299 Combination of Essential Oils, α-amylase and 25-hydroxy-vitamin-d3 Increases Carcass Production by feedlot Cattle

Abstract Our objective was to evaluate the effects of associating feed additives on feedlot performance of Nellore bulls. One hundred and sixtieth Nellore bulls (iBW, 380± 5.8 kg; age, 18 mo) were allocated in 20 pens (n = 8/pen), in a completely randomized block design, according to the treatments: 1) MON+VM - Sodium Monensin (MON, 25 mg/kg DM, Elanco Animal Health, Indianapolis, IN), + Virginiamycin (VM, 30 mg/kg DM, Phibro Animal Health Corporation, Guarulhos, São Paulo), and 2) CRD - Crina® RumistarTM + HyD® - a blend of essential oils, 90 mg/kg DM + exogenous α-amylase, 560 mg/kg DM + 25-hydroxy-vitamin-D3 at 1 mg/animal/d (DSM Nutritional Products, Basel, Switzerland). The initial BW was utilized as a criterion for block formation. Pens were considered experimental units (10 pens per treatment). Animals were adapted to the diets during 14 days with gradually increasing concentrate level from 70% to 86% of diet DM, and fed for 90 days. Weight assessments were performed at day 0 and 90 after 14h fasting. Data were analyzed using PROC MIXED of SAS and means were separated using the PDIFF statement, adopting P < 0.05. Feeding CRD increased the DMI (12.13 kg vs. 10.52 kg, P < 0.01), ADG (1.86 vs. 1.63 kg/d, P < 0.01) and final BW (542 vs. 521 kg, P < 0.01) compared to animals fed MON+VM. In addition, feeding CRD increased final HCW in 15 kg (311 vs. 296 kg; P < 0.01), carcass ADG in 0,16 kg/d (1.31 vs. 1.15 kg/d; P < 0.01) and dressing percentage in 0.48 percent points (57.34 vs. 56.86%; P < 0.01) compared to MON+VM. The G:F (0.155, P = 0.53) and biological efficiency (137.9 kg DM/15 kg carcass, P = 0.87) were similar among treatments. Therefore, the inclusion of Crina® RumistarTM +HyD® can be used as a tool to increase carcass gain of feedlot finishing cattle.