Vitamin E in the Nutrition of Cattle. I. Effect of Feeding Vitamin E Poor Rations on Reproduction, Health, Milk Production, and Growth

Abstract

A study was made to determine the role of vitamin E in the nutrition of cattle and especially as it relates to reproduction. 30 animals of mixed breeding (8 males and 22 females), including the 2d, 3d and 4th generation descendants of those in the original group, were fed throughout their lives on rations providing adequate quantities of all nutritive factors known to be essential except vitamin E. Five of the animals (1 male and 4 females), used as positive controls, received rations exactly like the others except that each of them was fed a supplement providing either alpha tocopherol or mixed tocopherols. All feed-stuffs fed were either vitamin E-free or extremely poor in this factor as detd. by rat tests. The rations fed included rice straw as the sole roughage, polished rice, heat processed brewers'' dried grains, distillers'' grains (solvent extracted), corn starch, dry skim milk, rendered lard, steamed bone meal, iodized salt, and vitamins A and D in concentrate form. Organs of reproduction developed normally in animals of both sexes. Spermatogenesis in males was not interfered with and all ejaculates studied were normal as to volume, sperm activity, morphology and longevity. The estrus cycle in its various phases, including ovulation, occurred regularly starting when heifers were about 7 months old. The growth rate of all animals was normal or above. A total of 30 services produced 25 conceptions in the cattle fed vitamin E-poor rations, but only 19 of these terminated in normal parturitions, since the other 6 cows died suddenly 1-3 months before they were due to calve. All calves born were normal in size and vigor at birth. There were no abortions and fetal membranes invariably were expelled within several hrs. after the calves were born. The avg. breeding efficiency of the 5 bulls used was 83.3%. One bull about 30 months old and 12 females ranging in age from 21 months to 5 years, died suddenly, apparently from cardiac failure as revealed by electrocardiograms. Six of the females had been pregnant 6-8 months when death occurred and 3 died within 3 days and one 19 days after calving. Gross post mortem examinations failed to reveal pathologic changes sufficiently marked in any of them to indicate a specific cause of death. Milk and butter-fat production of cows fed the vitamin E-poor rations did not appear to be significantly affected. Vitamin E does not appear to be required by cattle for successful reproduction, but long-continued feeding of rations containing very much less vitamin E than is present normally under practical conditions is likely to prove fatal to such animals. Feeding rations in practice as deficient as those fed in this expt. is exceedingly unlikely as all feeds fed to cattle were found to be relatively rich in vitamin E.