Experimental Zinc Deficiency and Recovery of Calves

Abstract
Seven Holstein calves, fed a low-zinc purified diet in two experiments, developed severe parakeratosis. Five comparable animals receiving the same diet supplemented with 40 ppm of zinc remained normal and made satisfactory weight gains. Zinc deficiency symptoms observed included: anorexia; dull and listless appearance; low weight gains, breaks in the skin with deep fissure formation around the hoofs; alopecia, especially on the rear legs with edematous soft swelling of the feet in front of the fetlocks with an accumulation of fluid; extensive dermatitis between the legs and behind the elbows; hard dehydrated skin on the body and head with that on the legs being tender and easily injured; red, scabby and shrunken skin on the scrotum; undersized testicles; inflammation of the nose and mouth with submucous hemorrhages; horny overgrowth of the mucosa on the lips and dental pad; and reduced blood zinc content and carbonic anhydrase activity. Addition of 260 ppm of zinc to the ration of three deficient calves in the second experiment beginning at 15 weeks of age resulted in rapid and dramatic recovery. All of the conditions listed above with the exception of the undersized testicles were corrected by zinc supplementation of the diet.

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