Effects of adding either functional oil or sodium monensin on feeding behavior and selectivity of particle ingredients of feedlot Nellore cattle

Abstract

The objective of this study will be to evaluate the effects of essential oil or monensin on feeding behavior and selective consumption of Nellore cattle. The treatments will be disposed as follows: Control (with no additives); Monensin (with 30 ppm of monensin), Essential Oil (with 500 ppm of essential oils) and Monensin + Essential Oil (30 ppm and 500 ppm respectively). It will be used 96 Nellore yearling bulls, with approximately 370 kg of body weight. Cattle will be blocked by weight, and randomly distributed in 24 pens, which will be considered the experimental unit. Visual observation will be made on d 54 of the study, and then every 5 min during 24 h. Feeding behavior data was collected as follows: time spent eating, ruminating, resting expressed in minutes and number of meals per day. Samples of orts and diets will be collected on day 54 of the study for particle size distribution determination, which was performed by sieving using the Penn State Particle Size Separator and expressed as preference index. Subsequently, diet samples and orts will be analyzed chemically, to determine the neutral detergent fiber (NDF) and dry matter (DM), and then evaluate the consumption of NDF and DM, rumination efficiency of NDF and DM and consumption efficiency of NDF and DM.