Selection for crimp frequency in the wool of Merino sheep. 2. Efficiency of conversion of food to wool

Abstract

Two experiments were conducted in which the efficiency of wool production of Merino sheep selected for increased (Crimps Plus) and decreased (Crimps Minus) crimp frequency, and a randomly selected control flock, was examined under pen feeding conditions. Ewes for the second experiment were chosen from the same genetic flocks as those used in the first experiment, after a further 1.8 generations (six years) of selection. In the first experiment, in which four levels of roughage diet were offered to ewes from each of the genetic groups, Crimps Minus ewes consistently produced more wool and with a greater efficiency than Random ewes, which were superior in these two characters relative to Crimps Plus ewes. Similar results were obtained in the second experiment, in which ewes were fed to maintain liveweight. Wool production and efficiency of Fleece Plus ewes were greater than those of Crimps Minus ewes indicating a higher genetic correlation between efficiency and fleece weight than between efficiency and crimp frequency.