Aug 20, 2021
There are high chances you or your horse have been bitten by a horse fly on more than one occasion. Even if horse flies are not harmful to humans, these are usually a problem for horses as they carry equine infectious anemia, also referred to as swamp fever.
This means when they bite horses, they can transmit this life-threatening disease. If infected, horses may experience fever, hemorrhaging and general illness. They are most common during summer months, and as this is transmittable between equine animals, it is important to stay safe from horse fly bites.
Biting flies pierce the horse’s skin and they feed on their blood, and nuisance flies lay secretions around the horse’s eyes, mouth, nose or other sensitive spots. This means it can cause different problems to horses.
Also, flies carry diseases and allergic reactions can result from fly bites. Even when flies are annoying to horses and riders alike, there needs to be a special consideration with working or competing horses.
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Horse flies (Tabanidae) are active around June and July and appear on warm days, especially around woodlands. They prefer feeding around the horse’s underside, legs, neck and withers. The bites appear as painful papules (like pimples) and wheals (small lumps).
Home-made fly repellents are of little protection against horseflies. Insecticides known as synthetic pyrethroids (permethrin or cypermethrin) are the best option to protect horses from these insects. These can be bought in tack shops.
Black flies (Simuliidae) are small and breed very quickly in moving water. They appear at dawn and dusk during spring and early summer. These commonly feed around the face, particularly inside the ears. They can cause allergic skin reactions and distract the horse.
Bites appear in painful lumps, often with some bleeding and crusting. Pyrethroid fly sprays disencourage these flies from approaching, but also physical barriers such as ear nets, or oil-based products, as citronella oil can be used. Vaseline applied inside the ears can be used to prevent insect bites.