Autoria: PORTO, M. O.; PAULINO, M. F.; VALADARES FILHO, S. de C.; DETMANN, E.; CAVALI, J.; SALES, M. F. L.; VALENTE, E. E. L.; COUTO, V. R. M.

Resumo: The objective of this study was to estimate requirements of energy, protein and macrominerals of young Nellore/Holstein crossbreds bulls supplemented on pastures of Brachiaria decumbens Stapf. Thirty-five young bulls, at 8.53±0.18 months of age and with initial body weight of 230.6±6.1 kg were used. Ten animals were slaughtered as reference, in different weight range, and the other animals were slaughtered at the end of the experimental period. For estimate of net energy requirements for weight, a regression equation between log of retained energy (RE) and log of empty body weight gain (EBWG) was constructed. Net requirements of Ca, P, Mg, Na and K were determined by the equation Y' = a.b.Xb-1, in which a and b represent the intercept and the coefficient of equation of prediction of macrominerals in body content, respectively. Requirements of metabolizable energy for maintenance (MEm) were obtained from retained energy in function of metabolizable energy intake (MEI). The requirements of MEm of Nellore/Holstein crossbreds young bulls on pasture was 125 kcal/EBW0.75/day. The efficiency of ME utilization for maintenance (km) of grazing Nellore/Holstein crossbred young bulls was 0.58 and 0.24 for gain. The total metabolizable protein requirements for an animal with 400 kg and with average daily gain of 1.0 kg, were 638.36 g/day. The dietetic requirements of Ca and P for an animal with 400 kg BW were 0.49 and 0.21% of DM, respectively. Daily metabolizable energy requirement for maintenance of grazing Nellore/Holstein crossbred young bulls was 11.6% greater than the values found for cattle in feedlot in Brazil (112 kcal/kg EBW0.75).

Ano de publicação: 2012

Tipo de publicação: Artigo de periódico

Unidade: Embrapa Acre

Palavras-chave: Animales jóvenes, Aumento de peso, Bezerro mestiço, Brachiaria decumbens, Capim Brachiaria, Energia, Fuentes energéticas dietéticas, Gado Holandês, Gado Nelore, Gado de corte, Ganado de carne, Ganho de peso, Gramínea forrageira, Nelore x Holstein, Nutrición animal, Nutriente mineral, Nutrição animal, Pastagem, Pastizales, Pastos forrajeros, Productos del cruzamiento, Proteína, Proteína dietética, Raza de bovinos Nelore, Raza de ganado Holstein, Suplemento mineral, Suplementos dietéticos minerales, Toros, Touro