When you are a horse owner, you spend the majority of the year wishing it was summer. Then when summer finally arrives, so do the pests. Especially the tiny flying ones which are capable of making your equine friend’s life quite miserable. There are various types of flies which literally make it their life goal to seek out horses, to either feed on them or lay their eggs on them. Leaving you with a cranky, stamping, head-shaking and generally irritated horse that won’t listen to you or perform properly. 

Know your enemy: types of Fly

If that is not annoying enough, horses are at risk of developing serious health problems from the various flying insects which attack them. Finding out about flies and their feeding habits is not most people’s idea of a good read but to keep your horse happy it is well worth doing a little research on the different types of flies that attack your horse and the different problems they pose. Among the most common fly species found throughout our country are: Horse Flies, Black Flies, Stable Flies, Bot Flies and Midges. 

Horse Flies, Black Flies & Stable Flies

Horse flies, Black flies and Stable flies all actively bite equines and other mammals to feed on their blood. This causes irritation and pain along with sore scabs and lumps. As we know that flies are not the pickiest of eaters, they can also easily introduce bacterial and viral infections into the wounds they create. Some horses develop allergic reactions to fly bites with symptoms like swellings or hives, in rare cases this can become quite serious. 


We all know how infuriating it is to find ourselves being bitten by a cloud of tiny midges or gnats, and they are just as irritating for equines. For some horses, they will be a relatively minor irritation with no real concerns. For others, midges will cause an allergic reaction known as ‘sweet itch’. These reactions vary in severity from horse to horse but will generally involve the horse becoming extremely itchy, which it tries to relieve by rubbing and scratching on any available surface until patches of hair fall out and the skin underneath forms raised, hardened and weeping plaques. Left untreated, this can continue spreading across the body and become very painful and miserable for the affected animal. 

Bot Flies

Bot flies don’t bite the horse but they do lay their eggs on the horse’s coat and when the larvae hatch, they travel through the horse to the intestines, where it will attach itself and remain until the following spring. When ready to pupate into the adult fly, it will leave via the horse’s faeces and get ready to continue the cycle. Each adult female Bot fly can lay hundreds of tiny eggs which are glued on to the horse’s hair, usually around the legs, shoulders and underbelly. As they are bee-sized and buzzy, their mere presence can be annoying for the horse but the biggest concern is preventing the larvae from reaching the horse’s internal system. Most healthy horses can cope fine with a few and won’t even show any clinical signs but left uncontrolled, a big infestation can contribute towards loss of condition and gastric problems such as ulcers or potentially even perforated bowels. 

How to minimise fly aggravation:

While it is impossible to eradicate or control flies, there is plenty of preventative action you can take to make your horse, pony or donkey’s life more comfortable in the summer months while fly activity is most prevalent. 

  • Thoroughly check your horse all over on a daily basis. Immediately clean any bites or lumps with an antibacterial. Monitor existing bites for any signs of allergy or infection until they are fully healed. Seek veterinarian advice if there are symptoms of infection or an allergic reaction is spreading. Remove any Bot fly eggs from the horse’s fur. There is a special tool for this, a bot fly knife, which makes it a lot easier than trying to pick them off. 
  • Keep the horse covered during turnout. Use a good quality mesh fly rug which covers the horse’s neck, mane, tail and has a panel covering under the belly. There are some which are combined lightweight and fly rugs which can be useful in our ever-changing summer weather. 
  • Fit a fly mask during turnout. For horses that are particularly bothered by flies around their face, a well-fitted mesh mask can protect them. Ensure that it does not interfere with their eyes or nostrils and that it will come off easily if they catch it in the field so they don’t injure themselves. However, not all horses will tolerate masks.
  • Stabling the horse during the day and turning out at night can be beneficial for some horses. Horse Flies and midges don’t like the dark and generally won’t follow your horse into the stable. 
  • When riding, there are several items on the market that may help your horse to be more comfortable; ear coverings, partial face masks and fly fringes which all fit under or to the bridle and fly rugs designed to be worn under the saddle. 
  • Fly repellent. There are hundreds of products available and it is difficult to know what to choose. Some people prefer more natural products which often contain ingredients such as Neem and Citronella oils, while others may prefer chemical-based products containing either DEET or even Permethrin. Bear in mind that Permethrin is not licensed in the UK to use directly on a horse, it is intended for use around stables and lorries. Finding a fly repellent that works for you and your horse is usually a case of trial and error. It is worth noting that on particularly bad days, even the strongest types of repellent may need to be reapplied several times to help keep your horse happy. 
  • Other skin & coat products. When purchasing shampoos or similar, it is worth buying ones that have additional fly repellent, skin-soothing or anti-itching ingredients, depending on what you think would benefit your individual horse the most.
  • Supplements. There are also several dietary supplements available which promise or are thought to help protect the horse from flies. The most widely known and traditional one is garlic. However, scientific research is patchy at best so there is no definitive proof that any of these actually work. 
  • Practice good stable and paddock management. Stable flies love dirty stables, so keep all stables and yard areas clean. Bot flies pupate in dry horse faeces, so poo-pick daily to remove them. 
  • Modern worming medications are also highly effective against Bot fly larvae, so as long as you maintain a correctly calculated and regular worming routine, you should not need to unduly worry about occasional larvae affecting your horse, but do not become complacent about removing the eggs in the first place.

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Lowenna Roskilly
When most children were learning to ride bikes, I was already riding horses. I've owned and ridden horses for most of my life and specialise in working with young horses with behavioural challenges. I'm also a keen nature lover and enjoy nature photography.

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