Ruminant Nutrition for Graziers

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Ruminant Nutrition for Graziers

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  • 1. Ruminant Nutrition for Graziers A Publication of ATTRA - National Sustainable Agriculture Information Service • 1-800-346-9140 • www.attra.ncat.orgBy Lee Rinehart Cattle, sheep and goats have the ability to convert plant carbohydrates and proteins into availableNCAT Agriculture nutrients for human use, making otherwise unusable land productive. However, proper care of theSpecialist land and its grazing animals requires a sound understanding of ruminant nutrition. This publica-©2008 NCAT tion provides managers with tools and references to consider biological and climatological variables and make decisions that ensure the ecological and economic viability of a grass-based ruminant livestock operation.ContentsIntroduction ..................... 1The Value of GrasslandAgriculture ........................ 2Ruminant Physiology .... 4Nutrient Requirementsof Grazing Livestock........5Forage Resources andGrazing Nutrition ...........11Matching NutritionalRequirements ofLivestock to the ForageResource ............................13 Cattle. Photo courtesy of NRCS.Supplementing Proteinor Energy: When is itNecessary? ........................14Forage Sampling andProduction (Yield)Estimates............................15Plant Toxicity andGrazing-RelatedDisorders............................16GrazingManagement ...................16References.........................17 Sheep. Photo by Linda Coffey, NCAT. Goat. Photo courtesy of USDA.Resources ..........................18 Introduction This publication covers the basics of animal nutrition from a grazing perspective. Much of Grazing animals are very important to what we understand about livestock nutrition agriculture. Of course, they provide meat, has been developed from studies and expe- milk, and fi ber. But grazing animals also rience with confinement feeding operations,ATTRA—National SustainableAgriculture Information Service can be incorporated into a crop rotation where concentrated nutrients in the form ofis managed by the National Cen- to take advantage of nutrient cycling. They grain, oilseed products, and harvested for-ter for Appropriate Technology(NCAT) and is funded under a can be utilized to control weeds or to ages are delivered to animals in a drylot.grant from the United States harvest crop residues. Grazing animals These types of practices leave out many ofDepartment of Agriculture’s RuralBusiness-Cooperative Service. can also be an added source of income, the biological and climatological variablesVisit the NCAT Web site (www.ncat.org/sarc_current. diversifying farm enterprises and thereby that accompany grazing situations: plantphp) for more informa- rendering a farm more sustainable from an species, forage stage of maturity, soil fertil-tion on our sustainableagriculture projects. economic point of view. ity and water holding capacity, annual and
  • 2. seasonal precipitation and mean temper- shrubs, trees) are not readily usable (from a ature, etc. As they plan for the nutritional digestive standpoint) by humans. needs of their grazing animals, graziers need However, grassland ecosystems (both to take each of these variables into consid- rangeland and temperate grasslands) pro- eration. This publication provides livestock duce plant materials that are highly digest- managers with the tools and references to consider all the variables and make informed ible to ruminant animals. Ruminant refers decisions that ensure the ecological and eco- to grazing animals that have the ability to nomic viability of a livestock operation. digest and metabolize cellulose, or plant fi ber, and ferment it to form the volatile A ranching operation can appropriately fatty acids and microbial proteins that the be thought of as a forage production and animal can then digest and use. This is of utilization enterprise. Ranchers are in the particular importance to the sustainability business of converting sunlight, water, and of agricultural production systems because carbon dioxide into a high-quality human grasslands and rangelands have the capac- food source. (Lalman, 2004a) Grasslands ity to produce millions of tons of this energy and rangelands occupy a large proportion source. Grazing of native and introduced of the U.S. land area. These ecosystems are forages on grasslands and rangeland thus is naturally able to capture sunlight and con- a very efficient way of converting otherwise vert it into food energy for plants. Humans non-digestible energy into forms available have harvested plant energy for thousands for human use: milk, meat, wool and other of years—since the beginnings of agricul- fibers, and hide. ture. Literally millions of tons of plant- derived food energy is harvested off arable lands each year in the United States. But The Value of Grassland most of the land in the U.S., and indeed Agriculture in most countries of the world, is not till- Forages are plants, either wild or tame, that able and is considered rangeland, forest, or are consumed as livestock feed. Grasses, desert. These ecosystems can be very pro- clovers and other forbs (broadleaf vascular ductive from a plant biomass perspective, plants), shrubs, and even some trees serve as but since they are generally non-farmable, forage for livestock, depending on the ecol- the plants they produce (grasses, forbs, ogy of the region. Arable land in the United States, or land that is capable of being culti- vated, accounts for only forty-three percent of Seven Principles of Ruminant Nutrition the country’s agricultural area (FAO, 2002). Arable cropland can be rotated into pasture 1. Ruminants are adapted to use forage because of microbes in their to take advantage of the soil-building char- rumen. acteristics of perennial grass ecosystems. 2. To maintain ruminant health and productivity, feed the rumen Also, perennial grasses tend to positively microbes, which in turn will feed the ruminant. affect water quality by serving as buffers in 3. Ruminant nutritional needs change depending on age, stage of riparian zones and increasing the water-hold- production, and weather. ing capacity of soils. Perennial grasses and 4. Adequate quantities of green forage can supply most —if not all— forbs as a component of annual cropping the energy and protein a ruminant needs. systems also help to reduce fuel and chemi- cal use, allowing some fields to be in pas- 5. Forage nutritional composition changes depending on plant ture or hayfield for several years between maturity, species, season, moisture, and grazing system. annual crop rotations. 6. Supplementation may be necessary when grass is short, too mature, dormant, or if animal needs require it (i.e., high-producing In North America, more than 50 per- dairy animal). cent of the land area is rangeland and thus potentially grazable. The topogra- 7. Excessive supplementation may reduce the ability of the rumen microbes to use forage. phy, soil characteristics, and water avail- ability in these ecosystems usually limitPage 2 ATTRA Ruminant Nutrition for Graziers
  • 3. ruminant livestock and wildlife, performing Soil Building Characteristics of Grassland Ecosystems symbiotic duties within the animal’s body. Animals occupy a niche and complete the Pastures help to increase organic matter and nutrient cycle by returning up to 90 percent humus in the soil, which results in: of ingested nutrients back to the soil in the • Granulation of soil particles into form of feces, urine, and their own bodies water-stable aggregates after death. Humans play an important role • Decreased crusting in this system as well. We engage in agri- • Improved internal drainage culture and derive food and fiber from the • Better water infiltration system for our consumption. • Fixation of atmospheric nitrogen Cattle, sheep, and goats have the ability to • Release of bound nutrients convert plant carbohydrates and proteins • Increased water and nutrient stor- into available nutrients for human use, age capacity and therefore render productive vast por- tions of otherwise unusable land. Grass- Source: Beetz, 2002 lands offer humans a nutritious supply of meat and milk. Many farmers and ranch-the kind of agriculture that can be devel- ers have changed production practicesoped on them to the grazing of livestock. to take advantage of this natural process,Livestock management on arid range- bypassing the energy intensive grain-fedlands has been extensively addressed by operations that have dominated Ameri-Allen Savory and Jody Butterfield of Holis- can livestock production for the past sev-tic Management International (www.holistic eral decades. Products from grass-finishedmanagement.org). Savory coined the term livestock are higher in omega-3 fatty acids“brittle environment” to denote ecosystems and conjugated lineolic acid than conven-that receive either low annual precipitation tionally raised counterparts. Additionally,or experience unpredictable and sporadic these products may reduce cholesterol andprecipitation. (Savory and Butterfield, 1998) reduce the incidence of certain types of can-These environments are usually character- cer. For more information on the nutritionalized by shallow soils, limited moisture, anddrought-tolerant perennial grasses, forbs, andshrubs. Brittle environments respond veryslowly to ecological disturbance. Savory hassuggested that the proper distribution, tim-ing, and intensity of grazing in these regionscan have a significant and positive effect onthe health of brittle environments. For moreinformation see the above website or contactATTRA at 800-346-9140.The principal attribute describing grass-land ecosystems and ruminant nutritionis interconnectivity. Grasslands and rumi-nant animals are intrinsically related, andpractices that impact one will necessarilyimpact the other. From the soil the systemderives water, nutrients, structural support,and temperature buffering. Soil popula-tions of microorganisms recycle nutrientsand make otherwise unavailable nutrientsavailable for plant uptake. Microorgan-isms also populate the rumens of grazing Photo courtesy of USDA, NRCS.www.attra.ncat.org ATTRA Page 3
  • 4. benefits of grass-based agriculture, visit The Role of Rumen Microorganisms Jo Robinson’s website www.eatwild.org. • Production of cellulase (to break down Ruminant Physiology fiber-rich plant material) Proper care of the land and its grazing • Synthesis of volatile fatty acids (used as animals requires a sound understanding of energy by the animal) ruminant nutrition. First we must under- • Synthesis of vitamins stand how a ruminant animal (cattle, sheep, goats) digests plant matter. • Synthesis of microbial protein Ruminant comes from the word “rumen,” which is the fi rst major compartment in cultivation. Cellulose is the portion of the plant the four-compartment stomach of the cow, structure that comprises the walls of the sheep, and goat. This structure is the plant’s cells, and is very fibrous and indi- “furnace” where microbial fermentation gestible. Monogastric (single-stomach, non- takes place. Millions of bacteria, proto- ruminant) animals do not have the ability to zoa, and fungi live in the rumen and break digest cellulose. Rumen microbes, however, down energy-rich plant parts, making produce cellulase, the enzyme that breaks them digestible for the host animal. After down the chemical bonds in cellulose, mak- the forage has been digested in the rumen ing it digestible to the microbe and, subse- and is broken down into small pieces, it quently, to the ruminant animal. can pass through the reticulum and oma- Another advantage of rumen fermentation sum, which function as strainers that keep is microbial synthesis of important vitamins large pieces of material from passing into and amino acids. All the vitamins the ani- the abomasum, or “true stomach,” where mal needs are synthesized by microorgan- digestion continues. From the abomasum isms, except vitamins A, D, and E. How- onward, the ruminant digestive system ever, animals fed high quality hay or green closely resembles other animal digestive pasture get their requirement of vitamins A systems with a small and large intestine, and E. Vitamin D is supplied through expo- colon, and anus. sure to sunlight, which is another advantage of pasture production. Amino acids are the Benefits of Ruminant Physiology building blocks of protein—a crucial nutri- As stated earlier, grazing anima ls ent for growth and reproduction in animals. have the ability to harvest and convert Rumen microbes synthesize these build- plant energy, especially cellulose, from ing blocks from ammonia, a by-product of grasslands and rangelands not suited to fermentation in the rumen. Given this fact, even poor quality forage can supply some protein for the grazing animal. Once it is understood how the rumen works to convert forage to digestible energy and protein, it becomes clear how important grazing animals are to the environment and, in turn, human culture. Grazing animals evolved with the prairies and ranges of the American West, the African steppes, and Mongolia and have contributed to the devel- opment of each specific ecological region. Without the ability to harvest plant energy from non-farmlands, humans would missPage 4 ATTRA Ruminant Nutrition for Graziers
  • 5. this crucial contribution to the local and Critical Components of Feed Qualityworld food supply. Grazing animals are thenecessary link between forages and people. Forage nutrient analysis can be a good tool to determine forage quality. However, forageRuminant Digestive Processes quality for grazing animals is more accurately determined by the following factors, which“Nutrients absorbed from the digestive tract are affected by observation and adaptiveinclude volatile fatty acids, amino acids, management of the grazing resource:fatty acids, glucose, minerals, and vitamins. Related ATTRA • forage intake PublicationsThese are used in the synthesis of the many • forage diversitydifferent compounds found in meat, milk A Brief Overview • forage quantity, availability, and densityand wool, and to replace nutrients used of Nutrient Cyclingfor maintaining life processes including • appropriate supplementation (energy in Pastures or protein), when necessaryreproduction.” (Minson, 1990) Digestion Assessing the Pasturebegins when an animal takes a bite from • appropriate minerals—offered free Soil Resource choicethe pasture. As the animal chews the feed is Cattle Production:formed into a bolus—a packet of food capa- • and clean, fresh water offered at all times. Considerations forble of being swallowed. Saliva is excreted, Pasture-Based Beefwhich further aids in swallowing and serves and Dairy Producersas a pH buffer in the stomach. Once in the The Basics Dairy Goats:rumen, the feed begins to undergo fermen- The nutritional concern for ruminants cen- Sustainable Productiontation. Millions of microorganisms ingest ters around energy (i.e., carbohydrates), Dairy Resource List:the feed, turning out end products which protein, minerals, vitamins, and water. Organic andserve as a major source of nutrients for the Energy (carbohydrates) is responsible for Pasture-Basedanimal. Some of the principle products maintenance and growth functions of the animal, and for the generation of heat. Pro- Dairy Sheepformed are ammonia, methane, carbondioxide, and volatile fatty acids (VFAs). tein grows tissue and performs other vital Goats: SustainableVFAs are absorbed and used as energy by functions. Other nutrients and minerals Production Overviewthe animal. Ammonia can be absorbed into such as vitamins A and E, calcium, phos- Grass-Based andthe animal’s system through the rumen wall, phorus, and selenium can be fed “free Seasonal Dairyingor can be consumed by bacteria to become choice” as a mineral supplement. The fol- Managed Grazing inmicrobial protein. This microbial protein is lowing section explores the nutrient require- Riparian Areasthen passed through the digestive system to ments of ruminants, beginning with intake. Meat Goats: Sustain-be absorbed in the small intestines. Intake able Production Intake is critically important for acquisi- Sustainable SheepNutrient Requirements of tion of nutrients by ruminants. Intake is the ProductionGrazing Livestock ingestion of feedstuffs by the animal, and Pastures: GoingFor producers, what are the important is regulated by the following factors, which Organicnutritional considerations for grazing live- are all interrelated: Pasture, Rangeland,stock? This is a good question, since live- • palatability and Grazingstock nutritionists have developed a science Management • foraging behaviorof nutrient analysis and subsequent ration Pastures: Sustainablebalancing. But the analyses are built on • chemical characteristics of the feed- Managementnutrient content of processed or harvested stufffeedstuffs delivered to ruminants in pens, • forage quantity, density, and avail-rather than grazing ruminants selecting a abilitydiet from pasture. For this reason, forage • dietary energy and fiber contentnutrient analysis may not be the most reli-able method to determine feed quality for • physiological stage of the animalgrazing livestock. • and temperaturewww.attra.ncat.org ATTRA Page 5
  • 6. Palatability is the flavor and texture of the feedstuff. Ruminants seek sweetness in their Secondary chemicals include “plant compound[s] capable of producing toxi- feed, probably because sweet is an indicator cosis by impairing some aspect of animal of soluble carbohydrates, the most critical metabolism. Everything is toxic, including dietary element for the animal after water. oxygen, water, and all nutrients if ingested Ruminants will in turn avoid feedstuffs that in high enough doses. Most plants, grasses are bitter, as these often are associated with included, contain toxins. Toxins typically set toxic secondary chemicals. a limit on the amount of food an animal can ingest. They do not produce harmful effects Foraging behavior describes how an animal if ingested in limited amounts. Under cer- goes about the grazing process. According tain circumstances, animals have difficulty to Fred Provenza, range researcher at Utah refraining from overingesting certain plants State University, the study of animal graz- that contain toxins—the so-called poisonous plants.” (Provenza, 2003) ing behavior involves understanding: • food habits and habitat preferences, and associated with plant defense. SecondaryA • the effects of nutrients and toxins on chemicals are often referred to as toxic sub- nimals stances, but toxicity is really just a matter of preference limit the degree, of dosage. All plants contain toxic “Our work has shown,” he writes, “how sim- amount ple strategies that use knowledge of behav- secondary chemicals to some degree, butof plants they con- ior can markedly improve the efficiency and animals have evolved an innate sense ofsume that contain profitability of agriculture, the quality of life what is good to eat.secondary chemicals for managers and their animals, and the Animals limit the amount of plants theythrough a feedback integrity of the environment.” (Provenza, consume that contain secondary chemicals 2003) For instance, grazing livestock, unlikemechanism that through a feedback mechanism that results closely confined livestock, have the opportu-results in satiety, or in satiety, or the feeling that they have had nity to graze selectively, and therefore tendthe feeling that they to select a diet higher in leaf content than enough. According to Webster, satiety is thehave had enough. what the overall pasture has to offer. (Min- “quality or state of being fed or gratified to son, 1990) For more information on grazing or beyond capacity, or the revulsion or dis- animal behavior see www.behave.net and gust caused by overindulgence or excess.” www.livestockforlandscapes.com. When ruminants consume enough of a cer- tain toxic substance, a feedback mechanism Bite size and bite rate also have an influ- induces a switch to an alternative source of ence on intake. The more dense a pasture sward, the more forage the animal can take nutrients. This is why cattle, sheep, and in with each bite. Research has shown that goats graze more (have higher intake) on a dense, vegetative pasture yielding at least a diverse pasture. The variety stimulates 2,000 pounds of dry matter per acre is ade- their appetite and provides alternative quate for maximizing bite size, and there- sources when they reach the limit of their fore intake. However, when pasture yield fi rst choice of plants. drops below 2,000 pounds of dry matter per acre, intake decreases. (Minson, 1990) Secondary Chemicals in Forages This exemplifies the fact that the relation- ship between grazing management, animal • Alkaloids in reed canarygrass and behavior, and nutrient uptake is not a sim- lupines ple relation. It is complex and constantly • Tannins in trefoil and lespedeza changing, following the changes of the sea- sons, forage quality, and forage quantity. • Terpenes in sagebrush and bitterweed Chemical factors include nutrients, but • Endophyte toxin in tall fescue also secondary chemicals that are oftenPage 6 ATTRA Ruminant Nutrition for Graziers
  • 7. Forage quantity, density, and availability ruminants are soluble carbohydrates. Whatdirectly influence forage intake, and intake an animal actually eats from a pasture isis directly related to the density of the often of higher nutritional quality than thepasture sward. Ruminants can take only a average of the pasture overall. Forages withlimited number of bites per minute while a dry matter digestibility (DMD) of 60 to 69grazing, and cattle in particular will only percent are considered high quality foragesgraze for about 8 hours per day. It is impor- from an energy perspective. Dietary fiber istant then to ensure that each bite taken by also a forage quality indicator.the grazing animal is the largest bite she Fiber is necessary for proper rumen function,can get. A cow grazes by wrapping her and is a source of energy as well. However,tongue around and ripping up forage; sheep high levels of fi ber in the diet decreaseand goats use their lips and teeth to select intake. Less digestible forages tend to stayhighly nutritious plant parts. Large bites of in the animal’s digestive system longerforage are therefore ensured by maintaining (slowing the rate of passage) so the animaldense pastures. remains “full” longer, and subsequentlyDense pastures are those with actively doesn’t eat as much. However, the younger Rgrowing and tillering forage plants. Til- a plant is the more soluble carbohydrates it uminantslering occurs in grasses that are grazed or contains, and the less fiber (cell wall com- possessmowed while vegetative, resulting in the ponents) it contains as well. Younger plants therefore are generally more digestible than nutritionalactivation of basal growing points (clustersof cells that initiate growth near the bottom mature plants. wisdom and willof the plant) and the growth of new stems Physiological stage refers to the stage of life select diets high inand leaves. Tillering results in a plant cov- the animal is in, and what level and type digestible organicering more basal area, which helps make a of production are being supported. The key matter, because thepasture denser, while protecting the soil. physiological stages in the life of ruminant most critical nutri-The length of the grazing period (the time animals are: ents selected byan animal is in a paddock) also has a • growth (i.e., young lambs, kids, and ruminants are solu-direct effect on pasture intake. An animal’s calves, including feeder animals) ble carbohydrates.intake decreases the longer she remains ina given paddock. This happens due to (1) • late pregnancy (very important inthe effect of plant disappearance (as plants sheep and goats)are grazed) and subsequent searching by • lactation (for dairy production orcattle for the next bite, and (2) the decrease maintenance of offspring)in forage crude protein content begin- • and maintenance (such as the cow’sning roughly two days after the animals dry period)have been turned in to the paddock. JimGerrish has shown that as an animal For example, the peak intake of dairy cattleremains in a paddock, intake and liveweight occurs after peak lactation. Between peak lactation and peak intake, the body mustgains decrease. (Gerrish, 2004) It is for draw on stores to maintain energy balance.this reason that most dairy graziers move Thus dairy animals generally lose bodyhigh-producing cattle to new paddocks after condition during this period. For this rea-each milking. son it is important to ensure high-qualityDietary energy and fiber content. As has pasture to maintain productivity and opti-been mentioned, livestock eat to the point of mum health, as well as to ensure the ani-satiety. Another good definition of satiety is mal’s ability to rebreed and enter into lac-gastrointestinal satisfaction. Ruminants pos- tation at the appropriate time the followingsess nutritional wisdom and will select diets season. On the other hand, a dry ewe canhigh in digestible organic matter, because gain weight on “fresh air and sunshine”—the most critical nutrients selected by maintenance requirements are low, and thiswww.attra.ncat.org ATTRA Page 7
  • 8. is the perfect time to let the sheep clean up Energy intake maintains body functions and over-mature forage, with no harm done. facilitates growth and development, includ- ing reproduction and lactation. Energy is Temperature affects the amount of feed an supplied to ruminants by highly digestible animal needs to maintain its body func- plant cell contents and a portion of the less tions. An animal’s metabolic rate increases digestible plant cell wall fraction. Starches as the temperature drops below the ani- like corn and barley are also high energy mal’s comfort zone. As temperature drops, sources, and are used extensively in the more energy is needed to maintain internal conventional livestock feeding industry as heat, so intake increases accordingly. Sub- sequently, animals typically will not graze well as for pasture-based systems where as much during hot, humid weather. energy supplementation is sometimes use- ful to enhance production. Options for Increasing Intake on Not all the energy taken in by a grazing High Quality Pasture animal becomes meat, milk, or wool. The hierarchy of energy digestion begins with High intake is one of the simplest meth- gross energy, which is the energy of intake. ods of ensuring adequate nutrition for high Some of the energy of intake is digestible, Intake is producing ruminants. Ensure high forage maximized when and some is not. What is not digestible is pastures are: intake by: excreted as fecal energy, and what is left • keeping forage in the vegetative for use by the body is digestible energy. • dense stage through grazing management, Metabolizable energy is the energy left after • digestible accounting for digestive and metabolism • palatable • diversifying pasture composition to losses. Some of the digestible energy is lost • diverse include several grass species, with as urine, and some as methane. What is left around 30 percent of the pasture in • correctly stocked legumes, and is energy used for the maintenance of body • plentiful (8-10” temperature, respiration, growth, reproduc- tall for cattle, 6- • maintaining a dense pasture so tion, and milk production. This fraction is 8” for sheep) animals will take larger bites. called net energy and is usually split into • familiar to the net energy for maintenance (NEm), net animal Energy energy for gain (NEg), and net energy for • fresh (not tram- pled or heavily Energy is the single most important dietary lactation (NEl). Animals can adjust to avail- manured) component for an animal after water. Energy able energy by putting on fat or by using is derived from carbohydrates, fats, pro- fat stores. For more information see the box teins, and from the animal’s body reserves. entitled “Body Condition Scoring.”Good, plentiful pastures assure healthy, productive animals. Animals are not productive when pastures are inadequate.Photo courtesy of USDA, NRCS. Photo courtesy of USDA, NRCS.Page 8 ATTRA Ruminant Nutrition for Graziers
  • 9. Body Condition Scoring Energy Partitioning. From USDA, 2003. Body condition scoring is a method of visu- ally appraising animals to arrive at a quali- tative description of nutritional status. Animals must not be too thin or too fat or complications can arise. If too thin, animals may not conceive, may be prone to disease, and usually have reduced milk production. If too fat, animals may experience difficulty giving birth (dystocia). Body condition scores are ranked on a numerical scale. The lower the number on the scale, the thinner the animal. For sheep and dairy cattle, the scale is from 1 to 5. For beef cattle, the scale is 1 to 9. Optimum BCS for Breeding Livestock Sheep ......................... 3.0 to 4.0 Dairy Cattle .............. 2.5 to 3.0 Beef Cattle ............... 4.5 to 5.0 The Resources section of this paper lists sev- When protein is degraded in the rumen it eral publications addressing body condition scores for various species. The publications is called rumen degradable protein. Rumen include charts to assist producers in making degradable protein is essentially food for visual appraisals of livestock and assigning rumen bacteria. When the microbes die the appropriate body condition score. they are passed through to the stomach and small intestines where they are digested by the animal. The resulting microbial protein is then absorbed into the animal’s blood-Protein stream. Some of the protein in the diet does“Crude Protein (CP) is calculated from not undergo degradation in the rumen, butthe nitrogen content of the forage. The CP passes straight to the abomasum or stomachvalue is important since protein contrib- for digestion. When protein escapes rumenutes energy, and provides essential amino breakdown and passes to the stomach it isacids for rumen microbes as well as the referred to as rumen undegradable proteinanimal itself. The more protein that comes or bypass protein.from forage, the less supplement is needed.However, most nutritionists consider energyvalue and intake of forages to be moreimportant than CP.” (Robinson et al, 1998) Protein Flow.As has been discussed, the energy value ofa forage is best determined by forage matu-rity, density, and availability. Protein in for-ages is most correlated with forage matu-rity, as more mature forages have a lowerpercentage of crude protein.Cattle require two types of protein in theirdiet. One type is degraded in the rumenand is used to meet the needs of the micro-bial population, and the other bypasses therumen and is used primarily to meet theproductive needs of the animal.www.attra.ncat.org ATTRA Page 9
  • 10. Bypass protein is important because a large important, especially for high-producing percentage of the rumen degraded protein livestock such as dairy animals, even in is absorbed as ammonia and, if in high con- protein-rich-pasture diets. centrations, can be lost through the urine as Some animal nutritionists suggest that urea. In high-producing animals this rep- bypass protein has been overemphasized. resents an inefficient utilization of protein, This is because the total proportion of so increasing the amount of protein that is bypass protein in most forages is around 30 bypassed to the intestines constitutes a more percent, which is very close to the require- efficient utilization of protein for growing or ments of the ruminant animal. In this case, lactating animals on high-quality pastures. they suggest, feeding the rumen microor- In forages, roughly 20 to 30 percent of the ganisms takes on particular importance, for protein taken in by the animal is bypassed if the rumen microorganisms are healthy, to the intestines. Lactating or growing they will supply the ruminant with the nutri- cattle generally require 32 to 38 percent of ents they need to maintain body functions their total protein intake to be in the unde- and remain productive. We must remember gradable form. (Muller, 1996) High-quality that ruminant animals evolved in symbio-V pastures can meet almost all the needs of itamins are sis with rumen microorganisms in a grass- high-producing livestock. For those animals land environment, and they are inherently important that require supplementation, corn, cot- adapted to this function. for the for- tonseed and linseed meals, brewers driedmation of catalysts grains, corn gluten meal, distillers dried grains, and fish meal are typically high in Minerals and Vitaminsand enzymes that bypass protein. The principle minerals of concern for live-support growth and stock on growing forages are calcium andbody maintenance The microbial degradation of protein is an magnesium. Others to consider are salt, energy-dependant process. Carbohydratesin animals. phosphorus, potassium, and sulfur. These are the energy-yielding nutrients in animal minerals are very important for cellular res- nutrition and are supplied by the produc- piration, nervous system development, pro- tion of volatile fatty acids in the rumen. tein synthesis and metabolism, and repro- Generally more microbial protein is synthe- duction. Mineral supplements are available sized from green forage diets than from hay in many formulations. Because soils differ or mature forage diets. When a ruminant in mineral content from place to place, it is animal grazes fresh forage on high-quality difficult to recommend a mineral mix that pasture, about 70 percent of the protein is works in all places, although most animal degraded in the rumen by microorganisms, scientists suggest at the very least a min- and about 30 percent escapes to the small eral mix with a calcium to phosphorus ratio intestine for absorption. Ruminant animals of 2:1. Consider using a loose mineral mix need approximately 65 to 68 percent of the fed free choice rather than mineral blocks protein to be rumen degradable for ade- for cattle on lush spring or small grain pas- quate rumen function and the development ture to avoid grass tetany (hypomagnese- of microbial protein. But if more protein is mia) and to ensure the animals are getting degraded in the rumen, less is available to enough mineral. the animal for absorption in the small intes- tine. This is important because researchers Vitamins are important for the formation of believe that rumen undegradable or bypass catalysts and enzymes that support growth protein consists of certain essential amino and body maintenance in animals. Green acids that are missing or deficient in rumen growing plants contain carotene, which is a degradable protein. Much of the rumen precursor to vitamin A. If ruminants are on degraded protein is absorbed as ammonia green forage (including green hay) vitamin and excreted out of the body via the urine, A should not be deficient. Vitamin A defi- and is therefore a waste of protein. This ciencies occur when ruminants are placed is why bypass or undegradable protein is on concentrate feeds, or when fed dry,Page 10 ATTRA Ruminant Nutrition for Graziers
  • 11. stored forage during the winter. B vitaminsare synthesized by rumen microorganismsso supplementation is not necessary. Vita-min D is synthesized in the skin from expo-sure to sunlight, so Vitamin E is the onlyother vitamin of concern that sometimesrequires supplementation.Mineral and vitamin supplementation isvery important to maintain herd health, andcareful attention must be paid in develop-ing a mineral and vitamin supplementationplan. Keep these things in mind when feed-ing these supplements to livestock:1. Keep mineral mixes dry. Wet mineral is unpalatable and is known to lose some of its efficacy when damp.2. Monitor consumption to make sure it’s Photo courtesy of USDA, NRCS. always available. Keep the feeders full.3. Don’t forget that some animals display toxic chemicals. Examples are knapweed, social dominance. Older, more dominant sagebrush, and scotchbroom. animals will often eat more than their Cattle require from 3 to 30 gallons of water share of mineral mix. Remedy this by having more than one feeder, separated per day. Factors that affect water intake into different parts of the pasture. include age, physiological status, tempera- ture, and body size. A rule of thumb is that cattle will consume about one gallon of water Sheep and Copper Toxicity per 100 pounds of body weight during win- ter and two gallons per 100 pounds of body Sheep are very sensitive to copper. If you have weight during hot weather. In general, you cattle and/or goats, and sheep on the same can easily double the estimates for lactating farm it is extremely important to supply them cattle. Water should be clean and fresh, as with different mineral mixes, as a mix that is for- mulated for cattle or goats will likely be lethal dirty water decreases water intake. It is good for sheep. Loose mineral mixes are better than to remember that all other nutrient metabo- blocks for sheep and goats. lism in the body is predicated on the avail- ability of water, and if an animal stops drink- ing, nutrient metabolism (which results in growth and lactation) will decrease.Check with your local Extension agent orveterinarian to determine the mineral andvitamin mixes and recommendations com- Forage Resources andmon to your area. Grazing Nutrition Nutrient content of forages varies with plantWater maturity. As the plant matures, it shuntsSheep and goats require one gallon of water sugars and proteins to the reproductiveper day for dry ewes, 1.5 gallons per day centers of the plant, namely the seed (infor lactating ewes, and 0.5 gallons per day the case of annuals) and the roots (in thefor finishing lambs. Water consumption will case of perennials). Plant maturity resultsincrease during the heat of the summer, and in more fibrous, and less digestible, leaveswhen the animals are grazing or browsing and stems. Various circumstances affectplants with high concentrations of secondary, plant maturity. Among the most commonwww.attra.ncat.org ATTRA Page 11
  • 12. factors contributing to plant maturity and relatively high TDN levels and protein com- subsequent forage quality are: positions of 5 percent. (Ricketts, 2002) Shrubs tend to have their highest nutrient • length of growing season (plants content in the spring as well, but generally mature faster in shorter growing retain a higher nutrient content throughout seasons) the growing season and into the dormant • moisture availability (moisture period. Most shrubs, such as greasewood stress reduces photosynthetic activ- and saltbush carry a protein content of ity and initiates dormancy) greater than 12 percent in the winter. Forbs • pasture plant species composition are high in protein as well. Purple prairie (some species remain vegetative lon- clover and dotted gayfeather have as much ger than others) or more protein, when green, than alfalfa • and the grazing system and clover. “These forbs are like little pro- tein blocks scattered on the landscape.” Of these factors, the one that livestock manag- (Ricketts, 2002) ers have the most control over is the grazing system. Controlled defoliation and adequate Grasses. Grasses are divided into two types: rest are crucial for plants to remain vegeta- warm season and cool season. On semi-arid tive, and therefore more nutritious, during prairies and western ranges, warm season the growing season. This topic is summa- grasses do most of their growing from May rized in the Grazing Management section to August, whereas cool season grasses do of this publication and covered in detail in their growing from March to June. Knowl- the ATTRA publications Pasture, Rangeland, edge of which grasses are in your pastures and Grazing Management, Rotational Grazing, will help you to decide when to graze them and Pastures: Sustainable Management. to take advantage of highest nutrient con- tent. In the spring, grasses will have a pro- Plant Type, Species, and Nutri- tein content of approaching 20 percent and will be around 10 percent protein when in tional Quality on Native Range mid-bloom, or when half the plants have There are three basic plant types commonly developed a seedhead. found in pastures, and each has its place in animal nutrition. These plant types are: On deteriorated dry western range sites, you might see a proliferation of Kentucky blue- • Grasses grass, bottlebrush squirreltail, and cheat- • Shrubs grass. The weedy grasses can be good in • Forbs nutrient value, but generally do not produce enough annual forage to meet the needs Grasses tend to be high in nutrients in the of grazing livestock, and are often vegeta- spring, and begin to decline as the grow- tive for a very short period of time, as with ing season progresses. By the time winter cheatgrass and squirreltail. Broadleaf weeds sets in, rangeland grasses such as rough become coarse and unpalatable very soon fescue and bluebunch wheatgrass will have after they begin to mature. Pastures that have greater than about 50 percent of these plantsFeeding Value of Forages should be considered for a serious revision of Crude Protein % the grazing system, or pasture renovation if TDN % Grass Legume appropriate. Consider multi-species grazing, because sheep and goats may eat the weedsVegetative 63 15 21 that cattle do not, thus bringing the pastureBoot or bud 57 11 16 back in balance.Bloom 50 7 11 Shrubs. Shrubs are very good to have onMature 44 4 7 native range because they are high in pro-Adapted from Fisher, 1980 tein for a greater part of the year. ManyPage 12 ATTRA Ruminant Nutrition for Graziers
  • 13. livestock and wildlife find these plants A Case for Species Diversityimportant for getting them through the win-ter. Shrubs on many western ranges include As shrubs and forbs typically have higher protein concentrations thanwinterfat, sagebrush, fringed sagewort, four- most grasses, why are they generally considered substandard as live-wing saltbush, snowberry, and rabbitbrush. stock forage? The main reason is that most shrubs and many forbs con-These plants will generally have more than tain secondary chemicals that are often toxic to grazing animals. Animalsseven percent protein content through the grazing sagebrush, for example, will very quickly get their fill as the levelwinter. Combined with other dormant for- of alkaloids accumulates in their systems However, livestock displayages, these plants can often supply an ani- nutritional wisdom and often eat small portions of various species in order to (1) obtain essential nutrients, and (2) neutralize the effects ofmal with its maintenance needs for protein more toxic plant species.if there are enough plants.Cattle are typical grazers, and utilize grassas their primary food source. They will, Berseem clover are often overseeded intomuch like goats and sheep, browse on win- warm season pastures with annual ryegrass orterfat and saltbush. A range site with 20 to small grains in the humid South to supply high30% of its cover in a diverse population of quality winter pasture to cattle from Octobershrubs serves to sustain all classes and spe- through April. Some excellent warm seasoncies of livestock as well as provide winter legumes to consider in temperate regions arefood and cover for wildlife. annual cowpeas and perennial peanuts. Tur-Forbs. Forbs, or non-woody broadleaf nips also make an excellent season extensionplants, are generally higher in protein than annual crop for providing high-quality graz-grasses. Many forbs are considered weeds, ing into the fall in some temperate regions.but most are often palatable and nutritious For more information on alternative forageswhen immature. Typical rangeland forbs to extend the grazing season, see the ATTRAthat are high in protein and digestibility publication Pasture, Rangeland, and Grazinginclude gayfeather, western yarrow, prairie Management at www.attra.ncat.org or call theclover, and Indian paintbrush. On dryland ATTRA help line at 1-800-346-9140.ranges, high-dormancy alfalfa can make avery good supplement for livestock, as do Matching Nutritionalbirdsfoot trefoil and cicer milkvetch, whichin addition to being high-quality forage, Requirements of Livestock tohave anti-bloat characteristics as well. the Forage Resource One of the most important questions a live-Plant Type and Species on stock manager can ask is “what do I needTemperate Pasture to know in order to match the nutritional requirements of my animals to the forageGrasses and forbs generally dominate shrubs resource?” To answer this question within temperate regions. On temperate pastures, the highest level of certainty, the producerwarm season grasses exhibit growth from as should perform the following crucial man-early as March to as late as September, andcool season grasses grow well from October agement tasks:into June, with reduced growth during the • inventory available forage resourceswinter months. Indicators of poor pasture (documenting re-growth, crop resi-condition on temperate pastures are grasses due, etc.)such as sandbur, rattail smutgrass, and little • prioritize grazing of highest qual-barley, and broadleaf weeds like curly dock, ity pastures by animals with high-croton, and hemp sesbania. est nutrient requirements (growing,The most common forbs used on temperate lactating)pastures include clovers, alfalfa, and vetches. • observe and determine the forageWhite clover, hairy vetch, red clover, or growth curve for your pastureswww.attra.ncat.org ATTRA Page 13
  • 14. • coincide the forage growth curve (birth) and lowest demand is three to four with peak animal demand months before parturition. (Gerrish, 2004) • monitor to ensure animal numbers For sheep, just before lambing to weaning and type are appropriate to forage are crucial times when nutrient require- resource ments are highest, especially just prior to lambing. For dairy animals, the entire lac- Forage Growth Phases tation period is critical. Knowing the forage growth curve for your pastures will allow Forage supply is not continuous through- you to match forage growth with animal out the year. You can expect anywhere demand. For example, consider having ewes from three to nine months of growing sea- lamb when grass is at optimum productivity son, and three to nine months of dormancy, and when the ewes need it the most. On the depending on the region. Cool-season pas- other hand, think about the needs of young ture growth begins in the early spring and stock. Unless you are selling at weaning, quickly produces very large amounts of for- you need a plan for high-quality pasture for age, then tapers off toward mid-summer. young growing animals. Given adequate moisture, cool-season pas- tures will often produce a second surge of growth in the fall before going dormant. Supplementing Protein or Warm–season pasture begins later in the Energy: When is it Necessary? spring and continues into early autumn Cattle, sheep, and goats, by nature grazing when day length shortens and tempera- and browsing animals, grow and reproduce tures fall. Warm-season pastures comple- well on pasture alone. However, an inten- ment cool-season pastures nicely by provid- sive and industrial agricultural production ing forage when cool-season growth wanes philosophy has dictated that crops and ani- in mid-summer. A diverse mix of cool- and mals should be raised faster, larger, and warm-season pastures benefits livestock more consistently than a pasture system managers by overlapping the growth curves can deliver. Thus confinement systems with of both types, meaning more high-quality delivered forages and concentrated feeds pasture than otherwise. have been the norm since the 1950s. Rais- ing animals on grass is slower than raising Peak Animal Demand animals on grain. However, a pasture-based The highest nutrient demand for beef cat- livestock producer will, with careful plan- tle is one to three months after parturition ning, realize cost savings and subsequent profitability through the efficiency of relying on the natural systems of nutrient cycling, biological pest controls, and perennial pasture productivity. The major operational expense confronting the livestock industry in most parts of the United States is for supplemental feed. In temperate regions of the country that experi- ence adequate rainfall and a lengthy grazing season, supplementation on green, growing, vegetative, well-managed pastures should not be necessary. However, young and lactating stock require more energy and protein than mature, non-lactating animals.District Conservationist Rhonda Foster and Grasslands management Specialist Well-managed grass-legume pasturesRalph Harris disucss intensive grazing rotations at a farm in Benton County, Georgia. can be highly digestible with protein con-The producer grazes his cattle on a 3 week rotation. Photo courtesy of USDA, NRCS. centrations approaching 25 percent whilePage 14 ATTRA Ruminant Nutrition for Graziers
  • 15. vegetative. These pastures can supply the Remember:nutrients needed to raise lambs, kids, heif- • Substitution effect—forage intakeers, or steers, or support lactating cattle, decreases with less fi brous, moresheep, or goats. The problem on high-qual- digestible supplements like corn.ity pastures often becomes one of ineffi-cient protein use. Supplementing energy • Supplementation of protein on low-with digestible fi ber in these situations can quality forages will increase for-make the animals utilize protein more effi- age intake, and therefore increaseciently. Digestible fi ber (energy) sources energy intake.include wheat middling (a coproduct ofwheat processing sometimes called midds), Concept of First Limiting Nutrientsoybean hulls, corn gluten feed, and whole Determine which nutrient is limiting and supplement that one first.cottonseed. (Jackson, undated) For instance, degradable intake protein requirements need to be met for microbial growth first. Then and only then consider bypass proteinCorn is grown on many small diversified supplementation, and only if it is deficient. Likewise, if energy is defi-farms, in rotation with pasture, legumes, or cient, protein supplementation will be wasteful and expensive.vegetables, as animal feed, and is an excel-lent source of low-fi ber energy for graz-ing ruminants. However, if corn is fed in Remember: on high-quality pastures,high quantities, forage intake will decline. energy is often the limiting nutrient. Digest-A pound or two a day for sheep and goats ible fiber feeds are good for ruminants onand five or six pounds per day for cattle high quality forage because they do notwill generally provide enough supplemen- reduce intake, and provide energy for pro-tal energy without decreasing forage intake. tein metabolism. Examples are: corn glutenLimiting corn supplementation to no more feed (corn gluten meal plus the bran), wheatthan 0.5 to 1.0 percent of body weight per midds (screenings from wheat flour process-day is recommended for cattle on pasture. ing), and whole cottonseed.(Sewell, 1993) Feeding Cottonseed Products to Cattle When to Supplement Three types of cottonseed products are typically fed to beef and dairy cattle. These are whole cottonseed with lint, cottonseed meal, and cot- • Supplementing energy is helpful on veg- tonseed hulls. Whole cottonseed is a very good source of protein for etative, well-managed pastures for more cattle. However, whole cottonseed contains a chemical called gossypol efficient utilization of forage protein (for that can inhibit the reproductive performance of breeding cattle, par- high producing animals). ticularly bulls. For this reason it is recommended that producers limit • Supplementing with protein is necessary whole cottonseed supplementation to calves at 1.5 pounds per day, on low-quality pasture and rangeland or stocker cattle at no more than 3 pounds per day, and mature cows at 5 when continuously grazing temperate pounds per day. Avoid feeding whole cottonseed to bulls. warm-season pastures. Forage Sampling andWhen supplementing ruminants on pasture, Production (Yield) Estimatesconsider the following questions: If you choose to have your forage analyzed • Will the added production cover the for nutrient content, the key nutrients to expense, especially if the feed is consider are crude protein (CP) and total shipped from off the farm? digestible nutrients (TDN). Acid detergent • Is there an inexpensive local source fiber (ADF) and neutral detergent fiber of protein? (NDF) are useful as well for determining energy content. ADF and NDF measure • Do you raise the feed on the farm? fiber, or cell wall contents. The higher the • Do you have necessary harvest, fi ber the lower the energy value is for a storage, and feeding equipment? feedstuff.www.attra.ncat.org ATTRA Page 15
  • 16. Although determined by a system that relies Your Local Cooperative on harvested forages, these two measures Extension Office will give the producer a good starting point to make decisions about supplementation. Contact your local Cooperative Extension For cattle, forage with 10 to 13 percent CP office for information on poisonous plants, and 55 to 60 percent TDN will meet all the forage analysis, and locally adapted forages. needs of most classes of livestock. Growing The USDA maintains an online database of and lactating livestock need added protein local Cooperative Extension offices on its and energy if the forage resource is not of website at www.csrees.usda.gov/Extension/ index.html. You will also find the phone num- adequate quality. Also important is mineral ber for your Cooperative Extension office in content. Different soils in different areas the county government section of your tele- of the country can be deficient in different phone directory. nutrients. Selenium and copper availability are a problem in the southeast and north- west, for instance. Check with your Coop- erative Extension office or state Extension Grazing Management forage or beef specialist to determine the Grazing management is the regulation ofG razing mineral needs in your area. the grazing process by humans through manage- Estimating forage yield in a pasture also the manipulation of animals to meet ment is the plays a very important role in developing a speci f ic, predetermined product ionregulation of the nutrition plan for grazing livestock. There goals. (Briske and Heitschmidt, 1991) are many ways to estimate forage yield, from The primary considerations of grazinggrazing process by the more time-consuming clip-and-weigh management are:humans through approach to more generalized estimates • temporal distribution of livestockthe manipulation of from plant height and density. The ATTRA (time)animals to meet spe- publication Pasture, Rangeland, and Grazing • spatial distribution of livestockcific, predetermined Management includes formulas and instruc-production goals. tions for estimating forage yield and develop- • kind and class of livestock ing an appropriate stocking rate. • a nd number of l ivestock (Heitschmidt and Taylor, 1991) Plant Toxicity and Grazing- If given a choice, livestock will only eat the Related Disorders highest quality, most palatable plants in a Graziers must pay careful attention to the pasture. In order to ensure that plant bio- negative health effects that certain plants diversity is maintained in the pasture it is can cause in livestock. Plant toxicosis occurs necessary to set up a grazing management either through the ingestion of (1) poisonous system to better control livestock grazing. plants or (2) forage plants that contain toxic The elements of grazing to control are tim- substances due to environmental or physi- ing and intensity of grazing. This means ological conditions. Plant poisoning can controlling the number of animals and how be significantly reduced by proper grazing long they are in a pasture. management. Poisonous plants contain res- Rotational grazing systems take full advan- ins, alkaloids, and/or organic acids that ren- tage of the benefits of nutrient cycling as der them unpalatable. If the pasture contains well as the ecological balance that comes enough good forage, there is little reason for from the relationships between pastures the animals to select bad-tasting plants. The and grazing animals. High density stocking ATTRA publication Pasture, Rangeland, and for short periods helps to build soil organic Grazing Management contains detailed infor- matter and develops highly productive, mation on plant toxicity and grazing-related dense, resilient pastures. disorders. In addition, your local Cooper- ative Extension office has information on Some other measurements to consider in poisonous plants in your area. managing livestock grazing include:Page 16 ATTRA Ruminant Nutrition for Graziers
  • 17. • forage density • after-grazing plant residue • paddock rest time • range condition and trend, • animal body condition, health, and physiological stage • grazing systems, including stocking rate and stock density • and pasture and rangeland monitoringThese considerations are covered exten-sively in other ATTRA publications. Formore information on grazing managementsee the ATTRA publications Pasture, Range-land, and Grazing Management; RotationalGrazing; and Paddock Design, Fencing, andWater Systems for Controlled Grazing. Photo courtesy of USDA, NRCS.ReferencesBall, D.M., C.S. Hoveland, and G.D. Lacefield. 1991. Klopfenstein, Terry. 1996. Need for escape protein bySouthern Forages. Potash and Phosphate Institute, grazing cattle. Animal Feed Science Technology 60:Norcross, GA. 191-199.Beetz, A. 2002. A Brief Overview of Nutrient Cycling Lalman, David. 2004a. Supplementing Beef Cows.in Pastures. ATTRA: Fayetteville, AR. OSU Publication F-3010. Oklahoma State UniversityBriske, D.D. and R.K. Heitschmidt. 1991. An Ecologi- Extension Service. http://pods.dasnr.okstate.edu/cal Perspective, in Grazing Management: An Ecologi- docushare/dsweb/Get/Document-900/F-3010pod.pdfcal Perspective, R.K. Heitschmidt and J.W. Stuth, eds.Timber Press, Portland, OR. Lalman, David. 2004b. Vitamin and Mineral Nutri- tion of Grazing Cattle. OSU Publication E-861. Okla-Cheeke, Peter R. 1991. Applied Animal Nutrition: homa State University Extension Service.Feeds and Feeding. MacMillan Publishing Company, http://pods.dasnr.okstate.edu/docushare/dsweb/Get/New York. Document-2032/E-861web.pdfFAO: Food and Agriculture Organization of the United New Zealand Society of Animal Production. 1987.Nations. 2002. FAO Statistics. Livestock Feeding on Pasture, A.M. Nicol, ed. Occa-Gerrish, J. 2004. Management-Intensive Grazing: The sional Publication No. 10. Hamilton, New Zealand.Grassroots of Grass Farming. Ridgeland, MS: GreenPark Press. Mathis, C.P. 2003. Protein and Energy Supplementa- tion to Beef Cows Grazing New Mexico Rangelands.Heitschmidt, R.K. and Taylor, C.A. 1991. Livestock Circular 564. New Mexico State University Coopera-Production, in Grazing Management: An EcologicalPerspective, R.K. Heitschmidt and J.W. Stuth, eds. tive Extension Service.Timber Press, Portland, OR. Merck & Co., Inc. 2006. Merck Vet Manual, 9thHolecheck, J.L., R.D. Pieper, and C.H. Herbel. Edition. Cynthia M. Kahn, ed. Whitehouse Station,1989. Range Management, Principles and Practices. NJ. www.merckvetmanual.com/mvm/index.jspRegents/Prentice Hall, Englewood Cliffs, NJ. Minson, Dennis J. 1990. Forage in RuminantJackson, K. No date. Choosing the Right Supplement. Nutrition. Academic Press, Inc., NY.www.attra.ncat.org ATTRA Page 17
  • 18. Muller, L. D. 1996. Nutritional Considerations for Body Condition Scoring Beef Cows. VirginiaDairy Cattle on Intensive Grazing Systems. Proceed- Cooperative Extension. www.ext.vt.edu/pubs/beef/ings from the Maryland Grazing Conference. 400-795/400-795.htmlNewman, Y.C., M.J. Hersom, C. G. Chambliss and Body Condition Scoring of Sheep. Oregon State Uni-W. E. Kunkle. 2007. Grass Tetany in Cattle. Florida versity. http://extension.oregonstate.edu/catalog/pdf/ec/Cooperative Extension Service, Institute of Food and ec1433.pdfAgricultural Sciences, University of Florida. http://edis.ifas.ufl.edu/DS137 Church, D.C., (editor). 1993. The Ruminant Animal: Digestive Physiology and Nutrition. Waveland Press.Provenza, Fred. 2003. Foraging Behavior: Manag- ISBN: 0881337404. (Order online froming to Survive in a World of Change. Logan, UT: Utah www.amazon.com).State University. www.behave.net Langston University, Agricultural Research and Exten-Ricketts, Matthew. 2002. Feed Less, Earn More. Mon- sion Programs. Goat Nutrient Requirement Calculators.tana GLCI Fact Sheet. www2.luresext.edu/goats/research/nutr_calc.htmRobinson, Peter, Dan Putnam, and Shannon Mueller. Nutrient Requirements for Goats1998. Interpreting Your Forage Test Report, in Cali- www2.luresext.edu/GOATS/research/nutreqgoats.htmlfornia Alfalfa and Forage Review, Vol 1, No 2. Univer- Maryland Small Ruminant Page: Feeding andsity of California. Nutrition. www.sheepandgoat.com/feed.htmlSavory, Allen and Jody Butterfield. 1998. Holistic Penn State University Dairy Cattle NutritionManagement: A New Framework for Decision Making www.das.psu.edu/dairynutrition(2nd edition). Washington, DC: Island Press. University of Wisconsin-Madison, Dairy ScienceSewell, Homer. 1993. Grain and Protein Supplements Department. Dairy Nutrition. www.wisc.edu/dysci/for Beef Cattle on Pasture. University of Missouri uwex/nutritn/nutritn.htmExtension. Nutritional Requirements of Cattle, Sheep,USDA. 2003. National Range and Pasture Handbook.Fort Worth: Natural Resources Conservation Service, and GoatsGrazing Lands Technology Institute. www.glti.nrcs. National Research Council. 1996. Nutrientusda.gov/technical/publications/nrph.html Requirements of Beef Cattle: Seventh Revised Edition, Update 2000. National Academy Press,Weiss, Bill. 1993. Supplementation Strategies for Washington, DC.Intensively-Managed Grazing Systems. Presentation atthe Ohio Grazing Conference, March 23, Wooster. National Research Council. 2001. Nutrient Requirements of Dairy Cattle: Seventh RevisedResources Edition. National Academy Press, Washington, DC. National Research Council. 1981. NutrientSome of the resources listed below are Web-based Requirements of Goats. National Academy Press,documents and programs. If you do not have Inter- Washington, DC.net access at home, contact your local public library.Many libraries have free Internet computers and National Research Council. 1985. Nutrienttraining for their patrons. Requirements of Sheep, Sixth Revised Edition. National Academy Press, Washington, DC.General Ruminant Nutrition andBody Condition Score The preceding four resources can be downloaded asBeef Cattle Nutrition Workbook, EM 8883-E. Decem- PDF files for free from the National Academies Pressber 2004. Oregon State University Extension. http:// website at www.nap.edu or by contacting:oregonstate.edu/Dept/EOARC/abouthome/scientists/ The National Academies Pressdocuments/DWB26.pdf 500 Fifth Street NWBeginner’s Guide to Body Condition Scoring: A Tool Lockbox 285for Dairy Herd Management. Penn State University. Washington, DC 20055www.das.psu.edu/dairynutrition/documents/363eng.pdf (888) 624-8373Page 18 ATTRA Ruminant Nutrition for Graziers
  • 19. Estimating Forage Production 2007. Columbus, OH: OEFFA. www.oeffa.org/Barnhart, Stephen. 1998. Estimating Available documents/OrganicLivestockDirectory2007.pdfPasture Forage, PM 1758. Iowa State UniversityExtension. www.extension.iastate.edu/Publications Ohlenbusch, P.D.,and S.L. Watson. 1994. Stocking Rate and Grazing Management, MF-1118. KansasBrence, L. and R. Sheley, 1997. Determining Forage State University Extension. www.oznet.ksu.edu/library/Production and Stocking Rates: A Clipping Procedure crpsl2/MF1118.pdffor Rangelands, MT199704AG. Montana StateUniversity Extension. www.montana.edu/wwwpb/pubs/ Pratt, W. and G.A. Rasmussen. 2001. Determiningmt9704.html Your Stocking Rate, NR/RM/04. Utah State University Extension. http://extension.usu.edu/files/publications/Gerrish, Jim. 2004. Forage Supply: The Grazier’s publication/NR_RM_04.pdfChecking Account, in Management-intensive Graz-ing: The Grassroots of Grass Farming. Ridgeland, MS: Provenza, Fred. 2003. Foraging Behavior:Green Park Press. Managing to Survive in a World of Change. Logan,Pratt, W. and G.A. Rasmussen. 2001. Calculating UT: Utah State University. www.behave.netAvailable Forage, NR/RM/03. Utah State University USDA. 2003. National Range and Pasture Handbook.Extension. http://extension.usu.edu/files/publications/ Fort Worth: Natural Resources Conservation Service,publication/NR_RM_03.pdf Grazing Lands Technology Institute. www.glti.nrcs.Grazing Management usda.gov/technical/publications/nrph.htmlBlanchet, K., H. Moechnig, and J. DeJong-Hughes. The Stockman Grass Farmer Magazine2003. Grazing Systems Planning Guide. St. Paul, MN: 234 W School StreetUniversity of Minnesota Extension Service Distribution Ridgeland, MS 39157Center. www.extension.umn.edu/distribution/livestocksys- 800-748-9808tems/DI7606.html www.stockmangrassfarmer.net/index.htmlMcCrory, Lisa and Charlotte Bedet. 2007. Organic A publication devoted to the art and science ofLivestock and Grazing Resources, Updated January grassland agriculture.Noteswww.attra.ncat.org ATTRA Page 19
  • 20. Ruminant Nutrition for Graziers By Lee Rinehart NCAT Agriculture Specialist ©2008 NCAT Paul Driscoll, Editor Amy Smith, Production This publication is available on the Web at: www.attra.ncat.org/attra-pub/ruminant.html or www.attra.ncat.org/attra-pub/PDF/ruminant.pdf IP318 Slot 52 Version 030308Page 20 ATTRA