The Effects of Prenatal Diet on Calf Performance and Perspectives for Fetal Programming Studies: A Meta-Analytical Investigation.

This meta-analysis aimed to identify knowledge gaps in the scientific literature on future fetal-programming studies and to investigate the factors that determine the performance of beef cows and their offspring. A dataset composed of 35 publications was used. The prenatal diet, body weight (BW), average daily gain (ADG) during pregnancy, and calf sex were elicited as possible modulators of the beef cows and their offspring performance. Then, the correlations between these variables and the outcomes of interest were investigated. A mixed multiple linear regression procedure was used to evaluate the relationships between the responses and all the possible explanatory variables. A knowledge gap was observed in studies focused on zebu animals, with respect to the offspring sex and the consequences of prenatal nutrition in early pregnancy. The absence of studies considering the possible effects promoted by the interactions between the different stressors' sources during pregnancy was also detected. A regression analysis showed that prenatal diets with higher levels of protein improved the ADG of pregnant beef cows and that heavier cows give birth to heavier calves. Variations in the BW at weaning were related to the BW at birth and calf sex. Therefore, this research reinforces the importance of monitoring the prenatal nutrition of beef cows.

Performance and digestibility of growing sheep fed with açai seed meal-based diets.

This trial was conducted to assess the efficacy of açai seeds in the diet of sheep, specifically, to evaluate the intake, digestibility, and weight gain in sheep that are fed with diets containing four different mixtures of açai seeds and coastcross hay. Sixteen noncastrated male sheep with an average initial body weight of 22 kg were randomly assigned to one of four diet treatments using initial body weight as a covariate. The diets used coastcross hay as the basal roughage in a 60:40 roughage/concentrate ratio. The concentrate was the same in all the treatments. The açai seed was added to the diet as a partial substitute for the coastcross hay to make up four diet treatments: 0 (control), 5, 10, and 15 % açaí added to the diet on a dry matter basis. The daily weight gain, final body weight, and feed intake were found to linearly increase with the increase in added dietary açai seed meal (P < 0.05). Moreover, increasing the proportions of açai seed meal did not significantly alter the nutrient tract digestibility, except that the crude protein level declined in a linear manner. The inclusion of açai seed as a substitute for coastcross hay increases the intake and the daily weight gain in sheep that are fed with diets using coastcross hay as the basal roughage in a 60:40 roughage/concentrate ratio.