Eficiência placentária em ovelhas e consequências para o desenvolvimento e sobrevivência das crias

Abstract

The placenta is of great importance in the development, nutrient transfer at all stages of pregnancy and the viability of the fetus. A placenta becomes more efficient because of its ability to sustain fetal growth, and some characteristics may influence its increase or decrease. The objective of this study was to verify the relationship between lamb weight and survival until weaning and placental efficiency and other maternal and offspring characteristics. For the analysis in which the weaning weight of the offspring was the dependent variable, and calving order, placental efficiency, number of males and females born by birth and season were the explanatory variables, a multiple regression model was used. In order to verify which characteristics influenced the probability of offspring surviving until weaning, we used a generalized linear model through Poisson regression with log link function, in which the explanatory variables were calving order, placental efficiency, number of males and females born by childbirth and season of birth. There was an influence of placental efficiency on lamb survival and weaning weight. Primiparous sheep calves showed reduced weaning weight and survived less weaning. Males had a higher weight at weaning than females, in contrast, the chance of surviving until weaning is lower in males. The birth season showed no significance in weaning weight and survival of the offspring