Sex differentiation in goat fetus

Document Type: Full paper (Original article)

Authors

1 Ph.D. Student in Histology and Embryology, Department of Anatomical Sciences, School of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran

2 Department of Anatomical Sciences, School of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran

3 Department of Basic Sciences, School of Veterinary Medicine, Shahid Chamran University of Ahvaz, Ahvaz, Iran

Abstract

Reproduction in domestic animals, as a major source of food and other products for human, has great
importance and study of related subjects including sex differentiation and gonadogenesis during fetal life can solve many questions on normal development and various disorders of urogenital system. Since studies on sex differentiation in goat fetus are scarce, this study was performed. Twenty-five goat fetuses with 5–40 mm crown-rump lengths (CRL) were obtained from slaughter-house and fixed in 10% formalin solution
immediately. The development and features of external genitalia of these fetuses as well as their sex
differentiation were then examined. In externally indifferentiated fetuses, the cranial half of the body was cut away at the diaphragmatic level and serial sections, 6-micron thick, were prepared and the ovarian and
testicular differentiation was studied. Results showed that considering the development of the external
genitalia, external sex differentiation occurs at 31 mm CRL in male fetuses and at 33 mm CRL in female
fetuses. Microscopic studies suggested that testicular tissue differentiation occurs at 23 mm CRL with
formation of tunica albuginea and medullary cords. Ovarian tissue differentiation occurs at 38 mm CRL with
establishment of cortical and medullary regions.

Keywords