The objective of this trial was to evaluate the biological and economical feeding systems feasibility during critical periods as an alternative to reduce the slaughter ages the animals raised in Brachiaria decumbens pastures. Sixty F1s Angus-Nellore weaned calves were randomly assigned in the following treatments: A) no supplementation; B) supplementation during the dry season after weaning; C) supplementation during the second dry season of the animal's life; D) supplementation during the both dry seasons; and E) supplementation during the first dry season and feedlot in the second one. The used supplement was a commercial ration, daily supplied at about 0.8% and 0.9% of liveweight, in the first and second dry periods, respectively. The feedlot treatment lasted 100 days, and the steers received ad libitum, a diet containing 40% of B. decumbens hay and 60% of concentrate. The experimental period was from weaning to slaughter (460 kg). During the first dry season, the supplemented calves showed higher daily gains (490 g) than non supplemented (70 g). In the second dry season, the confined steers presented the highest daily gains (1,285 g), followed by supplemented ones (580 g), while non supplemented steers lost weight (-180 g). There was an increase on the pasture stocking rate capacity where the animals were supplemented, in 20 and 30%, during the first and second dry periods, respectively. In the second dry season, the steers fed with restricted diet presented a compensatory gain when the feed restriction ceased, but it was not enough to allow them to reach the slaughter weight at the same age of the supplemented ones. The slaughter weight were: 30.1; 28.0; 26.6; 24.2 e 22.0 months for treats A, B, C, D and E, respectively. The economic analysis was also presented.
economic feasibility; feedlot; nutritive value; slaughter age; supplementation under grazing; stocking rate
