Animal performance, ingestive behavior, and carcass characteristics of grazing-finished steers supplemented with castor bean (Ricinus communis L.) meal protein.

This study was carried out to evaluate the effects of replacing soybean meal by castor bean meal on nutrient intake, digestibility, animal performance, ingestive behavior activities, carcass characteristics, and fatty acid profile from steers finished in pasture. Crossbred steers were weighed to determine the initial body weight (331.6 ± 37.4 kg), which were kept in 4 paddocks (8 animals/paddock), on pastures of Brachiaria decumbens during the finishing phase. Dietary treatments included CC00-without castor bean meal; CC33-153 g/kg of castor bean meal; CC66-308 g/kg of castor bean meal; and CC100-434 g/kg of castor bean meal. No treatment effects were detected (P > 0.05) for final body weight, average daily gain, feed efficiency, and hot carcass weight. The DM, CP, NDF, and NFC total intake were lowest (P < 0.01) for steers fed CC100 diet than others. No treatment effects were detected (P > 0.05) for digestibility. For ingestive behavior activities, data on DM and NDF from feeding rate were greater (P < 0.01) in CC00 v. castor bean meal steers. DM and NDF from rumination rate were greater (P < 0.01) in CC33 v. CC100 steers that was the lowest. Carcass measures, carcass composition, chemical composition of Longissimus thoracis muscle, and profile and the sum of fatty acids were not affected (P > 0.05) by castor bean meal replacement on the diets. Results from this experiment suggest that castor bean meal may replace soybean meal in pasture supplementation without altered digestibility, carcass characteristics, and fatty acid profile.