With the exception of isolated islands and polar regions horse-flies (or horseflies) are found throughout the world. They’re diurnal (awake during the day), and in the northern hemisphere appear during June and July.
Although renowned for their bite, only female horse-flies carry out this behaviour; protein is harvested from the blood and used to produce eggs.
Why are horse-flies bad?
Horse-flies are most attracted to the legs, neck, underside, and withers of a horse. Although generally only bumps appear where a horse was bitten, there is the potential for a more serious outcome: as horse-flies extract blood they’re able to pass blood-borne diseases from animal to animal. Perhaps the most significant of these diseases is equine infectious anaemia (EIA), otherwise known as swamp fever.
EIA is active throughout Europe, the United States, and many other countries. Although all precautions should be taken to prevent your horse from being bitten, a vaccine is available against the disease. In the most severe cases, EIA can result in sudden death.
How to keep horse-flies away
There are several things you can do to keep horse-flies away, although the most effective are rugging and the use of a potent fly spray.
It’s vital that your horse is sufficiently covered by a fly rug. It is particularly important that your horse’s underside is covered as it is common for horse-flies to attack this area; both the “Bug Buster” by Premier Equine and the “Vamoose Fly Rug” by Horseware cover the belly area.
It has been shown that darker horses are more attractive to horse-flies, as they are enticed by dark colours and motion. If your horse is particularly susceptible to flies then it’s worth looking into a full-face mask, such as the “Buster Fly Mask Xtra” from Premier Equine which covers the ears and nose. Horse’s eyes can become infected if they’re attacked by horse-flies, so a more basic facemask is important for all horses.
As you’re no doubt aware, the attacks don’t stop when you’re mounted and riding. Aside from sprays a fly-rug that’s meant for use when riding is a great option for deterring flies when hacking – for example, the “Amigo Flyrider” by Horseware.
Horse-flies are hardy things, and home-made fly sprays rarely act as much of a deterrent. Instead, invest in a good synthetic pyrethroid (SP) (a type of insecticide) from your local tack shop or online. However, note that most SP sprays cannot be applied daily. Furthermore, be aware that some fly species are known to have developed a resistance to the insecticide, so ensure you monitor its effectiveness.
Your horses natural defence
Remember, a horse’s tail is its natural defence against flies – it’s not entirely helpless. Also, as horse-flies do not like dark and shady areas try and introduce a shaded area to your paddock (planting a tree is a great way of achieving this), alternatively, consider leaving your horse in it’s stable during the day, and turn it out at night.
How to deter horse-flies (humans)
To reduce your chance of being bitten wear light clothing, and consider wearing a skin-safe insecticide (often included in suncream).
A bite from a horse-fly can be very painful, and although their bite is not generally harmful there’s always a chance of infection, and you may develop a rash, dizziness, weakness, wheezing, and/or swelling. If you are bitten the National Health Service (NHS) advise that you clean the area, apply a clean cold cloth (or similar), keep the wound covered to help reduce the risk of infection, and elevate the wound to reduce swelling. If your symptoms don’t improve in a few days, or you were stung around your mouth, throat, or eyes then you should contact your GP or the NHS on 111. For more information, see the up to date NHS guidance.