Wool weathering damage as measured by Methylene Blue absorption is linked to suint content

Abstract

Weather damage of wool in grazing sheep has long been recognised by the wool industry as a problem, resulting in fibre damage, fibre loss and poor dyeing performance. Merino wool from 3538 ewe and ram hoggets was used to estimate the heritability of Methylene Blue absorption. Methylene Blue absorption has a high heritability of 0.44 ± 0.04 and was strongly genetically correlated with suint index (0.88 ± 0.02) and wool moisture index (0.92 ± 0.03). Methylene Blue absorption was moderately genetically, negatively correlated with measures of clean wool colour and yield and positively with dust penetration. There was no significant correlation between Methylene Blue absorption and dust content or economically important measures of fleece value such as fibre diameter, curvature and staple strength. The strong genetic relationship between Methylene Blue absorption and suint index indicates that Methylene Blue absorption is a very good indirect measure of greasy wool suint content but may not be a satisfactory indicator trait to select for low weather damage.