Abstract

Selection objectives for wool characteristics are usually set by analysing past prices, considering the results of processing trials and trying to predict future changes. Deficiencies in the information for setting selection objectives were, until recently, the main problems in calculating selection weightings. The situation has largely been rectified and the major problem now is in translating the object into index weightings. Variation in the genetic parameters causes great variation in the indices and there are doubts about the accuracy of the estimates of genetic and environmental correlations available. Recently calculated objectives place more emphasis on fleece weight than earlier formulations. Bulk, colour, length, resistance to cotting and soundness (staple strength) seem sufficiently important to include in the objective but indexes calculated using present genetic parameters usually place little weight on them. The result is that the extra gains from including colour, cotting and soundness in the index will probably not compensate for the work involved. However inclusion of resistance to cotting and soundness in the objective leads to more attention to fleece weight in the index. Foreseeable changes in market conditions seem unlikely to change these conclusions but a different set of correlations or cost/benefit calculations might lead to modifications.

GM, Scobie, and JS Bircham

Proceedings of the New Zealand Society of Animal Production, Volume 45, , 193-196, 1985