Phenotypic variance of fibre diameter along wool staples and its relationship with other raw wool characters

Abstract

The variance of fibre diameter along the staple was estimated in a flock of 198 two-year-old Merino sheep, whose management and nutrition were typical of grazing sheep in central-western New South Wales. In a subgroup of this flock, it was found that the estimated variance of fibre diameter along the staple was highly repeatable between duplicate staples sampled from the same sheep, and variation in fibre diameter along the mid-side sample was representative of that variation in the whole fleece. In the main flock, variance of fibre diameter along the staple varied from 0.74 to 6.98 ¦m2 between sheep, but there were no differences between castrated males and ewes. Differences were found between sire groups in their susceptibility to environmental change. Phenotypic correlation between variance of fibre diameter along the staple and staple strength was -0.30 (P<0.001), but correlations with other raw wool characteristics were not different from zero (P>0.05).