Recent Advances in Mineral Nutrition of Goats - Goats and Nutrition

"Recent Advances in Mineral Nutrition of Goats"

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Recent Advances in Mineral Nutrition of Goats
By: George F. W. Haenlein
Cooperative Extension Dairy Specialist University of Delaware
Website: http://ag.udel.edu
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Abstract:
During the last five years major advances in research of macro- and microelement nutrition of goats have occurred. The uniqueness of goats in many aspects of mineral metabolism, especially Cu, I, Se, Mo, as has been documented. Nutritional requirements of Ca, P, Mg, Na, K, I, F, S, Zn, Mn, Cu, Fe, Cd, As, Se, Li, Co, Mo, Pb, Cr, Ni, V, Al, and Br from research with goats are discussed. Mineral deficiencies in goats in many countries are caused by low or variable contents due to season and maturity of plants and low digestibilities. The reliability of body tissues as an indicator of deficiencies varies greatly with mineral elements. Major performance improvements have been achieved, nevertheless, where mineral supplementations were applied correctly.
Introduction:
Required macroelements in feeding rations for goats are: Ca, P, Mg, Na, K, Cl, S. In smaller amounts required are microelements: Fe, I, Cu, Mn, Zn, Co, Mo, Se, F, Cr; to which have been added in recent years: Si, Sn, V, Ni, As, Cd, Li, Br, Pb (Lamand, 1981; Anke and Szentmihalyi, 1986; Haenlein, 1987; Kessler, 1991). Requirements of macro- and microelements, or minerals for short, are based on evidence of metabolic functions, which are structural and/or catalytic.
Minerals activate enzymes, are essential co-factors of metabolic reactions, function as carriers of proteins, regulate digestion, respiration, water balance, muscle reaction, nerve transmission, skeletal strength, pH balance, even mental balance, protect against diseases, are antagonists or synergists of other elements and play a vital role in resistance, adaptation and evolution of new breeds and strains.
Levels of requirements as well as thresholds of deficiency and toxicity vary with age, sex, production level, activity level, species and genetic strain of the animal. This discussion focuses on goats, since it must be recognized that mineral requirements are to a large extend species and breed specific and can only be extrapolated from research with other species and breeds within limits or in a general way (Table 1).
Significant species differences have been reported for Cu, I, Mo, As, among other elements (Bell, 1959; Haenlein, 1980a, 1991a; Anke and Szentmihalyi, 1986; Devendra, 1989). In case of Mo, goats will tolerate more than 300 mg Mo/kg DM in feed intake, while sheep tolerate only 30 mg/kg DM and cattle will already suffer from diarrhea at 10 mg Mo/kg DM (Falke and Anke, 1987). In case of Cu, toxicity symptoms are noted in sheep at 10-20 mg Cu/kg DM feed intake, while cattle tolerate up to 100 mg Cu/kg DM. Data are still needed but observations have indicated, that goats are tolerant of much higher Cu levels than sheep (Table 1) (Anke and Szentmihalyi, 1986; Zervas et al., 1989). In case of I, radioactively marked I showed that goats transfer 22 percent of diet I into milk vs. 8 percent in cows (Groppel et al. 1988). Colostrum from normal goats also had much higher I contents (3662 nmol/l) than from normal cows (416 nmol/l). Thyroids from goats were lighter than from sheep on equal feed supplies of I, which may indicate that more I is available in sheep for synthesis of T4/T3, and that goats are more sensitive to low I supplies (Groppel et al. 1989). Contents of less than 300 mcg I/kg DM white hair are indicative of insufficient I supplies for growing, pregnant and lactating Swiss goats, while for sheep the limit is 200 mcg I/kg DM white wool. Goat kids with less than 0.6 mg I/kg white hair, but calves with less than 1.8 mg I/kg black hair during week one have probably an I deficiency (Groppel et al. 1988).
Supplies of minerals are influenced by climate and soil on which feed plants grew, also by stage of maturity of the plants and its parts (Fiedler and Heinze, 1985; Szentmihalyi et al. 1985; Kalac, 1986). Cu contents in red clover have been reported to decrease from 13 to 8 mg/kg DM, in fescue grass from 11 to 6, in forage rye from 9 to 3, when sampled on April 30 vs. June 11 (Anke and Szentmihalyi, 1986). There are also many mineral interactions in the feed ration influencing net absorption (Haenlein, 1987). Mineral ions compete for anionic ligands to form insoluble precipitates, mineral ions compete for transport proteins, competing mineral ions block enzyme reactions, vitamins affect mineral absorption, fiber in the ration depresses mineral absorption, chelation between amino acids influences mineral absorption, antimetabolites in the G-I tract play a role, mineral absorption availability varies with the physical and chemical configuration of the mineral source, forage to grain ratios, water contents in the feed, acid-base balance, and feed additives all influence mineral gross and net absorption, i.e., digestibility minus excretions into the urine, feces and perspiration.
Symptoms of mineral deficiencies can be general, several or very specific (Table 2). Surveys around the world, have indicated prevalences in certain countries of mineral deficiencies and excesses, which can be helpful in focusing on alleviating programs (Table 3). Such soil and plant surveys must be related to metabolic uniqueness of different animal species, and it is recognized that animal tissue analyses are more definitive diagnostic tools, although different tissues have different affinities to macro- and microelements, some have none, and therefore have different indicator values (Table 4).
Mineral contents in feed resources, their strengths and weaknesses are nevertheless important to know, especially for goats, where browse, forbs and weeds, which have not been studied analytically very much, play such a vital feeding role (Devendra, 1990). Mineral supplementation on this basis has yielded improvement in milk production, reproduction, feed intake and reduced heat stress in other species (McDowell et al. 1983; Harris, 1991). It also has been pointed out (Miller, 1983), that even in the best studied species, cattle, there is no academic agreement as to the feeding recommendation levels of minerals, and there is less agreement and knowledge about the other less studied species, such as the goat. Excesses even of macroelements, such as Ca, can have serious consequences, which besides many other better known interferences will reduce clotting ability of blood and cause hemorrhagic conditions (Hall et al. 1991).
Research interest in the role of minerals for the improvement of livestock productivity, especially goats, is growing worldwide. Ramirez et al. (1990, 1991) showed tremendous variations in the amounts of daily voluntary mineral consumption by free-ranging Mexican goats (Table 5), which differed between certain months by as much as a factor of 5. If voluntary intakes and plant contents varied that widely during the year, it follows that the goats must have had at least subclinical deficiencies in some months, e.g., for Cu, Mn and Zn, and excesses in other months, e.g., for Fe, Mg, K and Na. What needs to be clarified is net absorption, which has been shown in other animal species to vary widely, and thus influence gross amounts required to be fed daily as well as gross plant contents to satisfy daily intake without supplementation (Table 6). Specific research papers on goats since the last major reviews (NRC, 1981; Kessler, 1981; Lamand, 1981; Haenlein, 1980b, 1987) will be discussed and have been presented in parts (Haenlein, 1991b).
Nutrition of Specific Elements - Calcium
Requirements in 42 male, 7-months old West African dwarf goats (Adeloye and Akinsoyinu, 1984/85), when gaining 100 g/day, were determined to be 380 mg Ca/kg BW/day or 78.3 mg Ca/kg metabolic BW/day for growth, and 127 mg Ca/kg BW/day or 35.0 mg Ca/kg metabolic BW/day for maintenance. Requirements in 18 lactating Beetal goats (Singh and Mudgal, 1987) were 664, 636 and 628 mg Ca/kg metabolic BW/day, when intake of digestible protein was at 125, 100 or 75 percent of requirements in midlactation. Maintenance Ca requirements were 540 mg Ca/kg metabolic BW/day, and 1.16 g Ca/g Ca secreted in the milk. Supplemental Ca decreased plasma Mg concentrations (Hines et al. 1986). Fecal excretion of all minerals was increased in goats given supplemental Ca. Percentage of apparent absorption of Ca, Mg and total minerals was lower in Ca supplemented goats.
Phosphorus
Requirements in 92 growing, pregnant and lactating German Alpine goats (Barhoum et al., 1987) were at least 3.0 g P/kg DM in the ration/day. Deficient supplies of 2.0 g P/kg DM/day (controls 3.4 g P/kg DM of ration/day) reduced pre- and postpartum growth, conception rate, feed consumption, milk yield, with no effects on fat contents while protein contents were increased, as were abortion rate and mortality (Table 7). Skeletal ash contents, especially of Ca and Mg were reduced, but mineral contents, particularly of Zn, Fe, Cu, Mg and Mn in the aorta and heart muscle were higher (Barhoum, 1989).
Magnesium
Deficiency reduced in vitro wheat straw degradation from normal 10.6, 12.3, 19.6 percent after 6, 12, 24 hr incubation, respectively, to 7.5, 11.2, 17.2 percent in goats and sheep alike, but acetate and propionate contents changed from normal 50.0 percent and 38.5 percent to 55 percent and 32.5 percent, respectively (Flachowsky et al., 1990). Feeding of maize to young goats seemed to prevent a whole-milk induced hypomagnesaemia (Hines et al. 1986), suggesting that Mg in normal goat milk is inadequate to maintain normal plasma Mg levels.
Sodium
Ratios of Na:K in saliva of less than 4 were diagnostic of incipient Na deficiency (McSweeney et al., 1988). In Na deficient goats, feed intake was reduced by 6 percent, weight gain by 20 percent, milk yield by 32 percent, while there were no effects on reproductive efficiency, although the sex ratio had changed in kids toward more females (Ivandija, 1987). For normal milk yields, goats should be given 1.74 g Na/kg ration DM/day, while levels of 0.31 g Na/kg DM/day are inadequate.
Potassium
High K levels in water hyacinth (Eichhornia crassipes) fed to goats ad libitum resulted in 80 g K/day intake and in death of all goats after 6 to 32 days, with lesions in kidneys, liver and heart (Mishra et al., 1987).
Iodine
Thyroid contents in long-term goat studies correlated highly with contents of I in feeds, hair/wool, milk, serum and all organs tested; hair being a good indicator of long-term I status in goats (Groppel et al. 1988, 1989). Feed and forage analyses showed that unsupplemented rations are probably often I deficient. Rations with marginal contents (0.11 to 0.13 mg I/kg DM) reduced feed intake of goats by 30 percent, and decreased growth, 1st services conception rate, increased abortions, length of gestation, kid mortality, goiter formation and partial hairlessness (Groppel et al. 1986a; b; c; d; 1987; 1990).
Fluorine
Deficiency has been studied in 19 goats over 5 years (Anke and Groppel, 1989). A detailed composition of a semisynthetic diet containing 60 inorganic compounds considered essential is also given with major constituents being 48 percent potato starch, 32 percent beet sugar, 10 percent casein, 3 percent sunflower oil and 3 percent urea. Control goats received 1.5 to 2.5 mg F/kg DM, but the experimental goats less than 0.3 mg F/kg DM feed. Feed intake was increased by 33 percent regardless of growth, lactating, dry or pregnant status. While As, Br, Ni or Cd deficient goats had reduced kid birth weights, many below 1.6 kg, no such effects occurred in F deficiency, although no overweight (more than 4 kg) kids were born either from F deficient does. Nursing kids gained 130 g/day regardless of whether normal or F deficient does were nursing. The semisynthetic ration was biologically fully equivalent to a normal goat ration. However, female kids from F depleted does and depleted during the nursing period gained 24 percent less than the controls. Compared to other mineral deficient goat male kids, Br deficiency or even Al deficiency had more growth retardation than F deficiency. Reproduction of female goats was not affected by F deficiency, although there was indication that with long-term deficiency mortality in kids and does was significantly higher. F deficient goats did not live longer than three years.
Milk yield was not affected by F deficiency in goats (Anke and Groppel, 1989), but they had significantly higher fat and protein contents after 35 days in lactation. F requirements are still unknown, but they are assumed to be 1 to 2 mg F/kg ration DM with a minimum of 1 mg F/kg DM. Only intrauterine depletions lead to growth depressions, which means that the essentiality of F needs further studies.
Sulfur
Studies with 16 mature Australian Cashmere goats indicated that methionine was not a major limiting amino acid affecting cashmere growth, and that the processes of trans-sulphuration in goats may be different from those in sheep (Ash and Norton, 1987). Supplementation with elemental or methionine S (10 g S/kg DM) depressed feed intake and growth in goat bucks (Anke et al. 1987a).
Zinc
Analyses of forage contents showed great variations depending on soils (Szentmihalyi et al. 1985). Red clover and other legumes had more Zn than grasses, and contents decreased with increasing maturity, in alfalfa by 23 percent, in ryegrass by 51 percent. Beet leaves had twice the contents of meadow grass (173 mg Zn vs. 88 mg Zn/kg DM), but grains had much less (Siegert et al 1986). In studies with 8 male, 60-day old goats, Zn secretion was 64 percent in feces and 11 percent in urine relative to intake (Kumar and Kaur, 1987). Daily requirements for growth were calculated to be 0.65 mg Zn/kg BW.
Deficiency of Zn increased Cu contents, especially in the brain, liver and uterus of female and male goats (Gruen et al. 1986). Similar mineral interrelationships were also noted in Cu deficiency, but less pronounced, meaning that Cu absorption increases in Zn deficiency but not vice versa. Other mineral interrelations were observed when feeding bentonite to goats which increased absorption of Fe but decreased that of Cu and Zn (Schwarz and Werner, 1987).
Manganese
In Mn deficient goats the status was identifiable from analyses of hair, kidney, heart, ovaries, pancreas and brain, but not blood plasma (Anke et al. 1988). Hair analyses were reliable when the differential development stages, anagenic, katagenic, telogenic, of hair, its color and type were considered.
Copper
Contents of forages were higher in leaves than stems, and decreased with plant maturity by 40 to 60 percent (Szentmihalyi et al. 1986). Certain browse, twigs and leaf tips of beech trees, pine, beech nuts, blueberry bushes provide increased Cu supplies to wild ruminants (Dittrich and Anke, 1986). Rumen contents from mufflon varied from 6.6 to 12.2 mg Cu/kg DM, and indicator organs also varied widely for Cu, Cd, Zn, Mn, indicating excess or deficiency conditions at certain times. Cu deficiency in goats (less than 2 mg Cu/kg DM/day vs. 8 mg Cu for controls) increased Zn contents in liver and ovaries, and decreased feed intake by 50 percent (Gruen et al. 1986). In Cu load studies, goats consumed more Cu and retained 6 to 9 times less in their livers than their trial lamb mates, indicating differences in utilization and resistance to toxicity between the species, possibly related to soluble hepatic Zn-on-Cu binding proteins (Zervas et al. 1989).
Iron
In studies of Fe, Zn and Cu interrelations in goats and bentonite feeding, high Fe intake led to reduced feed consumption and reduced disease resistance (Schwarz and Werner, 1987).
Cadmium
This is an essential nutrient for goats (Anke et al. 1987b). At less than 15 mcg Cd/kg ration DM plus water over a 10 year period with 79 goats, its deficiency had no significant effects on feed intake but impaired growth, caused myasthenia, reduced milk production, shortened life span and caused unthrifty kids (Anke et al. 1986a) (Table 8). Conditions were corrected with supplementation of 300 mcg Cd/kg DM. Cd deficiency symptoms are not normally expected in Europe, since farm sources test normally above the critical range. Minimum goat requirements for Cd have been set at 50 mcg/kg ration DM (Anke et al. 1987).
Arsenic
Nutrition at less than 35 mcg As/kg ration DM did not reduce feed consumption of 113 goats over a 13 year trial period, but resulted in reduced growth, mainly intrauterine, and after weaning, decreased conception, had less milk production and higher mortality (Table 9) (Anke et al. 1980a; 1987c). Secretion of As in milk of control goats did not differ from levels in milk of deficient goats. A blood-udder barrier exists apparently that is overcome only by high dietary amounts of As. None of the As deficient goats survived into a second lactation. Control kids stored considerably higher amounts of As in their organs than adult control goats, especially in kidneys. Apart from hair, contents of liver, kidneys, testicles reflect As status of adult goats best (Anke et al. 1987c). Contents of less than 10 mcg As/kg DM of liver, kidney or testicles of adult goats indicate deficiency, in kids the limit is about 25 mcg As/kg DM. Minimum As requirements of goats have been calculated to be 50 mcg/kg ration DM/ day, but most feedstuffs and water in Europe are expected to meet this level. Fishmeal can have 2,000 to 19,000 mcg As/kg DM, algae and mussels may be 10 times higher, and water sources can vary tremendously, with some hot springs being especially rich (Anke, 1985; Anke et al. 1986b).
Selenium
Dietary Se is absorbed at a much higher rate than e.g. Fe, Cu, Zn or Mn, and is not dependent on its chemical form of selenate, selenite or selenide (Angelow and Anke 1987a; 1987b). Goats bind Se to casein in their milk and about 3 percent of ingested Se appears in the milk with a correlation coefficient of r = 0.7. Se can be absorbed and is exhaled by the lungs (10 to 50 percent), but most is excreted by the kidneys while fecal excretion is about 10 percent. Se status of goats is best indicated from samples of blood besides milk, muscle, liver, lung and hair, while kidneys and brain reacted the least to Se deficiency (Szilagyi et al. 1986). Se treatment of deficient goats increased serum contents from 32 to 94 mcg Se/kg DM significantly in 4 weeks (Angelow et al. 1986). While milk Se contents decreased in control goats from 512 mcg Se/kg DM to 247 mcg by day 28 of lactation, in Se deficient goats the milk contents changed from 138 to 93 mcg. White hair samples of Se deficient goats tested 183 mcg Se by day 120; 129 mcg Se by day 210; 131 mcg Se by day 300; compared to 353, 333, and 377 mcg Se, respectively for the controls. Kids from Se deficient does had similar low hair contents at birth (Anke, et al. 1987d; e) (Table 10).
Lithium
Recent studies have indicated the essentiality of Li for animals (Anke et al. 1983). Li deficient goats gained less, especially in utero, than controls. Serum was a good indicator of Li status. Serum sorbitol, malate, isocitrate, glutamate dehydrogenases, and activities of aldolases and liver monoamine oxidase were significantly reduced in Li deficient goats (Szilagyi et al. 1989). Reproduction was not affected, but longevity was reduced. Li is not stored in the body in large amounts. Milk and colostrum of deficient goats had much less Li than controls. The Li content of cardiac muscles did not change with deficiency and they appear to have a strong internal control for Li. Different feedstuffs varied greatly in their Li contents.
Cobalt
Long-term supplementation with glass boluses containing soluble Co-Cu-Se compounds prevented Co and vitamin B12 deficiencies in goats (Zervas, 1986; Zervas et al. 1989) (Table 11).
Molybdenum
To use goats as model in studies of mineral metabolism has been proposed recently again (Hines et al. 1986), but as stated earlier that species differences can be considerable, Mo is a good example, where goats are tolerant of high dosages of Mo without showing ill effects in contrast to sheep and cattle (Falke and Anke, 1987). After fertilizing an alfalfa field with 200 kg Mo/ha, the Mo contents of the 1st cutting were increased from 0.88 to 255 mg Mo/kg DM. Feeding the high Mo alfalfa to 5 mature goat bucks increased their organ contents significantly, especially liver, serum, kidneys, but without ill effects over 4 weeks, including normal feces; mufflon on the same diet had, however, severe diarrhea. Increasing the daily Mo intake to 1,000 mg/kg DM produced no toxicity in the goats, but semen quality was decreased.
Deficiency in Mo leads to growth depression, disturbed reproduction and increased mortality (Anke and Risch, 1989). Molybdopterin is the Mo cofactor for xanthine dehydrogenase/oxidase, aldehyde oxidase and sulfite oxidase enzymes. The requirements of growing, pregnant and lactating goats were calculated to be at 100 mcg/kg ration DM/day.
Lead
Contents of Pb were found in the cerebellum, but not in liver, kidney or blood of goats when fed Pb contaminated forages, indicating minuscule amounts of animal tissue retention (Brams et al. 1988). The essentiality of Pb has been established in rats (Kirchgessner and Reichlmayr-Lais, 1986) and studied in sheep (Gruen et al. 1986).
Chromium
Apparently no studies with goats are available so far.
Nickel
Essentiality for goats has been established (Anke et al. 1980b; c). All pregnant and lactating Ni deficient goats had significantly decreased hemoglobin and hematocrit levels. Offspring of Ni deficient goats were born with low Zn contents in their ribs and liver. Parakeratosis-like changes of skin and hair were noted in Ni deficient goats. Milk and muscle analyses did not indicate Ni status, while kidney, brain, liver, heart and ribs did.
Vanadium
Experiments with 37 growing, pregnant and lactating goats over 6 years demonstrated the essentiality of V (Anke et al. 1986c). Deficient goats (less than 10 mcg V/kg ration DM) had deformed tarsal joints and forelegs, reduced 1st service conception rate, 27 percent abortion rate, small litter size, higher kid and doe mortality, reduced feed intake, 10 percent less milk yield, higher blood beta-lipoprotein, higher blood creatinine, less blood glucose, and increased enzymes of the citric acid cycle. Requirements were calculated to be 10 to 25 mcg V/kg ration DM/day.
Aluminum
Although probably not encountered in practical feeding conditions, low Al nutrition (0.2 mg/kg ration DM) in trials over 4 years with growing, pregnant and lactating goats resulted in increased feed consumption and higher milk yield with lower fat contents (Anke et al. 1990). Intrauterine Al poor kids had depressed feed intake after weaning. Reproduction was not affected, but longevity reduced. Ante and post partum Al poor kids had coordination difficulties of the hind limbs, especially on rising and walking.
Bromine
Essentiality of Cl and I is established, of F probable, but more data for Br are still needed (Anke et al. 1989). In 3 long term experiments with growing, pregnant and lactating goats, Br poor nutrition lead to significantly reduced growth, conception, milk and fat yield, lower longevity of does and kids, hemoglobin and hematocrit, and increased abortion rate.
Overall
With this much more goat research data available now, the formulation of mineral requirements is becoming less of an extrapolation of sheep and cattle work (Haenlein, 1987; Kessler, 1991) (Table 12).

TABLE 1. Differences in organ Cu contents among ruminants/td>

N Brain mg/kg DM Liver mg/kg DM Hair/Wool mg/kg DM

Deer 70 5.6 46 5.8

Elk 39 7.7 21 7.4

Fallow deer 107 9.4 111 9.2

Mufflon 45 19.0 66 6.6

Sheep 196 17.0 196 9.6

Cattle 177 11.0 137 7.2

Goats 70 14.0 10 4.7

(Anke and Szentmihalyi, 1986).

TABLE 2. Symptoms of mineral deficiencies in young goats

Ca P Mg Se K S Fe Cu Mo Co Zn Mn I NaCl

Growth slow x x x - x - x x x x x x x x

Appetite less x x x - x x x x x x x - x x

Reproduction less x x - x - x x x - x - x x -

Offspring weak x x - x - - x - - - - x x x

Milk less, (adult) x x - - x - - x - x x - x x

Other effects:

alopecia x x

anemia x x x

ataxia x x x x

cachexie x x x

cardiac problems x

dermatosis x

diarrhea x x

dyspnea x

estrus irregular x

goiter x

heat stress x

hoof deformation x

milk fever x x

osteophagia x

pica x x

rough hair x

skeletal deformation x x x

spontaneous fracture x

staring x x x x

stillbirth x

tetany x

weak, dull x

white muscle dis. x

x = positive; - = negative.

TABLE 3. Survey of mineral status in some countries

N B Cu Fe Mn Mo Zn

Egypt 198 -

Lebanon 16 - -

Syria 38 - -

Turkey 298 x - -

Iraq 150 x - -

Pakistan 237 x - - -

India 258 - - -

Sri Lanka 18 x

Nepal 35 - - -

Thailand 150 - -

Nigeria 153 - -

Malawi 97 - -

Ghana 93 -

Sierra Leone 48 -

Zambia 44 -

Tanzania 163 - -

Ethiopia 125 - x

Philippines 194 - x

New Zealand 35 - -

Tonga 20 x

Korea 90 x x

Mexico 242 x - -

Brazil 58 x x -

Argentina 208 -

Peru 68 x x

Belgium 36 x

Malta 25 - - x

Italy 170 x - -

Hungary 201 -

Finland 90 -

x = excess; - = deficient.

(Sillanpaeae, 1986).

TABLE 4. Significant differences in tissue contents in goats

Normal (N=31)
mg/kg DM Deficient (N=22)
mg/kg DM

Zn ribs 80 58

hair 117 93

testicles 74 55

Mn liver 10 4

hair 2.1 1.1

kidney 5.0 2.6

Cu brain 14.0 6.0

hair 4.7 3.0

plasma 0.7 0.4

liver 10.0 5.3

Li serum 4.0 0.8

hair 4.6 1.4

lungs 18.0 5.5

I milk 247 mcg/kg DM 6 mcg/kg DM

hair 192 68

serum (T1) 64 15

lungs 374 36

Se muscle 387 146

plasma 130 36

hair 350 150

milk 247 93

Mo liver 1231 432

hair 69 36

spleen 551 190

kidney 901 404

Ni ribs 611 174

hair 756 255

kidney 684 254

As liver 25 4.8

hair 86 39.0

kidney 28 5.8

(Anke et al., 1988).
(Plasma contents of Mn and Zn, and milk contents of Zn were non-significantly different between deficient and normal goats)

TABLE 5. Range of mineral contents selected by range goats in Mexico during different months of 1986, 1987 and 1988

Diet contents (OM)
1986 - 1987 Voluntary daily intake (OM)
1987 - 1988

Ca, g/d 10.9(4) - 40.7(12) 10.4(4) - 21.6(11)

Mg, g/d 1.8(3) - 11.0(8) 1.1(1) - 5.5(3,8)

Na, g/d 9.0(3) - 22.3(8) 4.0(4) - 17.8(11)

K, g/d 14.0(8) - 22.1(5) 4.0(1) - 18.0(8)

Cu, mg/d 11.1(12) - 36.6(4) 4.5(4) - 18.3(9)

Mn, mg/d 46.1(7) - 76.9(5) 36.7(1) - 94.6(5)

Fe, mg/d 174.1(7) - 755.6(5) 266.7(1) - 804.7(9)

Zn, mg/d 33.9(3) - 50.3(2) 21.7(1) - 72.1(10)

(Ramirez et al., 1990, 1991).

TABLE 6. Range in absorption coefficients for minerals

High ( percent) Low ( percent)

Potassium 95 80

Sodium 96 65

Chlorine 95 71

Sulphur 82 64

Calcium 49 16

Phosphorus 43 10

Magnesium 33 7

Iron ? 20

Copper 6 2

Zinc 51 16

Manganese 10 1

Iodine 9 ?

Selenium ? 10

Example calculations: Mg, g Cu, mg Zn, mg

Low absorption coefficient 10 2 16

Daily net requirement 4.9 5.5 100

Daily gross requirement 49 275 625

Forage contents required 0.31 percent 17 mg/kg 39 mg/kg

Higher absorption coefficient 20 4 30

Different gross requirement 24.5 138 333

Different forage contents required 0.15 percent 8.6 mg/kg 21 mg/kg

(Hartmans, 1986) (studies with cows).

TABLE 7. Effects of P deficiency in goats

Controls
(N = 24) P deficient
(N = 16)

Conception rate, percent

1st service 81 38 **

overall 86 58 *

Services/conception 1.4 3.1 **

Abortion rate, percent 0 15 **

Litter size 1.5 1.5 NS

Sex ratio, F:M 1: 0.8 1: 0.7 NS

Milk, P content, g/kg DM

day 14 9.2 9.7 NS

day 28 9.3 11.0 NS

day 56 9.7 10.0 NS

yield, kg/day 1.0 0.6 **

fat yield, g/day 35 18 **

protein yield, g/day 28 21 **

Mortality,

does, percent 15 69 **

kids, percent 7 62 **

Controls received 3.4 g P/kg ration DM/day; deficient goats received 2.0 g P/kg ration DM/day for 3 years.
NS = not significant P>0.05; * = P<0.05; ** = P<0.01.
(Barhoum et al., 1987).

TABLE 8. Effects of Cd deficiency in goats

Controls
(N = 71) Cd deficient
(N = 79)

Conception rate, percent

1st service 73 46 **

overall 85 72 NS

Services/conception 1.2 2.2 **

Abortion rate, percent 0 12 ** (1)

Litter size 1.4 1.6 NS

Kids/kidded doe at 91 days 0.65 0.41 **

Milk,

yield, kg/day 1.01 0.73 **

fat, percent 3.45 3.15 *

protein, percent 2.77 3.01 *

Mortality,

does, percent 30 41 *

kids, percent 8 43 **

(1) Mostly at 4th - 5th month of pregnancy.
(Anke et al., 1986; 1987b).

TABLE 9. Effects of As deficiency in goats

Controls
(N = 131) (1) Cd deficient
(N = 113)

Organ contents, mcg As/kg DM

colostrum 10 7.8 NS

milk 24 15 **

liver 25 4.8 **

kidney 28 5.8 **

testicles 14 3.2 **

cardiac muscle 32 26 NS

skeletal muscle 29 11 **

spleen 41 12 **

hair 86 39 **

brain 25 12 **

pancreas 35 20 NS

lungs 27 16 **

Conception rate, percent

1st service 75 57 **

overall 89 71 **

open (not conceiving) 11 29 **

Services/conception 1.3 1.9 **

Abortion rate, percent 0.8 15 ** (1)

Litter size 1.4 1.4 NS

Kids/kidded doe at 91 days 0.73 0.48 **

Sex ratio F:M 1: 1.6 1: 1.7 NS

Milk,

yield, kg/day 1.01 0.81 **

fat, percent 3.46 3.97 *

protein, percent 2.77 3.10 *

Mortality,

does, percent 24 48 **

kids, percent 5.8 32 **

(1) Adult goats; control kids had higher contents, e.g. kidney 737 mcg As/kg DM.
(Anke et al., 1987c).

TABLE 10. Effects of Se deficiency in goats

Controls
(N = 62) Cd deficient
(N = 21)

Conception rate, percent

1st service 81 58 NS

overall 93 64 *

open (not conceiving) 7 36 **

Services/conception 1.4 21.9 NS

Abortion rate, percent 0 0

Litter size 1.4 1.6 NS

Kids/kidded doe at 91 days 0.9 0.4 **

Milk,

yield, kg/day 1.2 0.9 **

fat, percent 3.45 3.96 *

protein, percent 2.70 3.08 *

Organ contents, mcg Se/kg DM

serum 130 36 **

milk 247 (1) 93 **

liver 1123 464 **

lungs 1239 515 **

hair 350 150 **

spleen 1648 838 **

kidney 5011 2771 **

cardiac muscle 1045 386 **

brain 716 604 NS

(1) midlactation milk; beginning lactation: 512 mcg/kg DM
(Anke et al., 1987e).

TABLE 11. Glass bolus (Co-Cu-Se) or Se injection effects in goats

Controls
(N = 10) Glass bolus
(N = 26) Se injection
(N = 16)

Plasma Cu, mcmol/l

0 day 15.2 13.4 NS 15.6

83 days 14.0 17.9 ** 14.7

356 days 12.7 16.3 ** 14.4

Serum vitamin B12, pg/ml

0 days 340 334 324

83 days 381 785 ** 359

356 days 328 534 ** 288

Whole blood Se, mcmol/l

0 day 0.72 0.72 NS 0.72

83 days 0.70 2.24 ** 1.64

356 days 0.79 1.35 ** 0.70

Blood parameter contents at time of sampling; Se injections after 71 and 344 days in trial.
(Zervas et al., 1989).

TABLE 12. The latest minimum mineral requirements of goats

Maintenance mg/kg BW/d Pregnancy g/kg fetus Lactation g/kg milk Growth g/kg BW Absorption percent

Ca 20(a) 11.5 1.25 10.7 30

P 30(b) 6.6 1.0 6.0 65

Mg 3.5(c) 0.3 0.14 0.4 20

K 50(d) 2.1 2.1 2.4(f) 90

Na 15(e) 1.7 0.4 1.6(f) 80

S 0.16 percent of DM intake if protein = 10 percent
0.32 percent of DM intake if protein = 20 percent

Fe 30 - 40 - 100 mg/kg DM/d

Cu 8 - 10 - 23

Co 0.1 - 0.15

I 0.1 - 0.4 - 0.6 - 0.8

Mn 20 - 40

Zn 10 - 50

Se 0.1 - 0.2

Mo 0.01 - 0.1

Ni 300 - 350 mcg/kg DM/d

V 10 - 25

Li > 2

(a) 0.7 percent of DM intake if at 3 percent of BW;
(b) 0.5 percent of DM intake;
(c) 0.2 percent of DM intake;
(d) 0.5 percent of DM intake;
(e) NaCl 0.5-0.6 percent of DM intake;
(f) 0.4 when 32 kg BW or more.

(Kessler,1991; Haenlein, 1987).

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