Meta-analysis of the effects of diets with lipid, glycerin and association of both in on rumen fermentation and feed efficiency in beef cattle on pasture or feedlot

Abstract

The principle for improving feed efficiency in ruminants involves minimizing energy losses through improving diet digestibility and manipulation of rumen fermentation toward propionate production and thereby decreasing methane production in the rumen. Thus, the project aims to evaluate and compare, by meta-analysis, ruminal fermentation, animal performance, feed efficiency and effects on methane emission in Nellore cattle when fed: lipid sources, glycerin and the association of both on pasture or feedlot. And so, to obtain information which supply system can be more efficient. For this purpose, a data set will construct compiling data from 23 experiments containing 60 dietary treatments and 560 cattle, referring to experiments already completed or being developed in the research group under the guidance of Prof. Dr. Telma T. Berchielli, from the Department of Animal Science, Faculty of Agricultural and Veterinary Sciences - UNESP Jaboticabal. Some parameters will be evaluated: Intake, ruminal fermentation (pH, short chain fatty acids, ammonia, bacteria and protozoa), digestibility, performance, feed efficiency and methane emission. The meta-analysis will be carried by graphical analysis (to observe biological coherency), correlation (to identify correlated variables) and variance-covariance analysis of the data using the GLM procedure. The analyzes will be performed using the SAS program. (AU)