Resumo

CARRILLO, Evaristo; MEZA-HERRERA, Cesar Alberto  e  VELIZ, Francisco Gerardo. Reproductive seasonality of young French-Alpine goat bucks adapted to subtropical conditions in Mexico. Rev. mex. de cienc. pecuarias [online]. 2010, vol.1, n.2, pp.169-178. ISSN 2448-6698.

Limited data is available on reproductive seasonality in French Alpine goat bucks raised under intensive conditions in northern Mexico, at subtropical latitude (26° N). A study was done of eleven young French Alpine bucks subject to natural, regional photoperiod variations (13:41 h/light at summer solstice; 10:19 h/light at winter solstice). Animals were fed alfalfa hay (17% CP) ad libitum and a commercial supplement (14% CP) at 200 g animal^-1 day^-1 during the experimental period (December to September). Sperm motility increased (P<0.05) from 1.5 units from January to May to 2.5 units from July to September. Sperm viability also increased, from 25 % in January to May to 40 % in July to September. Ejaculate volume was 0.1 ± 0.03 ml ejaculate^-1 from January to July, lower (P<0.05) than the 0.5 ± 0.04 ml ejaculate^-1 recorded in August, September and December. Latency to ejaculate in an artificial vagina decreased (P<0.05) from 102 ± 7 sec in December to July, to 52 ± 1 sec in August and September. The studied French Alpine bucks exhibited seasonality in semen quality characteristics, body and testicular variables and sexual response, with generally lower variable values and less sexual activity from January to July followed by increased values and activity.

Palavras-chave : Seasonal reproduction; Goats; French Alpine bucks; Sperm, Semen characteristics; Sexual behavior.