Leveduras vivas e virginiamicina na dieta de bovinos de corte semiconfinados

Abstract

The objective of this research was to study the effects of the inclusion of live yeasts (Saccharomyces cerevisiae, Procreatin®), virginiamycin (V-Max®) and the association of both, on the performance of beef cattle in semiconfined system, grazing a pasture of Brachiaria brizantha cv. Marandu. A total of 36 Nellore crossbred bulls were used, with an average age of 21 months and initial average weight of 307 ± 25 kg. The animals were distributed in a completely randomized design, and the experiment had a total duration of 112 days, divided into four periods of 28 days. All animals were supplemented at a level of 1.3% of body weight, considering each stage of the experimental period. The experimental treatments were: Supplement without additive (SC, control); Supplement containing 0.5 g.kg-1 of live yeasts (SL); Supplement containing 75 mg.kg-1 of virginiamycin (SV) and supplement containing virginiamycin (75 mg.kg-1) + live yeasts (0.5 g.kg-1) (SVL). The averages of the performance were compared by orthogonal contrasts, with a 5% level of significance, being: C1 = C vs. (SL + SV + SVL); C2 = SL vs. SV and, C3 = (SL + SV) vs SVL. In relation to the average daily gain (kg / day), there was no difference (P> 0.05) between the animals that received SC (1.07) and those that received supplements with additives (1.13), between those who received SL (1.09) and those who received SV (1.11) and those who received SL or SV (1.10) and those who received SL + SV (1.20). The results show that in the conditions of the present experiment the use of these additives does not bring improvements to the performance of semiconfined cattle.