Combined use of ionophore and virginiamycin on feeding behavior of confined Nellore steers fed high concentrate diets

• Grant number: 11/14481-5
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: September 01, 2011
• End date: July 31, 2012
• Field of knowledge: Agronomical Sciences - Animal Husbandry - Animal Nutrition and Feeding
• Principal Investigator: Jose Carlos Machado Nogueira Filho
• Grantee: Fernando Telles Mercado
• Host Institution: Faculdade de Zootecnia e Engenharia de Alimentos (FZEA). Universidade de São Paulo (USP). Pirassununga , SP, Brazil

Abstract

The isolated supplementation of ionophores or virginiamycin has been extensively studied and the results show improvement in animal performance and rumen fermentation of beef cattle receiving large amounts of rapidly fermentable carbohydrates. However, recent studies have shown that the use of these additives in combination may provide better results. Some authors explain that these effects are, in part, due to changes in chewing activity. Thus, the objective of this study is to evaluate the feeding behavior of Nellore steers treated with high concentrate diets and supplemented with the combination of ionophore and virginiamycin. The experiment was conducted in a 4x4 replicated Latin square design, in a 2x2 factorial arrangement, with two levels of concentrate (70 and 90% in DM) and two levels of virginiamycin (0 and 15 ppm) in the diet. In this way, eight ruminally cannulated Nellore steers were confined for four 21-day periods, and feeding behavior was evaluated through visual monitoring of eating and ruminating activities for 24 hours in each period. Feeding behavior will be correlated to ruminal fermentation variables so that the results will permit the establishment of nutritional recommendations to allow the utilization of high concentrate diets for Nellore cattle.(AU)