Metabolic effects of fetal programming in Nellore dams and calves evaluated by nitrogen isotopic fractionation

Abstract

Brazil beef cattle production is predominantly carried out in tropical pastures grasses in the central region of the country with Nellore animals. Consequently, the nutritional deficit of pregnant dams is common, especially in the middle and final thirds of gestation. Studies indicate that disturbances in critical phases of pre and postnatal life cause permanent effects on health and productivity in the beef cattle. The objective of the present study is to evaluate changes in protein metabolism of pregnant cows and their progeny in response to fetal programming and its consequences on the body composition and reproductive traits of these dams and on the birth and weaning weight of the offspring. One hundred and fifty pregnant Nellore cows will be used and, later, their progenies that are divided into three distinct protocols of supplementation aiming the fetal programming of the progeny: S of the cows receiving protein-energetic supplementation throughout gestation, another S of matrices only in the final third and S not receiving this nutritional stimulus, that is, being supplemented with only mineral salt. Productive and reproductive traits of the dams will be used as phenotypes as well as the birth and weaning weight of their progeny. For protein metabolism evaluation of the animals the nitrogen isotopic fractionation of will be used in the plasma of the animals, in the pastures and in the supplement. The N15/N14 ratios of the different treatments will be compared to determine if there are differences in their protein metabolism.