Introduction:
Flies are not just a nuisance for horses; they can also pose health risks and discomfort. It is therefore important to understand the different types of flies, how they affect horses and the best ways to manage them.
Types of Flies:
Stable Flies (Stomoxys calcitrans):
Description: These blood-feeding flies resemble house flies but are larger and have a painful bite.
Impact on Horses: They commonly bite horses on their legs, causing irritation and potentially leading to skin lesions.
Management: Regular manure removal, using fly sprays, and providing shelter can help reduce their population.
Horse Flies (Family Tabanidae):
Description: Large, robust flies with strong mouthparts for biting and feeding on blood. They hunt by sight meaning rendering many repellents ineffective.
Impact on Horses: Their painful bites can cause significant distress, skin irritation, and potentially transmit diseases.
Management: Implementing physical barriers such as fly sheets may help. Zebra print ones can confuse them and affect their ability to identify their prey. Icaridin-based insect repellents have been shown to be effectively repel them, in lab-based studies with human participants.
Face Flies (Musca autumnalis):
Description: These flies primarily target the face and head of horses.
Impact on Horses: Irritation and annoyance, potential transmission of eye diseases.
Management: Use of fly masks may help some, although a good fit is essential
to prevent rubbing. Repellent fly gels are also very useful, they stick to the skin better than a repellent spray and are ideal for more sensitive areas. Ear tags (such as the ones used for cattle) can also be effective but be aware that these contain insecticides, which may cause damage to other wildlife.
Bot Flies (Family Oestridae):
Description: These flies lay eggs on the horse's hair coat, which are then ingested by the horse during grooming.
Impact on Horses: Larvae can cause internal damage, leading to health issues if left untreated.
Management: Regular deworming and removing bot eggs from the horse's coat can help prevent infestations. Gel repellents can also prevent egg-laying activity.
Mosquitoes (Family Culicidae)
Description:
While primarily known for their nuisance to humans, mosquitoes can also bite horses, potentially transmitting diseases like West Nile virus and Eastern equine encephalitis.
Impact on Horses
Mosquito bites can cause irritation and discomfort to horses. They may experience itching, swelling, and redness at the site of the bite. Some horses may be allergic to mosquito saliva, leading to more severe reactions such as hives or even anaphylaxis in rare cases.
Management:
Apply equine-safe insect repellents regularly.
Fly masks can provide physical protection from mosquito bites, especially during peak mosquito activity times although a good fit is essential to prevent more skin
issues developing.
Midges (Family Ceratopogonidae):
Description:
They are similar to mosquitoes but smaller in size, with most species measuring only a few millimeters in length. Midges are known for their painful bites, which can cause irritation and discomfort to horses and other animals.
Impact on Horse:
The bites can lead to itching, swelling, and skin irritation, particularly in sensitive areas such as the ears, face, and belly. Some horses may be allergic to midge bites, experiencing more severe reactions such as hives or dermatitis - this condition is commonly known as 'Sweet Itch'. In rare cases, severe allergic reactions can occur, requiring veterinary attention.
Management:
Use of fly masks and sheets: these can provide physical protection from midge bites but may lead to overheating in horses during the hottest summer days, consequently making the skin sweaty and more itchy.
Use equine-safe insect repellents to deter midges from biting horses. Apply repellents according to the product instructions, focusing on exposed areas of the horse's body.
Prevention and Management Strategies:
-Environmental Management:
- Regular manure removal and proper sanitation practices.
- Use of fly predators or parasitic wasps to control fly populations naturally.
Physical Barriers:
Fly sheets, fly masks, and leg wraps to protect horses from bites, though these can sometimes increase body temperature and sweating (and therefore itching).
Chemical Control:
Fly sprays, insect repellents, and insecticide ear tags for additional protection.
Dietary Supplements:
Some studies suggest supplements may help repel flies when added to the horse's diet, such as garlic or apple cider vinegar. However, consult with a veterinarian before adding supplements.