Identifying the mating performance of individual rams in field flocks

Abstract

A method is described for identifying the individual rams which mate with each ewe in a mating flock. Different metallic elements were incorporated into raddles worn by each ram. The elements were identified by X-ray spectrophotometry from samples of raddlemarked wool taken from ewes and hence indicated the rams with which any ewe had mated. When this method was tested under field conditions there were found to be significant linear increases both in the non-return rate (P r. 0.05) and in the number of ewes lambing (P < 0.01) as the number of rams marking each ewe increased. In the four flocks examined, individual rams mated with 4.3 to 96 % of the mated ewes in each flock. Between 21 and 88 % of the ewes were marked by four or more rams. These flocks contained c. 3 % rams.