SKIN AND FOLLICLE ATTRIBUTES CONTRIBUTE TO DIFFERENCES IN CLEAN FLEECE WEIGHT IN SUPERFINE MERINO SHEEP

Variation between animals in clean fleece weight at the same fibre diameter can be attributed to a number of skin and follicle factors. The aim of this project was to determine what contributions various skin and follicle attributes make to variation in clean fleece weight. Two groups of ten sheep were selected from the CSIRO Finewool flock at the extremes of estimated breeding values for clean fleece weight and mean fibre diameter (high clean fleece weight and low fibre diameter, low clean fleece weight and low fibre diameter) and the differences between the groups in a wide range of skin and follicle attributes were determined. The associa-tions between the skin and follicle attributes with clean fleece weight and fibre diameter were also calculated. There were significant associations of follicle density, S/P ratio, dp/ds ratio, follicle branching and follicle shutdown on clean fleece weight. The correlations between staple length and clean fleece weight (0.50) were of similar magnitude to the correlations between clean fleece weight and follicle density (0.37 to 0.48) , follicle branching (0.50), S/P ratio (0.28) and dp/ds ratio (0.40). The data presented here suggest that several skin and follicle attributes make contributions to the wide distribution of fleece weights that we commonly observe in flocks at any given MFD