Effect of the administration of testosterone to mixed-breed bucks during spring (non-breeding season) on the sexual behaviour of bucks

Abstract

The sexual response of goats submitted to the male effect by exposing them to bucks treated or not with exogenous testosterone at the beginning (February) or the end (May) of the anestrus season was evaluated. In February, a group of goats (GI-T; n = 40) was placed in contact with four bucks treated with testosterone (GT), while another group of goats (GI-C; n = 40) was placed in contact with four untreated bucks (GC). This was repeated in May, the third group (GF-T; n = 40) was joined with and the fourth group (GF-C; n = 40). GT registered a higher number of flehmen, self-urination (p < 0.05), and mounts (p < 0.1) than GC. In February, more anogenital sniffing was recorded than in May, while in May more flehmen were recorded (p < 0.05). The sexual response of goats exposed to GC and GT was similar (> 70%; p > 0.05). Nonetheless, estrus latency was ten hours shorter for GT (p < 0.05). Estrus response was similar for both periods (> 85%; p > 0.05), while ovulatory response was higher in May than in February (p < 0.05). Testosterone-treated bucks induced an earlier and more synchronized estrus response. Also, a better ovarian response and conception rate were observed at the end of the anestrus season than at the beginning.