PSVII-9 Effects of Roughage Level on Animal Behavior in Nelore Cattle Receiving a High Concentrate Diet Under Tropical Conditions

Abstract Roughage levels have an important role in high concentrate diets. Also, Nelore cattle are the main breed produced in Brazil. The goal of this study was to evaluate the effects of roughage levels on Nelore behavior. Nelore Bulls (n = 20) with body weight of 420 kg ± 45 kg were used in this study, receiving 5 finishing diets with different roughage levels for 105 days. The diets were composed by corn silage, ground corn, soybean meal, citrus pulp, urea, potassium chloride and premix. During each 21-day period of the finishing diet, roughage levels were decreased. The first diet had 15% of NDF from forage, followed by 12%, 9%, 6% and 3% on DM basis. On 14 th of each period, animal behavior events were measured by 4 different people during 24 hours of evaluation. The variables recorded were resting time, chewing time, rumination time and meal events. During every 10 minutes, animal behavior data of the 20 Nelore bulls were collected. Furthermore, we used a polynomial regression by proc mixed in SAS. The rumination time was decreased when there was the reduction of roughage level. It was a linear effect P< 0.0001, starting from 369 minutes and 50 seconds (15% of NDF from forage) to to 129 minutes and 50 seconds (3% NDF from Forage). For resting time the outcome experienced was different, including 955 minutes of resting to the treatment with 15% NDF to 1,119 minutes to the lowest roughage level treatment, P< 0.0001. Regarding chewing time, there was a linear effect when the greatest chewing time was obtained to the diet with greatest roughage level ,15% NDF from Forage, P< 0.0001. there was no effect of roughage level on meal events, P > 0.0001. Thereby, the rumination time as well as chewing time may be helpful to the animal wellness in high concentrate diets.