Bulk and its structural basis: A review

R.H. Stobart, R.M.W. Sumner

MAF Technology, Whatawhata Research Centre, Private Bag, Hamilton, New Zealand

Proceedings of the New Zealand Society of Animal Production. 1991, 51: 339-346

Loose wool bulk has been identified as a desirable objective characteristic associated with superior end-product performance in many of the present uses of wool. These are specifically, improve appearance retention of carpets and improved insulation of knitting yarns and loose wool batts. Breeds have been shown to differ in their ability to produce high bulk wools. Loose wool bulk is strongly inherited in the adult fleece, it is not however expressed in the lamb fleece and subsequently cannot be used as a selection criteria until hogget shearing. Fibre crimp appears to be the major factor associated with bulk. Crimp formation in Merinos is related to follicle structure, cell mitotic activity and cellular differentiation within the follicle bulk resulting in the production of different cortical cell types. At this time it is not known if a similar situation applies to crossbred wool type sheep. The identification of a suitable measurable structural characteristic would facilitate the selection of high loose wool bulk crossbred wool type sheep at a young age.

Keywords: NZSAPAB; Loose wool bulk; measurement; fibre structure; follicle morphology; sheep breeds

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Last Updated 25-01-1997