Relation of Dietary Zinc to Composition of Sow Colostrum and Milk

Abstract

Analytical data are reported on colostrum and milk obtained from sows on diets which were varied only in content of zinc. Analyses of 61 samples of colostrum obtained within 13 hr. after farrowing gave a mean zinc content of 19.2 mg./kg. as drawn, or 93 mg./kg. of solids-not-fat. Twenty samples of colostrum (fall farrow) obtained at the time of farrowing and before pigs had suckled gave a mean value of 23 mg. zinc/kg. as drawn or 97 mg. zinc/kg. of solids-not-fat, while 17 samples (fall farrow) obtained within 13 hr. after the pigs had first suckled gave a mean of 14.3 mg. zinc/kg. as drawn or 91 mg. zinc/kg. of solids-not-fat. The data do not show any significant difference in zinc content of the colostrum attributable to dietary level of zinc. Samples obtained 35 days after farrowing from 16 sows in their second farrow (fall), which were fed on a lactation diet containing 45 mg. zinc/kg., averaged 6.9 mg. zinc/kg. of whole milk or 58 mg. zinc/kg. of solids-not-fat. Similar samples from 20 sows in the same season fed the same lactation diet to which had been added 100 mg. zinc/kg. averaged 10.3 mg. zinc/kg. of whole milk or 90.6 mg. zinc/kg. of solids-not-fat. These values represent a significant increase in zinc content of 49% and 56%, respectively, over those of the unsupplemented sows.