PSXIV-9 Effect of monensin, a blend of essential oils and Lithothamnium calcareum over two racial groups in finishing cattle diets

Abstract

Abstract This study aimed the evaluation of the effects of three feed additives – sodium monensin (MON; 32 mg/kg DM), Lithothamnium calcareum plus sodium monensim (LC+MON; LithoNutri® 5g/kg DM + 32 mg/kg DM) or a blend of essential oils (BEO; BioPhitus® 0.3g/kg DM) – and its interaction with two ratial groups of beef cattle – Nellore (NEL) vs. Crossbreds (CROSS) – on a finishing diet. Ninety Nellore bulls (initial BW = 394 ± 34 kg) and ninety crossbreds (initial BW = 406 ± 31 kg), were fed for 112 days, diets containing 8.5% sugarcane bagasse, 42.2% of fine ground corn, 41.7% of citrus pulp, 5% of soybean meal, 1.3% of urea, 0.35% of sodium chloride and 0.95% of minerals and vitamins. Treatments were NEL+MON; NEL+LC+MON; NEL+BEO; CROSS+MON; CROSS+LC+MON; CROSS+BEO in a randomized complete block with a 2 x 3 factorial arrangement (2 racial groups and 3 feed additives). There were no interactions between racial groups and feed additives (P > 0.05). Regardless of the additive used there were no differences in final BW (P = 0.237), ADG (P = 0.610), HCW (P = 0.120) or dressing (P = 0.095). Animals fed LC+MON had lower DMI (P < 0.01) than animals fed MON or BEO (7.74 kg, 8.64 kg, 9.26 kg, respectively). However, feed efficiency (G:F) of LC+MON did not differ from MON. Animals fed diets with BEO had lower G:F than animals fed diets with MON or LC+MON (P < 0.01; 0.1382, 0.1469 and 0.1550 respectively). Animals fed diets with MON or LC+MON were 6.3% and 12% more efficient than animals fed with BEO. Crossbred bulls had higher DMI (P < 0.001), ADG (P < 0.001), FBW (P < 0.001) and HCW (P < 0.001) than Nellore bulls. In summary, LC reduced DMI not altering feed efficiency. Diets containing BEO reduced G:F of the animals when compared with animals receiving diets containing MON.