Resumo

FERNANDEZ REYES, F; HERNANDEZ PICHARDO, J.E; RODRIGUEZ MENDEZ, S  e  VELASQUEZ OSORIO, H.D. FERTILITY IN MARES CUARTO de MILLA TREATED WITH HUMAN CHORIONIC GONADOTROPIN (hCG) USING FROZEN SEMEN. Rev Salud Anim. [online]. 2008, vol.30, n.3, pp. 184-188. ISSN 0253-570X.

The human Chorionic Gonadotropin (hCG) by its effect similar to the one of LH, was used to improve the percentage of conception in mares, using frozen semen in the artificial insemination. For this, 20 mares cycling of natural way, belonging to the breed Cuato de Milla (Quarter Horse), in their reproductive age (6 to 12 years of age), were selected in a farm located in Mexico D.F. The animals were divided into 2 groups: Group 1; mares treated with 2000 UI hCG when presented Graff follicle equal or higher than 35 mm and inseminated 30 hours after the application of this hormone. Group 2; considered the control group in which insemination was made 30 hours after the mares presented follicle equal o higher than 35 mm by means of the ultrasound observation. For the artificial insemination, frozen semen in straw of 5 mL containing a total concentration of 1000 million spermatozoa was used. The gestation diagnosis was made by means of the observation of the embryonic vesicle in day 16 after the artificial insemination, with a transrectal ultrasound of 5 MHz. The results show that group 1 (mares treatment with hCG) have an 80% fertility percentage (8/10), whereas group 2 (control group), presented a 20% fertility (2/10). It is concluded that hCG helped to improve the pregnancy percentage in treated mares.

Palavras-chave : hCG; ovulation; gestation-mares; insemination.