Abstract

Relationships between backfat thickness and wool characteristics for lines of Coopworth and Southdown sheep, selected for or against backfat thickness, were studied between years and between different age classes. On average, the lean Coopworth line grew 230 g more greasy wool (P < 0.001), which was 1.7 µm finer (P < 0.001) and less variable in diameter (P < 0.05) than the fat line. Other measured wool characteristics were not affected. The Southdown lines did not differ in fibre diameter, variability of diameter or curvature, within age groups. Southdown lambswool was finer (P< 0.001) than hogget or ewe wool (23.6 ± 4.9, 27.0 ± 5.6 and 26.7 ± 5.4). Fibre diameter differences observed in the Coopworth lines may have been a founder effect, as subsequent selection had little impact on it. Selection for leanness increased greasy fleece weight without affecting fibre diameter or staple length.

NC, Merrick, DB Baird, JC McEwan, and RW Purchas

Proceedings of the New Zealand Society of Animal Production, Volume 60, Hamilton, 159-161, 2000