Energy partition for maintenance and weight gain in Nellore and crossbred steers finished under grazing

Abstract

-The objective of this work was to estimate net energy (NE m ) and metabolizable energy (ME m ) requirements for maintenance and efficiency of use of metabolizable energy for maintanence (k m ) and gain (k g ) of grazingNellore and crossbred steers. It was used 24 castrated steers, 12 Nellore breed (386 kg SBW) and 12 ½ Limousin-Nelore crossbred (397 kg SBW). The comparative slaughter method was used. In each genetic group, animals were grouped in three similar groups: reference; restrict feeding and ad libitum feeding. The reference group was slaughtered in the beginning of the experiment whereas the others were slaughtered at the end of it. During the 104 days of the experimental period, the group under restrict feeding had access to pastures for 3.5 hours daily whereas the group with ad libitum feeding remained on pasture full time. Forage intake was estimated in two trials by using the double-indicator method. Values of NE m , ME m , k m and k g were estimated on the basis of empty body weight ( Revista Brasileira de Zootecnia