The increase on energy density in a diet, through lipid supplementation is a nutritional strategy that can be used in cattle fattening, performing satisfactory results. The objective in this trial will be evaluate the effects of different lipid sources on performance, intake, digestibility, carcass characteristics, microbial populations, ruminal fermentation and enteric methane production in nelore steers, from rearing to finishing phase in grazing systems. The lipid sources will be selected from an in vitro assay (experiment 1) where six sources will be tested: soybean oil, linseed oil, sunflower oil, palm oil, soy bean grain and megalac-E, from the six sources, four will be used in experiments in vivo. The experiment 2, rearing of animals, will be developed from May/2009 to March/2010. Ninety animals will be used, divided into 10 paddocks (two replicates of paddocks) receiving supplementation of 0.5% body weight during the dry and rainy seasons, distributed on a randomized block design with repeated measures over time (months of the year) with 16 replications. In April/2010 45 of these animals will be finished on pasture (experiment 3) receiving the same sources of supplemental fat. In both phase (rearing and finishing) will be evaluated the performance and methane production, by the end of finishing phase the carcass characteristics will be evaluated. Five animals, fitted with ruminal canullae, will be allocated in a Latin square for evaluations of ruminal variables, microbial population and fiber degradation.
News published in Agência FAPESP Newsletter about the scholarship: