PSXII-30 The combination of essential oils and exogenous amylases reduces fecal starch of feedlot finishing cattle fed different roughage sources

Abstract

Abstract Eighty-eight feedlot finishing Nellore bulls (358 ± 38.5 kg BW) were used in a randomized block design (initial BW) with a 2×2 factorial arrangement to test the effects of two feed additives (MON - Sodium Monensin, 26 mg/kg DM vs. Crina®RumistarTM - combination of blend of essential oils - 90 mg/kg DM + exogenous α-amylase - 560 mg/ kg DM; DSM Produtos Nutricionais Brasil S.A.) and two roughage sources (CS - corn silage vs. SB - sugarcane bagasse) on fecal starch. Animals were adapted to the high grain diets, starting with 20% of physically effective NDF of each roughage source, and gradually decreased to 10% after 20-d. Final diets contained 19.5% CS or 12% SB, corn grain (70.7 and 78.2% for CS and SB diets, respectively), 5.5% soybean meal, 4% mineral and vitamin mixture and 0.3% urea, on DM basis. Feed intake was daily recorded individually during 104 days using individual pens or Calan-gate system. To determine fecal starch concentration, feces from each animal were sampled on days 0, 58 and 85-d of the feeding period. Data were analyzed using the Mixed procedure of SAS considering roughage source, feed additives and interaction as fixed and block as random effects. No interaction between feed additives and roughage sources was observed. Animals fed CS had 20% higher DMI (P < 0.0001) than those fed SB, but roughage sources not affected (P = 0.15) fecal starch concentration. Diets containing different additives did not affect DMI (P = 0.17); however, animals fed Crina®RumistarTM had 21% lower fecal starch concentration (15.9 vs. 21.1 %DM; P = 0.01) than animals fed MON, respectively. Therefore, supplementation with Crina®RumistarTM is an effective substitute of monensin in finishing cattle fed high concentration diets regardless of roughage source, improving the use of starch by the animals and reducing its excretion, reflecting on a lower environmental impact.