Hairiness in wool and a method for selection based on the nature of the fibres and the distribution of halo hairs of the lamb's tail

Abstract

Hairiness in wool of Suffolk sheep as a fault was found to be associated with other defects like coarseness of wool fibres, hairiness of the britch, and the occurrence of pigmented fibres. The presence of these various defects was studied in the lamb's tail at docking time, and subsequently evaluated and correlated with the fleece.The tails were graded according to the nature of the fibres and the spread of halo hairs from the tip to the base into four principal grades which by further subgrading could be made into seven grades. The results were as follows:(1) There was wide variability in grades of tails within each flock.(2) Average grade of tails followed in general the mean quality of the adult fleece.(3) When Border Leicester were crossed with Welsh Mountain the tails of the two reciprocal crosses were found to be of hairy type of tail and nearly like the Welsh Mountain type.(4) The percentage of coloured tails in the least hairy grades was found to be inversely related to the quality of the tail grade and indirectly to the fleece quality.(5) The diameter of the wool fibres on the base of the tail is highly correlated with the diameter of fibres from the britch regions or mean fibre diameter from four regions of the body (mid-shoulder, midside, hip and britch).(6) The mean diameter of the wool fibres obtained from four different parts of the tail was correlated with those of the britch regions only.(7) The diameter and variability of fibres increased from shoulder to britch in the body and from base to tip in the tails.(8) The britch and tails of two groups of sheep, one group characterized by coarse and the other by fine britch and tail wool, were studied histologically. There were significant or highly significant differences in the following characteristics in the britch of the two groups: (a) total number of follicles, (b) primary follicles with no medulla, (c) total number of secondary follicles, (d) secondaries with no medulla, (e) secondaries with large medulla. The only type of follicle where a significant difference was found in the tail was in the number of secondary follicles with no medulla.