'Extreme Ewes' - an investigation of the relationship between clean fleece weight, fibre diameter and bodyweight

Abstract

A group of ewe hoggets from the QPLU$ Merino selection project was identified as being extreme for 8 combinations of clean fleece weight (CFW), fibre diameter (FD) and bodyweight (BW). They formed the basis of an experimental group to investigate the biology linking these 3 traits, along with other wool production, wool quality, growth, carcass and reproduction traits. This initial analysis has clearly established the usefulness of this sub-population of sheep as an experimental unit to further our knowledge in this area. The 8 groups are clearly divergent with respect to CFW, FD and BW. At the phenotypic level, CFW and the carcass traits were independent, as were BW and the wool quality traits. However, FD has varying relationships with a wide range of traits in addition to CFW, which will require careful monitoring with respect to the long term selection for reduced FD. The 8 groups of extreme ewes and their progeny will be further studied to quantify differences in skin biology, feed intake, reproductive performance, FD profiles and body composition as they age.