Grazing behavior, growth performance, carcass yield and economic analysis of steers supplemented with concentrate in an integrated crop-livestock system

This trial evaluated concentrate supplementation on grazing behavior, growth performance, carcass yield and economic analysis of off-season steer production in an integrated crop-livestock system (ICL). A randomized block design with the pastures (modules) as blocks, with 4 treatments, 4 groups of animals per treatment and 3 animals per group (N=48, 395±16 kg) was used to evaluate increasing levels of concentrate supplementation (1.0, 2.0, 3.0 and 4.0 kg/animal/day) containing 17% crude protein and 76% total digestible nutrients. The steers were kept in “Santa Fe” ICL Urocloa ruziziensis pastures during the dry season. Concentrate intake was 0.98, 1.45, 1.86, and 2.02 kg/animal/day, representing 0.23, 0.34, 0.44, and 0.47% of BW. Supplementation did not affect grazing time (P = 0.66); however, linearly decreased rumination time (P = 0.025) and increased idling (P = 0.043) and trough (P = 0.034) times. Average daily gain, carcass weight, dressing percentage and beef productivity linearly increased (P < 0.01) with increasing concentrate in the diets. All the supplementation levels were profitable, but the profit margin was greater in the highest level of concentrate supplementation. Concentrate supplementation to produce off-season Nellore steers in ICL was an efficient and profitable way to enhance growth performance and carcass yield without compromising grazing activity. Key words: beef cattle, behavior, carcass, intake, performance.