The effect of supplementary feeding with casein on wool growth of Corriedale ewes

Abstract

An experiment was conducted to determine the effects in wool growth of: (i) Pregnancy and lactation in sheep receiving daily supplements of formalin-treated casein. (ii) Formalin-treatment of the casein in pregnant and lactating sheep. (iii) Three experimental treatments were tested (i) Pregnant and lactating animals receiving a daily supplement of 45gms. of formalin-untreated casein (ii) Pregnant and lactating sheep receiving 45gms. of formalin-treated casein and (iii) Non-breeding sheep receiving 45gms. Of formalin-treated casein. (iv) Wool growth rate was determined by clipping of mid-side patches every 28 days and the components fibre diameter, fibre length growth and change in fibre numbers were measured.

Dry sheep produced more wool than pregnant and lactating animals and the differences were significant or highly significant in all except the first experimental period.

Formalin-treatment of casein did not have a significant effect on wool growth except in Period 1 of the experiment when sheep were in the very early stages of pregnancy.

There was no significant change in numbers of active follicles during the course of the experiment and of the other two components of production, variation of fibre cross-sectional area was more important than variation of length growth in explaining changes in wool production.