The warm months of July and August usually bring several diseases that are associated with flies and this unusually dry summer has seen more issues than normal.

Even though flies themselves cause disease, such as flystrike or maggots in sheep, they more commonly spread the disease-causing agents from animal to animal. Summer mastitis and sore eyes or conjunctivitis are two of the most-common entities seen in cattle.

Summer mastitis can cause animals to be quite sick, stiff and have painful swollen udders.

It usually results in permanent loss of function of the affected quarter.

Heifers calving down with only three quarters are far less valuable than heifers with a fully functioning udder, they will produce less milk and are also a nuisance in the milking parlour.

Most commonly, dry cows and maiden heifers, both suckler and dairy, are affected.

Prevention is best provided by spot-on antifly products, along with Stockholm tar applied to the cow’s udder.

Care needs to be taken while applying the tar to avoid injury.

Fly tags are another option. Control is difficult, but aim to keep susceptible animals away from fly habitats during the risk period.

Fly habitats include shaded sheltered areas often near bodies of water.

Early treatment is essential to ensure best outcome. Anti-inflammatories and antibiotics can be combined to give the best results, in my opinion.

Dry cows and heifers are often checked quickly and late in the evening, so the condition can often be missed for a few days, by which time the animal can be very sick.

Conjunctivitis is a common complaint in all types of animals over the summer months and can be caused by flies.

The condition is painful and annoying to the animal and requires treatment.

Treatment may involve injectables and/or topical eye ointments. In some cases, more detailed treatment is required.

In all cases of fly-related disease, prevention is better than cure. Contact your own vet for best control and treatment options for your animals.

Donal Lynch owns and runs Donal Lynch Veterinary, Tullamore, Co Offaly. Donal Lynch Veterinary is part of XLVets. XLVets is a group of progressive practices who are working together to achieve a better future for agriculture and veterinary in Ireland. See www.xlvets.ie for more.