Prevalence of the causes of fleece derangement among sheep flocks in New South Wales
1993
Johnson, P.W. | Boray, J.C. | Plant, J.W. (New South Wales Agriculture, Menangle (Australia). Elizabeth Macarthur Agricultural Inst.) | Blunt, S.C. (Wellingrove Station, Glen Innes (Australia))
Psorergates ovis was present in 53 of the 177 flocks surveyed and in 162 of the 3495 sheep examined. Of the single causes of fleece derangement, the most prevalent was grass seed contamination (15.7 percent) followed by infestation with sheep body lice, Bovicola ovis, (14.7 percent) and infestation with itch mite (7.8 percent). The prevalence of fleece derangement was significantly higher on sheep in which lice were the only ectoparasites found than on those in which itch mites were the only ectoparasites present. The results did not support a commonly held belief among farmers that arsenical compounds control infestations of itch mites more effectively than other types of pesticides. There was no significant difference in prevalence of fleece derangement between flocks treated with different pesticide groups and those that received no treatment, but mean fleece derangement score was significantly lower in sheep treated with organophosphates than in untreated sheep. Infestations of lice were significantly more prevalent in sheep from flocks treated with synthetic pyrethroids than those treated with organophosphates or those that received no treatment.
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