The suitability of linear body measurements for the prediction of pelvis area in Dorper sheep

Abstract

Birth stress is associated amongst other things with a small pelvic surface area in ewes. It is a factor which has far-reaching consequences for the producer. The use of pelvic area size as a selection criterion appears to be promising as pelvic area size is 50-60% heritable. The objective of this study was to develop an instrument that can measure the pelvic area of sheep and to be able to quantify the relationship between pelvic measurements and a number of easy-to-measure body measurements. A pelvis meter was developed and used to measure 322 Dorper ewes (± 12 months old, ± 48kg) and 272 Dorper rams rectally, and to take various body measurements on the same animals. No significant relationship was observed between pelvis measurements and linear body measurements in Dorper ewes or rams. The pelvis meter and measuring technique developed in the study are viewed as usable and accurate aid in measuring the pelvic area.