Crimp in Wool: Cortical Segmentation and Tensile Properties of Well-Crimped and Abnormally Crimped Fibres of Merino Wool

Abstract

Poorly crimped (or doggy) fibres, produced by follicles with hyperplasia of the outer root sheath tissue, have greater proportions of paracortex than adjacent well-crimped fibres. Associated with this increase in paracortex is an increase in strength, as indicated by significant increases in the stresses in wet poorly crimped fibres at the turnover and breaking points on the stress-strain curve. Use of the stronger mechanical properties of doggy fibres as a means of distinguishing such fibres from the poorly crimped fibres in steely wool, produced by sheep on a copper-deficient diet, is proposed.