Residual Feed Intake of Santa Inês Sheep and its relation with Methane Production and Carcass Characteristics

Abstract

The profitability of an animal production system is dependent not only on the use of quality and low-cost food in the diets but on the use and maintenance of more efficient herds. This has driven the search for the identification and selection of animals that use food and water efficiently, since the best use of diet brings benefits both for environmental reasons and for the profitability of the production system. However, there are not many works in the literature with these purposes for sheep, especially when it comes to water use efficiency; the results are still very contradictory. The comparison with results of work with cattle is often not possible, due to the particular traits of species, physiology, breeding and market objectives, nor some methods used for research with cattle troughs automatic measuring consumption, due to the greater selectivity of diet presented by sheep. This proposal aims to: 1. Assess and reassess the feed efficiency of lambs based on low and high ranking residual feed intake (RFI); 2- Asses the production of enteric CH4 gas and relate this variable to the characteristics of feed efficiency in sheep; 3- Asses the carcass traits of these animals, relating this variable to the classification of food efficiency assessed; 4- correlate feed efficiency measuring with stress by cortisol level and assessing animal behavior; 5- characterize different phenotypes and the proteomic profile of tissues and test possible associations with feed efficiency in hair sheep, in order to identify biological, biochemical and / or molecular markers to facilitate the early selection and sheep. The estimation of RFI and residual water consumption in automatic consumption measurement troughs, CH4 production, metabolic profile, and carcass and meat characteristics will be assessed. This project is expected to promote subsidies for sheep breeding programs based on feed efficiency and water use, increase the competitiveness of producing sheep industry from more efficient animals with higher productivity of systems and greater environmental sustainability. (AU)