TRACE ELEMENT DEFICIENCY IN RUMINANTS ENG · Trace elements and minerals are essential components...
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BRIEF COMMUNICATION: TRACE ELEMENT DEFICIENCY IN RUMINANTS VETLAB www.pathcarevetlab.co.za Introduction: Trace elements and minerals are essential components of complete rations in sheep, goats and cattle. A complex interaction exists between the trace elements [copper (Cu), iron (Fe), selenium (Se), zinc (Zn), molybdenum (Mo), cobalt (Co) and iodine (I)]. Macro-elements (minerals) [(calcium (Ca), sodium (Na), chloride (Cl), potassium (K), phosphate (PO4), magnesium (Mg), and sulphur (S)] are also involved in these interactions. In this pamphlet the elements involved in the more common problems will be discussed briefly. Before discussing the trace elements, the following should be considered: The need for trace elements is influenced by factors in the individual animal (e.g. age and production status), in the feed and/or grazing, in the water supply, the time of the year and the management. In some parts of the country the soil (and therefore the plants) will be deficient or have excess of some of the elements. It is essential for the veterinary surgeon and the farmer to be aware of what the status of macro- and micro- elements on the particular farm or in the area is. Before consideration is given to possible trace element deficiencies, optimal rations must be ensured: e.g. unlimited access to clean fresh water, sufficient energy (carbohydrates and fat) and protein (good quality feed and pasture for the age of the animal, the developmental stage and reproductive status). The correct macro- and micro-elements should be supplemented in the ration when needed. Addition of trace elements to a ration should only be considered if the projected and actual production standards for the animals have not been met. A deficiency has to be identified and proved. Optimal nutrition is judged by the body scores at weaning, before breeding, before partus and at the end of the breeding season. Macro-minerals: Calcium and phosphorous – plant leaves are usually high in calcium and low in phosphorous. Seeds have higher phosphorous and lower calcium. Low quality pasture tends to be low in phosphorous. If fed low quality hay with no seeds (grain), phosphorous should be supplemented. If corn silage or feeds with cereal grains are fed, these may be low in calcium. Sulphur – this is a major antagonist of selenium and copper. Magnesium – can be deficient in pastures. Magnesium is poorly absorbed from rations and grazing. This mineral is involved in basic cell metabolism and deficiency leads to “tetany”. Sodium chloride - ruminants need sodium chloride (salt) to remain thrifty, make economical weight gains and reproduce. Trace elements: Factors that influence the trace element concentration in plants include fresh or dried plant material, soil pH, soil texture, and the different types of plants as well as the stage at which the plants are harvested, for example: The trace elements that may play an important role in ruminants are: SELENIUM (Se): Selenium deficiency is a widespread problem in South Africa, especially along the coastal areas and on pastures. Selenium values in the body and feed is intimately linked to vitamin E. High rainfall leads to selenium deficiency in the soil and plants. Green feed and seeds are the major sources of vitamin E. Vitamin E content of plants may fall very rapidly during periods of drought. Vitamin E is poorly stored in the body and the animals must have daily intake of adequate amounts of selenium. (If there is an increase in the pH of the soil (alkaline), the uptake of selenium in the plants is increased. Increased selenium uptake is also due to poor drainage of pastures). CLINICAL SIGNS: Sheep: Selenium and vitamin E act as anti-oxidants in the body and remove free radicals produced during metabolism. The most frequent clinical sign of selenium deficiency is white muscle disease – also known as nutritional myopathy or stiff lamb disease. This is seen in lambs of 2 – 6 weeks old. It appears that stress factors (handling, shearing and parasites) may precipitate selenium deficiency. In reproduction selenium deficiency leads to reduced sperm motility in rams. In ewes, cystic ovaries with low fertility, retained placenta and foetal membranes may occur. The quality of the colostrum is also reduced. Cattle: White muscle disease can be found in suckling calves. They also show ill-thrift. In cows, reduced milk volume, reduced conception rates and retained placentas. Mastitis may also be seen. COPPER (Cu): If pasture copper levels are adequate for plant growth it will be high enough for livestock. (Excess iron (Fe), molybdenum (Mo) and sulphur (S) in the soil will reduce availability of copper to ruminants). Poor drainage of pastures will reduce copper availability to the plants. CLINICAL SIGNS: Sheep: Copper deficiency leads to wool abnormalities (steely wool and depigmentation), anaemia, scouring and ill-thrift, increased bone fragility (lower mineral content), and infertility (delay or suppression of oestrus, abortions and foetal death). Unweaned lambs develop swayback (enzootic ataxia). Goats: The main effect of copper deficiency is on the reproduction of goats where decreased conception rates, abortions, mummified foetuses and necrotic placentitis are seen. (Goats are less susceptible to copper toxicity than sheep). Cattle: Clinical signs include coat colour changes (spectacles around the eyes, grey or brownish tinge instead of black), rough coats, reduced production of milk, anaemia, scouring in calves especially when molybdenum is increased in the diet. In adult cattle sudden death, known as “falling disease” may be seen. It is important to realise that copper requirement in cattle is higher than the requirement in sheep. www.pathcarevetlab.co.za Grass (eg. perennial rye grass) Hay Legumes and herbs Mealie (corn) silage deficiencies including P, K, S, Cu, Zn and Mg. lower mineral content than in silage. higher mineral content than grass. higher in phosphorous and lower in Ca. - - - - Compiled by: Dr Lucia Lange PathCare VetLab
Transcript of TRACE ELEMENT DEFICIENCY IN RUMINANTS ENG · Trace elements and minerals are essential components...
BRIEF COMMUNICATION: TRACE ELEMENT DEFICIENCY IN RUMINANTS
VETLAB
www.pathcarevetlab.co.za
Introduction:Trace elements and minerals are essential components of complete rations in sheep, goats and cattle. A complex interaction exists between the trace elements [copper (Cu), iron (Fe), selenium (Se), zinc (Zn), molybdenum (Mo), cobalt (Co) and iodine (I)]. Macro-elements (minerals) [(calcium (Ca), sodium (Na), chloride (Cl), potassium (K), phosphate (PO4), magnesium (Mg), and sulphur (S)] are also involved in these interactions.
In this pamphlet the elements involved in the more common problems will be discussed briefly.
Before discussing the trace elements, the following should be considered:
The need for trace elements is influenced by factors in the individual animal (e.g. age and production status), in the feed and/or grazing, in the water supply, the time of the year and the management. In some parts of the country the soil (and therefore the plants) will be deficient or have excess of some of the elements. It is essential for the veterinary surgeon and the farmer to be aware of what the status of macro- and micro-elements on the particular farm or in the area is. Before consideration is given to possible trace element deficiencies, optimal rations must be ensured: e.g. unlimited access to clean fresh water, sufficient energy (carbohydrates and fat) and protein (good quality feed and pasture for the age of the animal, the developmental stage and reproductive status). The correct macro- and micro-elements should be supplemented in the ration when needed. Addition of trace elements to a ration should only be considered if the projected and actual production standards for the animals have not been met. A deficiency has to be identified and proved. Optimal nutrition is judged by the body scores at weaning, before breeding, before partus and at the end of the breeding season.
Macro-minerals:Calcium and phosphorous – plant leaves are usually high in calcium and low in phosphorous. Seeds have higher phosphorous and lower calcium. Low quality pasture tends to be low in phosphorous. If fed low quality hay with no seeds (grain), phosphorous should be supplemented. If corn silage or feeds with cereal grains are fed, these may be low in calcium. Sulphur – this is a major antagonist of selenium and copper.Magnesium – can be deficient in pastures. Magnesium is poorly absorbed from rations and grazing. This mineral is involved in basic cell metabolism and deficiency leads to “tetany”. Sodium chloride - ruminants need sodium chloride (salt) to remain thrifty, make economical weight gains and reproduce.
Trace elements:Factors that influence the trace element concentration in plants include fresh or dried plant material, soil pH, soil texture, and the different types of plants as well as the stage at which the plants are harvested, for example:
The trace elements that may play an important role in ruminants are:
SELENIUM (Se):Selenium deficiency is a widespread problem in South Africa, especially along the coastal areas and on pastures.
Selenium values in the body and feed is intimately linked to vitamin E. High rainfall leads to selenium deficiency in the soil and plants. Green feed and seeds are the major sources of vitamin E. Vitamin E content of plants may fall very rapidly during periods of drought. Vitamin E is poorly stored in the body and the animals must have daily intake of adequate amounts of selenium. (If there is an increase in the pH of the soil (alkaline), the uptake of selenium in the plants is increased. Increased selenium uptake is also due to poor drainage of pastures).
CLINICAL SIGNS:Sheep:Selenium and vitamin E act as anti-oxidants in the body and remove free radicals produced during metabolism. The most frequent clinical sign of selenium deficiency is white muscle disease – also known as nutritional myopathy or stiff lamb disease. This is seen in lambs of 2 – 6 weeks old. It appears that stress factors (handling, shearing and parasites) may precipitate selenium deficiency. In reproduction selenium deficiency leads to reduced sperm motility in rams. In ewes, cystic ovaries with low fertility, retained placenta and foetal membranes may occur. The quality of the colostrum is also reduced.
Cattle:White muscle disease can be found in suckling calves. They also show ill-thrift. In cows, reduced milk volume, reduced conception rates and retained placentas. Mastitis may also be seen.
COPPER (Cu):If pasture copper levels are adequate for plant growth it will be high enough for livestock. (Excess iron (Fe), molybdenum (Mo) and sulphur (S) in the soil will reduce availability of copper to ruminants). Poor drainage of pastures will reduce copper availability to the plants.
CLINICAL SIGNS:Sheep:Copper deficiency leads to wool abnormalities (steely wool and depigmentation), anaemia, scouring and ill-thrift, increased bone fragility (lower mineral content), and infertility (delay or suppression of oestrus, abortions and foetal death). Unweaned lambs develop swayback (enzootic ataxia).
Goats:The main effect of copper deficiency is on the reproduction of goats where decreased conception rates, abortions, mummified foetuses and necrotic placentitis are seen. (Goats are less susceptible to copper toxicity than sheep).
Cattle:Clinical signs include coat colour changes (spectacles around the eyes, grey or brownish tinge instead of black), rough coats, reduced production of milk, anaemia, scouring in calves especially when molybdenum is increased in the diet. In adult cattle sudden death, known as “falling disease” may be seen. It is important to realise that copper requirement in cattle is higher than the requirement in sheep.
www.pathcarevetlab.co.za
Grass (eg. perennial rye grass)
Hay
Legumes and herbs
Mealie (corn) silage
deficiencies including P, K, S, Cu, Zn and Mg.lower mineral content than in silage.higher mineral content than grass.higher in phosphorous and lower in Ca.
-
-
-
-
Compiled by: Dr Lucia Lange PathCare VetLab
VETLAB
www.pathcarevetlab.co.za
COBALT (Co):If the soil is alkaline (increased pH) the uptake of cobalt by plants is decreased. Poor paddock drainage increases cobalt uptake by the plants. Cobalt deficiency in pastures may also be due to high rainfall and leaching (also intensively cropped land and pastures).
CLINICAL SIGNS:Sheep:Cobalt deficiency is characterised by unthrifty sheep with weeping eyes, anorexia, decreased growth and lactation. Wool production is also affected (fragile wool fibres that easily break). Anaemia may be seen. In certain parts, “white liver disease”. Severe liver pathology leads to CNS signs characterised by depression, head pressing, aimless wandering. Cobalt deficiency also leads to increased susceptibility to infections.
Cattle:Cobalt deficiency causes wasting in cattle with increased susceptibility to parasites and diseases. (“Duinetering” is a condition encountered in the duned areas of the Southern Cape). Cattle less commonly develop cobalt deficiency than sheep.
MOLYBDENUM (Mo):The molybdenum content increases in plants that grow in alkaline soils. The increased molybdenum causes a secondary copper deficiency (molybdenum binds with copper and sulphur in the rumen and forms insoluble complexes (chelates) that are not available to the animal). They also interact with sulphur. In acidic soils molybdenum in the plants is decreased. CLINICAL SIGNS:These are usually associated with secondary copper deficiency.
ZINC (Zn):Zinc is linked to vitamin A synthesis in the metabolism of the animal. Sheep can store vitamin A in the liver in sufficient quantities for a 6-month period.
Zinc is involved in the integrity of collagen fibres, red blood cell fragility, epithelial surfaces, metabolism of essential fatty acids, carbohydrate and protein metabolism. Zinc deficiency has a direct effect on the cell growth of the testis and the ovaries. It affects reproduction due to reduced spermatogenesis and suppression of the secondary sex organs. This leads to reduced fertility and low conception rates. (In goats zinc deficiency causes parakeratosis).
In both sheep and in goats, zinc deficiency predisposes to conditions such as foot rot.
DIAGNOSIS:
SAMPLES FOR ANIMAL TESTING (Trace elements):Serum:The following elements can be tested in serum: copper, iron, and zinc and vitamin B12 (cobalt)
EDTA or heparin blood:This is used for testing of selenium in blood.
At least 10 samples of serum and EDTA should be submitted from animals with suspected trace element deficiencies. This will give an indication of the overall trace element status in the animals.
It is also important to remember that cobalt or vitamin B12 values in the blood increases with stress and if sheep are confined, the samples must be taken as soon as possible otherwise false elevated values will be found.
Liver:The trace elements that can be tested on liver samples include copper, molybdenum, selenium, zinc, iron, and magnesium. The liver samples can be fixed in 10% buffered formalin before submission to the laboratory.
Formalin samples:Pathology samples can be submitted from the central nervous system of sheep with suspected copper deficiency especially where swayback clinical signs are present. The spinal cord as well as the brain should be submitted.White muscle disease can be identified on histology when lesions are visible within the muscles and heart.Parkeratosis of the skin and epithelial surface can be seen in zinc deficiency.Liver samples to give an indication of possible cobalt deficiency.
SOIL TESTS:Remember to adjust the results of trace element analysis to the soil type as well as the presence of antagonists or competing elements. The growth stage of plants and the season should also be taken into account. (Soil testing is an indirect testing method and of limited value in diagnosing trace element deficiencies in the animal).
PLANT TESTS:These are useful to determine the role of molybdenum and sulphur in suspected cases of copper deficiency. Care should be exercised in interpreting plant values to indicate cobalt and selenium deficiency in the animal.
Many of the clinical signs caused by trace element deficiencies are subtle and insidious and will only be noticed when deficiencies are severe.Animal tests are more useful than soil and plant tests in determining deficiency diseases. The results must be correlated with the history and clinical signs shown in the animals. Animal tests are useful to identify emerging trace element problems.
The most effective “test” in the field is response to treatment for marginal deficiencies.
BRIEF COMMUNICATION: TRACE ELEMENT DEFICIENCY IN RUMINANTS
www.pathcarevetlab.co.za
Compiled by: Dr Lucia Lange PathCare VetLab
For more information please contact:
The PathCare Vetlab, CAPE TOWN, +27 21 596 3636
