INFLUENCE OF PHOTOPERIOD ON THE SECRETION OF TESTOSTERONE AS A RESPONSE TO SEXUAL STIMULUS IN MALE GOATS

Monthly sexual behavior tests were carried out for 1 yr in a group of 19 male goats (10 Verata breed and 9 Malaguena breed) 12 mo of age. Si multaneously with the tests, 5 blood samples were collected, 2 before and 3 after contact with females, to determine the influence of sexual stimulus on the secretion of testosterone. By means of radioimmunoass ay, it was determined that both breeds showed a significant increase i n testosterone secretion as a result of the sexual stimulus during inc reasing daylength (Verata: P<0.01; Malaguena: P<0.05), when testostero ne secretion levels prior to the stimulus were the lowest of the year. Moreover, the level of testosterone secretion was higher in the Verat a than in the Malaguena breed (P<0.01). A significant though low corre lation (P<0.05) between the rise of testosterone levels as a response to sexual stimulus and the degree of sexual behavior in the males was observed in the Verata breed. However, there was no correlation betwee n these factors in Malaguena male goats.