By Dr Basil Lowman, senior beef consultant SAC Consulting

Warm summer weather coupled with an abundance of rain has not only led to exceptional grass growth in virtually all areas but also an increased number of flies and summer mastitis.

According to Dr Basil Lowman, senior beef consultant at SAC Consulting – part of SRUC – there have been increased reports of the disease when summer mastitis can be carried by flies.

“Although everyone is flat out trying to bring in the harvest, it is essential stockpeople pay careful attention when checking cows," said Dr Lowman.

“Animals away from the main group, hungry calves, and swollen teats and udders, are obvious signs of a problem which needs immediate investigation, as the earlier the problem is identified, the greater the chance of saving the area.”

He said the animals most at risk are dry cows, but with levels of infection so high this year, cases are occurring in heifers and even the occasional stock bull and steers.

He added that while cows with calves are not considered to be at risk of summer mastitis, they can become susceptible within two to three months of calving, when they dry themselves off by preventing the calf suckling.

“The most important thing to do is to graze susceptible animals in exposed fields away from trees and open water where flies breed,” he said.

In addition, he said preventing flies from settling on cattle, and particularly around the orifice at the end of the teat, can be achieved by:

• Teat sealants: these are squeezed into the teat canal – similar to tubes of antibiotics, but longer-lasting and cheaper. It is essential the end of the teat is carefully cleaned and disinfected before the tube is inserted. They are supplied by vets who will explain how to use them

• Stockholm tar: an old-fashioned remedy with the tar forming a physical barrier over the end of the teat. However, it is difficult to apply and to be effective, needs replacing weekly. An alternative is to use polyurethane varnish as a teat dip

• Spray: use one of a number of products on the market aimed at deterring or killing flies

• Insecticide ear tags: for best effect, they need to be applied in early spring to kill as many flies as possible while numbers are relatively low

• Garlic: naturally occurring sulphur compounds in the ingredient seep out through pores and sweat glands, acting as a repellent to flies and other biting insects

Once a case of summer mastitis occurs, the level of infection carried by flies increases dramatically as they land on an infected area and then fly off to a neighbouring cow.

“The best way to avoid this is to bring all infected cows indoors, which will be necessary in any case if they are to be treated,” said Dr Lowman.