A review of wool fibre variation across the body of sheep and the effects on wool processing

• We very briefly describe wool processing and how variation in wool fibre characteristics affects it.
• We review many publications that present variation in wool fibre characteristics of the body of sheep.
• We briefly review the development of wool follicles across the body of sheep.
• We discuss the variation across the body with respect to other sources of variation and conclude that it has limited impact on processing outcomes.

Variations in wool characteristics due to location on the body of sheep are reviewed and compared with variation from other sources. The biological basis for variation and the relevance of this source of variation to industry are also discussed. For many traits, variation between sites on the body was trivial in comparison with variation between individual fibres within those sites and variation between sheep. To set the context within which wool variation could have an economic impact, fleece skirting and other wool processing steps that are influenced by fibre variation, or might increase or decrease the impact of variation are initially discussed. Processing intimately blends wool from numerous sources and distributes variation from individual fleeces and positions within fleeces among larger processing batches. Variation within fleeces and flocks is thus of limited concern in breeds with a history of selection for wool for industrially manufactured wool products. Variations in dye uptake caused by highly pigmented or medullated fibres are two exceptions that cannot be effectively hidden by blending. The balance of evidence suggests that reducing the variation in most fibre characteristics across the body of wool-producing breeds is not economically justified for conventional manufacture of apparel, interior textiles or lower value products on an industrial scale, though further research may be justified for high value uses or in breeds not selected for uniform wool production.