PSIII-31 Effects of associative use of additives on performance, carcass characteristics and serum D-lactate in Nellore x Angus young bulls

Abstract

Abstract The objective was to evaluate the effects of including virginiamycin or bacitracin in diets containing monensin or monensin plus virginiamycin and bacitracin on growth performance and carcass characteristics of feedlot young bulls. Seventy-two young bulls, with an initial average body of 417 ± 38.7kg were allotted in a completely randomized design. The bulls were placed in 18 pens (four animals per pen), with three treatments and six experimental replicates. The diets consisted of 85% concentrate and 15% of corn silage, with 11.4% CP, 75.7% TDN and 18.4% NDF. The treatments were: MON, 25 ppm of monensin in the diet; MONB: monensin plus 8.75 ppm of zinc bacitracin; and MONVM monensin plus 25 ppm of virginiamycin. Feedlot had 109d, with 27d of adaptation and 82d of experimental period. Performance was measured by daily intake records and weighing at the beginning and end of the feedlot. After feedlot, animals were slaughtered to measure carcass traits. Serum D-lactate was collected on day 7 and 43 of the experimental period. There was no significant effect of the additives on performance and most of the carcass traits (Table 1). However, young bulls receiving MONVM tended to have greater LM area. On the other hand, MON diet tended to increase marbling. Finally, there was a tendency for treatment x time interaction (P < 0.08) in the serum concentration of D-lactate. Bulls receiving MON had greater concentration on day 7 (109.5 µmol.µL-1), compared to other groups (66.7 and 89.9 µmol.µL-1 for MONB and MONVM, respectively). There was no effect of additives in the D-lactate content on day 43, being the treatments average 83.5 µmol.µL-1. In conclusion, the use of monensin and their association with virginiamycin or bacitracin did not affect performance but tend to influence carcass traits and serum D-lactate. Funded by Agroceres, Fapemig, CAPES, and CNPq.