Effects of adding either functional oil or sodium monensin to high-energy diets on rumen morphometrics, and rumenitis and liver abscess incidences of feedlot Nellore cattle

Abstract

The objective of this study will be to evaluate the effects of essential oil or monensin on on morphological parameters of rumen papillae and liver abscess 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. The animals will be harvested after 84-d on feeding. At harvest, one 1-cm2 fragment of each rumen will be collected from cranial sac and the number of papillae per cm2, papillae area and absorptive surface area will be evaluated. Likewise, rumenitis incidence and liver abscess will be determined.