. 2010. Livestock-Poisoning Plants of California. University of California Agricultural and Natural Resources Publication 8398, Davis, CA. Available at: https://anrcatalog.ucanr.edu/

Gadberry, S. and J. Jennings. 2016. Nitrate Poisoning in Cattle. University of Arkansas Division of Agriculture Research and Extension, FSA3024, Little Rock, AR. Available at: https://www.uaex.edu/publications/

Glunk, E., K. Olson-Rutz, M. King, D. Wichman, and C. Jones. 2015. Nitrate Toxicity of Montana Forages. Montana State University Extension MontGuide MT200205AG, Bozeman, MT. Available at: https://store.msuextension.org/

Green, B.T., K.D. Welch, J.A. Pfister, C.G. Chitko-McKown, D.R. Gardner, and K.E. Panter. 2014. Mitigation of larkspur poisoning on rangelands through the selection of cattle. Rangelands 36(1):10-15.

Green, B.T., D.R. Gardner, D. Cook, J.A. Pfister, K.D. Welch, and J.W. Keele. 2018. Age-dependent intoxication by larkspur (Delphinium) in Angus steers. Toxicon 152:57-59.

James, L.F., D.B. Nielsen, and K.E. Panter. 1992. Impact of poisonous plant on the livestock industry. Journal of Range Management 45(1):3-8.

Knight, A.P. and R.G. Walter. 2001. A Guide to Plant Poisoning of Animals in North America. International Veterinary Information Service, Ithaca, NY.

Leininger, W., J. Taylor, and C. Wambolt. 1977. Poisonous Range Plants of Montana. Montana State University Cooperative Extension Service Bulletin 348. Montana State University, Bozeman, MT.

Lesica, P. 2012. Manual of Montana Vascular Plants. Brit Press, Fort Worth, TX.

Majak, W., B. Brooke, and R. Ogilvie. 2008. Stock-poisoning Plants of Western Canada. Government of Canada, Agriculture Canada.

Montana Department of Agriculture. 2019. Montana state-listed noxious weeds. Montana Department of Agriculture, Noxious Weeds Program, Helena, MT. Available at: https://agr.mt.gov/Weeds

Montana State University, Schutter Diagnostic Lab, 119 Plant BioScience Building, P.O. Box 173150, Bozeman, MT 59715-3150. (406) 994-5150 [email protected] Website: http://diagnostics.montana.edu/

Panter, K., M.H. Ralphs, J. Pfister, D. Gardner, B. Stegelmeier, S. Lee, K. Welch, B. Green, T. Davis, and D. Cook. 2011. Plants Poisonous to Livestock in the Western States. U.S. Department of Agriculture, Agricultural Research Service, Agriculture Bulletin 415, Logan, UT. Available at: https://www.ars.usda.gov/is/np/PoisonousPlants/PoisonousPlants.pdf

Pokorny, M. and J. Mangold. 2020. Montana’s Noxious Weeds. Montana State University Extension Service EB0159, Bozeman, MT. Available at: https://store.msuextension.org/

Sallenave, R. 2016. Water quality for livestock and poultry. New Mexico State University Cooperative Extension Service, Guide M-112, Las Cruces, NM. Available at: aces.nmsu.edu/pubs/_m/M112.pdf

Smith, M., J. Waggoner, and S. Sims. 2010. Larkspur: Managing grazing to avoid poisoning cattle. University of Wyoming Range Facts MP-111.13, Laramie, WY. Available at: http://www.wyoextension.org/publications/

Stonecipher C.A., D. Cook, K.D. Welch, D.R. Gardner DR, and J.A. Pfister. 2020. Seasonal variation in toxic steroidal alkaloids of foothill deathcamas (Zigadenus paniculatus). Biochemical Systematics and Ecology 90:104044.

Stonecipher C.A., K.D. Welch, S.T. Lee, D. Cook, and J.A. Pfister. 2020. Geographical and seasonal variation in water hemlock (Cicuta maculata) toxins. Biochemical Systematics and Ecology 89: 104012.

Stubbendieck, J., M. Carlson, C. Dunn, B. Anderson, and D. Redfearn. 2018. Nebraska Plants Toxic to Livestock, Including Bloat-Causing Plants, Rangeland, Pastureland, and Cropland. University of Nebraska Extension EC3037, Lincoln, NE. Available at: https://extensionpubs.unl.edu/

Taylor, J. E. and J. R. Lacey. 2004. Range Plants of Montana. Montana State University Extension Service Bulletin EB 122, Bozeman, MT. Available at: https://store.msuextension.org/

Texas A&M University. 2019. Plants of Texas Rangelands: Virtual Herbarium. Texas A&M AgriLife Extension System, Department of Ecosystem Science and Management, College Station, TX. Available at: https://rangeplants.tamu.edu/common-name-index/

USDA, NRCS. 2020. Cover Crops. Agronomy Technical Note MT-93. USDA-NRCS, Bozeman State Office, Bozeman, MT. Available at: https://www.nrcs.usda.gov/wps/portal/nrcs/mt/home/

USDA, NRCS. 2019. The PLANTS Database. National Plant Data Team, Greensboro, NC 27401-4901 USA. Available at: http://plants.usda.gov

Voss, J.L. 2019. Guide to Poisonous Plants. Colorado State University, College of Veterinary Medicine and Biomedical Sciences, Fort Collins, CO. Available at: https://csuvth.colostate.edu/poisonous_plants

Weathers, Shirley A. 1998. Field Guide to Plants Poisonous to Livestock: Western U.S. Rosebud Press, Fruitland, UT.

Whitson, T., L. Burrill, S. Dewey, D. Cudney, B. Nelson, R. Lee, and R. Parker. 2002. Weeds of the West. The Western Society of Weed Science, Newark, CA.

Wyoming Department of Agriculture. 2018. Wyoming state designated noxious weeds, Wyoming Department of Agriculture, Weed and Pest Program, Cheyenne, WY. Available at: http://wyagric.state.wy.us/divisions/ts/sections-a-programs/weed-a-pest

- 42 -

GlossaryAcute poisoning – Adverse effects from a substance

resulting either from a single exposure or from multiple exposures in a short period of time.

Alkaloid – Naturally occurring basic, organic, nitrogenous compounds.

Anemia – Deficiency of red blood cells or hemoglobin in the blood.

Ataxia – Loss of full control of bodily movements.

Bloat – A disease in livestock characterized by an accumulation of gas in the stomach. To make or become swollen with fluid or gas.

Cannabinoids –Psychoactive chemicals, obtained from plants of the Cannabis genus, that have toxic effects on the nervous system.

Chronic poisoning – Adverse effects from a substance result of a long-term exposure when toxins accumulate over time and damage is permanent.

Cicutoxin – An unsaturated alcohol which acts on the central nervous stimulant.

Colic – Severe, often fluctuating pain in the abdomen caused by intestinal gas or obstruction in the intestines.

Congenital – Existing at birth, but not hereditary.

Cotyledon – An embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed.

Cyanosis – Blue coloring of the lining of the mouth.

Cystitis – Inflammation of the bladder.

Dicoumarol – Toxic product synthesized from coumarin in moldy sweetclover.

DDMP – A complex compound (2,3-dihydro-3,5-dihydroxy-6-(H) -pyran-4-) that inhibits the dopamine transporter system of the brain affecting cranial nerves.

Edema – Excess of watery fluid collecting in the cavities or tissues of the body.

Endophyte – An organism, often fungi or bacteria, living within a plant between living plant cells. The relationship with the plant varies from symbiotic to bordering on pathogenic.

Fetal mummification – Shriveling or shrinkage of fetus by absorbing all fluid of fetus and uterus.

Forb – A broad-leaved herbaceous plant.

Furanocoumarins – Organic chemical compounds associated with photosensitivity through ingestion and direct contact with the skin. When the phytochemicals enter the nucleus of epithelial cells and form a bond with the DNA, it causes the cells to die resulting in the skin being unable to protect itself from sunlight.

Gallic Acid – A substance, occurring in a free state or combined as gallotannin, causing skin and mucosal irritation.

Glycoside – Any group of organic compounds occurring within plants that produce sugars and related substances upon hydrolysis.

Hemolysis – Rupture or destruction of red blood cells.

Hepatic – Relating to, affecting, associated with, supplying or draining the liver.

Hepatopathy – An abnormal or diseased state of the liver.

Hydrogen cyanide (HCN) – (also known as prussic acid) Extremely toxic, volatile, rapidly acting poison that inactivates cellular respiration by depriving cells of oxygen.

Hypericin – A phototoxin contained in pigment glands that fluoresce in the presence of sunlight and causes acute inflammation and necrosis of cells of the skin capillaries. Only white or unpigmented skin areas are affected. These areas itch and become red, swollen, and sore, and the skin may peel or come off in large sheets (photosensitization).

Hypertonic muscle – Too much muscle tone so that areas are stiff and difficult to move.

Irisin – A toxin chemical found in Iris rhizomes which can cause abdominal pain, burning sensation of the mouth and throat, and vomiting if ingested and mild skin irritation upon skin exposure.

Integumentary – The outer protective layer of an animal or plant. The integumentary system comprises the skin and its appendages (hair, hooves) which protect the body from damage.

Isocupressic acid –A diterpene acid that interferes with blood flow to the uterus and can induce abortion in cattle in the last three months of pregnancy.

Jaundice – Yellowing of the skin or whites of the eyes, caused by obstruction of the bile duct, liver disease, or excessive breakdown of red blood cells.

Laminitis – Inflammation of the sensitive layers of tissue inside the hoof in horses and other animals. It can cause extreme lameness.

- 43 -

Monoterpene – A class of terpenes produced in plants that often have a strong odor and may protect the plants.

Mycotoxin – A toxin produced by a fungus. Major classes of mycotoxins include aflatoxins, trichothecenes, fumonisins, zearalenone, ochratoxin, and ergot alkaloids.

Neurotoxic diterpenoid – Toxins, including andromedotoxin and grayanotoxin, present throughout the plant. Symptoms of poisoning include vomiting, depression, hypotension, irregular heartbeat, colic, convulsions, inability to coordinate voluntary muscles and recumbency.

Nitrotoxin – Neurotoxin compounds contained in some milkvetch species that are poisonous to cattle, sheep and horses with cattle being the most commonly affected. Symptoms of nitrotoxin poisoning include weakness (staggered gait, clicking of hooves while walking), ataxia, muscle tremors, depression, recumbency and death.

Oxalate – Poisonous salt of dibasic acid.

Petechial hemorrhage – Tiny pinpoint red mark caused when the body is deprived of oxygen.

Photophobia – Extreme sensitivity to light.

Photosensitivity – Light sensitivity causing abnormal skin reaction to direct sunlight exposure.

Photosensitization – Sensitization of the skin to light. The development of an abnormal capacity to react to sunlight typically by edematous swelling and dermatitis.

Plains – Plains and valleys are the lowest elevation habitat in a given area. Plains are influenced by the Great Plains which generally have more growing season precipitation than valleys.

Poison – A substance that can cause the illness or death of a living organism when introduced or absorbed. Synonym: toxin; Adjective: poisonous.

Prostration – Lying stretched out on the ground.

Prussic acid – (also known as hydrogen cyanide) Extremely toxic, volatile, rapidly acting poison that inactivates cellular respiration by depriving cells of oxygen.

Rectal prolapse – Rectal walls have prolapsed to a degree where they protrude out the anus and are visible outside the body.

Recumbency – Laying down, unable to walk or remain standing.

Renal – Relating to the kidneys.

Rumen stasis – Collapse of ruminal function, cessation of normal rhythmic contractions for more than two minutes.

Selenium – An essential trace nutrient for animals. In certain plants it accumulates to levels that are toxic to livestock when those plants are growing in selenium-rich soils.

Sesquiterpene lactone – A terpene (sesquiterpene) containing a lactone ring. It can cause allergenic (irritate eyes, nose, gastrointestinal tracts) or neurotoxic (necrosis or death of neural tissue) effects.

Sulfate – A salt or ester of sulfuric acid. Animals consuming plants with high levels of sulfate will reduce sulfate to hydrogen sulfide in the rumen resulting in degenerative changes in the brain causing depression, blindness or death.

Tannic acid – A form of tannin that is a weak acid and a type of polyphenol found in some plants.

Tannin – A bitter-tasting organic substance present in some galls, barks, and other plant tissue.

Teratogen – A chemical or agent (e.g. alkaloid) which crosses the placenta and interferes with embryo or fetus development producing an embryonic or fetal defect. Extent of the defect depends on the teratogen and the stage of development.

Tetany – A stimulated neuromuscular activity caused by deficiencies of calcium and/or magnesium.

Tetradymol – A sesquiterpene that is a liver toxin.

Thiaminase – An enzyme that produces thiamin (vitamin B1) deficiency in livestock by destroying ingested thiamine after ingestion and reducing thiamine availability. Thiamin deficiency results in retinal degeneration, blindness, depression, weight loss, and hemorrhaging syndrome.

Thujone – A ketone and monoterpene, which occurs naturally, has a menthol odor, and may cause effects resembling epilepsy.

Toxin – A substance produced by a living organism that is poisonous to another living organism. Synonym: poison; Adjective: toxic.

Valley – Valley and plains are the lowest elevation habitats in a given area. Valleys are generally in mountainous areas and rain-shadows.

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Plants Poisonous to Livestock in Montana and Wyoming

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