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RESUMO OLIVEIRA, M. C. Metabolismo de ovelhas alimentadas com diferentes dietas e níveis de energia na gestação e lactação. [Metabolism of ewes fed with different diets and energy levels during gestation and lactation]. 2019. 71 f. Dissertação (Mestrado em Ciências).

The objective of this study was to evaluate different levels of metabolizable energy (ME) intake of late-gestating ewes on the productive and reproductive performance of their female offspring. Seventy-one crossbred ewes were distributed in three treatments: CTL = ME level according to recommendations of the NRC (2007); LESS = CTL less 10% ME per kilogram of dry matter (DM); and PLUS = CTRL plus 10% ME per kilogram of DM. Ewes were synchronized with hormonal protocol, controlled natural mating, and confirmed pregnancy using ultrasonographic imaging. The diets were given at the end of gestation (50 days) through weaning (60 days). The female progeny, from birth to the first mating season, received the same nutrition and sanitary management as their dams. They were weighed every 15 days from birth to the eighth month of age (first mating season), and the mortality rate was measured. The mating season lasted 34 days. The confirmation of pregnancy was performed with 30 and 60 days. The chi-square test was used to compare mortality and pregnancy rates, all with a 5% probability. Ewes in the LESS diet presented lower birth weight up to 8 months of age when compared to CTL and PLUS diets (P < 0.005), which were not different from each other (P > 0.005). Mortality was influenced by the maternal diet (P = 0.0017), with values of 57.1, 20, and 7.41% for the LESS, CTL, and PLUS groups, respectively. The pregnancy rate was 21.4, 70 and 55.6% for the LESS, CTL, and PLUS groups, respectively, with a difference between them (P = 0.0390). We concluded that the supply of low energy diets for dams caused losses in the performance and reproduction indexes of replacement ewes.