EVALUATION OF METHODS OF ESTIMATING POPULATIONS OF THE SHEEP KED, MELOPHAGUS OVINUS (L.) (DIPTERA: HIPPOBOSCIDAE), ON MATURE EWES AND YOUNG LAMBS

Abstract

Six methods of estimating populations of the sheep ked, Melophagus ovinus (L.), on mature ewes and young lambs of four breeds were evaluated. The actual populations were determined by picking off and counting all the keds. The total live count method gave the highest degree of accuracy, the ratios of the sample counts to the actual populations not being affected by variations in the degree of infestation, body size, or fleece characteristics. A valid estimate was obtained by counting all the keds on only one side of the sheep. In the vertical parting methods the ratios increased as the distance between the partings decreased, and counts were affected by marked differences in body size and fleece characteristics. The 12-inch parting method accounted for only a small portion of the ked population and the accuracy was low. In the 5-minute count the ratio depended on the degree of infestation, body size, and to a lesser degree the fleece characteristics.