Clinical mastitis affects nearly twice as many cows as previously thought, but following an effective control strategy to reduce cases could be worth 0.3-0.5p/litre.

University of Bristol researcher Andrew Bradley told British Mastitis Conference delegates that the average incidence in a survey of 100 UK farms was 69.5 clinical cases for every 100 cows.

That’s 74% more than previous studies had suggested.

“It has been generally accepted that clinical mastitis affects 40 cows in every 100.

This study indicates a much higher incidence, with herd size having no bearing on levels.”

But a farm specific intervention plan can reduce the incidence of clinical cases dramatically, said Dr Bradley.

“The starting point for any plan must be to identify the causes of mastitis and apply control measures appropriate to those causes.

“On farms in the study, contagious mastitis was responsible for less than 10% of cases, making control of environmental pathogens key to reducing cases.”

As a follow up to the mastitis incidence study, Dr Bradley and colleagues tested out the benefits of various intervention measures.

Intervention measures designed by Dr Bradley and his colleagues were implemented on 26 farms, with a control group of 26 left to implement their own standard intervention measures.

“Intervention plans we recommended included pre-milking management, milking machine maintenance, calving cow management, biosecurity and treatment strategies.

Different measures were implemented on different farms according to their mastitis problems and current management strategies.”

Overall, on farms which had intervention measures recommended by the study team, incidence of clinical mastitis reduced by an average of 19%.

But on farms where they complied with 66% or more of the recommendations the average reduction in cases was more than 30%.

However, where compliance was less than 33%, cases reduced by only 5%.

Potentially, achieving the average 19% reduction on all UK farms could save producers a total of 40m, calculated Dr Bradley.

jonathan.long@rbi.co.uk