PS3-24. Performance and Carcass Characteristics of Feedlot Beef Cattle Fed Diets with or Without Roughage and Supplemented with a Technological Pack.

Abstract The objective of this study was to evaluate the effect of a technological package in diets with or without traditional roughage on the performance of feedlot cattle. Two hundred and twenty-four non-castrated male Nellore cattle were used and randomly allocated to 32 pens. The experimental design was a completely randomized block design in a 2 × 2 factorial arrangement. The factors evaluated were the presence or absence of roughage in the diets and the supplementation with the technological package. Four experimental treatments were used: NRM – no-roughage diet + monensin; RDM – diet with 9% roughage + monensin; NRV – no-roughage + technological pack; and RDV – diet with 9% roughage + technological pack. Monensin was provided at 30 mg/kg DM (Elanco), and the technological pack (Victus® Performance) composed by the combination of Crina® Ruminants (essential oil blend, 100 mg/kg DM), organic zinc and chromium (60 and 0.3 mg/kg DM, respectively), and Hy-D® (25-OH-vitamin D3, 0.1 mg/kg DM), provided by dsm-firmenich, Switzerland. The animals were weighed at the beginning and at the end of the feedlot period, which lasted 100 days. Data were analyzed using SAS (Version 9.4, SAS Institute, Cary, NC, USA). Residual normality and homogeneity of variances were verified using PROC UNIVARIATE, and analysis of variance was performed using PROC MIXED, adopting a significance level of 5%. Final body weight was greater in animal fed diets containing roughage (P = 0.041) and in those supplemented with the technological pack (P = 0.033). Consequently, the average daily gain of supplemented animals was also greater (P = 0.021). Dry matter intake (kg/day) was greater in diets with roughage (P = 0.001), while intake expressed as a percentage of body weight was influenced by diet (P = 0.001) and additive type (P = 0.042), with higher values observed in diets containing the technological pack. Feed efficiency was improved both by diets without roughage (P = 0.003) and by the use of the technological pack (P = 0.031). Final hot carcass weight was higher in animals supplemented with the technological package (P = 0.041), whereas carcass yield was influenced only by the inclusion of roughage (P = 0.002), being greater in diets without roughage. Daily carcass gain was higher in diets without roughage (P = 0.047) and in supplemented animals (P = 0.039). Carcass gain to feed ratio and carcass yield were improved in diets without roughage (P < 0.001 and P < 0.018, respectively) and in animals receiving the technological pack (P < 0.001 and P < 0.022, respectively). In conclusion, roughage inclusion improved growth performance, whereas its removal enhanced carcass efficiency. The technological pack consistently outperformed monensin, supporting its use as a nutritional strategy for feedlot cattle fed high-concentrate diets. For image description, please refer to the figure legend and surrounding text.