Wool production and heterosis by the Merino, the Polwarth, and their reciprocal crosses [sheep]
1993
Butler, L.G. | Horton, B.J. | Williams, P.M. (Tasmanian Dept. of Primary Industry, Kings Meadows (Australia)) | Banks, R.G. (New England Univ., Armidale (Australia). Dept. of Animal Science)
Tasmanian Merinos and Polwarths were mated in each of 2 years to produce 2 drops of Merino, Polwarth, and F1 reciprocal cross progeny. Polwarths had weaning weights similar to Merinos but were 14 percent heavier as hoggets. Polwarths grew a similar amount of wool of 11 percent greater fibre diameter; however, wool production was 9 percent less efficient based on metabolic weight. Polwarths displayed an advantage in resistance to footrot. There was a marked Polwarth maternal effect of about 16 percent on weaning weight but no effect on hogget weight. The Polwarth maternal effect on fleece weight and efficiency was 9 percent. In a comparison with a single-born male, ewes weighed 5 percent less at weaning and 7 percent less at hogget shearing and produced about 6 percent less wool although of comparable fibre diameter. Twins weighed 17 percent less at weaning, but only 3 percent less at hogget shearing. They grew about 5 percent less wool, which was of 2 percent greater fibre diameter and 5 percent higher wool score, but efficiency was 2.5 percent lower. There appeared to be some heterosis for weaning weight (10 percent) and hogget weight (6 percent), but little heterosis in wool growth (2-3 percent) or efficiency (-2 percent).
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