The aim of this study was to estimate the energy requirements of crossbreed ewe lambs in a feedlot fed with increasing levels of concentrate in the diet. 36 ewe lambs were evaluated with initial body weight of 23.7±3.67kg. Six animals were slaughtered at the beginning of the experiment to obtain the reference group values. Animals (30) were distributed in five treatments: maintenance (feed restricted with Tifton grass hay) and those supplemented with increasing dietary levels of concentrate (20, 40, 60 and 80%) on a dry matter basis (six animals per treatment). The ewe lambs were slaughtered when they reached 37.70±9.89kg. The concentrate levels influenced the utilization efficiency of metabolizable energy for maintenance (km) and consequently the daily requirements of metabolizable energy for maintenance. The net energy requirements for maintenance of crossbred lambs in growth is 57kcal/FCW 0.75/day, where FCW is body weight on fasting. The ewe lambs with 20kg presented net energy requirement for 100g daily weight gain of 465kcal/day. The ewe lambs with 40kg of body weight required 930 kcal/day of net energy for the same gain. The net energy requirement for maintenance of ewe lambs can be estimated by the equation: NEm (Mcal/day) = 0.057 * FCW0.75. The net energy requirement for crossbred ewe lambs gain (Mcal/day) can be estimated from the equation: NEg (Mcal/day) = 0.524*FCW 0.75*GEBW1.21, where GEBW represented gain empty body weight. Diets affect the efficiencies of uses of metabolizable energy for maintenance (km) and gain (kg).
[1]
C. Ítavo,et al.
Carcass and non-carcass components of feedlot ewes subjected to increasing levels of concentrate in the diet
,
2014
.
[2]
J. Abreu,et al.
Estimativas dos requisitos nutricionais de ovinos em condições brasileiras
,
2008
.
[3]
A. J. Regazzi,et al.
TESTE PARA VERIFICAR A IGUALDADE DE PARÂMETROS E A IDENTIDADE DE MODELOS DE REGRESSÃO NÃO-LINEAR. I. DADOS NO DELINEAMENTO INTEIRAMENTE CASUALIZADO
,
2003
.
[4]
F. Owens,et al.
Review of some aspects of growth and development of feedlot cattle.
,
1995,
Journal of animal science.
[5]
Daniel Wallach,et al.
Mean squared error of prediction as a criterion for evaluating and comparing system models
,
1989
.
[6]
C. Ferrell,et al.
Cow type and the nutritional environment: nutritional aspects.
,
1985,
Journal of animal science.