An evaluation of Merino wool quality:I. The incidence of coarse fibres in two Australian Merino flocks

Abstract

SUMMARYThe fibre length and diameter distributions of the wool of two Merino flocks were evaluated at the neck, mid-side and breech positions, to determine the incidence of fibres which were off-type by reason of excessive length, diameter or possession of a medulla.The ranges of fibre lengths for 10·5–11·0 months' growth were 1·0–17·5 cm. in flock 1 and 1·0–16·5 cm in flock 2. There was no evidence of a bi-modal length distribution in either flock.Fibre diameters at 15–16 months were observed in the range 6–69 μ in flock 1 and 5–52 μ in flock 2. Medullated fibres ranged from 7 to 50 μ in flock 1 and 5–64 μt in flock 2. The incidence of medullation increased in an antero-posterior direction from 0·17 to 0·28% in flock 1 and 0·11 to 0·28% in flock 2.Tests for homogeneity of variance were applied to the estimates of fleece characters in this study as well as estimates of other workers. From these comparisons it is suggested that sheep in the present study are representative of the Merino breed in staple length, fibre diameter and to a lesser extent crimp frequency. The considerable between-animal variation in the observed incidence of medullation should aid in selection against that character with a consequent improvement in wool quality.