BACK TO QUEBEC CITY 2002 TITLES
Effect of libido reestablishment
in semen characteristics of goats (Capra hircus)
V. Prado1, A. Orihuela2,
S. Lozano1 and I. Pérez-León1
1Instituto Tecnológico
agropecuario de Oaxaca, Ex-hacienda de Nazareno, Xoxotlán Oaxaca,
México. 2Facultad de Ciencias
Agropecuarias de la Universidad
Autónoma del Estado de Morelos, Cuernavaca Morelos, México
The association between libido re-establishment and semen characteristics of sexually mature goats was evaluated. Nine two-year old bucks were trained to mount a restrained estrous-induced female and ejaculate in an AV (artificial vagina). Each buck was subsequently subjected to eight weekly trials in which one of the following two treatments was alternately applied. In treatment 1, males were individually exposed to the same female during a four-hour period throughout which their ejaculates were collected and analyzed. Treatment 2 was the same as the former, except that a different doe replaced the stimulus animal for the 2nd two hours. In treatment 1, three (33%) of the males achieved at least 9 ejaculations, averaging 2.3±0.8 mounts, before each ejaculation. Inter-ejaculatory interval increased from 47.7±42.4 to 3609 sec, while ejaculation volume and sperm concentration decreased from 0.9±0.3 to 0.2 ml and from 4.3±1.8 to 0.6 spermatozoa/109/mL in the 1st and 9th collection, respectively. In treatment 2, three (33%) of the males performed 7 ejaculations during the first two hours. After changing the stimulus animal, all males (100%) ejaculated again, and two (22.2%) achieved 5 more ejaculations. These males averaged 3.0±1.2 and 2.3±1.9 (P>0.05) mounts before each collection for the 1st and 2nd two-hour period, respectively. Reaction time, semen volume and sperm concentration recovered 57% (P=0.29), 82.3% (P=0.01) and 90% (P=0.16), respectively after changing the stimulus female. It is concluded that after changing the stimulus animal following a two-hour session, libido in goats was reestablished, and the quality and quantity of the ejaculations improved.