Evaluación de implantes de norgestomet reutilizados en protocolos de sincronización del estro en vacas Brahman

Evaluación de implantes de norgestomet reutilizados en protocolos de sincronización del estro en vacas Brahman

RESUMEN

Objetivo. Evaluar las concentraciones de progesterona, la manifestación de estro y las tasas de preñez en vacas Bos indicus sometidas a varios protocolos de sincronización del estro con un implante de norgestomet usado previamente. Materiales y métodos. Sesenta vacas recibieron un implante auricular de norgestomet reutilizado y fueron distribuidas en uno de cuatro protocolos: (1) benzoato de estradiol (BE) + progesterona (P4) + prostaglandina F2α (PG) (BE+P4+PG); (2) valerato de estradiol (VE) + norgestomet (NG) (VE+NG); (3) el mismo protocolo BE+P4+PG, asociado con 400 UI de gonadotropina coriónica equina (eCG) (BE+P4+PG+eCG); (4) el mismo protocolo VE+NG, asociado con 400 UI de eCG (VE+NG+eCG). El implante fue removido el día 9, con inseminación artificial (IA) 12 horas después de la detección del estro. La preñez fue diagnosticada 45 días después de la IA. Las muestras de sangre fueron tomadas los días 0, 4 y 9 (después de colocar el implante) para el análisis de progesterona por RIA. Resultados. En el día 4, las concentraciones de progesterona fueron menores en vacas tratadas con BE+P4+PG (0.90 ± 0.73 ng/ml; p<0.01). Las vacas que recibieron VE+NG+eCG tuvieron mayor concentración de progesterona en plasma (p<0.05) en el día 9 (4.72 ± 0.79 ng/mL) que otros protocolos. Hubo mayor porcentaje de detección de estro (p<0.05) en vacas tratadas con VE+NG+eCG (66.7%). Las tasas de preñez no fueron afectadas por los protocolos (p>0.05). Conclusiones. Los implantes de norgestomet reutilizados fueron eficaces para sincronizar el estro y alcanzar tasas de preñez adecuadas en vacas Brahman.

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