Abstract

This experiment was carried out to evaluate the animal performance, feed efficiency and carcass characteristics of 27 crossbred bulls (½ Angus vs. ½ Nellore), finished in feedlot for 120 days, with the addition of distinct levels of essential oils in the diets. The experiment was conducted in a completely randomized trial and animals were distributed into three treatments: control (CON), addition of 500 mg/kg of DM/animal/day of a mix of essential oils (E500), and addition of 1000 mg/kg of DM/animal/day of a mix of essential oils (E1000). The essential oils supplemented to the diets were based on a combination of vegetal extracts from: oregano, garlic, lemon, rosemary, thymus, eucalyptus and sweet orange. The bulls had an average age of 12±2 months and weight of 243.4±6.8 kg when the trial started. The roughage and concentrate ratio was 10% and 90%, respectively. The inclusion of essentials oils in the diets did not affect final body weight, average daily gain, and feed intake, but there was a tendency for improved feed efficiency for the E500 treatment. The ADG ranged from 1.55 to 1.70. Average DMI and feed conversion were 7.07 kg/day and 4.31, respectively. Essentials oil levels did not affect the carcass characteristics. More studies are needed to elucidate the synergism of combinations of essential oils in the rumen.

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