Characterization of different phenotypes for sheep residual feed intake, water use efficiency, and its correlations with blood biochemistry

Abstract

The profitability of an animal production system depends not only on the use of quality and low-cost foods 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 efficiently use food and water since the best use of the diet brings benefits both in terms of the environment and the profitability of the production system. However, in the literature, there are not many works with these purposes for sheep, especially when it comes to water use efficiency, and the results are still very contradictory. Comparison with the results of studies carried out with cattle is often not possible, due to the particular characteristics of the species, physiology and breeding, and market objectives, nor are some methods used for research with cattle in automatic troughs for measuring consumption, since the greater selectivity of the diet presented by the sheep species. Thus, it is extremely important to carry out and include feed efficiency as a selection criterion in sheep genetic improvement programs. Therefore, this proposal aims to: 1- Evaluate the feed efficiency of lambs based on the classification of residual food intake (CAR); 2- Evaluate the efficiency of the residual water consumption of lambs; 3- Evaluate the blood biochemical profile of lambs with divergent phenotypes for CAR; 4- Correlate different measures of food efficiency with water consumption and blood biochemistry; Feed efficiency measures will be evaluated such as weight gain, growth rate, feed conversion, estimation of CAR and consumption and residual gain, and consumption of residual water in troughs for automatic measurement of consumption of Dorper lambs. With this project, it is expected to promote subsidies for sheep selection programs based on food efficiency and water use, increase the competitiveness of the sheep industry, using more efficient animals, with greater system productivity and greater environmental sustainability.(AU)