Thermal characteristics of the testis and epididymis of the boar.

Intra-testicular temperatures of conscious boars were in the range 35.0-36.5 degrees C; values for the caput epididymidis were 35.5-37.0 degrees C and for the cauda epididymidis 35.3-37.0 degrees C. The modal temperatures of these tissues were approximately 2.5, 1.5 and 1.9 degrees C respectively below rectal temperature (38.2 degrees C) and each tissue temperature varied diurnally. With increasing environmental temperature (from 23 to 34 degrees c), testicular and epididymal temperatures increased, and the differential between tissue and rectal temperature levels diminished. The temperature of the caput epididymidis changed most with rising environmental temperature. It is possible to predict testis or epididymal temperature from environmental or rectal temperature.