Effects of different feeding frequencies on histologic parameters of rumen epithelium of feedlot Nellore cattle

• Grant number: 12/17868-0
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: November 01, 2012
• End date: October 31, 2013
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Danilo Domingues Millen
• Grantee: Ivan Carlos Batista Junior
• Host Institution: Universidade Estadual Paulista (UNESP). Campus Experimental de Dracena. Dracena , SP, Brazil

Abstract

This study will evaluate the effect of different feed frequencies (1x, 2x, 3x, or 4x) on histologic parameters of the ruminal epithelium of Nellore cattle finished in feedlot. Forty-eight Nellore yearling bulls, backgrounded on pasture and with an average initial weight of 370 kg, will be allocated in a covered feedlot and kept on a concrete floor for cleaning easily, with one animal per pen (7.4 and 1.0 m² per animal m trough per animal) with water ad libitum at an automatic water trough. Yearling bulls will be randomly assigned to pens according to the following treatments: 1) feeding 1x daily (8:00), 2) feeding 2x daily (8:00 and 14:00), 3) feeding 3x daily (8:00, 11:00, and 17:00) and 4) feeding 4x daily (8:00, 11:00, 14:00 and 17:00). Animals will be blocked by weight at the beginning of the study, therefore the experimental design will be completely randomized blocks, in which each treatment will contain 12 animals (one animal/pen), which will be considered the experimental unit for this study. All the animals in the study will be adapted for nine days using two diets: 60% and 73% concentrate for 5 days and 4 days, respectively. On day 10 of the trial, all animals will receive the 86% concentrate diet. Animals will be slaughtered when reaching at least 490 kg of empty body weight. After slaughter, rumens from all animals will be evacuated and washed, and fragments of 1 cm2 from the ventral sac will be harvested for future histological analysis, such as height, area, and thickness of the papillae, keratin layer thickness, and mitotic index.(AU)