Empty body chemical composition of Nellore steers at different feeding levels estimated by indirect methods

Aferri, GabrielaPereira, Angélica Simone CravoCorte, Rosana Ruegger Pereira da SilvaSilva, Saulo LuzMoreira, Marcelo ZachariasLeme, Paulo Roberto

Thirty-six Nellore steers at 20 months of age on average and initial body weight of 360 kg, fed ad libitum for 78 days and two levels of feed restriction for 58 days and posterior ad libitum feeding for 78 days were used to estimate body composition using the methods of indirect deuterium oxide or the 9th-10th-11thribs cut. The body water content was calculated with equations established for Nellore steers. The chemical body composition was different for the ether extract content. The animals subjected to feed restriction presented higher body fat content when estimated by deuterium than by the rib cut. The deuterium oxide or 9th-10th-11thribs cut methods used for body composition determination were effective to estimate body contents for animals fed ad libitum, however, not for animals on feed restriction. Comparatively, the indirect method of deuterium oxide was better than the 9th-10th-11thribs cut method to estimate body composition in Nellore steers submitted to feed restriction; however, both methods were similar in animals fed ad libitum.(AU)

1. beef cattle
2. rib cut
3. fat thickness
4. feedlot
5. feed restriction