We have seen a noticeable increase in the incidence of strep uberis mastitis in our practice. We carry out mastitis sample culturing in-house and, in the first half of this year, we have seen at least 50% to 60% of samples testing positive for strep uberis. On certain farms, clinical mastitis cases seem to be almost exclusively caused by this bacteria.

I was recently involved in a mastitis investigation with one of our dairy farmers. He was getting issues with raised SCC and repeat clinical cases of mastitis. We took samples from 12 of the problem cows. Nine were positive for strep uberis. The cases were mainly occurring in early lactation, but there were also fresh cases in cows calved three to four months. We were also seeing cows getting recurrent mastitis in the same quarter despite previous antibiotic therapy.

Cows can become infected with strep uberis in two ways. They can pick up the bacteria from environmental sources, such as straw bedding, which we typically see in freshly calved cows. However, it may also spread at milking time via milkers’ hands or contaminated liners. Therefore, it can spread quite quickly through a herd. Another difficulty with strep uberis is that quarters that recover from infection are more prone to re-infection, so some cows get apparent persistent infections.

Management of strep uberis mastitis must include consistent hygiene at milking time, as well as focusing on the potential environmental sources.

It may be necessary to replace bedding and disinfect calving pens several times during the calving season.

Analysing the milking routine with a critical eye for weak points in hygiene will be necessary to identify factors leading to the spread of mastitis. It will also be important to identify problem cows and potentially dry off the cow or the problem quarter early.

In the case of the farmer mentioned above, we advised him to clean out and disinfect the calving pens, to dip the clusters in peracetic acid between cows and to dry off three cows which had had persistent mastitis in multiple quarters. We were able to advise on an appropriate treatment protocol. These measures led to a dramatic reduction in clinical cases and much better control of SCC levels. Speak to your vet about identifying the cause of mastitis and coming up with a mastitis control plan.

Mark Drought works at Avondale Vet Clinic, Arklow, Co Wicklow. Avondale Vet Clinic 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. For further information, go to www.xlvets.ie.