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Conducta estral, concentraciones de LH y función lútea en cabras en anestro estacional inducidas a ciclar mediante el contacto con cabras en estro

Veterinaria Mexico 01/1999;
Source: DOAJ

ABSTRACT El presente trabajo tuvo como objetivo determinar el efecto de las cabras en estro sobre la actividad ovárica de sus compañeras en anestro estacional. Se utilizaron un total de 30 cabras anéstricas divididas aleatoriamente en tres grupos. El grupo I estuvo formado por 10 cabras inducidas al estro con acetato de melengestrol (MGA) combinado con una inyección intramuscular de gonadotropina sérica de yegua gestante (PMSG); el grupo II estuvo formado por 10 cabras no tratadas y mantenidas en contacto directo con los animales del grupo I durante todo el experimento, y el grupo III, formado por 10 cabras sin tratamiento que se mantuvieron alejadas de los otros dos grupos. En todos los animales se detectaron calores diariamente y se obtuvieron muestras de sangre dos veces por semana con el propósito de determinar las concentraciones de progesterona y establecer la presencia o ausencia de ovulación. Además se tomaron muestras de sangre para la determinación de LH cada 2 h desde las 36 hasta las 72 h posteriores a la aplicación de PMSG. Se consideró que un animal tenía actividad ovárica cuando sus valores de progesterona alcanzaron1ng/ml. En el grupo I, el 100% de los animales respondieron con ovulación al tratamiento. En el grupo II el 80% de los animales ovularon en un periodo de 13 días, y en el grupo III, que actuó como testigo, 40% de los animales ovularon. Los picos preovulatorios de LH se observaron a las 54.59 y 64 6 h para los grupos I y II, respectivamente; no se observaron picos de LH en el grupo III. Las diferencias observadas entre los grupos I y II con respecto al grupo III para el porcentaje de presentación de ovulación e inducción de estros fueron significativas (P < 0.05). Se concluye que la presencia de cabras en estro es capaz de inducir el estro, picos preovulatorios de LH y ovulación sincronizada en una proporción considerable de cabras en anestro estacional, lo que indica una inducción real de actividad ovárica y no simplemente una conducta de imitación.

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