Return of reproductive cyclic activity in Morada Nova sheep at metabolizable energy different levels

Abstract

The objective, in this work, was to evaluate the effect of metabolizable energy offered on reproductive cyclic activity return of Morada Nova sheep, at different energy levels, during the lactation, since the pregnancy last third, 39 sheep, distributed in three treatments, during the rainy and dry season, were used. Experimental diets were formulated to meet a daily intake of 2.2, 2.8 and 3.4 Mcal of Metabolizable Energy (ME)/day and 150 g of crude protein, and the serum levels of progesterone and cortisol regarding, besides the reproductive performance, were evaluated. An entirely casualized design was used in a subdivided scheme for the hormone, and generalized linear models, by the Poisson distribution and binomial distribution in the non-parametric data. There was effect from interaction between period and treatment (P<0,05) for cortisol and progesterone serum, as well as for reproductive performance. The animals went through stress condition, which interfered in the return of reproductive cyclic activity and extended the anoestrus post-partum period, during the dry season. The offer of ME 3.4 Mcal must be recommended for Morada Nova sheep since the pregnancy last third because of the best performance rates and reproductive performance.