Mark Cathcart, Tina Horn, and Alana West

DairyModule 4: Feed and Nutrition

Objectives

In this module, you will learn the distinctive characteristics of a ruminant animal, the parts and functions of their digestive system, and their dietary

needs.

You will also learn about some ingredients used in a dairy cow’ feed ration.

Learning Objectives:• Cloverbud (ages 5-8) should:

• Know what a ruminant is• Be able to name 2 ruminant animals• Be able to distinguish the difference between a forage and a concentrate

• Junior (ages 9-13) should:• Be able to name the parts of the rumen• Be able to identify 3 ruminant animals• Know the difference between a forage and a concentrate and identify

examples of each• Senior (ages 14-18) should:

• Be able to name the parts of the rumen and their function• Know what determines the dietary needs of a dairy cow at different

stages of her life• Know the nutrients needed by a dairy cow

Nutrition Overview• Ruminants

• Parts of the ruminant stomach and their function• Feed/Rations

• Forages• Concentrates• Commodity Feeds• Supplemental Feeds• Vitamins and Minerals

• Total Mixed Rations

The RuminantWhy can a dairy cow eat grass, but other farm animals and

humans cannot?

Cows are RUMINANTS (mammals that can digest cellulose from plants and chew their cud).

Ruminants have a different type of digestive system; rather than a small stomach like people, cows have a very large, four-part

stomach.

Other ruminants include: sheep, goats, bison, buffalo, deer, antelopes, giraffes, and camels.

The Ruminant Stomach

These four specialized

compartments are populated by billions

of bacteria and protozoa

that enable cows to digest foods we could never eat!

Each of these compartments is responsible for helping to digest feed such as hay, silage, and grass.

RumenThe rumen is the largest stomach compartment, with a capacity of 40-50 gallons or 300 lbs. of feed!

Known as the fermentation vat, the rumen stores food and allows for fermentation of the feed.

Bacteria, fungi, and protozoa are types of microorganisms that live in the rumen and digest feed.

This compartment makes up 25% of the newborn calf’s stomach capacity and 80% of the mature cow’s stomach capacity.

ReticulumIt is also known as the honeycomb.

The closest stomach compartment to the heart.

Cows do not chew their food thoroughly. Therefore, foreign materials such as nails, stones, etc. can collect here. Sometimes this can causes a disorder known as traumatic gastritis or “hardware disease”.

Farmers often give their cows magnets to prevent the sharp metals from puncturing the heart.

OmasumThe omasum is also called manyplies.

The main function of the omasum is the dehydration of partially digested feed.

AbomasumThe abomasum is the enzyme and acid secreting portion of the ruminant stomach.

The abomasum is also called the true stomach, and is much like a human’s stomach.

Wondering how to remember the

compartments in the correct order? Hint: the are backwards alphabetically.

Now that we know she is a ruminant, how do we feed a dairy cow?

What we feed a dairy cow is called a ration. Rations are most often put together by a nutritionist. This is what a dairy cow needs in her diet (ration).

Protein VitaminsEnergy MineralsFiber Water

A Balanced Diet In order to properly calculate a dairy animal’s ration, many questions must be answered. What is her…?

Cow• Milk production level• Breed• Stage of lactation• Body condition• Current production (pounds, fat %, and protein %)

Calf• Age• Body condition• Average daily gain

(ADG) you want

Heifer• Age• Breed• Body condition• ADG• Is she pregnant? If

yes, how close is she to calving?

What is used to meet those nutritional needs?

Forages Concentrates

Forages are the vegetative portion of plants in a fresh, dried, or ensiled state.

Because a dairy cow is a ruminant, she can utilized forages to meet most of her nutritional needs.

Forages are the foundation of a dairy cow’s diet.

Forages provide fiber, protein, energy, vitamins, and minerals.

Corn Silage is the base forage for most rations.

Forages

Types of Forages

SilageHaylage

HayPasture

The type of forage used in a ration depends on the animal you are feeding, her nutritional requirements, and decisions

made by the dairyman.

Silage is the harvested whole plant that is stored and allowed to ferment.

The ensiling/fermentation process allows the forage to be kept and fed throughout the year.

Ensiling also increases the palatability (taste) and digestibility.

Corn silage is the most common forage base for lactating cows.

Silage

Ensiled or wrapped forage such as alfalfa, grass, or small grain.Small grains in SC: Rye, Wheat, Triticale and Barley

Haylage enables dairymen to put feed alfalfa and grasses up a higher moisture and protein content and can also allow them to take a crop off

when weather does not allow for proper drying time.

Often provides more protein and fiber than corn silage, but less energy and less feed.

Haylage

HayHay is the aerial (above ground) portion of a grass or legume that is cut

and cured for the purpose of feeding animals.

Legume Hay - high protein, nitrogen fixing forages - Alfalfa and Clover

Grass/Non-legume Hay - Timothy, Bermuda, Orchard grass, Fescue, Mixed(Commonly grown in South Carolina)

Advantages Feeding of HayHas 85% dry matter, and lots of fiber

Can be stored easily

PasturePasture is the base forage for most dairy heifers and beef cows.

Some dairy producers have adopted grazing in their milking herds to reduce costs and labor.

Advantages to pasture based dairiesHigh quality pasture provides an extremely

digestible source of protein and energy. Lower feed and labor cost.

Manure distribution

Disadvantages to pasture based dairiesInconsistent quality and quantity of feed

Difficult to balance rationEnergy utilized in traveling to lots

ConcentratesConcentrates are feeds often high in energy or protein and low in fiber.

Dairy Cows need concentrates to meet their dietary needs.

Concentrates make up for nutrients that forages may lack.

Energy Concentrates examples: Corn, barley, wheat, and oats

Protein Concentrates examples: Soybean meal, fish meal, peanut meal, distiller’s grain, and some bloodmeal

Corn Soybeans

By-Product FeedsThey most often are the by-product of a grain used for human consumption

such as the production of human foods, beverages, or fiber. By-product feeds are used to stretch feed supply, reduce feed cost, or

increase the appetite of the cow.Examples of Commodity Feeds: Wet and Dry Brewers Grain, Corn Gluten Feed, Cottonseed,

Distillers Grain, Potato Chips, Citrus Pulp, Cookie Meal, Candy, etc.

Whole Cottonseed

Citrus Pulp Pellets

Corn Gluten Feed

Supplemental FeedsSupplements have a specific reason and value in a ration. There are

many supplements, but the most popular are:

• Rumen Buffers (Yeast Cultures, Bicarbonate of Soda)• Help by reducing the acidity in the rumen • They can increase dry matter intake, rumen microbial protein production, and

fiber digestion, resulting in increased milk production and milkfat production. • Mold Inhibitors

• Added to feed to reduce the incidence of feed heating in the bunk and help prevent mold development

• Fat• Used to increase the energy density in a ration

MineralsMacrominerals

Generally required in relatively large quantitiesCalcium

Magnesium Potassium*

Sulfur Chlorine

Phosphorus Sodium

*Potassium is the mineral needed by the dairy cow in the largest quantity

Microminerals Also known as trace minerals

Required in relatively small quantitiesCobalt Iodine

Manganese Zinc

CopperIron

Selenium

Vitamins

The fat-soluble vitamins

Vitamin A* Vitamin D Vitamin EVitamin K

*Beta-carotene, found in most legumes and grasses, is a precursor of Vitamin A.

The water-soluble vitamins

B complex vitamins* and Vitamin C

*B complex vitamins:Thiamine (B1) Niacin (B3)

Choline Riboflavin (B2) Pantothenic Acid (B5)

Folic Acid (B9) Biotin (B7) B12

Vitamins are classified as either fat-soluble or water-soluble.

Total Mixed RationDairy cows are most often fed a Total Mixed Ration (TMR) which is a blend of all feedstuffs (forages & concentrates) in one feed.

Advantages of feeding a TMR include: • Eliminate selective feeding• Lower percent fiber needed in ration • Consistent ration • Easier to balance precisely • High dry matter intake • Fewer digestive upsets • Free-choice mineral not needed • Can feed a variety of by-products • Higher average milk production

Common Forage TermsCarbohydrates - the major source of energy in dairy cattle diets

Total Digestible Nutrients (TDN) – the measure of energy in a dairy cattle diets

Crude Fiber – the total fiber in a dairy cattle diets

Succulents – feeds high in moisture like silage, green chops, and wet by-product feeds

Author and for more informationTina Horn- Extension Associate- Clemson University Cooperative Extension Servicethorn@Clemson.edu

ReviewersMark Cathcart- Union County 4-H Agent- Clemson University Cooperative Extension ServiceAlana West- Newberry County 4-H Agent- Clemson University Cooperative Extension Service