Merck Manual

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Professional Version

Buffalo Flies


Charles M. Hendrix

, DVM, PhD, Department of Pathobiology, College of Veterinary Medicine, Auburn University

Last full review/revision Aug 2013 | Content last modified Jun 2016

Buffalo flies, Haematobia irritans exigua, are similar to horn flies in size and appearance and in feeding and breeding habits. The buffalo fly is a primary pest of cattle and water buffalo but occasionally feeds on horses, sheep, or wildlife. It is distributed throughout northern Australia and New Guinea and is found in parts of southern, southeastern, and eastern Asia as well as Oceania; it is not found in New Zealand. Its life cycle is similar to that of the horn fly; the adult leaves the host long enough to oviposit on fresh manure, where development occurs. The life cycle may take as few as 7–10 days, depending on weather conditions.


Buffalo flies irritate and annoy animals, usually biting about the shoulders and withers. Bite wounds may provide a site for screwworm (Chrysomya bezziana) infection. During hot weather, the flies move to shaded parts of the body. Affected animals suffer blood loss and are irritated by the flies; feed efficiency and production may be affected adversely.


Buffalo flies can be identified by their dark color, size (approximately half that of a stable fly), and bayonet-like proboscis that protrudes forward from the head.

Treatment and Control:

Insecticides should be avoided in the treatment of buffalo fly populations. Many of the chemicals used to treat these flies result in meat residues. Buffalo flies have developed resistance to the synthetic pyrethroids and to some of the organophosphates. Buffalo fly traps have been developed in Australia. The trap consists of a rounded, clear plastic tent through which the cattle walk. The flies are brushed off the cattle within the tent and are then trapped inside where they die of desiccation. These traps remove ~80% of the buffalo flies each time the cattle pass through. When cattle pass through the trap every day or every second day, sufficient fly control is usually achieved.

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