Use of various supplements in the feeding of crossbred bovine femalesunder confinement

To evaluate different supplements on growth and profit, 36 crossbred females bovine with initial weights of 99.5±22.1, 186.8±52.2 and 303.5±21.3 kg for weanings, yearlings and heifers respectively, were assigned to six experimental groups balanced way for 84 days in an area of tropical dry forest. The animals were individually confined and given ad libitum water and harvested grass. Were offered 3 kg/animal/day of each treatments, namely T0 (10.45% CP, 0.22% Ca and% P 0.45), T1 (17.73, 1.76 and 0.64), T2 (20.91, 0.76 and 0.95), T3 (15.27, 1.31 and 0.81), T4 (14.80, 3.83 and 0.64) and T5 (13.95, 1.43 and 0.66). In each animal was determined biweekly height at the withers (HW) and weekly weight (BW), consumption of supplement (CS) and forage (CF). The studied variables were analyzed using split plot in time design and Tukey mean test-HSD. The economic evaluation was performed by partial budget. The BW (kg) averaged during the trial was affected by treatment, T3 was the highest (231.51), followed by T2 and T4 (227.17 and 226.19, respectively). The lowest BW were presented by T1 and T5 (215, 37 and 212.28) both being overcome by T0 (218.85). The daily weight gain and individual CS showed no difference between treatments with an average of 0.605±0.16 and 2.78±0.49 kg/animal/ day. The CF as fed (kg/animal/day) showed significant differences being T2, T3 and T4 higher (7.10, 7.22 and 7.196, respectively) when compared to T0 (6.25), while T1 and T5 showed an intermediate performance (6.87 and 6.66, respectively). The economic evaluation showed that although some treatments promoted a better BW versus control, the difference was not significant enough to outweigh the costs to beef up valued from 5.5 to 11 Bs/kg body weight, resulting in average rates for all treatments return on costs from −15.3 to −9.03%, respectively, a situation reverted only by 8.92% to T2 for 11 Bs/kg, concluding that it is only possible to use T2 if these females are valued as future bellies to milk production.