Relation between skin structure and wool yellowing in Merino and Romney sheep

R.M.W. SUMNER and A.J. CRAVEN
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton, New Zealand

Proceedings of the New Zealand Society of Animal Production 65: 197-202

Five adult Merino and five adult Romney ewes were skin sampled on the back, midside and belly regions of the body following a study measuring the relationship between rate of sweat secretion and wool yellowing under various controlled environmental conditions. Densities of primary follicles, secondary follicles, sweat (sudoriferous) glands and sebaceous glands, as well as dimensions of the sweat and the sebaceous glands were measured. The density of secondary follicles was negatively related to wool yellowing and there was a weaker positive relationship between the density of primary follicles and wool yellowing. Underlying these relationships were associations of measurements suggesting sebaceous gland output restricted wool yellowing while sweat gland output encouraged wool yellowing. In addition, large sweat glands were related to increased sweat secretion rate. The results of this study suggest there may be two potential avenues to minimise fleece discolouration while the wool is growing on the sheep; either increasing sebum production or reducing sweat production

Keywords: NZSAPAB; Romney; Merino; wool yellowing; wool follicles; sweat glands; sweat; sebaceous glands

Last Updated 23/07/2005