29 August 2008 15:15
My 26-year-old gelding suffered infections in his sheath last summer, caused by flies. I first noticed him having problems urinating – he would move into his normal position but would be unable to pass water. He would then walk around with his hindlegs apart and his muscles contracting as if he was about to urinate.
Veterinary investigations found flies had got inside his sheath and laid eggs, causing an infection. Treatment worked for a while but the problem returned. I have tried numerous potions and sprays, and even modified a rug with fringes, but nothing worked.
I am concerned how many times the infection will occur this year. I am considering a new Fal Pro sweet itch rug as it hangs very low around the legs. Do you have any other suggestions?
By Your Horse
Vet Malene Jørgensen replies:
Flies can be a real nuisance. I think it would be a good idea to try the Fal Pro rug as it comes down quite far on each side. It is also a light colour with a thick black band along the bottom. Research has shown that flies rarely go from light coloured areas to dark areas, so this simple design might just work.
Flies develop in all sorts of places from manure to fast running water and meadows. They can be vectors for summer sores and eye worms but, in general, the constant irritation caused by flies lapping tear fluid, wounds and other moist areas, such as the sheath, can be bad enough.
You will have to find the most effective repellent for the flies in your area. The effectiveness of repellents depends on the type of fly – you need to identify the specific species. This can be done by examining the flies on the walls of the stable or checking the horse’s droppings for eggs or larvae. Your vet might know which flies are most likely to be in your area.
Identification of sensitivity to some of the flies can be determined by a skin test, where a small amount of the antigen is injected into the horse’s skin to provoke a reaction. This can also be done by taking a blood sample for examination in a laboratory. Ask your vet for details.
The most effective fly control is likely to be a combination of:
● Stabling during the active hours of the particular fly.
● Protective rugs and masks.
● Removal of manure and feed or hay residues from the field.
● Insecticides placed in the stable (baits) or sprayed on the walls.