Use of ultrasonographic fetometry for the estimation of days to kidding in dairy does.

The objective of this study was to predict the number of days to kidding in dairy goats by ultrasonographic measurement of three consecutive ribs and intercostal spaces or trunk diameter of fetuses. Two groups of primiparous and multiparous goats were examined by transabdominal ultrasonography. Actual kidding date was used to compute the true number of days to kidding relative to the ultrasound examination day. Linear regression models were built to predict days to kidding based on fetal measurements, parity, and number of kids. The model using the width of three consecutive ribs and intercostal spaces (n = 29 goats) showed a curvilinear relationship between days to kidding and rib distance ( R 2  = 0.60; P  < 0.01). The trunk diameter model (n = 135 goats) showed a curvilinear relationship between days to kidding and trunk diameter with an effect of parity ( R 2  = 0.81; P  < 0.01). [ABSTRACT FROM AUTHOR]