How can I protect my dogs from horsefly bites?

Q: I usually take my two Labradors with me when I tend to my horses and have noticed that there seem to be a lot of horseflies around this year, which can give 
a nasty bite. I generally spray myself with insect repellent to keep them away from me, but what can I do 
to protect my dogs, assuming there is a risk of them being bitten too? (Read do stinging nettles hurt dogs?)

A: Dogs that spend a lot of time outdoors, especially in a farm environment, are certainly at risk 
of being bitten by flies. A single fly 
bite may not do much damage, 
but multiple bites can lead to skin irritation that can sometimes 
become quite serious.

Flies can’t usually bite a dog’s 
body because a thick layer of hair 
or fur protects them, but there are certain less well-protected areas that are more vulnerable, such as over his ears and around his legs, nose and muzzle. A bite or two in these areas 
is likely to cause no more than minor pain and irritation.

The more a dog 
is bitten, however, the more he will 
rub or scratch himself and each time a fly bites it punctures the skin and creates small ulcers that ooze blood. 
In severe cases, these small wounds can become infected and, in turn, more likely to attract flies.

Protect bitten areas with a thin layer of Vaseline

Dogs and horsefly bites

If you see horseflies congregating around your dogs or you notice small blood spots on their ears and nose, 
you can assume that they are being bitten.

Protect them by using fly repellent, which is available at 
your local pet store. Alternatively, products intended for flea and tick control may also protect dogs 
against flies.

If a dog sustains multiple fly 
bites, protect the area by applying a thin layer of petroleum jelly or Vaseline; remember to reapply 
it if your dog goes swimming or 
the area otherwise becomes wet.

Clean any open wounds or sores 
daily with mild soap and water and apply an antibiotic ointment to 
prevent infection.

Keep the dog indoors as much as you can until 
the wounds heal completely.

Close-up of a horsefly

Q: I am sure my dog must have been bitten the other day. We were out walking on the heath when he suddenly spun round, sat down and started nibbling his hind leg. Even after we got home, he was still whimpering and rubbing his side. I couldn’t feel any swelling, but it was clearly sore. He flinched and occasionally yelped, and rubbed himself on the carpet over the next couple of hours. Could he have been bitten by a horse fly? And if it happens again, what should I do?

A: You are probably correct. There are various species of biting flies, including the common horse fly. Few seem to cause anything more than discomfort, though with some bites the effect can last up to a day. On heathland, you can expect to find people exercising their horses, and there are increasing numbers of deer around. These will attract numbers of horse flies, which closely resemble the house fly, but unlike the latter can in inflict substantial injuries. In woodland, you often come across large colonies of wood ants, which are much larger than the common, domestic variety. They will bite if disturbed. If it happens again, soothe the pain until the effect of the bite wears off . Try rubbing a little arnica into the skin at the site of the injury, or use skin creams obtainable from chemists that contain a local anaesthetic.