The Effect of Exposure to High Ambient Temperature on Spermatogenesis in the Dairy Bull

Abstract

Four Guernsey bulls, varying in age from 19 to 34 mos., were subjected to continuous exposure at various ambient temps. in 2 exptl. chambers. Conditions ranged from 70 to 99[degree] F. in one chamber and from 70 to 52[degree] F., and 52 to 86[degree] F. in the other chamber. Stress, manifested by restlessness followed by lethargy, excess salivation, generalized weakness, hanging of the head when standing and tremors and ataxia in one animal, was not apparent until the temp. approached or exceeded 90[degree] F. Ejaculate volume was not appreciably affected, although avg. initial motility, sperm concn. and total sperm counts decreased markedly for all animals either during or following exposure to high ambient temp. Impaired spermatogenesis occurred following exposure to approx. 100[degree] F for 2 wk. in 2 animals and approx. 86[degree] F for 5 wk. in the other 2. Two bulls showed recovery of impaired spermatogenesis, the other 2 produced ejaculates practically void of sperm for as long as 2 mos. following chamber exposure. Sex drive was not seriously impaired in any of the 4 bulls.