Evaluación de un empadre rotativo con monta natural: Efecto en el rendimiento reproductivo de vacas Cebú
Fecha
2003-01-01
Autores
Molina-Sánchez, Rafael
Galina-Hidalgo, Carlos S.
Díaz-Sánchez, María S.
Galicia-Angeles, Luis
Estrada Konig, Sandra
Título de la revista
ISSN de la revista
Título del volumen
Editor
México. Secretaría de Agricultura y Desarrollo Rural
Resumen
Para determinar el efecto de un sistema de manejo rotativo de lossementales, en el comportamiento reproductivo de vacas cebú encondiciones de monta natural, se utilizaron seis sementales Brahmancon experiencia sexual, evaluados mediante un examen andrológicopara fertilidad. Se estableció una época de monta de seis semanassubdivididas en periodos no consecutivos de tres semanas, para rea-lizar la rotación de los toros en un empadre fijo (EF; grupo A sema-nas 1, 2 y 3 y B semanas 5, 6 y 7) y uno rotativo (ER; grupo Asemanas 5, 6 y 7 y B semanas 1, 2 y 3). Se seleccionaron 88 vacascebú multíparas, con ternero al pie y 61±36 días posparto prome-dio. Se obtuvieron muestras de sangre para cuantificar progesterona,exámenes ultrasonográficos dos veces por semana para observar laactividad ovárica y medición de la condición corporal. Las varia-bles fueron la relación de vacas que pueden quedar gestantes conlas de anestro, transición y ciclando, y una comparación de vacasgestantes con ciclando. En las semanas 1, 2 y 3 el grupo A (EF)presentó más vacas en anestro (lote p=0.03 y semana p=0.001); y elB (ER) más vacas en transición (lote p=0.003). Durante las semanas5, 6 y 7 en el grupo B (EF) disminuyó el número de vacas en transi-ción (semana p=0.03) y 83% de las vacas quedaron gestantes. En elgrupo A (EF), las gestaciones fueron mayores en las primeras tressemanas (54%) contra 46% del grupo A (ER) en las semanas 5, 6 y7. Es factible que los resultados estuvieran influenciados por la con-dición corporal de las vacas. Por tanto, la fertilidad del hato (35%)está relacionada con el número de vacas que se mantengan en anestro(28%), indistintamente del programa de empadre utilizado.
In order to determine the effect of a rotational sire system on thereproductive performance in zebu cows, six Brahman bulls withsexual experience were used. These animals were evaluatedpreviously for breeding soundness. A six weeks breeding periodwas subdivided in two non-consecutive three week period forrotation of bulls in a fixed mating system (EF; group A weeks 1,2, and 3; and B weeks 5, 6, and 7) and a rotational system (ER;group A weeks 5, 6, and 7; and B weeks 1, 2, and 3). A total of 88multiparous zebu cows with calf at foot and 61±36 dayspostpartum, on average, were used. Blood samples to assessprogesterone and ultrasonographic examination of the ovariestwice weekly, to evaluate ovarian function, and measurement ofbody condition, were taken. Response variables were the relationamong cows that may become pregnant with the ones in anestrus,transition to cyclicity and cyclicity; besides, a comparison betweencows cycling and pregnant was evaluated. During weeks 1-3 ingroup A (EF) more cows were in anestrus (group p=0.03 and weekp=0.001); and in B (ER) more cows were in transition(group=0.003). During weeks 5-7, in group B (EF) cows intransition were reduced (week p=0.03) and 83% of the cows werepregnant. In group A (EF) there were more cows pregnant (54%)in the first three weeks as compared to 46% in group A (ER) inweeks 5-7. It is possible that results were influenced by cows bodycondition. It is concluded that overall fertility of the herd (35%)was related to amount of cows in anestrus (28%). This relationshipwas not affected by the type of mating program used.
In order to determine the effect of a rotational sire system on thereproductive performance in zebu cows, six Brahman bulls withsexual experience were used. These animals were evaluatedpreviously for breeding soundness. A six weeks breeding periodwas subdivided in two non-consecutive three week period forrotation of bulls in a fixed mating system (EF; group A weeks 1,2, and 3; and B weeks 5, 6, and 7) and a rotational system (ER;group A weeks 5, 6, and 7; and B weeks 1, 2, and 3). A total of 88multiparous zebu cows with calf at foot and 61±36 dayspostpartum, on average, were used. Blood samples to assessprogesterone and ultrasonographic examination of the ovariestwice weekly, to evaluate ovarian function, and measurement ofbody condition, were taken. Response variables were the relationamong cows that may become pregnant with the ones in anestrus,transition to cyclicity and cyclicity; besides, a comparison betweencows cycling and pregnant was evaluated. During weeks 1-3 ingroup A (EF) more cows were in anestrus (group p=0.03 and weekp=0.001); and in B (ER) more cows were in transition(group=0.003). During weeks 5-7, in group B (EF) cows intransition were reduced (week p=0.03) and 83% of the cows werepregnant. In group A (EF) there were more cows pregnant (54%)in the first three weeks as compared to 46% in group A (ER) inweeks 5-7. It is possible that results were influenced by cows bodycondition. It is concluded that overall fertility of the herd (35%)was related to amount of cows in anestrus (28%). This relationshipwas not affected by the type of mating program used.
Descripción
Palabras clave
CEBÚ, BOVINOS, REPRODUCCIÓN ANIMAL, APAREAMIENTO, COMPORTAMIENTO ANIMAL, BOVINES, ZEBU, ANIMAL REPRODUCTION, MATING, ANIMAL BEHAVIOR