Invasive Species Compendium

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Abstract

Changes in live weight and fleece characteristics during the lifetime of three breeds of New Zealand feral sheep that differ in fleece type.

Abstract

Live weight after joining and nine fleece characteristics were recorded throughout the lifetime of flocks of Hokonui, Campbell Island and Raglan sheep grazing at Whatawhata and Winchmore Research Centres between 1991 and 2004. The wool characteristics were measured in 585 individual wool samples collected at shearing from 90 breeding ewes sampled between one year of age and up to 12 years of age. Data on live weight, fleece weight, staple length, mean and variability of fibre diameter, fibre curvature, crimping and core bulk were analysed after adjustment for effects of grazing location and reproductive performance during the previous year. The three flocks differed in all measured characteristics, with all except live weight, mean fibre curvature and core bulk exhibiting a significant flock by age interaction. Live weight attained a maximum at six years of age, while greasy fleece weight and staple length decreased after two years of age. Core bulk decreased after three years of age. Fibre curvature decreased and time to form a crimp increased throughout the sheep's life. Fibre diameter variability between and along fibres showed a variable age response between flocks. The three feral flocks exhibited a different age response to continuously farmed breeds.