Seasonal changes in male reproductive functions of Japanese serow

Abstract

Since 1979 the authors have conducted basic studies on the reproductive physiology of male Japanese serows, and have published two reports on spermatogenesis in 1981 (Tiba et al. 1981a,b). From these previous studies, it was strongly suggested that reproductive activities in the male are subject to seasonal fluctuation; that is, in fully adult males over 2¹/₂ or 3 years of age, spermatogenesis showed a decline from December to March of every year. It was also clarified in the previous studies that sexual maturation in the male begins within 6 or 7 months after birth. Further studies have been performed on the endocrine activity of the testis and on secretory activity in the seminal vesicle. This chapter considers seasonal changes in testicular and serum testosterone levels and the fructose content of the seminal vesicle.