|Nutrition of Meat Goats|
Nutrition of Meat Goats
Feeding is an essential aspect of goat raising and may be the highest expense of any meat goat operation. Goats raised for meat need high quality feed in most situations and require an optimum balance of many different nutrients to achieve maximum profit potential. Because of their unique physiology, meat goats do not fatten like cattle or sheep do, and rates of weight gain are smaller. Therefore, profitable meat goat production can only be achieved by optimizing the use of high quality forage and browse and the strategic use of expensive concentrate feeds. This can be achieved by developing a year round forage program allowing for as much grazing as possible throughout the year.
Nevertheless, many people still believe that goats eat and do well on anything from newspapers to tin cans. Attempting to manage and feed goats with such a belief will not lead to successful meat goat production.
The goat is not able to digest the cell walls of plants as well as the cow because feed stays in their rumen for a shorter time period. A distinction as to what is meant by "poor quality roughage" is necessary in order to make decisions concerning which animal can best utilize a particular forage. Trees and shrubs, which represent poor quality roughage sources for cattle, because of their highly lignified stems and bitter taste, may be adequate to high in quality for goats. This is so because goats avoid eating the stems, don't mind the taste and benefit from the relatively high levels of protein and cell solubles in the leaves of these plants. On the other hand, straw, which is of poor quality due to high cell wall and low protein, can be used by cattle but will not provide even maintenance needs for goats because goats don't utilize the cell wall as efficiently as cattle.
Goats must consume a more concentrated diet than cattle because their digestive tract size is smaller with regard to their maintenance energy needs. Relative to their body weight, the amount of feed needed by meat goats is approximately twice that of cattle. When the density of high quality forage is low and the stocking rates are low, goats will still perform well because their grazing/browsing behavior allow them to select only the highest quality forage from that on offer. Thus, they are able to perform well in these situations, even though their nutrient requirements exceed those of most domesticated ruminant species.
Nutrients are substances that aid in the support of life for the animals. Meat goats require nutrients for body maintenance, growth, reproduction, pregnancy, and production of products such as meat, milk and hair. The groups of nutrients that are essential in goat nutrition are water, energy, protein, minerals and vitamins. The nutrient requirements of bucks, young goats and does with a high production potential and at various stages of development and production are shown in Table 1. These nutritional requirements have been calculated to be met on a daily basis. Weanling goats, followed by does during the last month of gestation and high lactating does, and yearlings, require a higher quality diet than average lactating does, adult bucks and dry does. In order to feed them adequately, animals should be grouped according to their nutritional needs. Therefore, wealings goats, does during the last month of gestation, high lactating does and yearlings should be grouped and fed separately from the rest of the herd having lower nutritional needs. In a grazing situation, animals having the highest nutritional requirements should have access to lush, leafy forage or high quality browse. In a barn feeding situation such as during some winter months, these same animals should be offered the highest quality hay available. Whether grazed or barn fed, goats should be supplemented with a concentrate feed when either the forage that they are grazing or the hay that they are fed do not contain the necessary nutrients to cover their nutritional requirements. Total digestible nutrients (TDN), which are a measure of energy and quality of feeds, are shown in Table 1. To give producers an idea where these requirements fall, low quality forages contain 40-55% TDN, good quality forages contain from 55 to 70% TDN, and concentrate feeds contain from 70 to 90% TDN.
Water is the cheapest feed ingredient. However, production, growth and the general performance of the animal will be affected if insufficient water is available. Water needs vary with the stage of production, being highest for early lactating does, and during times when the weather is warm and forages are dry. In some instances, when consuming lush and leafy forages, or when grazing forages soaked with rain water or a heavy dew, goats can get all the water they need out of the feed. However, water is almost always needed by some members of the herd such as lactating does. Because it is difficult to predict water needs, goats should always have access to sufficient high quality water.
Energy comes primarily from carbohydrates (sugars, starch and fiber) and fats in the diet. Bacteria that are present in the rumen of goats ferment sugars, starches fats and fibrous carbohydrates into volatile fatty acids. These acids are absorbed and used for energy. Fat is efficiently used for energy, but the amount that can be included in the diet is limited. Usually added fat should not represent more than 5% of a diet because it depresses ruminal fermentation. For example, if whole cottonseed is used as a supplement, it should not be more than 20% of the diet because whole cottonseed contains 25% fat. Whole cottonseed also contains a good level of protein and phosphorous, and at 0.5 to 1.0 lb per day makes an excellent supplement to low quality forage. If the diet consumed by goats contains an excess of energy, that extra energy can be stored in the body as fat, mainly around certain internal organs.
Protein is usually the most expensive component of the goat diet. Protein is required both as a source of nitrogen for the ruminal bacteria and to supply amino acids for protein synthesis in the animal's body. When the levels of protein are low in the diet, digestion of carbohydrates in the rumen will slow down and intake will decrease. Inadequate levels of protein in the diet can affect growth rate, milk production, reproduction and disease resistance negatively, because insufficient amino acids are getting to the intestines to be absorbed by the body. Unlike energy, excess of protein is not stored in the body of the goat. Therefore, it is important to feed enough protein to cover the nutritional requirements of the animal. Protein nutritional requirements vary with developmental and physiological stages and level of production (Table 1).
Goats require many minerals for basic body function and optimum production. Providing free choice a complete goat mineral or a 50:50 mix of trace mineralized salt and dicalcium phosphate is advisable under most situations. Major minerals likely to be deficient in the diet are salt (sodium chloride), calcium, phosphorous and magnesium. Most forages are high in calcium, so calcium is low only if high grain diets are fed, which would be unusual for goats. Low quality, weathered forages will be deficient in phosphorous, especially for high and average lactating does. The ratio of calcium to phosphorous in the diet is important and should be kept about 2:1 (Table 1). Grass tetany can occur when goats in early lactation are grazing lush, leafy small grain, annual ryegrass of grass/legume pastures. Under those conditions, It is advisable to provide a mineral mix that contains 5 to 10% magnesium.
Trace minerals likely to be low in diets are copper, zinc and selenium. Selenium is marginal to deficient in all areas of North Carolina and most of the Southeast, and many commercial trace mineralized salts do not contain it. Trace mineralized salts that include selenium should be provided to the goat herd at all times. Producers should make sure that the trace mineralized salts they buy contain selenium. In case selenium is absent, they should encourage their local feed store to include it in the mix or to order trace mineralized salts that contain selenium.
Vitamins are needed by the body in very small quantities. The vitamins most likely to be deficient in the diet are vitamin A and D. All B and K vitamins are formed by bacteria found in the rumen of the goat and are not considered dietetically essential. Vitamin C is synthetisd in the body tissues in adequate quantities to meet needs.
Vitamin A is not contained in forages, but carotene found in green, leafy forages is converted into vitamin A in the body. In addition, vitamin A is stored in the liver and fat of goats during times when intake exceeds requirements. Goats consuming weathered forages or forages that have undergone long-term storage should be fed a mineral mix containing vitamin A, or should receive vitamin A injections.
Vitamin D may become deficient in animals raised in confinement barns. Animals should have frequent access to sunlight because it causes vitamin D to be synthesized under their skin, or they should receive supplemental vitamin D. Good quality sun-cured hays are excellent sources of vitamin D. A deficiency in vitamin D results in poor calcium absorption leading to rickets, a condition where the bones of young animals and joints grow abnormally.
FACTORS INFLUENCING ANIMAL REQUIREMENTS
A certain amount of each nutrient is required for maintenance of the body, which is the need for nutrients the animal has to keep warm, and to maintain its body weight. A mature dry doe or a mature wether are examples of animals having maintenance requirements only. Additional requirements above those needed for maintenance are required for growth, pregnancy, lactation and hair production. As the productivity of meat goats is increased through selection and crossbreeding with goats having a higher production potential, such as the Boer goat, nutritional requirements will also increase. Therefore, the more productive goats should be fed high quality feed, especially weaned kids being prepared for market, young replacement doelings and does in late gestation and early lactation. Does lactating twins or triplets have grater nutritional requirements than does lactating a single kid.
Goats grazing very hilly pastures will have higher nutritional requirements than goats on level pastures of the same quality because they will expand more energy to gather feed on difficult terrain.
In some situations where brush control in rough areas is the primary purpose of keeping goats, less productive animals can be roughed through and forced to work on brushy areas. If their body condition deteriotates, these animals can then be grazed on better quality pastures. Once desirable body condition is achieved, the same animals can again be used to control brush.
NUTRITIONAL MANAGEMENT OF MEAT GOATS
Nutrition of Newborn Kids. Colostrum is the first milk produced after parturition . Colostrum contains a high content of immunoglobulins (antibodies), vitamin A, minerals, fat and other sources of energy. Antibodies are proteins which help the goat kid fight diseases. The ability of kids to resist diseases is greatly affected by the timing of colostrum intake and the quantity and quality of the colostrum fed. Reports from cattle indicate that if left alone, 25% of the young do not nurse within 8 hours and 10 to 25% do not get sufficient amounts of colostrum. Colostrum should be ingested or bottle-fed (in case of weak kids) as soon as kids have a suckling reflex. In cases of extremely weak kids, they should be tube-fed. The producer must be certain that all newborn kids get colostrum soon after birth (within the first hour after birth, and certainly within the first 6 hours) because the percentage of antibodies found in colostrum decreases rapidly after parturition. It is crucial that the antibodies in colostrum be consumed before the kids suck on dirty, pathogen-loaded parts of its mother or stall. In addition, the ability of the newborn kid to absorb antibodies also decreases rapidly 24 hours after birth. Newborn kids should ingest 10% of their body weight in colostrum during the first 24 hours of life for optimum immunity. The extra colostrum produced by high lactating does during the first 24 hours following kidding can be frozen for later use when needed. Only first milking from healthy animals should be frozen for later feeding, and the colostrum from older animals that have been on the premises for several years is typically higher in antibody content against endemic pathogens than is colostrum from first fresheners. Revaccination against tetanus and enterotoxemia (over-eating disease) 2 to 4 weeks before the kidding date is commonly used to improve the protective value of the colostrum against these conditions. Ice cube trays are ideal containers: once frozen, cubed colostrum can be stored in larger containers and the trays used for another batch. Ice cubes are the perfect size for newborn kids, thus thawed colostrum is always fresh, and wastage reduced to a minimum. It is recommended to thaw colostrum either at room temperature or at a fairly low temperature. Colostrum should never be overcooked during the thawing process.
Nutrition of Replacement Does
Doe kids needed for replacement should be grazed with their mothers during as much of the milking period as possible and not weaned early. Following weaning, doe kids should be separated from the main herd and have access to high quality forage and receive good nutrition through first kidding at 1-2 years of age, depending on the nutritional plane. Leaving doe kids with the main herd will result in undernourished does that are bred too young and too small; these animals will never reach their production potential. A yearly supply of replacement does that are healthy, of good size, and free of internal and external parasites, is essential to the success of any meat goat enterprise.
Pregnancy Disease (Ketosis)
During late pregnancy, does require a relatively high level of nutrients. In fact, nutritional requirements are as high during late pregnancy as they are during lactation, especially if the pregnant doe is carrying more than one fetus. Not only are extra nutrients needed by the developing fetuses, but they also crowd the abdominal cavity and reduce ruminal volume. As a result, large amounts of feed cannot be consumed. Because of this, does fed a poor quality diet (especially if they are fat) can develop ketosis and die due to inadequate energy intake. Grain and protein meal and to a lesser extent whole cottonseed are the prefered feeds to overcome this problem.
Inadequate nutrition during late pregnancy will also result in small, weak kids at birth, and high early death losses, especially in twin and triplets. When forage or browse is low in quality, (40 to 55% TDN; 10% protein or less), does in late pregnancy and early lactation should be provided with about 1 lb/day of a 16% protein concentrate.
In goats, clinical obstruction of the urinary tract is most frequently seen in young, castrated males and the calculi are usually comprised of calcium phosphate salts. Castrated goats kept as pets and show bucks are at high risk for developing the condition due primarily to the feeding of excessive grain in the diet. If the diet contains too much phosphorous relative to calcium, supplemental calcium from feed grade limestone is required to maintain a calcium:phosphorous ratio of 2:1 to 4:1.
Producers should be concerned with the body condition of their breeding animals. The term body condition refers to the fleshing of an animal. Does should not be allowed to become too thin or too fat. Failure in reproduction, low twinning rates and low weaning rates will result if does are too thin. Overly fat does can suffer pregnancy toxemia, but fat does are rarely a problem .
Simply looking at an animal to determine its body condition can easily be misleading. Rather, animals should be touched and evaluated in a chute. The easiest area to feel and touch to determine the body condition of an animal are the rib areas, on either side of the spine, by running a hand over those areas and pressing down with a few fingers. In doing so, one is able to determine the amount of fat covering the ribs. Other areas to monitor are the shoulders, the tail heads, the pins, the hooks, the edge of the loins and the backbone. Practice makes perfect, thus use your animals to get a feel for it. An easy way to start is to select a few animals that are over conditioned and some others that are thin to get a feel for extreme cases. Then introduce a small group of animals and compare their condition to the animals having extreme body condition. Producers should develop an eye and a touch for the condition of their animals and strive to maintain a moderate amount of condition on their goats. If you can easily see the backbone and ribs, the goats are most probably undernourished. When body condition starts to decrease, it is a sign that supplemental feed is needed or that animals should be moved to a higher quality pasture. Waiting until goats become thin to start improving their feeding regime may lead to large production losses.
One should also be concerned with the body condition of the breeding bucks. Bucks will have reduced fertility if they are too thin. On the other hand, if bucks are overfed and become too fat, they may have no desire to breed does.
Flushing means increasing the level of feed offered to breeding does, mostly energy, starting about one month prior to the introduction of the bucks, to increase body weight, ovulation rate and hopefully litter size. Increasing the level of energy offered to does should continue throughout the breeding season and for approximately 30 to 40 days after removing the bucks, for adequate implantation of the foetuses in the uterus. Body condition is used to determine whether flushing will be of benefit to breeding does. Does in extremely good body condition will tend not to respond to flushing. On the other hand, does that are in relatively poor condition as a result of summer pastures of poor quality, high worm loads, late kidding of twins or triplets, will respond favorably to flushing by improving their body condition.
Flushing can be accomplished by moving breeding does to a lush nutritious pasture 3 to 4 weeks prior to the introduction of the bucks. This cost-effective flushing method is underutilized in the Southeast where forage is abundant. Another method is feeding ½ lb/day of a high energy supplement. Corn is the grain of choice for flushing; whole cottonseed is another low cost, high energy supplement. The goal being to increase the intake and body weight, breeding does should be grouped according to their body condition and fed accordingly to first improve their body condition, then to maintain it.
SUGGESTED SUPPLEMENTAL FEEDING PROGRAM FOR GOATS
As a general recommendation, trace mineralized salt containing selenium should be given to all goats year around. A complete goat mineral should be offered free choice year-around in most production situations. When goats are raised on browse, abundant forage should be made available to allow goats to be very selective and to ingest a high quality diet that will meet their nutritional requirements. When forage or browse is limited or of low quality (< 10% protein), lactating does (and does in the last 30 days of gestation) and developing/breeding bucks should be fed 1.0 lb/day of a 16% protein mixture (77:20:2.5:0.5 ground corn : soybean meal : goat mineral : limestone). Alternatively, ground corn and soybean meal can be substituted by whole cottonseed for lactating does. Low to medium quality forage (> 10% protein) will meet requirements of dry does and non-breeding bucks. When forage or browse is limited or of low quality (< 10% protein), weanlings and yearlings should be fed 1.0 lb/day of the 16% protein mixture. Goats can be forced to eat very low quality feed including twigs, tree bark, etc., but producers should be aware this practice will hurt the productivity of superior meat and fiber goats.
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Last modified October 1998
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