Abstract
The total number of fibres on sheep (NT) is calculated by means of the formula NT = WT /w, where WT is the clean fleece weight and w the mean clean fibre weight. WT is obtained by multiplying the greasy fleece weight by an estimate of the yield, and w is estimated from samples of scoured wool. The variation over the sheep's body of yield and mean clean fibre weight was investigated and the accuracy of the estimate of total fibre number was deduced. It was found that mean clean fibre weight showed no consistent trend over the body and that the trend in yield was small.