An analysis of the variation in wool production between commercial properties from a survey of a wheat-sheep shire in New South Wales

Abstract

A survey of Merino breeding properties in the Weddin Shire of New South Wales was used to relate the variation in wool production among properties to physical and management factors. Clean wool production averaged 3.15 kg per sheep and showed little variation between the eastern, central and western portions of the shire. However, clean wool production per hectare was greatest in the eastern portion where rainfall, pasture improvement and stocking rate were highest. Overall, ewes produced 88% as much wool as the wethers but variation was great, with 23% of the properties surveyed producing more wool per sheep from their ewes. The difference in productivity for properties in the highest and lowest quartiles was 71% when ranked on clean wool production per sheep. The difference was 184% when ranked on clean wool production per hectare, and even though stocking rate more than doubled, individual productivity increased. Similar differences in quartile production were observed in each portion of the shire. Regression analysis was used to test the importance of 9 physical and 10 management factors as determinants of the variation in clean wool production between properties. Four factors (stocking rate, managerial assessment, sheep strain/bloodline and location within shire) accounted for 74% of the variance in wool production per hectare, but after adjusting for the time of shearing, only 16% of the variance in wool production per sheep was explained. In a more specific analysis of wool production of the properties' ewe flock, 42% of the variance was accounted for by the source of genetic material, stocking rate, pasture improvement, time of lambing, the proportion of Merino ewes and an assessment of managerial ability. Research workers considering on-farm experimentation in wool production should be aware that large productivity differences can occur between nearby properties. Therefore, treatments should be allocated to properties based on known wool production. Further, results obtained from either the ewe, wether or hogget flocks may have application to only that class of sheep because of the large differences in commercial management imposed on them.