Effect of Fibrolytic Enzyme and Different Supplementation Strategies on Performance and Carcass Characteristics of Nellore Bulls in the Finishing Phase in Pasture

The objective of this study was to measure performance and carcass characteristics of grazing Nellore bulls fed with fibrolytic enzyme (Fibrozyme®-Alltech) or not within two different supplementation strategies during the finishing phase in the dry season at low latitude. Twenty-eight Nellore bulls (24 mo; BW = 442 ± 16 kg) were used in a randomized complete block design with treatments in a 2 × 2 factorial arrangement of two supplementation strategies (constant or increasing levels) and presence (1.5g/100 kg BW) or absence of the fibrolytic enzyme product. The supplement was provided at the level of 10 g/kg BW supplement/d throughout the experiment (constant), or at 4, 8, 12 and 16 g supplement/kg BW during successive 35-d periods, with a total average of 10 g/kg BW. The increasing supplementation may compensate for the reduction in pasture quality and quantity as the dry season progressed. The pasture was composed of Brachiaria brizantha cv. Marandu (7 ha), divided into 7 paddocks (each one with 1 ha). Electronic individual feeding troughs (Intergado®) allowed all treatments to be represented in each paddock. The supplements were provided daily and the supplement intake (SI) was measured daily. Three reference animals were slaughtered initially to estimate the hot carcass weight (HCW). The remaining animals were slaughtered in a commercial abattoir after 140 d. The supplement efficiency (SE; g carcass gain/g supplement consumed) was calculated. All data were analyzed using the MIXED procedure of SAS (alpha = 0.10) with paddock considered random and animal as the experimental unit. There was no interaction (P>0.10) between factors for BW, HCW, dressing percentage (DP), ADG, and SE. Final BW and ADG were not affected by supplementation strategy or fibrolytic enzyme. Feeding fibrolytic enzyme increased HCW (332 vs 324 kg, P = 0.098), and dressing percentage (58.4% vs 57.4%; P = 0.078) and SE (0.134 vs 0.123; P = 0.066). There was an interaction (P < 0.10) between supplementation strategy and enzyme for SI; the SI was lower with increasing supplement and enzyme (9.58 g/kg BW; P = 0.045) compared to the other treatments (mean = 9.92 g/kg BW). In conclusion, under the conditions of this study, providing the same amount of supplement with different strategies during the finishing phase in pasture does not alter animal performance. The inclusion of fibrolytic enzyme increased HCW, DP and SE.