Prevention is always better than cure when it comes to combating summer mastitis in dairy cows as fly populations reach their peak.

According to NADIS, losing a quarter to summer mastitis can reduce a cow’s future milk production by 10% and the infection may cause up to 100kg liveweight loss.

Cases tend to surge in July and August, as warmer temperatures encourage fly activity, and wet weather makes the problem worse.

With the an unsettled summer and above average temperatures, Michael Oakes, NFU dairy board chairman and Disease? Not On My Farm! ambassador recommends carefully considering fly exposure to avoid costly illness in herds.

“Flies like mild, damp and sheltered spots, so we’re more likely to find transmitted infections in dry cows or heifers next to a wood or brook,” says Mr Oakes.

“From personal experience, summer mastitis can quickly become very toxic – ruining a good cow.".

The first sign of mastitis infection is usually a swollen teat with thick, clotted discharge. Large numbers of flies are often clustered around the udder, irritating the cow and causing her to kick frequently.

Within a week, visible swelling can develop into isolated behaviour, joint stiffness and reluctance to graze, rapidly impacting a cow’s body condition.

“I’ve found you often have to accept a loss in milk yield and sacrifice the infected quarter to save the cow, so it’s critical to act fast with treatment, or better still, implement preventative measures before flies strike,” he adds.

To avoid losses, Steph Small, MSD Animal Health dairy veterinary adviser, recommends farmers invest in preventative measures to reduce the chance of cows becoming sick.

“Fly control is the first line of defence against summer mastitis and is especially important if there’s no other option but to use grazing pastures next to woodland,” says Ms Small.

“A pour-on suspension such as Butox® Swish will deter biting or nuisance flies for eight to ten weeks, allowing cows to graze contently,” she advises.

“For most effective protection, apply this early in the grazing season before eggs and larvae start to develop to prevent the fly population spiraling out of control.

“Any investments in disease prevention will far outweigh the costs of mastitis treatment and subsequent production losses.”

Ms Small concludes that diligent monitoring is crucial to spot early signs of infection.

“Checking cows regularly for swollen teats, and monitoring fly numbers surrounding the udder will help ensure prompt effective treatment.

“If you suspect a case of summer mastitis, contact your vet immediately for treatment advice.”