Experimentally Produced Zinc Deficiency in the Goat1

556

J O U R N A L OF D A I R Y S C I E N C E

:Between Milkings. Nature, 176: 35. 1955. (4) RAGSDALE, A. C., TURNER, C. W., AND :B~AD-~, S. The Rate of Milk Secretion as Affected by an Accunm]ation of Milk in the Mammary Gland. J. Dairy Sci., 7: 249. 1924. (5) SCHMm% G. H. Effect of Milking Intervals on the R~te of Milk Secretion. J. Dairy Sci., 43: 213. 1960. (6) TUCKER, H. A., REECE, R. P., AND MATHER, R. E. Udder Capacity Estimates as Affected by Rate of Milk Secretion and Intramammary Pressure. J. Dairy Sci., 44: 1725. 1961. (7) TL~RNER,H. A. Dependence on Reduced Milk in the Udder of the Cow upon Total Milk Yield. :Its :Bearing upon Supposed :Inhibi-

EXPER[MENTALI,Y

PRODUCED

tion of Secretion. Australian J. Agr. Research, 4: 118. 1953. (8) TURNEI~,H. A. Changes in the Capacity of the Udder of the Dairy Cow During the Course of Lactation. Australian J. Agr. Research, 6: 145. 1955. (9) TURNER, H. A. Sources of Variation in Residual Milk and Fat in Dairy Cow. Their ]qelation to Secretion Rates and Persistency of Lactation. Australian J. Agr. Research, 6: 514. 1955. (10) TURNER, H. A. The Effect of Unequal :Intervals :Between Milkings upon Milk Production and Diurnal Variation in Milk Secretion. Australian J. Agr. Research, 6: 530. 1955.

ZINC DEFICIENCY

In earlier experiments a zinc deficiency was produced and described in calves (3-5) and lambs (6). However, knowledge concerning the effects of a zinc deficiency on ruminants is very incomplete. Diets which have been used to produce this deficiency in ruminants are quite expensive. Thus, feed costs would be a limiting factor in experiments in which a large number of cattle are maintained on such a zincdeficient diet for extended periods. Also, if appreciable numbers of large cattle were to be sacrificed without salvage value, the expense would be large. In these and other situations, goats would have a considerable advantage over cattle. However, a zinc deficiency had never been reported in goats. The purpose of this study was to deternfine if a zinc deficiency could be produced in goats. Seven male kids were purchased from a local goat farm at approxinmtely ] wk of age. These were fed a limited quantity of whole cow's milk until 10 wk of age, a total of 102 lb of milk per goat. Weekly totals for the second through the 10th weeks of age were 14, 14, 16, 14, 14, 11, S, 7, and 4 lb. Beginning at 5 wk of age they were given a low zinc purified diet ad libitum. The diet contained the following: egg albumin (autoclaved), 15.0 lb; glucose monohydrate, 51.7 lb; cellulose,* 10.0 lb; dried whole whey (spray process), 10.0 lb; stabilized lard, 3.0 lb; KHCO~, 2.0 lb; NaHCO~, 3.5 lb; dicalcium phosphate (anhydrous, food grade), 2.0 lb; CaCO~ (marble dust), 1.0 lb; KC1, 250 g; NaC1, 220 g; MgO ~, 55 g; FeSO~'H.~O ~Journal Paper No. 350, College Experiment Station, College of Agriculture Experiment Stations, University of Georgia, Athens, Georgia. Supported in part by a PtIS research grant No. AM 07367-01 NTN from the National Institute of Arthritis and Metabolic Diseases, Public Health Service. 2 Solka-Ploc :BW-100, manufactured by the :Brown Co., :Berlin, New Hampshire. 3 Sold under the name of Magox, Feed Grade (guaranteed to contain 55~e Mg).

IN TttE

GOAT

1

(72.5% Fc by assay), 7.9 g; MnS04" H._,O, 1.5 g; C u S O , ' H ~ 0 , 0.9 g; CoC03 (45-50% Co by assay), 10 rag; K I , 8 rag; thiamine HC1, 410 mg; riboflavin, USP, 900 mg; nicotinic acid, USP, 1.0 g; calcium pantothenate, (45%), 1.5 g; pyridoxine HC1, 500 mg; folic acid, USP, 100 rag; menadione, ' 150 mg; d-biotin, 12.0 rag; cyanocobalamin (0.1% trituration in mannitol, 0.1% B-12), 3.0 g; vitamin E (100,000 I U / l b Type F-100), 800 mg; vitamin D~ (200,000 I U / g ) , 1.0 g; vitamin A pahnitate (250,000 I U / g ) , 10.0 g; choline C1 (70%), ]20 g; oxytetracycline HC1 (25 g / l b ) , 40 g; and oleandomycin (25%), 2.0 g. This diet is similar to that used previously to develop a zinc deficiency in calves (3, 4). The modifications were an attempt to reduce the cost of the fol~nula. They also resulted in a moderate increase in the zinc content to 5.3 ppm. All of the goats were fed the low zinc purified diet until 1.5 wk after milk feeding was discontinued. At that time three were selected at random to serve as controls, and 40 pplu of supplemental zinc, as ZnO, was added to their diet. Following the addition of zinc to their diet, the controls consumed considerably more feed (Figure 1) and gained substantially more weight than those fed the low zinc diet (Figure 2). Reductions in growth and feed intake have been shown to accompany a zinc deficiency in calves (3, 4). I t appears that the goats had developed a borderline zinc deficiency prior to the time zinc was added to the diet of the controls. Otherwise, these wide differences between the controls and those fed the low zinc groups probably would not have occurred so quickly. In a previous experiment, in which calves were fed a somewhat more deficient diet, 4 wk were required, after milk feeding was discontinued, before differences in weight gain and feed intake could be detected (4). This compares with the immediate effect with the goats.

TECHNICAL

NOTES

557

of the zinc-deficient individuals five days prior to death are shown in Figures 3, 4, and 5. ~4.0 v

3.0

w

TROLS

ZN ADDE

v

c~ I.O

I

TINUED

tL AGE (WEEKS)

Fro. 1. Average weekly feed intake of four goats fed the low zinc diet until 18 wk old and three fed the low zinc diet until 11.5 wk of age and the same diet with supplemental zinc thereafter. Within 4 wk after zinc was added to the diet of the controls, two of the zinc-deficient goats had developed severe clinical symptoms comparable to those previously described for zincdeficient calves (3, 4). These symptoms ineluded: listless, weak and unthrifty appearance; dull rough hair coat; loss of hair and or keratinized skin, especially on rear legs, neck and head, around mouth, and on scrotum; breaks and fissures on feet; red and inflamed mouth with ulcers and horny overgrowth of dental pads; shrunken scaly scrotum; and very small testicles. The reader is referred to the previous publication for a more detailed description of changes characterizing zinc deficiency in canes (3-5). There was an appreciable variation in the severity of the syndrome. Six weeks after zinc was added to the control diet, three of the deficient ones died within a six-day period. Photographs of one

FIG. 4. A zinc-deficient and a control goat. Note lack of testicle development and skin lesions on the deficient animal.

16

oo12 )"I"

-~°~

/;F

_.c/DEFICIENT

8

OC~ m6 4

OL

ZN ADD

-----I0 ~

FIG. 3. A zinc-deficient goat photographed five days prior to death.

/MILK

DISCONTINUED

,

I

4 AGE

8

12

16

(WEEKS)

Fro. 2. Average body weights of four goats fed the low zinc diet until 18 wk old and three fed the low zinc diet until 11.5 wk of age and the same diet with supplemental zinc thereafter.

Skin and testicular tissues were taken for microscopic examination from one of the deficient animals and from one of the controls. On the following day the deficient goat died. The tissues were fixed in ] 0 % formalin, imbedded in paraffin, sectioned and stained using standard technic. Microscopic examination of the skin of the deficient animal showed changes of parakeratosis previously described for the calf (4, 5). There was an increase in the keratin layer of the skin, a retention of the nuclei, exfoliation together with some exudation containing red blood cells (Figure 7). Photomicrographs of skin from the normal goat is also shown for comparison (Figure 6). The testicles from the deficient goat were much smaller than those of

55~

JOURNAL OF DAII%Y SCIENOE ~hese were m i n o r k i d n e y damage, elongation )f r u m e n papilli, a n d h o r n s t h a t were s h o r t e r :han normal, with huge wrinkles. A t this time t is not possible to evaluate the significance, f any, of these deviations f r o m normal. Zinc deficiency in goats is quite c o m p a r a b l e o t h a t in cattle (3-5). T h e r e f o r e goats can be ~sed f o r such studies a n d should g r e a t l y faciliate p r o g r e s s in developing a more complete m d e r s t a n d i n g of zinc n u t r i t i o n a n d metabolism n ruminants. A CK~N'O W L E D G M E N T S

The authors thank Dr. J. D. Morton, Dr. J. D. ~dens, and Dr. D. M. Blackmon for clinical ex.minntion; and Dr. Dennis Sikes for the necropsy ~'ork. Appreciation is extended to tile K r a f t ~oods Company, Garland, Texas, which contribLted the dried whole whey; to the Chas. Pfizer !ompany, Terre Haute, Indiana, which, through he courtesy of Dr. E. B. Patterson and Dr. W. M. ~eynolds, contributed the antibiotics and most f the vitamins; to Hoffmann-La Roche, Inc., Nutay, N. J., which, through the courtesy of Dr. J. C. ~auernfeind, contributed the biotin; to the Commrcial Solvents Company, New York, N. Y., ,'hich, through the courtesy of Dr. Donald R. )owden, contributed the choline; and to Basic ~corporated, Cleveland, Ohio, which through the ourtesy of Mr. M. S. Hoffman, contributed the mgnesimn oxide. :

:

:

:

:

FIG. 5. Feet of a zinc-deficient goat.

the controls. Microscopic e x a m i n a t i o n of the testicle showed changes generally consistent with those previously r e p o r t e d f o r r a t s (1, 2). The tubules were l a r g e r t h a n those of the control, showed no evidence of m a t u r a t i o n of the g e r m i n a l epithelium a n d were lined only b y s p e r n I a t o g o n i a ( F i g u r e 9). P h o t o m i c r o g r a p h s of a cross section of the testicle of the control g o a t is shown f o r c o m p a r i s o n ( F i g u r e 8). Necropsies of the goats which died indicated t h a t two had p n e u m o n i a . I t a p p e a r s t h a t deaths f r o m a zinc deficiency in calves a n d goats are by nonspecific routes. A p p a r e n t l y , the zinc deficiency g r e a t l y weakens the aninials, pern d t t i n g secondaI~- factors to be fatal. B e g i n n i n g 4 wk a f t e r the t h r e e deficient goats died, the controls a n d the one r e m a i n i n g deficient a n i m a l were given a p r a c t i c a l calf diet. The recovery of the deficient g o a t f r o m the s y n d r o m e was quite r a p i d . This agrees w i t h p r e v i o u s i n f o r m a t i o n with calves (4). None of the control goats developed a n y clinical symptoms of a zinc deficiency. N e c r o p s y a t 28 wk of age did not reveal a n y a b n o r m a l i t i e s f o r the three control goats. However, the zinc-deficient g o a t which h a d a p p a r e n t l y recovered clinically on n e c r o p s y was n o r m a l w i t h t h r e e exceptions.

W. J. MILLER W. J. PITTS

C. M. CHF~ON Dairy Department AND S. C. SCHMITTLE P o u l t r y Disease R e s e a r c h U n i v e r s i t y o f Georgia Athens REFERENCES (1) FOLLIS, R. H., JR., DAY, H. G., AND MCCOLLUM, E. V. Histological Studies of the Tissues of Rats Fed a Diet Extremely Low in Zinc. J. Nutrition, 22:223. 1941. (2) MILLAR, M. J., FISCHER, M. I., ELCOATE, P. ~'., AND MAWSON, C. A. The Effects of Dietary Zinc Deficiency on the Reproductive Systeni of Male Rats. Can. J. Biochem. Physiol., 36: 557. 1957. (3) M~LLER, J. K., AND MILLER, W. J. Development of Zinc Deficiency in Holstein Calves Fed a Purified Diet. J. Dairy Sci., 43: 1854. 1960. (4) MILLER, J. K., AND MILLER, W. J. Experimental Zinc Deficiency and Recovery of Calves. J. Nutrition, 76: 467. 1962. (5) MILLER, W. J., AND MILLER, J. K. Photomicrographs of Skin from Zinc-Deficient Calves. J. Dairy Sci., 46: 1285. 1963. (6) OTT, E. A., SMITH, W. H., STOB, M., AND BEESON, W. M. Zinc Deficiency Syndrome in the Young Lamb. J. Nutrition, 82:41. 1964.

T E G H N I C A L NOTES

559

FIG. 6. Section showing microscopic appearance of normal skin from control goat. × 81.4. FIG. 7. Section of skin from deficient goat. Note excessive keratin formation and exudation. × 81.4. Fro. 8. Section showing microscopic examination of testis from control goat. × 81.4. FIG. 9. Section of testis from deficient goat. Note tubules are lined only with spermatogonia. × 81.4.

EFFECT OF SAMPLING TIME AFTER DEATH ON OSMOLALITY AND SODIUM AND CHLORIDE CONCENTRATIONS OF BOVINE AQUEOUS HUMOR 1 The possible effects of vitamin A deficiency on some of the inorganic constituents and osmolMity of aqueous humor ( A H ) removed after death from the eyes of male Holstein calves are controversial. In one experiment (2), osmolality and sodium and chloride concentrations in A H of the deficient calves were affected, but in another (3) no effect was observed. I t was noted, in re-examining the statistics of these studies, that the average osmolality was considerably greater for the first experiment (2) than f o r the second (3), 307 versus 290 milliosmols per kilogram of water. In a subsequent study (4) dealing with hypervitaminotic-A calves, an averScientific contribution No. 77, Agricultural Experiment Station, University of Connecticut, Storrs. This study was supported in part by grant-in-aid funds provided by PHS research grant, NB-0210805, from the National Institute of Neurological Diseases and ]~lindness, Public Health Service.

age osmolality of 290 was observed, which agreed with the value of the second study. Upon searching for possible differences in the conduct of these experiments, it was found that in the initial study (2) less attention was paid to removing the A H as soon as possible after death than in the subsequent ones (3, 4). Therefore, it appeared that the difference might be related to the length of time after slaughter that the A H was allowed to remain in the anterior chamber of the eye prior to sampling f o r analysis. It was postulated by one of us (M.C.C.) that osmolality of AH increased with an increase in the time of sampling after death as a result of a gradual increase in the concentra£ion of its constituents and that the latter was due possibly to dehydration and/or equilibration by diffusion with constituents from other ocular compartments or tissues (I, 6). To test this hypothesis, the AH was removed