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Rights & Permissions Free Resources Display this book on your site! Related Titles Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fat, Fatty Acids, Cholesterol, Protein, and Amino Acids (Macronutrients) Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate Other Related Titles Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries (1981) Board on Agriculture (BOA) Web Search Builder Use this book's key terms to search within this book, across our collection, or across the Web. Skim This Chapter Skim this chapter and use this chapter's key terms to search within this book. Reference Finder Paste in your own text to find books that relate to your topic. Page 2   E-mail  Facebook  Digg  Stumble  Twitter More The following HTML text is provided to enhance online readability. Many aspects of typography translate only awkwardly to HTML. Please use the page image as the authoritative form to ensure accuracy. 2 NUTRIENT REQUIREMENTS ENERGY Efficient utilization of nutrients depends on an adequate supply of energy, which is of paramount importance in determining the productivity of goats. Energy deficiency retards kid growth, delays puberty, reduces fertility, and depresses milk production (Singh and Sengar, 1970; Sachdeva et al., 1973). With continued deficiency the animals show a concurrent reduction in resistance to infectious diseases and parasites. The problem may be further complicated by deficiencies of protein, minerals, and vitamins. Energy limitations may result from inadequate feed intake or from the low quality of the diet. Low energy intake that results from either feed restriction or low diet component digestibility prevents goats from meeting their requirements and from attaining their genetic potential. High water content of forages may also become a limiting factor. Energy requirements are affected by age, body size, growth, pregnancy, and lactation, which have been treated as separate items in presenting requirements (Table 1). Energy requirements are also affected by the environment, hair growth, muscular activity, and relationships with other nutrients in the diet which, for best results, need to be supplied in adequate amounts. Temperature, humidity, sunshine, and wind velocity may increase or decrease energy needs depending upon the region. Stress of any kind may increase energy requirements. Shearing mohair from Angora goats and pashmina from Cashmere goats decreases insulation and results in increased energy needs, especially during cold weather. Goats are more active and travel greater distances than sheep, which increases energy requirements. Maintenance requirements of goats on pasture, browse, and range, especially in mountainous and transhumance grazing, are considerably higher than those of stable-fed animals. The magnitude of this increase is considered in Table 1 at three levels of activity, and depends on availability of feed, water, topography, elevation and distances travelled in grazing. Good quality roughages furnish about 2 Mcal metabolizable energy (ME) per kg dry matter (DM). Roughage-concentrate mixed rations are sometimes necessary to increase the energy content of the diet to 2.5 or 3.0 Mcal ME/kg DM when feeding early weaned kids or high-producing dairy goats. The efficiency with which energy is utilized for weight gain, pregnancy, and lactation usually increases with increasing levels of ME concentration in the diet. It is probable that under certain conditions goats require a minimum of fats in their diet (Fehr and Delage, 1973; Morand-Fehr and Sauvant, 1980), but more studies are needed to better define these requirements. The energy requirements of goats reported here are amounts needed for maintenance (including physical activity), optimum growth, reproduction, and milk and fiber production; they do not represent maximum levels under ad libitum intake. Energy requirements for the various categories of goats in Table 1 have been expressed as digestible energy (DE), ME, and net energy (NE) for maintenance, gain, pregnancy, lactation, and fiber production. Figures for total digestible nutrients (TDN) have been included because they are still widely in use around the world. For converting one form of energy into another the recommendations of Garrett et al. (1959) have been used: 100 Mcal gross energy (GE)=76 Mcal DE=62 Mcal ME=35 Mcal NE. These values are higher than would be expected in forage-only diets; however, their relative relationships would still hold. For converting one standard of energy requirement into another, the following equalities have been employed (two or three significant decimal figures are included to reduce rounding errors): 1 kg starch equivalent (SE) or European starch unit (ESU)= 5.082 Mcal DE=2.356 kcal NE 1 kg digestible organic matter (DOM)=1.05 kg TDN 1 kg SE or 1 ESU=1.15 kg TDN=1.10 kg DOM 1 kg DOM=4.620 Mcal DE 1 kg TDN=4.409 Mcal DE 1 feed fettening unit (ffu)=1.650 Mcal ME Page 2 Front Matter (R1-R8) 1 Introduction (1-1) 2 Nutrient Requirements (2-9) 3 Table of Nutrient Requirements (10-12) 4 Herbage and Browse Utilization (13-14) 5 Ration Formulation and Examples of Typical Rations (15-20) 6 Nutrition-Related Metabolic Disorders (21-23) 7 Feed Composition Tables (24-72) Bibliography (73-91)

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries 2 NUTRIENT REQUIREMENTS ENERGY Efficient utilization of nutrients depends on an adequate supply of energy, which is of paramount importance in determining the productivity of goats. Energy deficiency retards kid growth, delays puberty, reduces fertility, and depresses milk production (Singh and Sengar, 1970; Sachdeva et al., 1973). With continued deficiency the animals show a concurrent reduction in resistance to infectious diseases and parasites. The problem may be further complicated by deficiencies of protein, minerals, and vitamins. Energy limitations may result from inadequate feed intake or from the low quality of the diet. Low energy intake that results from either feed restriction or low diet component digestibility prevents goats from meeting their requirements and from attaining their genetic potential. High water content of forages may also become a limiting factor. Energy requirements are affected by age, body size, growth, pregnancy, and lactation, which have been treated as separate items in presenting requirements (Table 1). Energy requirements are also affected by the environment, hair growth, muscular activity, and relationships with other nutrients in the diet which, for best results, need to be supplied in adequate amounts. Temperature, humidity, sunshine, and wind velocity may increase or decrease energy needs depending upon the region. Stress of any kind may increase energy requirements. Shearing mohair from Angora goats and pashmina from Cashmere goats decreases insulation and results in increased energy needs, especially during cold weather. Goats are more active and travel greater distances than sheep, which increases energy requirements. Maintenance requirements of goats on pasture, browse, and range, especially in mountainous and transhumance grazing, are considerably higher than those of stable-fed animals. The magnitude of this increase is considered in Table 1 at three levels of activity, and depends on availability of feed, water, topography, elevation and distances travelled in grazing. Good quality roughages furnish about 2 Mcal metabolizable energy (ME) per kg dry matter (DM). Roughage-concentrate mixed rations are sometimes necessary to increase the energy content of the diet to 2.5 or 3.0 Mcal ME/kg DM when feeding early weaned kids or high-producing dairy goats. The efficiency with which energy is utilized for weight gain, pregnancy, and lactation usually increases with increasing levels of ME concentration in the diet. It is probable that under certain conditions goats require a minimum of fats in their diet (Fehr and Delage, 1973; Morand-Fehr and Sauvant, 1980), but more studies are needed to better define these requirements. The energy requirements of goats reported here are amounts needed for maintenance (including physical activity), optimum growth, reproduction, and milk and fiber production; they do not represent maximum levels under ad libitum intake. Energy requirements for the various categories of goats in Table 1 have been expressed as digestible energy (DE), ME, and net energy (NE) for maintenance, gain, pregnancy, lactation, and fiber production. Figures for total digestible nutrients (TDN) have been included because they are still widely in use around the world. For converting one form of energy into another the recommendations of Garrett et al. (1959) have been used: 100 Mcal gross energy (GE)=76 Mcal DE=62 Mcal ME=35 Mcal NE. These values are higher than would be expected in forage-only diets; however, their relative relationships would still hold. For converting one standard of energy requirement into another, the following equalities have been employed (two or three significant decimal figures are included to reduce rounding errors): 1 kg starch equivalent (SE) or European starch unit (ESU)= 5.082 Mcal DE=2.356 kcal NE 1 kg digestible organic matter (DOM)=1.05 kg TDN 1 kg SE or 1 ESU=1.15 kg TDN=1.10 kg DOM 1 kg DOM=4.620 Mcal DE 1 kg TDN=4.409 Mcal DE 1 feed fettening unit (ffu)=1.650 Mcal ME

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries 1 European feed unit (Efu)=2.500 kcal NE 1 kilojoule (kJ)=0.239 kcal 1 kcal=4.184 kJ Maintenance Energy requirements for maintenance of goats have been derived from pooled means of experimental data reported in terms of kcal ME/Wkg0.75 per day. These include: 111.00 (Haenlein, 1950); 115.09 (Majumdar, 1960); 90.35 (Devendra, 1967a); 109.93 (Singh and Sengar, 1970); 100.00 (Flatt et al., 1972); 92.92 (Akinsoyinu, 1974); 91.87 (Winter and Goersch, 1974); 87.31 (Itoh et al., 1979); 101.98 (Rajpoot, 1979); 113.34 (Sengar, 1980). The average is 101.38 kcal ME/Wkg0.75, which is comparable to figures provided for sheep: 98.31 (ARC, 1965); 95.75 (Olatungi, 1974); 91.99 (Adu, 1975); and 97.58 (NRC, 1975). But the figure is low compared to those for dairy cattle: 128.58 (ARC, 1965); 113.02 (NRC, 1978); and 115.22 (Rattray et al., 1974). The mean value of 101.38 kcal ME/Wkg0.75 has been used in Table 1 to determine goat maintenance requirements for body weights ranging from 10 to 100 kg. The energy requirements have also been expressed as they vary with energy concentration in the diet from 2.0 to 2.4 Mcal ME/kg DM. Activity The basic ME requirement has also been used to calculate values for grazing at three levels of muscular activity. A 25 percent increment was applied to the basic maintenance requirements in the case of light activity under grazing conditions of intensive management and under tropical conditions. A 50 percent increment should satisfy ME requirements on semiarid rangeland pasture and on slightly hilly land. Grazing on sparsely vegetated grassland and on mountainous transhumance pasture, which necessitates daily long-distance travel for grazing and watering and great differences of altitude, may require a 75 percent increment in the basic maintenance needs to meet additional energy requirements. Goats under stablefed conditions and with minimal activities should be fed according to the basic maintenance requirements only. Pregnancy Energy requirements for pregnancy in Table 1 have been derived from the difference of the basic requirements for maintenance (101.38 kcal ME/Wkg0.75) and two experimental values suggested for pregnancy: 173.60 (Akinsoyinu et al., 1978) and 180.94 (Rajpoot 1979). These values yield a mean of 177.27 kcal ME/Wkg0.75, which compares closely with 182.41 (McDonald et al., 1973); 179.33 (Akinsoyinu, 1974); and 190.43 (NRC, 1975) for sheep; and 172.97 (NRC, 1978) for dairy cattle. The value of 0.80 Mcal ME in Table 1 also compares well with French recommendations (Morand-Fehr and deSimiane, 1977). In view of the limited information available and the considerable variability among breeds of goats, no differentiation has been made between does producing single kids and those producing twins. An allowance of an additional 20 percent, as recommended for multiple birth in sheep by McDonald et al. (1973), has been included. It is understood that pregnancy means the last 2 months of gestation; no extra energy requirements for early pregnancy have been determined. The values take into consideration the weight of the animal and the fetuses. Growth Energy requirements for weight gain have been based on three experimental values: 10.18 (Devendra, 1967b); 5.14 (Akinsoyinu, 1974); and 6.43 (Rajpoot, 1979). These values have a mean of 7.25 kcal ME/g of gain, which is equivalent to 4.09 kcal NE. This value is also comparable to those for sheep: 3.74 (Garrett et al., 1959); 3.19 (Evans, 1960); 4.29 (ARC, 1965); 4.21 (Olatungi, 1974); and 2.90 (NRC, 1975). The values for dairy cattle are: 4.19 (Garrett et al., 1959); 2.94 (ARC, 1965); and 3.32 (NRC, 1978). Additional requirements, shown in Table 1, for all growing goats with daily weight gains of 50, 100, and 150 g, have been based on 7.25 kcal ME/g of gain. Lactation Energy requirements for lactation have been stated separately for the components of maintenance at different levels of activity and milk production. The requirements have been derived from four experimental values: 1260.00 (Knowles and Watkins, 1938); 1155.90 (Devendra and Burns, 1970); 1328.57 (Winter and Goersch, 1974); and 1240.00 (Rajpoot, 1979). These values yield a mean of 1246.12 kcal ME/kg of 4 percent fat-corrected milk (FCM). This value is comparable to 1202.29 (Blaxter, 1967; McDonald et al., 1973) and 1240.00 kcal ME/kg of 4 percent FCM (NRC, 1978) for dairy cattle. For the requirements of milk production in Table 1 the value of 1246.12 kcal ME/kg of 4 percent FCM has been used over a milk fat range of 2.5 to 6.0 percent For each 0.5 percent change in fat content from 4 percent milk, an addition or subtraction of 16.28 kcal ME has been applied (NRC, 1978). French recommendations are similar (Morand-Fehr and deSimiane, 1977). Fiber Production Energy requirements for fiber production by Angora goats have also been incorporated into Table 1, based on calculations by Huston et al. (1971). Although attempts have been made to determine the energy required for mohair fiber production (Gallagher and Shelton, 1972), the values have yet to be established. The values listed in Table 1 were computed by using a 33 percent efficiency of ME for mohair fiber production. No estimates for pashmina production have been made; however, the recommendations for mohair production can be used as a guide.

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries PROTEIN Proteins are the principal constituents of the animal body and are continuously needed in the feed for cell repair and synthetic processes. The transformation of feed protein into body protein is an important process of nutrition and metabolism. Proteins consist of amino acids and are the building blocks of all body cells. Secretions such as enzymes, hormones, mucin, and milk have additional amino acid requirements. Proteins are, therefore, vital for animal maintenance, growth, reproduction, and milk production. However, nonprotein nitrogen (NPN) can substitute for parts of the required protein for these functions (Morgen et al., 1907, 1908, 1909, 1910, 1922, 1925; Lawrow et al., 1924; Ungerer, 1924; Paasch, 1925; Honcamp and Keudela, 1927; Williger, 1927; Ziemer, 1931; French, 1957; Champredon and Pion, 1972a,b,c; Fauske, 1972; Kameoka et al., 1972; Mba et al., 1974; Gruhn et al., 1975; Haryu et al., 1975; Harmeyer and Martens, 1980). Protein deficiencies in the diet deplete stores in the blood, liver, and muscles, and predispose animals to a variety of serious and even fatal ailments. Below a minimum level of 6 percent crude protein (CP) in the diet, feed intake will be reduced, which leads to a combined deficiency of energy and protein (Perkins, 1957; Platt et al., 1964). This deficiency further reduces rumen function and lowers the efficiency of feed utilization. Long-term protein deficiencies retard fetal development, lead to low birth weights, affect kid growth, and depress milk production (Singh and Sengar, 1970). Protein requirements for maintenance, growth, pregnancy, and lactation have been stated along with the energy requirements in Table 1. They have been presented in terms of total protein (TP) and digestible protein (DP). The former has been recommended as the most accurate guide for converting proteins from feed composition tables to quantities required (Broster, 1972; Preston, 1972; Satter and Roffler, 1975), but DP values are also used widely around the world. In the past most people have estimated protein requirements based on metabolism trials employing graded protein levels in the diet. The amounts of protein needed to maintain the animal in nitrogen equilibrium were taken as the maintenance requirement. Nitrogen equilibrium was defined as the state in which nitrogen intake matches nitrogen outgo from all sources. The difficulty with this concept is that adult animals can adjust their nitrogen output and reach equilibrium, particularly at lower levels of nitrogen intake. Thus, nitrogen equilibrium as an indicator of adequate protein intake is of questionable value (Singh, 1976) and has not been used here in the determination of protein requirements of goats. Instead, protein requirements have been computed as a ratio to energy. Some workers have calculated the protein required for maintenance from the endogenous urinary nitrogen (EUN) excretion. Brody (1945) used a factor of 4 to convert EUN to the amount of digestible nitrogen needed for maintenance, while Elliott and Topps (1963) employed a factor of 2.96 for cattle. Neither of these factors can be used satisfactorily for goats; the EUN and maintenance requirements must be determined separately. Two types of biologically determined protein requirements have been reported. They pertain to minimum and maintenance levels, which must not be confused. The minimum protein requirements for goats have been reported: 1.61 (Majumdar, 1960a); 1.42 (Devendra, 1967a); 1.22 (Singh and Mudgal, 1978); 1.42 (Rajpoot, 1979); and 1.41 (Devendra, 1980b). The mean value is 1.42 g DP or 2.03 g TP/Wkg0.75 (70 percent average digestibility of total feed protein found in these studies). Maintenance Protein requirements for maintenance have been reported: 2.66 (Haenlein, 1950); 2.50 (Majumdar, 1960b); 2.85 (Singh and Sengar, 1970); 3.19 (Winter and Goersch, 1974); 2.12 (Itoh et al., 1979); 3.05 (Rajpoot, 1979); and 3.40 (Sengar, 1980); the mean value is 2.82 g DP or 4.15 g TP/Wkg0.75, with an average digestibility of 68 percent for total protein. This compares closely with 4.739 TP (NRC, 1975) for sheep and 4.09. g TP/Wkg0.75 (NRC, 1978) for dairy cattle. For the recommendations in Table 1, the calorie-to-protein ratios were determined to be 1 Mcal DE to 22 g DP to 32 g TP. Growth Except for the minimum maintenance requirements of protein, no other biologically determined values for body functions exist. For this report, the experimentally determined energy requirements for maintenance have been used for the development of protein requirements on the basis of calorie-to-protein ratios. In order to complete Table 1, the requirements of protein for weight gains have been derived from the following values: 0.274 (Devendra, 1967b); 0.139 (Akinsoyinu, 1974); and 0.173 (Rajpoot, 1979); the mean is 0.195 g DP or 0.284 g TP/g gain. Pregnancy No experimental values have been found for protein requirements of pregnancy. However, two values were calculated from two references: 4.68 (Akinsoyinu et al., 1978) and 4.90 (Rajpoot, 1979); the mean is 4.79 g DP or 6.97 g TP/Wkg0.75. This value takes into consideration maintenance requirements during the second half of gestation, and is about 10 percent lower than the value of 7.76 g TP/Wkg0.75 for dairy cattle (NRC, 1978). Lactation Protein requirements for milk production were determined from experimental values: 67.83 g DP or 96.90 g TP/kg milk of 4.5 percent fat (Devendra and Burns, 1970) and 46.56 g DP or 66.51 g TP/kg milk of 5.22 percent fat (Rajpoot, 1979), with a mean of 57.20 g DP or 81.71 g TP/kg of milk with 4.86 percent fat. This value is somewhat lower than the 98 g TP/kg of milk with 5 percent fat for

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries dairy cattle (NRC, 1978). In the absence of specific experimental evidence, the protein needs for different milk fat contents have been derived from those recommended for dairy cattle (NRC, 1978). It should be noted that the amounts of protein presented in Table 1 for growth, pregnancy, and lactation are based on calorie-to-protein ratios for maintenance, and therefore cannot be considered accurate for every situation because of differences in reproductive and productive rates. Some flexibility based on experience and judicious judgment is, therefore, advisable. French recommendations (Morand-Fehr and deSimiane, 1977) are similar to those listed in Table 1. Activity Protein requirements in Table 1 for muscular activity at the three levels above maintenance have not been determined experimentally. Recommendations for protein (TP and DP) requirements for horses at different stages of work include 26 and 36 percent increments above maintenance for light and medium work for mature animals of 200 to 600 kg body weight (NRC, 1973). This assures that the protein-to-calorie ratio required for maintenance is continued under conditions of work (Crampton, 1964). Later reports indicate that the needs for protein replacement could be small during light work and that excessive protein increases can be undesirable. Supplying greater amounts of concentrates during increased muscular activities may provide additionally needed protein (NRC, 1978). To establish requirements for this report, the TP and DP values for the three activity levels of goats were derived from the protein-to-calorie ratios for the maintenance-only level and low, medium, and high activity levels. Fiber Production Protein requirements for fiber production by Angora goats, shown in Table 1, are based on work published at the Texas Agricultural Experiment Station (Huston et al., 1971). MINERALS Requirements of minerals have not been established definitively for goats at either maintenance or production levels. However, some classical studies in mineral metabolism have been conducted with goats as experimental subjects. These include studies by Fingerling (1911, 1913), which addressed calcium and phosphorus requirements of lactating goats. Hart et al. (1921, 1924, 1927) and Henderson and McGee (1926) reported data on calcium metabolism in goats, which led to the discovery of the role of vitamin D in calcium absorption and metabolism. Lintzel and Radeff (1931) reported important work on iron nutrition in goats. In general, these and more recent studies support assumptions that some mineral requirements in goats are similar to those in other ruminant species; therefore, mineral requirements listed in Table 1 rely for the time being on values recommended for sheep (NRC, 1975) and dairy cattle (NRC, 1978). The literature on mineral nutrition in goats was recently reviewed (Haenlein, 1980). In addition to the elements in organic matter (oxygen, nitrogen, carbon, and hydrogen), seven major and nine minor minerals are considered dietary essentials for livestock. The major minerals that must be fed in relatively large amounts are calcium, phosphorus, sodium, chlorine, magnesium, potassium, and sulfur. Minor or trace minerals, required in small amounts, include iron, iodine, copper, molybdenum, zinc, manganese, cobalt, selenium, and fluorine. Others which are possibly essential at extremely low levels are chromium, nickel, vanadium, silicon, tin, and arsenic. Most of these essential or possibly essential elements occur naturally in feedstuffs at levels that do not constitute problems in nutrition. However, situations often exist when one or more minerals, especially the major ones, are sufficiently low to reduce productivity. Trace minerals in particular can be present in toxic amounts. Proper balance of minerals and bioavailability from supplements are often more important than actual levels (Miller, 1981). Functions and practical implications of various important minerals are discussed individually. Calcium Calcium is a critical nutrient in ration formulation for all species of livestock. Although most of the calcium found in the body is in the skeleton, the element has numerous crucial functions in the soft tissues. A deficiency of calcium in young animals leads to retarded growth and development, and can predispose them to rickets. Because milk is high in calcium (Macy et al., 1953; Parkash and Jenness, 1968), rations for lactating goats need a higher calcium level. Fingerling (1911, 1913) found that if lactating goats did not receive the necessary amounts of calcium and phosphorus in their diets, they would draw from body stores of these elements without initially affecting milk yield or milk composition. If the calcium deficiency continued for weeks, the yield of milk decreased. At intakes of higher levels of calcium the goats replenished their body calcium stores and milk production increased. Changes in milk composition were not observed. Certain minerals interact with calcium metabolism. Experiments using ligated intestinal loops in anaesthetized goats and radioactively labeled calcium injections (Gibbons et al., 1972) showed that intestinal calcium transport is enhanced by carbohydrates and by low luminal concentrations of sodium. Calcium absorption occurred principally in the duodenum, to a far lesser extent in the jejunum, and least in the lower ileum. Under grazing conditions calcium is seldom a problem with either Angora or meat-type goats, but it can be very important for high-producing dairy goats. Low calcium diets lead to reduced milk production. Appropriate calcium levels in the diet are also important in the preven-

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries tion of parturient paresis (milk fever). The calcium content of goats milk is reported to be in the range of 1.14 to 1.63 g/kg (Macy et al., 1953; Parkash and Jenness, 1968). A median value would be 1.38 g/kg, which is marginally higher than for dairy cattle. This value has been used in formulating the recommendations in Table 1. Suggested calcium supplements or sources include bone meal, dicalcium phosphate, ground limestone, and oyster shell. The percentage composition of these and other sources is found in Table 3. Phosphorus Phosphorus is required for both tissue and bone development. A deficiency will result in slowed growth, depraved appetite, and unthrifty appearance; it is often accompanied by low levels of phosphorus in the blood. Fingerling (1911) showed that the general conclusions about calcium-deficient diets also applied to phosphorus. Goats were able to sustain milk production from body reserves for several weeks of negative phosphorus balances. During phosphorus deficiencies, when intake was one-fifth of normal for two months, the production of milk declined 60 percent. Supplementing the diet with P2O5 and CaO to achieve daily levels of 6 g phosphorus and 14 g calcium raised milk yields by 10 percent in two weeks and by 15 to 25 percent in four weeks, while diets remained isocaloric and isonitrogenous. The phosphorus level in goats’ milk ranges from 0.84 to 1.22 g/kg (Macy et al., 1953; Parkash and Jenness, 1968). The calcium-to-phosphorus ratio should not drop below 1.2:1 in diets for goats, even though no unanimity exists on the importance of the ratio. The significance of the calcium-to-phosphorus ratio in the genesis of urinary calculi is discussed later on. A phosphorus deficiency in grazing goats is more likely than a calcium deficiency. It might be encountered with any type of goat grazing on phosphorus-deficient forages. Documented examples of phosphorus deficiency in grazing goats are rare, however. This can be explained by their varied habitats and tendency to browse plants that may be high in phosphorus. Formulation of rations to include adequate phosphorus will be more important with high-producing dairy goats when they are fed with harvested or formulated feedstuffs. Sodium and Chlorine Common salt (sodium chloride) is perhaps the mineral most commonly supplied to animals. They require both sodium and chlorine, but sodium is the mineral most likely to be lacking (Schellner, 1972). When provided free choice, goats may consume salt in excess of their requirements, but with no apparent ill effects. Animals that do not receive sufficient salt may show depraved appetites and consume soil or debris. If goats are not provided free choice, salt should be added to the feed. A recommended level would be 0.5 percent of the complete feed or proportionately higher levels in supplements. Salt is important in several other ways. Placing it in less frequently grazed pastures may influence goats to move to those areas. Salt is also often incorporated at high levels to regulate free intake of nutritional supplements. Trace mineralized salt should not be used in this manner, however; it may lead to an oversupply of some trace elements. Goats in arid regions may have problems with the salt content of some water sources, which can reduce intake of water and feed. Magnesium Magnesium is required for many enzyme systems and for proper functioning of the nervous system. It is also closely associated with the metabolism of calcium and phosphorus. Symptoms of magnesium deficiency are anorexia, excitability, and calcification of soft tissue. The most noted problem associated with hypomagnesemia is grass tetany, a malady that frequently occurs in animals grazing on lush green grass or winter cereals in pastures fertilized with nitrogen and potassium. Treatment consists of intravenous administration of calcium and magnesium in the gluconate form. Goats do have a marginal ability to compensate for low dietary magnesium by reducing the rate of its excretion (Razifard, 1971, 1972a,b). Both urinary excretion and milk flow, which contains 0.13 to 0.36 g magnesium per kg, are reduced when magnesium is low in the diet. Potassium Potassium, though required in relatively large amounts, is usually present in roughage-based diets to the extent that it does not constitute a problem. Marginal deficiencies result in reduced feed intake, retarded growth, and reduced milk production. More severe deficiencies cause emaciation and poor muscular tone. In growing sheep the potassium requirement is considered to be 0.5 percent of the diet, whereas with lactating dairy cattle the requirement is placed at 0.8 percent of the complete ration (Ward, 1966). These levels are also postulated as the requirements of growing and lactating goats, respectively. Ration values below these are infrequently encountered, and are usually restricted to high-concentrate diets, in which the major ingredient is low in potassium, or to diets of severely weathered or winter range forage. Potassium supplements may be in chloride, bicarbonate, or sulfate form. Sulfur Sulfur is a component of all body proteins and is particularly high in goat hair, which consists of a high proportion of the sulfur-containing amino acids, methionine and cystine. Marginal deficiencies cause poor animal performance, and more extreme cases result in excessive salivation, lacrimation, and alopecia. Studies with goats fed supplemental sulfur are rare, but it appears likely that deficiencies of sulfur may be more widespread than previously believed. A recent study by Wheeler et al. (1975)

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries indicates potential shortages of sulfur in forage sorghums. Another study by Gartner and Hurwood (1976) indicates that tannic-acid-containing plants such as Acacia aneura may provide inadequate amounts of available sulfur. This is of particular concern with range goats, which liberally graze and browse tannin-containing plants. Recommendations are normally expressed in terms of a sulfur-to-nitrogen ratio of 1:10. However, this ratio may be misleading if either or both sulfur and nitrogen are unavailable because of the presence of complexing substances such as tannic acid. Sulfur requirements would then range from 0.16 to 0.32 percent of the diet for ration protein values of 10 to 20 percent. Sulfates, such as sodium sulfate and ammonium sulfate, are the most available forms of sulfur for ration formulation. Common feedstuffs may contain adequate sulfur, but shortages can occur in forages grown on certain types of soils or in rations containing a high proportion of NPN as protein supplement (Varma and Sawhusey, 1970). The high-producing Angora goat may have an elevated sulfur requirement because of mohair growth, but this possibility needs to be investigated. It has been shown that sulfur-containing amino acids, administered postruminally, stimulate fiber production (Reis and Schinkel, 1964). Although mechanisms exist, the required technology has not reached the stage of practical application. Iron Iron is a component of blood hemoglobin that is required for oxygen transport. It is also required for some enzyme systems. Although iron deficiency seldom occurs in mature grazing animals, it may occur in young goat kids because of their minimal body stores of iron at birth and the low iron content of milk (Jenness, 1980). The work of Lintzel and Radeff (1931) suggests that this may be more true with goats than with cattle. If iron deficiencies are observed and it is desired to continue the kids on a milk diet, injections of iron-dextran (150 mg) at two-to-three-week intervals are recommended. In a recent study (Hamada et al., 1970) acceptable tissue color was observed in animals fed a diet containing 0.03 percent ferrous iron. Thus, this value might be taken as a minimum. Ferrous sulfate and ferric citrate are more available than other sources such as ferric oxide and are recommended for ration formulation. The literature is too sparse, however, to state definite feeding requirements for iron. Iodine Iodine is necessary for the formation of thyroxine. In states of iodine deficiency the thyroid gland becomes enlarged, a condition called goiter (Honeker, 1949). It is most frequently observed in the young at birth, especially in weak or dead kids. Iodine-deficient areas are widespread in the world, including parts of the United States. Deficiencies are readily corrected by feeding iodized salt (Sutphin et al., 1971). However, iodized salts should not be force-fed (as when salt is used as a feed limiter) because this action could lead to excessive intakes of iodine. Goats appear to be somewhat unusual with respect to iodine metabolism (Lengemann, 1970, 1979), but no good basis for unique recommendations exists so far. Copper and Molybdenum Copper and molybdenum are interrelated in animal metabolism and should be considered together (Hennig et al., 1974). Levels of both can be too low or too high or the level of one can be low and the other too high. The most common problem occurs when a normal or low level of copper is accompanied by a high level of molybdenum. In this case copper is excreted and a deficiency occurs. This condition can be corrected with copper therapy. Few studies on copper and molybdenum have included goats (NRC, 1980). It appears that sheep are sensitive to copper toxicity and resistant to molybdenosis, but it is not known whether this is also the case with goats. Zinc Zinc deficiency symptoms include parakeratosis, stiffness, of joints, excessive salivation, swelling of the feet and horny overgrowth, small testicles, and low libido (Neathery et al., 1973). Reduced feed intake and weight loss also occurs with zinc-deficient diets. Zinc must be supplied continuously because little is stored in the body in readily available form (NRC, 1979). Minimum daily requirements for goats have not been established. Young males have developed deficiencies at levels of 4 ppm (Neathery et al., 1973); adult females developed signs on 6–7 ppm when they were lactating. There is also some evidence that males require more zinc than do females (Groppel and Hennig, 1971; Schellner, 1972). Direct and indirect evidence indicates minimum requirements of 10 ppm. Levels of 1000 ppm may be toxic. Manganese Manganese is an essential mineral in diets for goats (Groppel, 1969; Anke et al., 1972, 1973a,b,c; Hennig et al., 1972; Schellner, 1972). Deficiency signs include reluctance to walk, deformity of the forelegs, and reduced reproductive efficiency. So far, data are inadequate to suggest optimum levels. Deficiency signs have developed on 5.5 ppm, but not on 90 ppm in the diet (Anke et al., 1973b). Other Minerals Fluorine and selenium can be encountered at either deficient or toxic levels in natural diets. Fluorine deficiency appears to be rare; toxic levels result largely from industrial pollution. With sheep, acute fluorine toxicity occurs at levels above 200 ppm (NRC, 1975). Selenium toxicity occurs in sheep from prolonged consumption of plants containing over 3 ppm. The classical deficiency of selenium is white muscle disease (Hebert and Cowan, 1971),

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries but milder deficiencies result in reduced performance, especially reproductive efficiency. Selenium supplements may be added to salt supplementation or provided through injections. Cobalt is a component of vitamin B12. Deficiency signs include loss of appetite, emaciation, weakness, anemia, and decreased production. In sheep an intake of 0.1 ppm is considered adequate. It is assumed that the same would apply to goats. Cobalt sulfate or cobalt chloride added at the rate of 12 g per 100 kg of salt should provide an adequate intake, but this would be indicated only in situations in which cobalt has been shown to provide a response. A few additional references on specific mineral studies with goats can be found in the appended bibliography. VITAMINS Vitamins are a group of compounds essential for normal body processes. Typical range or pasture diets of goats should contain adequate levels of vitamins or vitamin precursors to maintain normal health of the animal. Pen-fed animals, goats held on restricted diets, and high-producing animals may need a supplemental vitamin supply (Honeker, 1949). Recommendations in Table 1 for vitamin requirements of goats rely on similar values for sheep (NRC, 1975) and dairy cattle (NRC, 1978) until more specific experimental evidence for goats becomes available. Vitamin A Vitamin A is involved in many areas of body metabolism, and as a result deficiency signs are varied. Experimental evidences of vitamin A deficiencies include keratinization of the epithelia of the respiratory, alimentary, reproductive, and urinary tracts, and of the eye. Signs include multiple infections, poor bone development, birth of abnormal offspring, and vision impairment Night blindness, the inability to see under poorly lighted conditions, is the classic deficiency sign. Experimentally produced signs of a vitamin A deficiency in goats include: loss of appetitie, loss of weight, unthrifty appearance, night blindness, and a thick nasal discharge (Schmidt, 1941). Vitamin A is not contained in forages, but its precursors are common in plants and are usually present in proportion to plant pigments. However, not all plant pigments give rise to equal vitamin A activity. Beta-carotene is the standard form of provitamin A. One mg of beta-carotene in the diet is equivalent to approximately 400 IU of vitamin A. Other pigments, xanthophylls for example, are less active. Vitamin A is stored in the liver and fat of animals during times when intake exceeds requirements. During periods of low carotene supplies in the diet, this stored vitamin A can be mobilized and utilized without signs of a vitamin A deficiency. Eveleth et al. (1949) reported that a vitamin A deficiency in sheep is unlikely if green feed is available during one season of the year. Schmidt (1941) found the tolerance of adult sheep and Angora goats to low carotene diets to be similar. However, Angora kids were found to be more tolerant than lambs. Goats that have had access to good quality green feed can probably be held on a low carotene diet for a minimum of three months without showing signs of a vitamin A deficiency. Typical goat diets contain adequate carotene to prevent vitamin A deficiency. The tendency of the goat to search out palatable green plant parts ensures it an advantage over other ruminant species. However, goats that are forced to consume more conventional cattle or sheep diets because of the unavailability of browse would not have an advantage (Davis, 1942; Caldas, 1961). Vitamin A deficiency in goats in the tropics would be rare except under such circumstances. Old weathered hays are poor sources of carotene, which is readily oxidized. Green leafy hays are good sources, and dehydrated legume hays, especially pelleted, are the best natural sources. Synthetic vitamin A is readily available in feed additive and injectable forms from commercial suppliers. The newer formulations are relatively stable, but old premixes and injectables should not be used. Vitamin D Vitamin D is essential for the absorption and metabolism of calcium and phosphorus. In its absence, or at low levels, normal bone development is impaired. Soft, irregular shaped leg and rib bones resulting from a vitamin D deficiency are signs of “rickets.” Thus, vitamin D has been referred to as the antirachitic factor. A form of rickets can also be seen in the newborn of an adult female deficient during pregnancy. Otherwise, deficiencies in adult animals are considered rare. Vitamin D is available to animals both through the diet and as a result of exposure to sunlight. Ultraviolet radiation from sunlight acts on ergosterol, a plant sterol, and on 7-dehydrocholesterol, a sterol of animal origin, to produce compounds having antirachitic activity (vitamin D2 and D3, respectively). Thus, sun-cured hays are excellent sources of vitamin D. Animals exposed to sunlight can obtain some of their requirement directly from irradiation of 7-dehydrocholesterol in the skin. DeLuca (1974) discovered that activation of vitamin D3 occurs in the liver and kidney of animals. Vitamin D deficiency is unlikely under normal grazing conditions, although a form of osteodystrophia has been produced experimentally in goats. Vitamin D should be supplied to growing animals that are denied sunlight over extended periods because of cloud cover or confinement to housing. Vitamin E Vitamin E deficiency in sheep is commonly associated with white muscle disease, also called stiff lamb disease. This malady is seen in young nursing lambs and will improve with vitamin E therapy (Muth et al., 1958). An

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Nutrient Requirements of Goats: Angora, Dairy, and Meat Goats in Temperate and Tropical Countries associated selenium deficiency will intensify the disease. Vitamin E is alleged to improve reproductive efficiency, but dietary supplementation experiments have not produced consistent results. Evidence of spontaneous vitamin E deficiency signs in goats is lacking. It is suggested that the probability of lowered productivity in goats as a result of a vitamin E deficiency is remote. However, vitamin E transferred to the milk is considered important because of the antioxidant properties that aid in milk storage. Vitamin K Vitamin K, the blood clotting vitamin, is plentiful in a variety of feedstuffs and, in addition, is readily synthesized in the rumen. A deficiency is unlikely. B Vitamin Complex The B vitamins are not considered dietetically essential in adult goats because they are normally synthesized by microorganisms in the rumen. Only vitamin B12 (cobalamin) is likely to be deficient in animals having a functional rumen. Cobalt is required for synthesis of vitamin B12 and if absent or at extremely low levels in the diet of goats, a vitamin B12 deficiency will occur. The B vitamins should be included in diets of very young kids nursing their dams, animals with poorly functioning rumens, sick animals, and those with radically changed diets. Vitamin C Vitamin C is synthesized in the body tissues in adequate quantities to satisfy requirements and under normal circumstances need not be added to diets of goats. WATER Water is obviously important for goats, and the amount required depends on that needed for the maintenance of normal water balance and to provide for satisfactory levels of production. The normal body water content of the goat varies with age, amount of fat in the body, and environmental temperatures. It would be expected to exceed 60 percent of the body weight and 75 percent of the nonbony tissues. Shkolnik et al. (1980) have shown that some goats, such as the black Bedouin of the Negev and Sinai deserts, have the capacity to store as much as 76 percent of their body weight. Water requirements may be met by free water consumption, but other important sources include water contained in the feed ingested and metabolic water resulting from oxidation of energy sources. Major water losses include those from urine, lactation, evaporation, and perspiration. A safe general recommendation is to provide goats with all the clean water that they will drink (ad libitum intake). Extremes in water temperature will increase energy requirements. Taste factors will also affect normal water intake (Goatcher and Church, 1970). Although the above observations are logical, it should be remembered that a high proportion of the world’s goat population lives in areas where water requirements are not easily met. The uniqueness of goats in meeting their water requirements deserves further study. The example of the black Bedouin goat suggests that other genotypes may differ in their ability to meet water requirements. Regardless of breed, water intake must exceed milk production. In a study reported by Bergmann (1932), 3.5 kg of water was consumed for each kilogram of milk produced by dairy goats under temperate conditions. French recommendations are 145.6 g water per Wkg0.75 for maintenance and 1.43 kg water per kilogram of milk as a production requirement (Morand-Fehr and Sauvant, 1978). In the humid tropics Devendra (1967) found that penned indigenous meat goats had a mean daily free water intake of 680 g, of which 80 percent was consumed during the day. Goats are often more sensitive and reluctant than other species to drink from foul-tasting water sources. If they are forced to drink poor quality water, the result may be infection or undesirable mineral intake. Also, in many parts of the world goats drink from impounded water, and entrapment (bogging in mud) can be a real hazard, especially with Angoras. Goats are among the most efficient domestic animals in the use of water, approaching the camel in the low rate of water turnover per unit of body weight (Maloiy and Taylor, 1971; Macfarlane and Howard, 1972). Goats appear to be less subject to high temperature stress than other species of domestic livestock such as wooled sheep or many breeds of cattle and require less water evaporation to control body temperature. They also have the ability to conserve water by reducing losses in urine and feces. In many environments the water intake through forage may be high relative to other species because of their ability or willingness to browse. The result is that goats are less dependent on free water sources than other domestic species, but do not equal certain wild animal species in this respect. Factors affecting the free water intake of goats are lactation level, environmental temperature, water content of forage consumed, amount of exercise, and salt and mineral content of the diet. Therefore, the daily range of free water intake may be from zero to several liters. When feeding on dry forages and when water is lacking, the efficiency of reproduction will suffer (Brown and Lynch, 1972; Lynch et al., 1972). Suboptimum water intake will result initially in reduced feed intake, then reduced performance and gradual starvation. Acute problems result when goats are unable to maintain water balance or control body temperature.

Representative terms from entire chapter:

protein requirements