The relationship between greasy fleece weight and clean fleece weight in the South Australian Merino

Abstract

The correlation between clean fleece weight and greasy fleece weight in South Australian strain Merino hoggets of both sexes in three widely different seasons was found to be Rams, 0.841, 0.890, 0.701 and Ewes, 0.846, 0.850 and 0.839. A covariance analysis of clean and greasy fleece weights showed no significant differences between slopes of individual sires, but significant differences between sire group means, indicating genetic variability for these two traits. It is concluded that the correlations are high enough to make selection for clean fleece weight by partial culling on the basis of greasy fleece weight, followed by scouring of midside samples of the fleece from the top sheep for greasy fleece weight, as advocated by Beattie (1956), practicable. The use of the clean fleece weight, greasy fleece weight relationship will rarely be sufficient on its own to formulate a selection plan. The conditions for the use of other aids to estimate clean fleece weight, such as the Neale squeeze machine, are discussed.