Horseflies, gadflies and botflies
Written by Noa |
As temperatures rise, the number of biting and bloodsucking insects also increases. In addition to causing unrest and slowed growth, they increase the risk of infections in grazing livestock.
Flies
Small wounds in the skin make it easier for pathogens to enter the body. With a few simple measures, nuisance caused by insects can be prevented. In the UK, we encounter various types of outdoor flies, of which the head fly (Hydrotaea irritans) is perhaps the most notorious. The horn fly (Haematobia irritans) also causes significant discomfort.
Head fly
The head fly resembles the common housefly, which we often see against windowpanes when doors and windows are open. The head fly does not bite but feeds on wound fluid and other secretions. However, it can transmit the bacterium responsible for summer mastitis, which causes severe inflammation in the udders of cows. Summer mastitis mainly affects dry cows grazing outdoors. The head fly is most active from roughly June until the end of September.
Horn fly
The horn fly feeds on blood. When a swarm of horn flies lands on the back and flanks of a peacefully grazing cow, the irritation is intense. The numerous bite wounds can lead to infections. Horn flies lay their eggs in fresh manure. The complete life cycle takes about ten days. As horn flies are highly cow-specific, they can be effectively controlled using insecticides.
Horseflies
Horseflies are large, fast-flying insects with broad bodies and prominent eyes. The females are particularly bloodthirsty, feeding on the blood of large mammals and sometimes humans. Male horseflies are less aggressive and mainly feed on nectar. The larvae live in moist soil and feed primarily on decaying plant matter. Horseflies are commonly found in coastal regions. They can cause significant unrest in livestock, and if animals are constantly harassed, it may result in reduced growth.
Cattle grubs
Buzzing cattle grubs can cause panic among grazing livestock. Although they have been largely controlled, they still occasionally appear in border regions. From June onwards, the adult cattle grub lays its eggs on the hairs of the cow. The larvae hatch after a few days, bore through the skin, and migrate into the body, later causing the well-known warble swellings in winter. During the grazing season, the damage is mostly limited to the disturbance caused by the buzzing flies. The adult fly only lives for a few days in June.
Preventing nuisance
The presence of flies depends heavily on soil type, vegetation, and nearby open water. In wooded areas with a humid microclimate, it can be beneficial to regularly control flying insects. Adding garlic to feed may help. Various sprays and gels are also available.
If you have any questions about this topic, please contact us at veterinarian@vetsend.co.uk.
