Resumen

LEITE, P.A.G. et al. Induction of the out-of-season ovulation (with LH and GnRH) and estrus (with progesterone) in goats. Arq. Bras. Med. Vet. Zootec. [online]. 2006, vol.58, n.3, pp. 360-366. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352006000300012.

In order to achieve estrous synchronization, intravaginal sponges impregnated with 60mg of medroxyprogesterone acetate (MPA) were implanted in 45 goats for nine days. On day 7, 200IU of equine chorionic gonadotropin (eCG) and 37.5µg of cloprostenol were administered to each doe. The animals were randomly allocated in three treatments with 15 animals each. Twenty four hours after intravaginal sponge removal, does were administered 1ml saline solution (control T₁), 5mg LH (T₂) and 2.5µg GnRH (T₃) intramuscular injection. Percentages of animals in estrus were 100.0; 73.3 and 66.6 (P<0.05) and average intervals from sponge removal to start of estrus were 34.8, 29.3 and 31.5 hours for T₁, T₂ and T₃, respectively, being those differences not statistically significant. The average intervals from sponge removal to ovulation were 46.6, 52.1 and 41.6 hours for T₁, T₂ and T₃, respectively, with the difference between T₂ and T₃ being statistically significant (P<0.01). Ovulation time averages were 21.3, 26.8 and 22.3 hours after injections for T₁, T₂ and T₃ , respectively.

Palabras llave : goat; synchronization; ovulation; LH; GnRH; MPA.