Effects of essential oils and exogenous enzyme in low starch diets for finishing feedlot cattle

Abstract Text: The objective of this study was to evaluate the effects of the combination of essential oils (Crina^® Ruminants) and α-amylase (Ronozyme^® RumiStar^TM) on performance of Nellore bulls finished in feedlot. One hundred twelve Nellore bulls (initial BW =  349 kg ± 33) were fed during 90 d with diets containing 54.5% ground corn, 8.5% sugarcane bagasse, 16% soybean hulls, 12% whole cottonseed, 5% soybean meal, 3% minerals and vitamin supplement and 1% urea. Animals were blocked based on initial BW and randomly allocated in 14 pens. Treatments were: MON (Sodium Monensin, Tortuga^® – 26 mg/kg DM) or CRINA-RUM (Crina^® Ruminants, DSM^®, 90 mg/kg DM and Ronozyme^® RumiStar^TM, DSM^®, 560 mg/ kg DM). Response variables included: final body weight (FBW); dry matter intake (DMI), average daily gain (ADG), feed efficiency (G:F), hot carcass weight (HCW) and dressing percentage (dressing, %). Pen was considered the experimental unit. The data were analyzed using PROC MIXED of SAS and means were compared by Tukey test considering the block as random effect and treatments as fixed effects. Animals fed with CRINA-RUM had 9.9% greater DMI (10.30 vs. 9.28 kg; P < 0.001) and a tendency for greater FBW (529 vs. 523 kg; P = 0.07) compared with animals fed MON, respectively. There was no effect of treatments on ADG (1.65 and 1.72 kg, for MON and CRINA-RUN respectively, P = 0.14). Animals fed MON had greater G:F compared with CRINA-RUN (0,178 vs. 0,166, P < 0.01). The combination of essential oils and α-amylase increased HCW and dressing percentage. Animals fed CRINA-RUM had 6.4 kg more carcass compared with MON (298.2 vs. 291.8 kg respectively, P = 0.015) and dressing percentage were 56.3 vs 55.8% for CRINA-RUM and MON respectively (P < 0.01). In conclusion, the use of essential oil combined with α-amylase improved intake, carcass dressing and weight in animals fed low starch diets combined with coproducts and can be an alternative to monensin.

Keywords: beef, coproducts, starch