Effect of different male-to-female ratios and testosterone administration upon the male sexual behavior and the out-of-season reproductive response of anestrous goats

• Published in: Small ruminant research 2015-12, Vol.133, p.21-29
• Main Authors: Ángel-García, O., Meza-Herrera, C.A., Contreras-Villarreal, V., Guillen-Muñoz, J.M., Leyva, C., Robles-Trillo, P.A., Rivas-Muñoz, R., Rodríguez-Martínez, R., Mellado, M., Véliz, F.G.
• Format: Article
• Language: English
• Subjects: Female anestrus season; Goats; Male effect; Male resting season; Sexual and reproductive outcomes; Testosterone exogenous
• ISSN: 0921-4488; 1879-0941
• DOI: 10.1016/j.smallrumres.2015.10.013

•Testosterone quickly elicited a high sex drive with a full repertoire of sexual behaviors, promoting.•An enhancement not only in the appetitive but also in the consummatory sexual behaviors.•An increased goat́s sexual activity while triggered an anticipated onset in the ovarian function.•Such induction and synchronized estrous behavior occurred regardless the male-to-female ratio.•Results are key to design out-of-season reproductive strategies under marginal production systems. The possible effect of testosterone administration and the male-to-female ratio regarding the male sexual behavior during the resting season and the out-of-season reproductive performance of anestrous goats exposed to the male effect under subtropical conditions (26° N) was evaluated. In the experiment-1 two treatments were considered (1) Testosterone-treated bucks (TTB; n=4; 25mg, i.m., testosterone, every 3-days×3-week), and (2) Non-testosterone treated bucks (NTTB; n=4; i.m. saline every 3-days×3-week). Thereafter, both experimental groups were exposed to adult goats over two days (1h×2days) and two sexual behavior tests were performed: appetitive sexual behavior (ASB) and consummatory sexual behavior (CSB). In the experiment-2, multiparous lactating and anoestrous crossbred goats (n=60) were randomly assigned to one of four treatments with different male-to-female ratios (MFR): (1) High MFR goats [HMFR; n=20, 1:10 ratio], (2) Low MFR [LMFR; n=10, 1:5 ratio] each group exposed to two NTTB, (3) High MFR goats [HMFR+T; n=20, 1:10 ratio], and (4) Low MFR [LMFR+T; n=10, 1:5 ratio] each group exposed to two TTB. While the TTB displayed higher ASB (p0.05; 100% vs 0%) nor sexual behavior irrespectively of the male-to-female load. The HMFR+T depicted a higher ASB (p