B575
Nutrition

essential nutrients | roughage to concentrate ratio | characteristics and evaluation of feeds | water supplies

Basics of Sheep and Goat Nutrition

Introduction: Feeding management of sheep and goats is both a science and an art! One of the primary advantages of raising sheep/goats, is that they are "self harvesters," or in other words, they do not need to be fed expensive feedstuffs (i.e. silage, pellets, bulk or bagged rations, etc.) all the time. Sheep and goats are "nature’s scavengers." However, this does not imply that they can be fed garbage. In fact, many goats are very picky about what they will and will not eat. Sheep and goats should be provided with a balanced diet throughout the year. This is referred to as "life-cycle nutritional management."

The digestive system of sheep and goats is referred to as a ruminant system. A ruminant has four compartments to its stomach, unlike humans and pigs, which have a single stomach. The ruminant farm animals are sheep, goats, llamas, and cattle. The four compartments to a ruminant stomach are the rumen or "paunch," the reticulum or "honeycomb," the omasum or "manyplies," and lastly, the abomasum or "true stomach." The rumen is the largest of the four and the compartment that makes it possible for the digestive breakdown and utilization of relatively high levels of fibrous type plants and/or feedstuffs.

Because of the nature of their digestive systems, sheep and goats are capable of making abundant use of roughages, including range forage and improved farm pastures. Even suckling lambs will often fatten sufficiently on good pasture, and when sold directly off pasture, may not experience price discrimination when compared to grain fed lambs. It is usually to the advantage of the owner to provide abundant forage and other roughage for his/her breeding flocks/herds and restrict the feeding of concentrates to emergency periods and times when nutritional needs may be greater than can be met with high quality roughages alone. For does and ewes, the times of greatest nutritional needs are during late gestation and throughout lactation.

When drought restricts the growth and availability of forage, emergency supplementation may be required. During these times, both quality and quantity of forage may be reduced. Extremely heavy snowfall may also bring on an emergency situation. In the latter case, the problem may be one of substituting for, rather than supplementing the range forage. When supplementation is necessary, about 0.25 to 0.50 pound/head/day is usually fed. The amount that is actually fed depends upon the extent of the range deficiency and the condition of the animals. Supplementing more than this is expensive and will result in reduced consumption of range forage. Expenses will be increased without compensating return through greater production. Some ranges normally lack in certain essential nutrients such as phosphorus. Usually it will pay to provide these lacking nutrients in a supplement.

Additional periods of greater nutritional needs for the breeding flock/herd may be just before and during the breeding season, the last 4-6 weeks of gestation, and during lactation. At these times, the condition of the animals, determined by actually catching and examining them, should be the guiding factor in the amount of concentrates to feed.

Sheep and goats are naturally adapted to grazing on pastures and ranges which supply a variety of forage plants, and they thrive best on forage that is short and fine rather than high and coarse.

Essential Nutrients

The following five nutrients are essential for maintaining a balanced diet for a small ruminant:

  1. Energy (carbohydrates, fats)
  2. Protein
  3. Minerals
  4. Vitamins
  5. Water

Energy: Lack of energy is probably the most common nutritional deficiency of small ruminants. This results from the lack of feed or from the consumption of poor quality feeds. Inadequate energy results in retarded or cessation of growth, loss of weight, reproductive failure, increased mortality, and higher parasitic infection due to lowered resistance. Some energy needs can be obtained through the consumption of roughages. Concentrates may also be used to supplement the ration when roughages are limited or of poor quality.

Energy is used primarily in the following two ways:

  1. To satisfy maintenance requirements of the animal.
  2. To ensure growth and gain.

Energy requirements have been expressed in different ways and feeding grades established for different ages. Some of the more common ways of expressing energy values and requirements are as follows:

  1. Total Digestible Nutrients (TDN) - 1 kg TDN equals approximately 4.4 DE (Mcal), 3.6 ME (Mcal), and 2.0 NE (Mcal).
  2. Digestible Energy (DE)
  3. Metabolizable Energy (ME)
  4. Net Energy (NE) - This is currently one of the most valuable ways of expressing energy. It can be used to express the energy requirements for maintenance (NEM), growth (NEG), or for lactation (NEL).

Protein: Protein is used for growth, replacement of body tissues and fluids, to maintain a healthy reproductive status, and for fiber growth. Insufficient protein results in reduced appetite, lowered feed intake, and poor feed efficiency. Under extreme conditions, lack of protein causes severe digestive disturbances, nutritional anemia (lack of red blood cells), and edema (fluid build-up).

The quality of protein (level and balance of amino acids) is not a critical factor in small ruminant nutrition; the quantity fed is more important than the source. Urea and other forms of non-protein-nitrogen (NPN) can be used to provide up to one-third of the protein in a ration that is deficient. Green pastures and legume hays are excellent practical sources of protein for sheep and goats.

Minerals: Minerals have three main functions in ruminant nutrition:

Mineral elements that are essential for sheep and goats are calcium, phosphorus, sodium, potassium, chloride, magnesium, iron, iodine, sulfur, copper, cobalt, molybdenum, selenium, and zinc. Most adult sheep and goats consume around 0.66-1.76 lbs. of mineral mix per head per month. (Many of the following reference numbers were taken from: Pugh DG: Sheep & Goat Medicine, Ed 1, Philadelphia, 2002, WB Saunders; and Nutrient Requirements of Sheep, Ed 1, 1985, National Academy of Science, National Research Council.)

  1. Sodium (salt): Animals deprived of salt develop a craving for it and may resort to chewing wood and/or licking dirt. Salt should make up about 0.2-0.5% of a small ruminant’s total ration.
  2. Iodine: This is necessary for the formation of thyroxine, and deficiency results in an enlarged thyroid gland. Iodine deficiency symptoms are seldom observed in mature animals, but can result in weak and dead young. This problem is corrected by feeding 0.10-0.80 ppm in the diet (goats require 0.60 ppm).
  3. Calcium: Rations lacking in calcium and phosphorus or both result in sub-normal bone development. Calcium deficiency symptoms are sometimes slow to develop because additional calcium supplies in the body may be used to fill the body’s needs when the ration is deficient. Once these supplies run out, then signs of calcium deficiency result. (See hypocalcemia page F338.) Sheep and goats require 0.20-0.90% calcium in the diet.
  4. Phosphorus: Because of its role in both vitamin and enzyme activity, this mineral is important in the metabolism of almost all nutrients. Phosphorus deficiency results in slow growth, high feed requirements, decreased appetite, unthrifty appearance, and listlessness. It also causes weak newborns, decreased milk production, and lower efficiency of feed utilization. Forage containing below 0.16% phosphorus is usually considered deficient for ewes/does during gestation, and 0.20% is considered borderline during lactation. Legumes and young forages are usually adequate in phosphorus. A calcium-to-phosphorus ratio of 1:1 to 2:1 is recommended.
  5. Copper: Deficiency in copper results in muscular incoordination and produces "steely" or "stringy" wool in sheep. Newborn animals may be weak. Certain areas of the U.S. have adequate copper levels, while others are deficient. Copper can be supplied in copper deficient areas by adding copper sulfate to the diet. Caution should be used when supplementing copper, particularly in sheep. Goats require about 10 ppm in the diet, while toxicity can result if this level is fed to sheep.
  6. Cobalt: Cobalt’s function is to promote the synthesis of vitamin B12 in the rumen. Deficiency (less than 0.10 ppm) causes a loss of appetite, lack of thrift, weakness, and anemia. Cobalt "bullets" or pellets are available.
  7. Sulfur: Sulfur in some form is essential, and practically all common feedstuffs contain more than 0.15% sulfur.
  8. Magnesium: This mineral plays an important role in carbohydrate metabolism and in the proper functioning of the nervous system. Rations containing as much as 0.12-0.18% magnesium are considered adequate.
  9. Potassium: Most sheep and goat rations should contain 0.50-0.80% potassium. Toxicities and deficiencies are rare in sheep and goats.
  10. Selenium: Selenium is associated with vitamin E metabolism and is important in prevention of muscular dysfunction. Diets should contain about 0.10-0.30 ppm of selenium for goats and 0.10-0.20 ppm for sheep.
  11. Molybdenum: Excess molybdenum may be toxic and cause copper deficiency. If this occurs, scouring, lameness, and loss of weight can result.

Examples of Minerals Added to Grain Mix or Free Choice Fed (ad libitum):
  1. Salts (NaCl, composed of sodium and chloride) - Iodized salt, sulphurized salt, mineralized salt (trace minerals, Co, Mg, Mn, etc.), salt and cottonseed meal mixed.
  2. Calcium and phosphorus supplements - Steamed bone meal, oyster shell flour and/or flakes, limestone, bone char, di-calcium phosphate, and sodium tripolyphosphate.

The Roughage to Concentrate Ratio (R:C Ratio)

A ruminant diet is often a mixture of two components: "roughage" and "concentrate." Because some animal feeds and diets can have both concentrate and roughage characteristics, classifying feedstuffs by using these two terms can be difficult. In many senses, the two terms represent the classification extremes of a feedstuff or diet. In reality, each feedstuff or diet is somewhere in-between a roughage or concentrate:


Roughage:
High crude fiber
Large particle size
Low digestibility
Low content of digestible energy  
Low density		 →
Concentrate:
Low crude fiber
Small particle size
High digestibility
High content of digestible energy  
High density

Examples of Roughages - high in fiber and low in energy (TDN, NE):
  1. Legume roughages (baled, ground, or chopped) - Alfalfa hay, alfalfa meal (suncured or dehydrated), alfalfa leaf meal (suncured or dehydrated), alfalfa stem meal (suncured).
  2. Mixed-legume and non-legume (baled, ground, or chopped) - Alfalfa and cereal hays (oats, barley, and wheat), alfalfa and straw, wild native hays.
  3. Low grade by-products (hays) - Cereal straws, molasses, cottonseed hulls, almond hulls, oat hulls, rice hulls, corn cobs.
  4. Silages (water removed to help preserve) - Corn silage, sorghum silage, alfalfa silage, oat and vetch silage, grain silage (added to a legume as pea silage).

Examples of Concentrates - low in fiber and high in energy (TDN, NE):
  1. Cereal grains/seed concentrates (fed whole, rolled, cracked, or ground) - Barley, corn, oats, wheat, grain sorghums (milo), beans, peas, corn and cob meal, rice, rye, millet, and buckwheat.
  2. By-product concentrates - Beet pulp, orange pulp, lemon pulp, cane molasses, beet molasses, dried potatoes or meal, dried figs, dried dates, dried raisins, dried apples, dried peaches, dried apricots, dried tomato pomace, bakery waste, dried olive pulp, dried and/or wet melons.
  3. Cereal by-products (milling) concentrates - Wheat bran, wheat mixed feed (millrun), brewers dried grain, brewers dried yeast, hominy feed, and corn gluten feed or meal.
  4. Vegetable protein concentrates (oil meals) - Flake or cake cottonseed meal, soybean oil meal, linseed oil meal, coconut oil meal (copra), sesame oil meal, safflower oil meal, peanut oil meal, and canola oil meal.
  5. Animal protein concentrates* - Meat and bone scraps, meat scraps, tankage, fish meal, blood meal, dried skim milk, dried buttermilk, and dried whey.

* Note: These packing house products are not always available from renderers due to APHIS regulations. Always check with authorities before feeding.

Characteristics and Evaluation of Feeds

Hay: Good quality hay is an important resource in feeding does/ewes and when introducing animals to grain. The quality of hay depends on its composition and the time of cutting. The earlier the hay is cut and the higher its legume (alfalfa, clover etc.) content, the better the quality. Save the best quality hay for the weaners, and if severe conditions exist, preserve it for the lactating mothers. When buying hay, always buy by weight; do not buy on a per-bale basis, if possible, without checking the weights of the bales first. Bale weights can vary as much as 100%.

Straw: Straw can be used as the roughage part of a ration during extreme conditions (drought), but its protein content and digestibility is low. Short, fine stemmed straw is more acceptable than coarse straw. All of the cereal grains leave straw as a residue following grain harvesting (wheat, barley, oat, rye, etc.). Ammoniated treated straw has shown benefits in reducing the costs of wintering ewes in early pregnancy.

Oats: Because of its high fiber content that helps to reduce digestive problems, oats are the safest cereal grain to feed. Oats often have a higher cost per energy unit when compared to other grains, like wheat. If there are limited quantities of oats on the ranch, they should be reserved for weaner lambs and other special purposes (for example, quickly introducing animals to grain diets). Oats are, however, lower in protein than most other grains (around 12% crude protein). In the absence of a green harvest, some protein supplementation will be needed if low-protein oats form the major part of the ration for weaners, ewes/does, and lambs/kids.

Wheat: Because its fiber content is very low, wheat should be introduced carefully to avoid digestive problems and even death. Wheat, like other grains, has a high energy content. It is likely to be one of the cheapest sources of energy and the most readily available. The wastage of wheat and barley when fed on the ground seems to be less than the wastage of oats.

Barley: Barley contains more fiber than wheat and has close to the same energy value. Experience has indicated that it may produce fewer digestive problems than wheat. However, barley still needs to be fed with the same care as wheat when animals are being introduced to it.

Sorghum and Corn: Sorghum tends to have about the same energy value as most of the other grains. Corn, however, generally has one of the highest energy values of all the feed grains. Corn grain can have a net energy of 0.86 Mcal per pound.

Peas and Beans: Peas and beans have close to the same energy value as wheat, but have much higher protein contents. These can be used to the greatest advantage by adding small quantities (up to 20% or 30%) to enrich low-protein rations for weaners and lactating animals.

Pellets, Cubes, and Wafers: Some producers choose to fed pellets because of the ease of storage and ease of feeding. However, the value of these feeds is largely determined by considering their energy and protein content. Generally, the more fiber they contain, the lower their energy content. Pellets generally have a higher protein content than grains. In most cases, however, there is no advantage in paying a premium for pellets with a very high protein content unless they are used, like peas or beans, to balance a protein-deficient ration. Pellets should be introduced carefully to avoid digestive upsets. Because pellets may vary in their composition, care should be taken when feeding a new batch of pellets to animals that have been eating different pellets for some time. The rate of passage for pellets is faster than most roughages. This means that consumption will increase significantly. Be sure to limit feed the pellets to the sheep/goats, especially ewes/does or rams/bucks to prevent problems.

Visual Evaluation of Feeds:

When choosing a particular hay, the following should be considered:

  1. Consider the color and cutting dates - Green, freshly cut hay generally contains more vitamins and nutrients. Third and fourth cutting hays may be excellent quality, but are sometimes too rich in protein and too low in fiber for the particular needs of the animal.
  2. Different types of hay vary widely in amounts of protein, energy, vitamins, and minerals. A forage analysis is the only way to be sure of the nutrient levels provided by a particular feed. (See page B577.)
  3. Pick the quality of hay that meets the specific animal’s needs for its stage of growth, production, age, and environmental conditions. Often, the highest quality hay is "too good" and can create digestive system problems and rumen dysfunction.
  4. Evaluate the hay for general condition. Do not feed dusty or moldy hay.
  5. Stem-to-leaf ratio - A high leaf ratio makes a feed more nutritious and palatable. A feed with plenty of leaves has a greater value per ton.

When choosing a type of grain, the following should be considered:

  1. Evaluate the color and smell - All grains should be brightly colored and have no foul odor. Changes in color and smell may indicate bacteria or mold contamination. Avoid grain that is dirty or contains rocks, sticks, etc.
  2. Grain that is high in moisture or light in weight (pounds per bushel) will have a lower density of nutrients.
  3. Kind of grain - The energy value of grains varies widely. Corn is considerably higher in energy value than oats; conversely, oats are higher in protein than corn.


Sheep and Goat Water Supplies

Basic ranch or farm water management should provide sufficient water for immediate stock needs, with a safety margin to ensure adequate supplies during a drought or periods of reduced rain and/or snowfall. The adequacy of livestock water supplies on a ranch will be determined by two main factors:

  1. Quantity of water available - daily availability and annual storage capacity per head, and
  2. Water quality - palatability and content of salts.

Water Quantity: When planning water facilities and the quantity of water required by livestock, these factors should be considered:

  1. Species of animal (sheep, goat, etc.).
  2. Age of the animals and related body size.
  3. Environmental conditions - temperature and humidity.
  4. Degree of activity - distances between feed and water.
  5. Type and amount of feed - green or dry.
  6. Physiological state of the animal - dry, pregnant, or lactating.
  7. Health of the animal.
  8. Water quality - the higher the salt content the lower the intake.

Daily Water Requirements:
Animal    Gallon(s) Per Day
Rams and Billies    1.0 - 2.5
Dry Ewes and Does    1.0 - 2.5
Lactating Ewes    2.0 - 4.0
Lactating Does    2.0 - 4.5
5 - 20 lb. Lambs and Kids    0.1 - 0.3

* These are average figures, and individual intakes may be affected by the factors affecting water consumption listed earlier.

When planning ranch or farm water schemes, it is necessary to ensure sufficient capacity to meet peak daily requirements and peak seasonal needs.

Water Quality: The quality of stock water is determined by the mineral content of the water. The level of salt (salinity) is the most important mineral to consider. Water with a high mineral content will cause stock to go off feed, drop body condition, and may lead to death. Reproduction and lactation processes may also be affected.

Stock tolerance to the mineral content in the water depends on:

  1. The salt content - consider the concentration of total salts and the type of salt found in the water.
  2. Climatic conditions - high temperatures increase water intake; they also increase evaporation and raise the salt content in troughs and storage facilities.
  3. Species of livestock.
  4. Acclimatization - allowing access to a water supply low in mineral content prior to increasing the salinity level may encourage the stock to drink water.
  5. Type of feed - green feed vs dry feed. Green feeds tend to be higher in water and lower in salt content.
  6. Physiological state or level of production - pregnant and lactating stock are less tolerant to high mineral levels than other adult stock.

Recommendations for total dissolved solids (ppm) in water:

* Salinity levels are usually expressed as "parts per million" (ppm) of total soluble salts (tss).

Algae: Build-up of algae in tanks and dams can block intake pipes and tanks. A rapid build-up of algae during warm conditions in summer and autumn may lead to stock losses from algae poisoning.

Algae can be controlled in dams and tanks by the use of "blue stone" (copper sulphate). Copper sulphate will corrode metal tanks, troughs, and pipes; careful dilution will reduce corrosion.

* Most states have water testing services available. It is recommended that a local cooperative extension service county agent be contacted for more specific information.