A Comparison of Five Methods of Estimating Clean Fleece Weight

Abstract

Clean fleece weight obtained by scouring the whole fleece from a total of 139 yearling ewes and 61 yearling rams was compared to (1) the results obtained from scouring small side samples, (2) multiple regression equations predicting clean fleece weight from wool density, body weight, staple length and grease fleece weight, (3) a method described by Neale and McFadden (1954) and (4) the results obtained from a new machine designed by P. E. Neale for estimating clean fleece weight. All methods of estimation appear to be reasonably accurate as shown by the correlation coefficients between whole fleece scouring and each of the four methods described above. These correlations were 0.92., 0.95, 0.87, and 0.87, respectively. It was shown by the multiple correlation coefficients that very little information concerning clean fleece weight is lost in predicting clean fleece weight by the multiple regression method if wool density and body weight were omitted from these equations. The small increase in accuracy of the small sample and multiple regression methods over the machine method does not compensate for the saving of time and expense involved as the machine method requires less than 2 min. per fleece for the estimate. The machine requires no technical skill or knowledge for its operation and is applicable to all flocks. Also, the clean fleece weight estimate derived from the machine is independent of all other traits.