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Estimating the incidence of fly myiases in Australian sheep flocks: develpment of a weather-driven regression model

journal contribution
posted on 2023-05-17, 02:30 authored by Wardhaugh, KG, Morton, R, Bedo, D, Brian HortonBrian Horton, Mahon, RJ
The blowfly, Lucilia cuprina Wiedemann (Diptera: Calliphoridae), is the primary myiasis (strike) fly of sheep in Australia. Most strike occurs in the anal-perineum area (crutch), but strike to the neck, shoulders, back and withers (body) is also important. Regression analysis was used to determine the extent to which the weekly incidence of flystrike can be explained by variations in fly abundance and/or recent changes in weather, pasture conditions or flock management. Strike and flock management data were collected by questionnaire surveys of 30-60 sheep properties in each of three major sheep-producing areas in southeastern Australia, namely, Gunning (southern New South Wales), Inverell (northern New South Wales) and Flinders Island (Bass Strait). After using simulation modelling to remove effects due to shearing, crutching and/or insecticide treatment, pasture growth index was found to be the most important explanatory variable affecting the incidence of all forms of myiasis. Others were average weekly air temperature, the amount and frequency of rainfall, relative humidity, dung quality index and a factor denoting seasonal effects. Together, these variables accounted for 48.4% of the variation in body strike, 56.8% of that in crutch strike and 51.9% of that in other forms of strike. Prediction was improved by the inclusion of additional lagged variables describing previous strike, fly abundance and fly activity. With these additions, the variation explained increased to 60.4% for body strike, 68.0% for crutch strike and 58.3% for other strikes. © 2007 The Royal Entomological Society.

History

Publication title

Medical and Veterinary Entomology

Volume

21

Pagination

153-167

ISSN

0269-283X

Department/School

Tasmanian Institute of Agriculture (TIA)

Publisher

Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Repository Status

  • Restricted

Socio-economic Objectives

Sheep for wool

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