Effectiveness of Carotene and Failure of Ascorbic Acid to Increase Sexual Activity and Semen Quality of Vitamin A Deficient Beef Bulls

Abstract

Observations are recorded on the reproductive performance of 6 first generation Hereford x Shorthorn males reared on a carotene-deficient basal diet supplemented with restricted levels of alfalfa, which furnished 45 to 140 f of crude carotene per kg. of body wt. daily. One male on the 45 ? level showed symptoms of vitamin A deficiency as a calf and later failed to demonstrate copulatory ability. Successful semen collections and fertility were established in the other 5 males, all of which received 50 V or more of crude carotene per kg. live wt. At the end of a preliminary semen collection period, 2 of the males were subjected to a period of vitamin A depletion and the other 3 were continued on their respective levels of carotene as controls. The progress of the degree of vitamin A deficiency was followed by chemical detns. of carotene and vitamin A in the blood plasma and ascorbic acid in the blood plasma and semen. Sexual activity and ability decreased rapidly with the development of symptoms of vitamin A deficiency. Semen samples collected as the depletion progressed showed marked increases in % of abnormal spermatozoa and cellular debris with progressive decline in motility. Injns. of ascorbic acid failed to stimulate sexual activity or modify the quality of the semen produced by the vitamin A-deficient males. Carotene feeding restored the males to apparently normal activity and semen production. Histological evidence of previous testicular injury due presumably to vitamin A deficiency was evident after as long as 20 months of carotene feeding.