Protecting Your Horse From Flies

It seems that the weather in the UK is currently set to ‘wet’ and all we’ve had over the past 12 months is rain. If you own horses there are lots of things to think about when the weather turns damp – mud fever, rain scald, chills – the list is endless. But when the rain abates and the temperature is up, there’s one thing that drives all horses and their owners bonkers, and that’s flies.

Many flies are simply attracted to the smell of a warm animal and its manure, and merely irritate the animal by buzzing around, but others, like midges, black flies and mosquitoes can bite horses and cause itchiness and discomfort and if the animal has a reaction to the bites it can mean treatment and large vets bills.

Many owners’ first port of call during fly season (usually the summer months) is fly spray and after that there are a number of special fly rugs, fringes and masks, all of which claim to protect your beloved equine from flying nibblers.

Which flies affect horses?

Most of the flies that affect horses in the UK belong to the Culicoides family of biting insects, including the biting midge and sand fly, as well as a type of black fly that is a member of the Simulium Equinum family. The midges and sand flies tend to feed on the body area, while the black flies prefer the ear area.

Culicoides are sight hunters, which may explain why grey horses seem to get bitten more often than darker animals – they are easier to see. The midges bite after mating as the females need a meal of blood to help their eggs mature and even though these midge attacks occur primarily in the summer and early autumn, global warming means the UK is warm and damp through the whole year and horses can therefore be affected at any time.

Sweet Itch

Sweet Itch is a nasty skin condition which occurs when an animal develops an acute allergic reaction to insect saliva. As yet there is no known cure which essentially means that affected equines are under a ‘life sentence’ to suffer every time the temperature rises.

When the horse’s immune system launches an attack on invading insect saliva, which usually contains harmless proteins, it can sometimes go into ‘overdrive’ and attack its own skin cells as well. The resulting cell damage is what we know as Sweet Itch.

Symptoms include intense itching, hair loss, flaky, thickened skin and weeping, crusty sores which could develop secondary infection. The mane and top of the tail near the croup are the most commonly affected areas, while the withers, neck, belly, ears, forehead and sheath can also be affected.

Because it is in so much discomfort, an animal suffering with Sweet Itch may display a number of behaviours to try and mitigate the irritation, including swishing the tail, frequent rolling and scratching, as well as searching out field companions for lots of mutual grooming. Where there are no field mates or fences on which to scratch, a horse may scratch out its mane using its hind feet and bite excessively at affected areas. They may also drag themselves around in order to scratch hard-to-reach areas. Sweet Itch is considered by vets to be a reportable condition, which means if you want to sell a horse that is known to suffer with Sweet Itch, you must inform any potential new owner.

Keeping the flies at bay

As previously mentioned, there are a number of lotions, potions, masks, rugs and fringes that can be used to help alleviate the suffering of horses when they’re affected by flies, but perhaps prevention is the best place to start.

Avoid turnout during fly feeding times and make sure horses are stabled in the early morning and at dusk, when flying insects are most active. If the horses are stabled, make sure the stable environment is as clean as possible. Remove droppings and soiled bedding as soon as possible and similarly in the field, poo pick regularly and remove muck heaps and any rotting vegetation. Standing water is also a magnet for insects so try and keep your horses away from any large puddles or areas of stagnant water. Avoid turnout in boggy fields as midges and other biters love damp, warm conditions.

If you have a horse that is already affected by flies, whether it has Sweet Itch or not, an in-feed repellent such as garlic or apple cider vinegar can help and although there is little scientific evidence to support their efficacy, many owners report that they work.

There are lots of fly rugs and masks on the market and these can be effective in preventing bites. Rugs specifically designed for Sweet Itch will stop even the tiniest insect biting your horse as some other fly sheets will only deter larger flies. Your horse and his rugs must be kept as clean as possible to prevent the odours of dirt and sweat attracting flies and it may be worth having two rugs – one to use while the other is being cleaned.

Your horse should be hosed or sponged after a long ride or schooling if he is sweaty and he can be bathed using an insecticidal shampoo, although this should not be done too often as it will strip his coat of natural oils and dry out his skin.

Chemicals – to use or not to use

Many owners are not keen on using harsh chemicals on their horse’s skin and there are a number of natural products that are used by many riders who prefer a homeopathic approach. Choosing commercial fly sprays can be costly and again, many owners turn to essential oils and make up their own sprays. Oils that are regularly used include lavender, citronella, eucalyptus, tea tree, neem and lemongrass and these can be combined and added to water or even cold tea, which many people swear by. Paraffin in water is also said to be effective, although this is flammable so care must be taken.

For those who would prefer a chemical approach, products containing permethrin or DEET are useful. DEET (diethyl-meta-toluamide) products should never be used in a concentration of more than 20 per cent as the insecticide is toxic and can be absorbed through the skin or by other animals during mutual grooming. This means that many DEET products are only available in low concentrations which reduce its efficacy.

Saltidin / Picartin is a relatively new alternative to DEET and is non-toxic. It is available in products for humans in the UK but is yet to be licensed for use on horses here, although it is registered for equine use elsewhere. Benzyl Benzoate is also sometimes used as an insect repellent in horses, but it can sting in strong concentrations and some animals respond negatively to it.

Permethrin is also used as an insecticide and is not known to harm most mammals or birds as it is not readily absorbed by the skin, however permethrin is highly toxic to cats and fish so care must be taken when using it and disposing of packaging. Permethrin is a strong chemical which kills insects indiscriminately, but which can be used to control ticks and mosquitos as well as other biting insects. It can also be used on rugs and other items such as saddle cloths to increase protection.