14 August 2015

Buffalo fly costs the Australian cattle industry more than $98 million/year according to the recently released MLA-funded report, Priority list for endemic diseases in the red meat industry. It came in third on the cattle list, following cattle tick and BVDV/Pestivirus.

The buffalo fly, Haematobia irritans exigua, is a small biting fly, about 3.5–4 mm in length. It feeds off cattle and buffalo, and causes irritation which can result in reduced production if cattle are heavily infested.

In recent cattle industry surveys, producers have nominated buffalo fly as the major parasite problem of cattle. It is a serious pest to cattle producers in Northern Australia and is slowly moving south.

Buffalo flies were accidentally introduced into northern Australia from Asia in the mid nineteenth century. Since then they have spread through northern Western Australia, the Northern Territory, Queensland and north-eastern NSW. They first entered NSW in 1978 and since then have spread south. The distribution of buffalo flies within NSW varies from season to season. Warm, moist conditions favour multiplication and spread.

Spread

Spread of buffalo flies between herds and between animals occurs when:

newly emerged flies are seeking their first host – they can fly up to 10 km in search of a host flies are dislodged from an animal female flies return to a different host after laying eggs in dung movement of infested animals can be an important method of spread between herds

Bulls and dark-coated cattle, especially black cattle, seem to carry the largest fly burdens. 

The impact

Buffalo flies cause a number of problems:

Lower weight gain and lower milk production have been measured in heavily infested cattle. It is generally considered that infestations of more than 200 flies per animal are necessary to reduce production. Many infested cattle develop sores in the inner corners of their eyes. Some cattle are ‘allergic’ to buffalo flies and are intensely irritated by as few as four or five flies. These cattle scratch and rub themselves constantly, which results in large sores on their necks and sides. The value of the hide is reduced when cattle have developed skin sores as a result of buffalo fly infestation.

Prevention

Numbers of flies can be minimised using walk-through fly traps, introducing dung beetles, applying insecticide ear tags (during the peak fly period of January to May) and culling animals particularly susceptible to fly irritation.

Treatment

Chemical options should be considered only after the fly population reaches 200 per animal.

Tips for producers using chemical treatments:

follow the labels and manage the delay of resistance and withholding  periods and export slaughter intervals only use the recommended rates coordinate treatment with neighbours to ensure the regional population is being decreased

Resources

Department of Agriculture and Fisheries Queensland fact sheet

NSW Department of Primary Industries PrimeFact

How to build a buffalo fly trap

 

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