Desempenho e comportamento de vacas nelores e suas crias puras ou mestiças no Brasil Central
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Data
2009-08-07
Autores
Rodrigues, Walvonvitis Baes [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo desta pesquisa foi avaliar a influência do grupo genético do bezerro no comportamento de mães e suas crias. Usaram-se 24 vacas Nelore paridas e seus bezerros, dos quais oito eram Nelores, oito ½Simental ½Nelore, e oito ½Red Angus ½Nelore. Avaliaram-se as medidas de freqüência e duração das mamadas, tempo de pastejo e ruminação dos bezerros e vacas. Os bezerros puros mamaram mais freqüentemente que os mestiços (3,51 vs. 3,17 vezes/dia), porém com menor duração de mamada (7,37 vs 7,80 minutos). A freqüência de mamadas, duração de cada mamada e tempo total de mamadas diminuíram com o aumento na idade do bezerro. Nos bezerros, pastejo e ruminação aumentaram com a idade; porém, nas vacas, aumentou o tempo de pastejo e diminuiu o de ruminação com o passar dos dias. Os bezerros mestiços pastaram, em média, 18 minutos a mais que os puros, e os machos, 16 minutos a mais que as fêmeas. Os bezerros machos ruminaram, aos 40 dias de idade, 25 minutos a mais que as fêmeas, mas esta diferença diminuiu com a idade e desapareceu por volta dos 220 dias. As mães de mestiços ruminaram, em média, 10 minutos a mais que as mães dos puros. O comportamento da mãe e de sua cria é influenciado pelo grupo genético desta última.
The objective was to evaluate the effect of a calf's genetic group on the behavior of dam and calf. We used 24 Nellore dams and their calves, of which eight were Nellore, eight were ½Simmental ½Nelore and eight ½Red Angus ½Nellore. Grazing and rumination times, as well as suckling frequency and time, were measured. The straightbred calves suckled more often than the crossbreds (3.51 vs. 3.17 times/day), but their suckling lasted less time (7.37 vs 7.80 minutes). Suckling frequency, suckling length and total time spent suckling decreased as calf age increased. Calf grazing and rumination time increased with age; however, the cows’ grazing time increased and rumination time decreased as the days postpartum went by. The crossbred calves grazed, on the average, 18 minutes longer than the crossbreds, and the males grazed 16 minutes longer than the females. The male calves grazed, at 40 days of age, 25 minutes longer than the females, but this difference decreased as they grew up and disappeared around 220 days. The dams of crossbreds ruminated, on the average, 10 minutes longer than the dams of straightbreds. In conclusion, dam and calf behavior are influenced by the calf's genetic group.
The objective was to evaluate the effect of a calf's genetic group on the behavior of dam and calf. We used 24 Nellore dams and their calves, of which eight were Nellore, eight were ½Simmental ½Nelore and eight ½Red Angus ½Nellore. Grazing and rumination times, as well as suckling frequency and time, were measured. The straightbred calves suckled more often than the crossbreds (3.51 vs. 3.17 times/day), but their suckling lasted less time (7.37 vs 7.80 minutes). Suckling frequency, suckling length and total time spent suckling decreased as calf age increased. Calf grazing and rumination time increased with age; however, the cows’ grazing time increased and rumination time decreased as the days postpartum went by. The crossbred calves grazed, on the average, 18 minutes longer than the crossbreds, and the males grazed 16 minutes longer than the females. The male calves grazed, at 40 days of age, 25 minutes longer than the females, but this difference decreased as they grew up and disappeared around 220 days. The dams of crossbreds ruminated, on the average, 10 minutes longer than the dams of straightbreds. In conclusion, dam and calf behavior are influenced by the calf's genetic group.
Descrição
Palavras-chave
Amamentação, Pastejo, Desempenho, Nelore (Zebu), Cruzamento (Genetica), Crosses, Grazing, Suckling, Rumination
Como citar
RODRIGUES, Walvonvitis Baes. Desempenho e comportamento de vacas nelores e suas crias puras ou mestiças no Brasil Central. 2009. vii, 73 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina Veterinária e Zootecnia de Botucatu, 2009.