The Effect of Prepartum Vitamin A Supplementation on the Health and Performance of the Young Calf

The relationship of the quantitative and qualitative factors of the maternal diet other than extreme deficiencies to the health of the newborn calf has received only limited attention, yet it is apparent that not only is such information of physiological significance but also of economic importance to the dairyman.Spielman et al. (21,22) and Wise et al. (25) were able to demonstrate an increased amount of vitamin A in the blood and livers of newborn calves and in colostrum when the dams were fed supplementary vitamin A during the later stages of the gestation period.The purpose of the present study was to determine the effect of prepartum vitamin A supplementation on the health and performance of the young calf. EXPVaI~E~r~ P~OCEDUR~A total of 59 cows of the Brown Swiss, Guernsey, Holstein and Jersey breeds calving in the Cornell University herd from October, 1946, to Ju/y, 1947, were allotted to one of four dietary groups 30 days prior to the calculated parturition date.Breed, age, number of previous gestations, length of dry period and previous feeding history were considered in placing cows in a particular dietary grouping.The four dietary groupings were as follows: (a) a basal ration of good quality timothy and clover mixed hay, corn silage and a grain mixture containing 12 per cent crude protein; (b) basal ration plus 1 million I.U. of vitamin A daily in the form of alfalfa leaf meal; (c) basal ration plus 1 million I.U. of vitamin A daily as vitamin A alcohol; (d) basal ration plus 1 million I.U. of vitamin A daily as vitamin A ester.The hay and silage contained an average of 11.8 and 5.0 ~ of carotene per g., respectively, as determined by the method of Moore and Ely (10) as modified by Nelson et al. (11).Cows calving during October and November received a limited amount of fall pasture.These cows were divided equally among dietary groupings.The dehydrated alfalfa leaf meal contained an average of 114 rag. of carotene 2 per lb.It was hand mixed with the grain and fed once daily.The alcohol and ester forms of vitamin A s, ~ were administered orally once daily in capsules.The potencies of the alcohol and ester forms of vitamin A, as measured by the Evelyn photoelectric colorimeter, were on the average 13.75 and 13.65 rag. of vitamin A per g. of oil.