Abstract

The effect of sheep breed and wool type on the incidence of the skin defects "pinhole" and "raised rib" was investigated. Six breeds/crosses were used - pure Romneys and Suffolk x Romney, Dorset x Romney, East Friesian x Romney, Texel x Romney and Merino x Romney crosses. Skins were recovered at slaughter and processed to dyed crust leather, then scored numerically for the severity and extent of pinhole and graded into the "Run" (best quality), "Pinhole", and "Thirds" grades. The presence or absence of raised rib on the skins was noted. Wool bulk and fibre diameter were measured. Skins from Romneys had the least pinhole and Merino crosses the most. Skins from Texel, Dorset and East Friesian crosses were also significantly more likely to be downgraded due to pinhole than those from Romneys. Within-breed differences in the level of pinhole were due to wool bulk differences, with a higher wool bulk correlated with more pinhole. Merino-cross skins were much more likely than the skins from pure-bred Romneys or the other crosses to have raised rib. Texel-Romney-cross skins were more likely than pure-bred Romney skins to have raised rib. There was no difference between the mean wool fibre diameter for ribby and non-ribby skins, but the ribby skins had a significantly higher wool bulk.

SM, Cooper

Proceedings of the New Zealand Society of Animal Production, Volume 62, Palmerston North, 69-71, 2002