Histological and Histochemical Studies on the Prenatal Development of Testis in Goat (Capra hircus)

The study has been conducted on the prenatal development of testis on 70 goat embryo/foeti, categorized into group-I (0-30 days), Group-II (31-60 days), Group-III (61-90 days), Group-IV (91-120 days) and group V (121days-till birth), having 14 embryos/ foeti in each group. The genital ridge was observed at 23 days of gestation. It contained an accumulation of mesenchymal cells, immature RBC’s, differentiating fibroblasts and primordial germ cells. The formation of sex cords was evidenced on 44 day of gestation. It contained small mesenchymal cells and large cells arranged in a chain like manner. The convolution of the sex cords started between 61-90 days of gestation, which increased with the increase in the gestation period and at 125 day of gestation few sex cords attained the form of reverse question mark. The sustentocytes (Sertoli cells) were observed among the small cells of sex cords at 56 day of gestation. The tunica albuginia appeared just beneath the germinal epithelium at 44 day of gestation. It consisted of 2-4 layers of mesenchymal cells, fibroblasts and small capillaries. The thickness of tunica albuginia increased with the increase in the age of foetus and between 6190 days of gestation, the outer thick fibrous and inner thin vascular layer could be demarcated separately. Few mesenchymal cells start differentiating into interstititial endocrine cells (Leydig cells) located in the interstitial spaces at 44 day of gestation.