Essential Oils in the Diet of Young Bulls: Effect on Animal Temperament

Plant extracts and essential oils can be alternative products to antibiotics, because several plants produce secondary metabolites with antimicrobial properties. Additionally, they may act on the olfactory system which sends signals to the central nervous system releasing endorphins that may affect the feeling of an animal's welfare while altering an anima'ls temprement. This study was conducted to evaluate the animal temperament of 40 young crossbred bulls (½ Brown Swiss - ½ Nellore) 10 ± 2.2 months old with an average body weight of 219 ± 11.7 kg. Young bulls were randomly assigned to one of five diets: control (CON), no clove or cinnamon, clove leaf included to supply 3500 mg/anima/day (CLO35); clove leaf included to supply 7000 mg/animal/day (CLO70), essential oil of leaf cinnamon to supply 3500 mg/animal/day (CIN35), or essential oil of leaf cinnamon to supply 7000 mg/animal/day (CIN70). The animal temperament was evaluated by calculating the chute score, exit score and temperament score for periods (each 28 days during 6 periods) and among diets. The data were submitted to an analysis of variance using general linear model procedures with SAS v9.0. The diet and period were considered fixed effects, while the animals were considered a random effect. Differences between means were evaluated using a tukey test of 5% of significance. The addition of clove or cinnamon essential oils did not alter (P>0.05) animal temperament. The analysis of temperament score (P=0.55), chute score (P=0.71) and exit score (P=0.06) did not show significance difference among the diets. The exit score was similar among the six periods (1.57, 1.80, 2.98, 2.02, 2.73, 2.66 respectively), however, chute score and temperament score were greater (P<0.001) in the first period compared to other periods. The values for chute score were 1.85, 1.40, 1.35, 1.33, 1.20, 1.17 and temperament score were 2.31, 1.81, 1.67, 1.69, 1.50, 1.56, respectively, for periods 1 to 6. The results of this study suggest that clove and cinnamon essential oils can be added in high-grain finished diets as an additive without changing the animal temperament.