Observations on Vitamin A Deficiency in Young Dairy Bulls

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Abstract
The effects of varying levels of vitamin A on the reproductive development of 13 Holsteins, 4 Jersey, and 3 Guernsey bulls were studied. Complete blindness developed in bulls receiving 2,000 I.U. of vitamin A daily. Following supplementation of the ration with 4,000 and 6,000 I.U. of vitamin A daily, very slight spermatogenesis was observed; only moderate sperm production was found following 5 months of therapy with 100,000 I.U. of vitamin A daily. Bulls which received 4,000 and 6,000 I.U. daily of vitamin A until 300 lb. in weight, and then 8 and 16 I.U. daily per lb. of body wt., exhibited convulsions, showed evidence of night blindness, and 3 became totally blind. Sexual maturity was delayed, sex drive inhibited, and spermatogenesis limited. Cystic pituitary glands were observed in all bulls except the controls. His-tological differences were observed, however, in both the anterior pituitary glands and the adrenal glands of the bulls.