Follicle productivity and wool production in Romney ewes

Abstract

Fibre diameter and fibre length arrays of monthly samples of 10 mature Romney ewes were each subdivided into seven groups such that group 1 contained the coarsest or longest 15% of fibres and group 7 the finest or shortest 15% of fibres. A study was made of the relation between the characteristics of these seven groups and the level of wool production over a period of 18 months.

There was a linear relationship of the form y = a + bx between fibre cross-sectional area d², fibre length per day l , or fibre volume per day d²l (y), and the level of wool production (a), at each of the seven levels within the array. A similar linear relationship held between the change in d², l , or d²l associated with a change in the level of wool production and the corresponding value of d², l, or d²l on which this change was based. In three of the 10 ewes the change in fibre length associated with a change in wool production was constant over the array; in the other ewes the absolute length change increased in the faster-growing fibres. In all ewes the percentage change in d², l , or d²l decreased with increasing fibre size.

In four of the five ewes whose wool was free from medullation the change in fibre volume per unit area of fibre cross section associated with a change in the level of wool production was a constant over the array.

Some aspects of follicle efficiency and follicle competition are discussed. It is concluded that in mature ewes all follicles have the same "efficiencies" and do not compete for fibre substrate. The spatial relationship of the follicles did not, affect wool production.

The concept of a "basic pattern" of wool production is introduced and discussed.