Desempenho de vacas de corte Purunã submetidas a diferentes manejos de amamentação

Abstract

Resumo -O objetivo deste trabalho foi avaliar o desempenho ponderal e reprodutivo de vacas de corte submetidas a diferentes manejos de amamentação. Durante a estação de monta, de 85 dias, foram avaliadas 161 vacas de corte da raça Purunã, de acordo com os seguintes manejos de amamentação: desmame precoce, vacas separadas dos seus bezerros aos 75 dias pós-parto; amamentação controlada, vacas separadas de seus bezerros aos 75 dias de idade, mas colocadas para amamentar uma vez ao dia durante a estação de monta; e desmame convencional, vacas mantidas com seus bezerros ao pé até o final da estação de monta, aos 160 dias de idade dos bezerros, em média. As taxas de prenhez não foram significativamente afetadas pelos manejos de amamentação, tendo sido de 97% no desmame precoce, de 96% na amamentação controlada e de 90% no desmame convencional. No entanto, o desmame precoce resultou em menor eficiência reprodutiva (28,26 kg), quando comparado à amamentação controlada (35,09 kg) e ao desmame convencional (35,34 kg). Vacas de corte mantidas em boas condições corporais ao parto e ao início da estação de monta apresentam alta taxa de fertilidade, independentemente do manejo de amamentação dos bezerros.Termos para indexação: amamentação controlada, anestro pós-parto, desmame precoce, eficiência reprodutiva, intervalo entre partos, taxa de fertilidade. Performance of Purunã beef cows subjected to different nursing managementsAbstract -The objective of this work was to evaluate the weight and reproductive performance of beef cows subjected to different nursing managements. During the breeding season of 85 days, 161 beef cows of the Purunã breed were evaluated, according to the following feeding managements: early weaning, cows separated from their calves at 75 days postpartum; controlled nursing, cows separated from their calves at 75 days of age, but taken to nurse once a day during the breeding season; and conventional weaning, cows kept with their calves until the end of the breeding season, at 160 days of age of calves, in average. Fertility rates were not significantly affected by weaning managements, being 97% for early weaning, 96% for controlled nursing, and 90% for conventional weaning. However, early weaning resulted in lower reproductive efficiency (28.26 kg), when compared to controlled nursing (35.09 kg) and conventional weaning (35.34 kg). Beef cows maintained in good body conditions at birth and at the beginning of the breeding season have a high fertility rate, regardless of calf-feeding management.

<b>Body size and its effects on productive efficiency of cows with predominant Nellore genetic composition

“…The larger proportion of kilograms of calf in relation to the cow weight both at calving and at weaning are indicative of efficiency, as they demonstrate production as a function of the cost of maintenance of the females, which is the highest production cost. These efficiencies can be influenced by the time of birth of the calves and cow age (Bocchi, Teixeira, & Albuquerque, 2004), cow genetic group and calf sex (Ribeiro et al, 2001), nutritional level pre-and postpartum (Ribeiro et al, 2001;Vaz et al, 2016), and calf age at weaning (Moura et al, 2014;Vaz et al, 2010). The present findings are corroborated by the literature, where the cow body size did not lead to increased calf weights relative to the cow weight (Vaz et al, 2016), these two variables being actually proportional to the size of the dam.…”

Influence of weaning management at 30, 75 and 180 days of age on non‐esterified fatty acids and reproductive performance in beef cows

“…A complementary analysis demonstrated that the PP at the end of the PD was higher in heavier cows at calving and with higher levels of P4 at 30 dPP, especially in W180 cows. Studies showed that the highest PP was observed in cows with greater body condition at calving and a low rate of pregnancy loss, emphasizing the importance of ensuring good nutritional status in the pre‐calving period to achieve BCS greater than 3.0 (Ayres et al, 2014; Moura et al, 2014) and to anticipate the return to postpartum cyclic activity (Joner et al, 2018). However, there was no difference in BW at birth between treatments, although W180 cows had a relatively lower BW that may have influenced this result.…”

Factores ambientales y parámetros genéticos para algunas características reproductivas en bovinos Chacuba

“…El desempeño reproductivo de bovinos para carne en el trópico es afectado por factores ambientales, generalmente asociados con la condición corporal al parto y su dinámica durante el periodo posparto (1) . El intervalo entre el parto y el reinicio de la actividad ovárica puede ser un obstáculo importante para la mejora de la eficiencia reproductiva, ya que es el principal responsable del aumento del intervalo entre partos (2) , que es influenciado por la raza, nutrición, producción de leche, presencia del becerro, estación del año, presencia del semental (3) y el número de parto (4) .…”

“…Otra medida para valorar la eficiencia reproductiva del ganado bovino son los días abiertos, además, la obtención de información requiere menos tiempo; por tal motivo, su uso se justifica en la selección para mejorar el comportamiento reproductivo (8) . Dado que los Reproductive performance of beef cattle in the tropics is affected by environmental factors usually associated with body condition at calving and their dynamics during the postpartum period (1) . The interval between calving and the resumption of ovarian activity can be a major obstacle to the improvement of the reproductive efficiency, as it is responsible for the calving interval (2) , which is influenced by breed, nutrition, milk production, presence of the calf, season of the year, presence of the sire (3) and number of calving (4) .…”