Foetal development in red deer (cervus elaphus) 1. Growth of the foetus and associated tissues

Abstract

ABSTRACTEighteen pregnant red deer hinds were slaughtered at known stages of gestation between 72 and 224 days (term = 233 days). The udder was removed and the gravid uterus was separated into foetal, placental, empty uterus, amniotic fluid and allantoic fluid components. Equations were fitted to the weights of each component to describe the effects of stage of gestation. Hind weight at mating had no significant effect. For the foetal weight (Y, kg) the data were closely fitted by a version of the Gompertz equation,loge Y = 3·016 — 14·267exp (–0·01138t) – 0·086swhere t is time in days from conception and s is the sex of the foetus (male = −1, female = 1). The weights of the placenta and empty uterus were similarly fitted by versions of the Gompertz equation and mammary tissue by an exponential relationship. However, the weight of (logc) amniotic fluid was bestdescribed by a third degree polynomial, and that of (loge) allantoic fluid by a linear equation.Using the equations and their first differentials, respectively, estimates were made of mean weights and daily rates of gain at different stages of gestation. These indicated altogether relatively slow growth and low weight of the red deer conceptus. Udder development occurred typically late in pregnancy.