چكيده لاتين :
The aim of this study is determination pattern of development of testis structure in goat fetus. The samples in this study included the pregnant slaughtered goats in industrial slaughtered house in autumn season and unit of sampling was including 100 separated fetuses from uterus of pregnant mothers. The method of sampling was accidental .The age of collected fetuses were calculated according to Gall et al. (1994) as X=2.74 Y+30.15. After dissection of fetuses from different ages, the testis samples for histological study and performing histotechnique procedures were put in 10% buffered formalin and stained by methods of H&E, periodic shift add and Masson,s trichnome and studied under light microscope . Data were analyzed by ANOVA and Tukey test and SPSS software. The results of microscopic studies, Showed that gonads in 35 days of pregnancy were as a mass connected to mesonephrosis. Primary sign of differentiation of testis in 35 days of pregnancy was observed that it was built of white membrane and in 42.5 days of pregnancy primary genital cords were formed. In 50 days of pregnantcy, we observed myoid cells that surround the genital cords and a few days after that leydig cells in internal space of testis observed. Genital cords until to birth surrounded with Sertoli cells and gonocytes were in the center of cords so that it seems as solid tubule until birth. According to the results it was obtained that the time of differentiation of testis ruminants is different. The amount of biometry increased with growth of fetus gradually. So a significant difference between the age ol groups was observed. (p<0.05). Vet.J.of Islamic.Azad.Univ., Garmsar Branch. 5,1:5-13, 2009.
