Sexually inexperienced, photo-stimulated, 27-month-old male goats showed undiminished sexual behavior and ability to induce estrus and ovulation in anestrous females

Abstract

Sexually inexperienced male goats aged 8–21 months displayed relatively low sexual behavior when exposed to females for the first time. We aimed to determine whether i) photo-stimulation can overcome sexual inexperience in 27-month-old male goats, ii) sexually inexperienced, photo-stimulated male goats aged 27 months display the same sexual behavior as experienced goats, and iii) sexually inexperienced and experienced photo-stimulated male goats induce estrous behavior and ovulation in anestrous female goats. Five sexually inexperienced and five sexually experienced males were subjected to artificially long days (16 h of light and 8 h of darkness per day) for 2.5 months and then were exposed to females at 27 months of age (n = 50/group) for 15 days. Plasma testosterone concentrations did not differ between the two groups (P > 0.05). Sexual behavior was recorded on days 0, 1, 2, and 3 after introduction to the female groups. The inexperienced group displayed more nudging on day 2 than on days 0, 1, and 3 (P < 0.05), and both experienced and inexperienced males recorded more anogenital sniffing on days 0 and 3 than on days 1 and 2 (P < 0.05). Both experienced and inexperienced males made more mounting attempts on days 0 and 2 (P < 0.05), and experienced males made more mounts with intromission on day 3 (P < 0.05). The interval between the introduction of males to females and first estrus, estrous behavior, ovulation, and pregnancy rate were similar in both inexperienced and experienced males (P > 0.05). In conclusion, sexually inexperienced or sexually experienced photo-stimulated males aged 27 months displayed high sexual behavior and stimulated estrous behavior and ovulation in anestrous female goats.