Fly Control

With warmer temperatures moving in, this is a great time to focus on preventing the problems caused by flies for cattle and optimum production goals. Flies can be costly to a dairy replacement operation by reducing feed intake at different times of the year. Proper control of flies and their effects can be a challenge for many farmers. Prevention and appropriate treatment depends upon which fly species causes the irritation.

Some of the most common irritating flies are:

1. Horn flies (Haematobia irritans) - this is one of the most serious and injurious pests for cattle as they are known for transmitting mastitis-causing bacteria. These flies spend most of their time on the animal and take 20 to 30 blood meals a day. The resulting pain and annoyance interferes with feeding, resting and other routine actions of cattle.
2. Face flies (Musca autumnalis) - face flies are considered to be severe enemies of cattle. These flies spend most of their feeding on mucous secretions from the eyes and mouth of cattle, while sucking on areas around the mouth. They tend to cause irritation and can spread the bacteria that cause pinkeye.
3. Stable flies (Stomoxys calcitrans) - the bites inflicted from these flies are very painful as they take 2 to 3 painful blood meals per day, usually on the legs of cattle. Stable flies cause cattle to bunch up, stomp and kick.
4. House flies (Musca domestica) - house flies spend their time feeding on decaying organic matter and spoiled feed. Eggs are laid in rotting organic matter, such as old hay or manure. This species of flies causes mild irritation to cattle.

Preferred practices for managing fly infestation:

1. Ear Tags are recommended for flies that spend most of their time on the host. These flies include the horn flies and face flies. Although ear tags are recommended, farmers need to remember there is a limited lifespan for ear tags. It is suggested to wait for the fly season to attach the ear tags. Contract heifer grower and veterinarian, Don Gardner recommends waiting until June to worm out heifers and attach fly tags for the best fly control results. Another tip is rotating between organophosphate-and-pyrethrin-based ear tags as it will slow fly resistance to the chemicals.
2. Pour-on is a fly control method that may assist in protecting against all species. This treatment is labor intensive and must be repeated often for continued results.
3. Insect growth regulators (IGRs) can be used in feed rations to prevent horn fly development in manure. IGRs should be fed throughout the fly season in order to maintain complete control over flies.
4. Environmental control is an important element in controlling the house fly population as well as reduces their nesting environment.
5. Other options for managing flies and problems linked with flies are using parasitic wasps, back rubbers and traps.

Although these are recommended management practices for controlling flies, the best fly control strategy varies by geographical location, rainfall, stocking density and management. Producers need several different forms of fly control throughout the season to ensure proper control. It is always advised to seek advice from your veterinarian and nutritionist for more definite recommendations specific to your operation.

DCHA Gold Standards II advocate for practices that control internal and external parasites. Control measures will vary based on your geography. Remember to consult with your herd veterinarian for appropriate fly-control measures to use on your operation.

See DCHA Gold Standards II to learn more about pest management.