Testicular Endocrine Function in Hereford Bulls Exposed to High Ambient Temperature1

Publisher Website
Google Scholar
Abstract
Eight Hereford bulls were placed in a light, temperature and humidity controlled chamber in groups of four. Each group was exposed to 21 C; 50% relative humidity (RH) for seven weeks (control period) and subsequently to 35.5 C; 50% RH for seven weeks (heat period). Rectal temperature and respiration rate rose rapidly during the first two days of heat treatment and remained significantly (p < 0.01) above control values for the duration of the treatment period. Spermatogenesis, evaluated by semen characteristics and histological examination of testes at the termination of the experiment, was impaired by heat. Testosterone plasma concentration fell to 43% of control levels during the first two weeks of heat treatment (p < 0.01), but rose to near control levels during subsequent weeks. Testosterone metabolic half—life, metabolic clearance rate, and 24—hr production rate were similar at the conclusion of both the control and heat period. These results indicate that testicular endocrine function in these bulls was able to acclimate to the hot environment, following a transient period of depression. (Endocrinology92: 509, 1973)

This publication has 0 references indexed in Scilit: