Associative effect of essential oils, tannins, and sodium monensin on the performance of steers finished in feedlot

Abstract

The objective was to evaluate the productive performance, ingestive behavior, apparent digestibility of the diet and carcass traits of beef steers finished in feedlot under the effect of including tannins and essential oils (TAN+EO) alone or combined with sodium monensin (MO) in the feed. For this purpose, 30 ½ blood Angus steers from the same herd, with an average age of 12 months and an average initial body weight of 367.8 kg were used. The experimental design was randomized blocks, consisting of three treatments: MO - diet with sodium monensin (25 mg kg DM-1); TAN+EO - diet with tannins and essential oils (1.5 g kg DM-1); and MO+TAN+EO - diet with sodium monensin + tannins and essential oils (25 mg kg DM-1 + 1.5 g kg DM-1), with five repetitions, where each repetition was represented by a stall with two animals. Diets were formulated and consisted of a mixture of 40% corn silage and 60% concentrate, which was fed to the animals twice a day, at 06h00 am and 05h30 pm. There was no difference (P>0.05) in average daily weight gain of animals between treatments, with an average of 1.392 kg day-1. Carcass yield was higher for animals that received the compound of essential oils and tannins (55.72%), compared to animals fed the combination of tannins, essential oils and monensin (54.54%) but did not differ from those supplemented with sodium monensin alone (55.58%). Supplementation with essential oils and tannins improved the apparent digestibility of the diet, however, did not promote changes in the ingestive behavior and carcass traits of steers. The combination of essential oils and tannins with sodium monensin did not show a potentiated effect on animal performance, digestibility of DM, digestive and ingestive behavior and carcass traits of feedlot finished steers compared to the combined use of essential oils with tannins.