Efeito da suplementação com probiótico no cortisol sérico e no ganho de peso em bovinos

Abstract

This study evaluated the effect of probiotic supplementation on both weight gain and serum cortisol concentration in cattle. Forty Nelore calves around 18 months old were randomly assigned to one of two groups (N=20 calves each) which received only mineral mixture (GC) or mineral mixture supplemented with 4.0 g probiotic Proenzime® per animal per day (GP). The cattle were subjected to handling stress by the usual weighing practices in the corral as well as blood sampling on days 0, 75 and 150. Live weight gain increased in GP (8.20 Kg; 17.07%) from day 0 to 75 (P<0.05); no weight differences were detected from day 76 to 150 (P>0.05). Cortisol concentration increased in GC cattle on day 150 (P<0.05). In GP cattle serum cortisol was constant over the experiment (P>0.05). On day 150, cortisol concentration were higher in GC as compared to GP. No correlations were detected between live weight gain and serum cortisol on days 75 (r= -0.005ns) and 150 (r= -0.007ns). These results indicate that: probiotic administration enhances weight gain in cattle for 75 days but not longer; and day 150 probiotic supplementation can lower cortisol concentration in cattle that are frequently stressed by handling and weighing practices in the corral.