Seasonal Changes in Production of Semen in Free-Ranging Rhesus Monkeys1

Publisher Website
Google Scholar
Abstract
This study describes for the first time the occurrence of seasonal variations in the semen of free-ranging rhesus monkeys (Macaca mulatta). During the breeding season, the animals produce semen which is normal in volume, quality, and physical characteristics, and contains a highly uniform population of motile and structurally normal spermatozoa; during the nonbreeding season, the animals either do not respond to electrostimulation, or they produce only minimal volumes of an ejaculate with abnormal physical characteristics, and consisting of a markedly reduced number of spermatozoa which are mostly nonmotile, structurally anomalous, degenerating and/or undergoing massive phagocytosis by macrophages. Testicular biopsy specimens from the same animals disclose that these semen variations are accounted for by marked differences in the activity of the seminiferous tubules which show florid spermatogenesis during the breeding season, and nearly complete spermatogenic arrest during the nonbreeding season. The seasonal variations noted in this study correlate well with other anatomical and physiological changes known to occur in these animals in association with their annual reproductive cycle, and provide another element of distinction between free-ranging and laboratory macaques where these seasonal fluctuations are either suppressed or greatly reduced.

This publication has 0 references indexed in Scilit: