Zinc Deficiency in Reproducing Gilts Fed a Diet high in Calcium and its Effect on Tissue Zinc and Blood Serum Alkaline Phosphatase

Abstract

Three trials involving a total of 28 gilts in each of two treatment groups were conducted to determine the effect on reproduction of adding 100 ppm. zinc to a high-calcium (1.6%), corn-soybean meal diet (30–34 ppm. Zn). Gilts of mean weight of 75, 91 and 79 kg. for trials 1–3, respectively, were fed the diets throughout the breeding, gestation and lactation periods. Zinc did not influence weight gain of the gilts and skin lesions were rare. The number of live pigs per litter was significantly increased by the zinc supplement in trials 1 and 3, but not in trial 2. Birth and weaning weights were not different. No parakeratosis or congenital defects were evident at birth. Zinc-supplemented gilts had higher concentrations of zinc in serum, liver and bone and of alkaline phosphatase in serum. Analyses of young at birth showed that maternal dietary zinc greatly increased the zinc concentration in liver, but the zinc contents of some tissues were not affected by the zinc supplement. Significantly lower activities of serum alkaline phosphatase were observed in the young of the unsupplemented groups at birth and subsequent to about 5 weeks of age, but values were similar in both groups from 1 to 4 weeks of age, when the diet was primarily milk. The data indicate that borderline zinc deficiency can be a problem in reproducing gilts fed a high calcium, corn-soybean meal diet. The less severe zinc deficiency in trial 2 was apparently related to a difference in dietary zinc availability.