Effects of diet composition during the finishing period on protein and lipid deposit in young bulls

摘要

The INRA feeding system aims at simulating young bull's growth and body composition in response to dietary changes during the finishing period. Presently, tissue deposition is modified by net energy intake in relation to age and breed, without considering the relative proportion of energy nutrients. But at fixed NE density, rations based on concentrate or maize silage support fatter gains (Garcia et al, 2008), which justifies better characterization of diet composition in prediction models. Our objective is to simulate the absorbed energy nutrient fluxes, their time variation and relative proportions, as well as their effects on lipids and proteins of carcass and visceral depots of finishing bulls. A dynamic model of growing cattle (Hoch and Agabriel, 2004) provides the framework and helps target variables of interest to reveal these effects. The present work aims to quantify diet effects on energy nutrient fluxes of young bulls during fattening and to link them to body, carcass, or visceral lipidcontent.