Buffalo flies ramp up
Buffalo flies (Haematobia irritans exigua) increase with rising soil temperatures and frequent rainfall, stimulating young adult flies to emerge from their pupal stage in the soil and seek out their cattle hosts on which to live and feed.
These small blood-sucking parasites bite cattle up to 40 times a day, causing considerable irritation and distress to their host. They can also spread diseases such as pinkeye and the Stephanofilaria sp. worm, which causes severe skin sores around the eyes and body of affected cattle.
Reducing chemical control
Cattle of any age can be affected by buffalo flies, however cattle with dark coats and bulls tend to attract greater fly numbers, with bulls typically showing more signs of distress by their presence.
Some cattle can also be hypersensitive to buffalo flies, causing exaggerated reactions (‘allergies’) to very few fly bites. Culling these hypersensitive cattle can be an effective management option to increase the threshold over which chemical treatment is required.
Genetic selection, dung beetles and the use of fly traps are also possible non-chemical control methods that may reduce overall chemical use on farm.
If cattle are showing signs of fly worry, or if there is prolonged and high fly pressure ie. 200 flies per head for beef cattle or 30 flies per head for dairy cattle, long-acting control is recommended such as insecticidal ear tags. This will reduce the number of flies present and provide vital welfare benefits to cattle. As for any treatment method, it’s essential that insecticidal ear tags are used strategically to prolong the efficacy of the actives available.
Rotating active controls
Elanco endorses a buffalo fly control program which rotates actives both within-a-season and from season-to-season. The active used in the shoulder fly seasons should be different to that used in the ear tag.
For instance, if a macrocyclic lactone (ML) drench has been used at the start of the buffalo fly season for broad spectrum parasite control, then a different active group should be used for the ear tag used for the peak fly season.
This can be a synthetic pyrethroid (SP) ear tag such as Cylence® Ultra or organophosphate (OP) ear tag such as Patriot® or Co-Ral® Plus.
It’s vital tags are used correctly to ensure their continued performance as well. This means using the correct number of ear tags per head and removing tags at the end of their published efficacy period. Applying too few ear tags or leaving them in beyond their efficacy period may accelerate resistance development.
Long range spread
As buffalo flies are able to travel up to 10 km in a day, they can readily spread between cattle, across properties and from introduced cattle.
For this reason, it’s important to engage with your neighbours and community to formulate a control program together. This helps ensure the local buffalo fly populations are controlled by actives that are effective, regardless of where the flies travel.
Article written by Kim Krilich of Elanco for Seasons magazine.
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