The relationship between cortical structure and fibre diameter in primary and secondary wool fibres of yearling Perendale sheep.

摘要

Midside skin and wool samples were taken from 32 Perendale ewes at 12 months of age. Loose wool bulk values ranged from 17.1 to 34.3 cm3/g; bulk was correlated with mean crimp frequency, staple length, mean fleece fibre diameter, follicle curvatureand proportion of para-mesocortex. Medullation was present in only 2.8% of fibres and was not significantly related to wool bulk. Primary fibres were coarser than secondary fibres (37.4 vs. 31.9 mum). The proportion of fibres with a bilateral cortical cell type arrangement decreased with increasing fibre diameter. The mean proportion of para-mesocortex was lower in primary than secondary fibres (19.2 vs. 24.1%). There was a significant within sheep relationship between proportion of para-mesocortex and fibre diameter. While primary and secondary fibres were different in mean fibre diameter and cortical structure, the relationship between cortical structure and fibre diameter did not differ between the 2 follicle populations.