The experiment was carried out at Federal University of Lavras (UFLA), with the aim of evaluating the efficiency of using two non-protein nitrogen sources (urea and amireia), as well as the level of intensity for the synthesis of ruminal microbial protein upon the ewe performance. Twenty-four female lambs of Santa Inês breed distributed into a completely randomized experimental design in a factorial scheme 2x3 were used, being two sources of NPN and three levels of microbial synthesis intensity (100% and 60% of synthesis potential and minimal synthesis). The variables studied were DM intake, daily average weight gain and feed conversion. The results showed that maximizing the microbial protein synthesis did not influence the animal performance independently of the NPN source. For sheep close to the mature size, when the objective is not to reach high levels of, not attending the maximum microbial protein synthesis potential does not result in a worse performance.
Feeding management; microbial growth; non-protein nitrogen; nutrition; sheep; ruminant
