Resumo

NAVA-TRUJILLO, Héctor et al. Brief communication: Effect of post-mating progestagen administration on pregnancy rate in crossbred goats following an induced estrus. Rev. Cient. (Maracaibo) [online]. 2008, vol.18, n.5, pp.578-581. ISSN 0798-2259.

Estrus induced with progesterone or progestagens have low fertility compared to natural estrus. However, post-mating progesterone administration has been reported by increases embryo development and pregnancy rate; therefore the aim of this study was to evaluate the effect of post-mating progestagen administration on pregnancy rate after medroxyprogesterone acetate (MAP) induced estrus in crossbred goats. Estrus induction was started at 31.3 ± 1.7 days post-partum with intra- vaginal sponges impregnated with 60 mg of MAP during 14 days and at time of sponge removal were applied 500 IU of eCG intramuscular. Estrus was detected every 6 hours from 24 hours onwards after sponge withdrawal. Goats were naturally mated with two entry bucks. Five days post-mating, mated goats were randomly assorted into two groups, control group (n=18), without any treatment, and MAP group (n=18), receiving a sponge with 60 mg of MAP for fourteen days. Ultrasonographyc diagnosis of pregnancy was performed at day 50 post-mating. MAP treatment, did not affect the pregnancy rate, with 44.4% (8/18) in MAP group, while in control group was 55.5% (10/18), P>0.05. In conclusion, MAP treatment with a sponge impregnated with 60 mg of MAP between days 5 and 19 post-mating did not affect the pregnancy rate after progestagen induced estrus during the early post-partum period in crossbred tropical goats.

Palavras-chave : Goats; post-partum; estrus synchronization; progestagen; pregnancy.