HOW TO CONTROL AND TREAT BUFFALO FLY IN CATTLE

Courtesy Elanco

Buffalo Fly Prevalence in Australia 

The buffalo fly (Haematobia irritans exigua) is a major pest and cattle welfare issue in northern Australia. Like the cattle tick, the buffalo fly was accidentally introduced into northern Australia from Asia in the 19th century. Since then, this pest has spread across much of the tropical north and as far south as central New South Wales. The prevalence of buffalo fly has fluctuated further south over recent years, with one of the most likely reasons for this being climate change.  

Buffalo flies can only survive 1 or 2 days off their cattle or buffalo host, with females leaving briefly to lay their eggs in fresh dung pats before returning to a host. The life cycle is temperature dependent with warm, wet weather conditions between 25°C and 35°C favouring egg development. Under ideal conditions, a life cycle can be completed in just 10 – 20 days allowing populations to build up rapidly over a season. Buffalo fly can readily spread between cattle, across properties and from introduced cattle. 

The Health and Welfare Impacts of Buffalo Fly 

The buffalo fly is a small external, blood-sucking parasite, up to 4mm in length that feeds off cattle and buffalo. Buffalo flies bite their host up to 40 times per day, mainly attacking the withers, shoulders, flanks and around the eyes, and causing severe irritation and production setbacks when infestations are high. Cattle rub on infrastructure to find relief, which not only results in damage but causes lesions on the hide of cattle. This reduces hide value and may also restrict access to live export. Flies can also spread diseases such as the bacteria causing pinkeye (Moraxella bovis) and the Stephanofilaria sp. worm, which causes severe skin sores around the eyes and body of affected cattle. Such sores can become infected and attract other flies. The distress that buffalo flies cause can disrupt grazing time and reduce overall feed intake, resulting in productivity setbacks. 

Buffalo flies are now considered the most costliest endemic disease for the Australian cattle industry, costing $170.3 million annually in prevention and production costs, according to a 2022 Report on Endemic Diseases for the Red Meat Industry.¹ 

Susceptibility of Cattle to Buffalo Fly 

Cattle of any age can be affected by buffalo flies. However not all cattle will experience the same level of fly infestation, with cattle with dark coats, bulls and those in poor condition likely to carry larger fly burdens. Bulls tend to show more signs of stress from the presence of flies. Some cattle can also be ‘allergic’ or more sensitive to flies and are intensely irritated by as few as 4 or 5 flies. 

Controlling Buffalo Fly on Cattle 

An integrated approach to control buffalo fly should be used to reduce fly numbers to an acceptable level, so that production losses are minimised and cattle welfare isn’t compromised. Non-chemical control methods, such as fly trap tunnels and dung beetles can be used to lower fly burdens and reduce reliance on insecticide use. Culling sensitive cattle and selectively breeding cattle genetically predisposed to carrying fewer flies are also strategies that can be adopted. However, using chemical controls and treatments currently remain the most effective way to manage buffalo flies, particularly when fly pressure is high. Methods include insecticide ear tags (e.g. Patriot™, Co-Ral™ Plus, Cylence™ Ultra), sprays and pour-on’s (e.g. Baymec™ Pour-On, Acatak™ Duostar).  

Buffalo fly resistance is well-documented so it is important that treatments are used strategically to ensure they remain effective, including:  

• Follow label instructions for correct application and removal of ear tags at the end of their control period 
• Monitor fly pressure and treat accordingly: 
• Use short residual treatments (e.g. pour-on’s) during low fly pressure 
• Use long residual control (insecticidal ear tags) during high fly pressure i.e. when fly worry is obvious, or when there are >30 flies per dairy cow or >200 flies on beef cattle 
• Co-ordinate the chemical class used for each season with neighbouring properties – a community approach to control and resistance management is important given buffalo flies can travel from one property to the next 
• Know the resistance status in your area so that you don’t use actives that may not be effective 
• Keep a record of what chemical controls you use to ensure that you rotate chemical actives within a season and from season to season.