Failing to accurately diagnose the cause of mastitis and high cell counts could be costing UK dairy herds dear, according to leading mastitis vet Andrew Biggs.

Speaking to Farmers Weekly in advance of this week’s Dairy Event Mr Biggs revealed the preliminary results of an ongoing Intervet funded survey of the causes of clinical mastitis and high cell counts in UK cows.

“The main causes of both these problems in samples analysed were as would be expected, Strep Uberis and Staph Aureus. But there were also a number of minor pathogens present indicating teat management and milking routine aren’t quite right in some herds.”

“However, 37% showed no significant growth of any pathogens. This could be for a number of reasons, including some clinical cases which are being caused by non-viable E Coli.”

Cell counts in the herds submitting samples were higher than many would aim for, with several in the 250,000-300,000 cells/ml range.

However, these pale compared to the highest sample recorded – 517,000 cells/ml, explains Mr Biggs. “At this level it would be illegal to sell milk, as it is in excess of the 400,000 cells/ml limit operating across the EU.”

And while many farmers may consider cell counts in this range to be normal, Mr Biggs points out that with many milk buyers paying premiums for cell counts below 200,000, many farms could be missing out on 0.5p/litre a day.

“That might not sound much, but in a 200 cow herd yielding 7500 litres it means the herd is losing £25 a day, or £9125 a year.”
Looking at the causes of infection, Mr Biggs believes many Staph Aureus problems can be related back to 2001 when herds reduced their culling regimes due to foot-and-mouth.

“Culling fewer cows means the infection has spread further through the herd making it even more difficult to get on top of.”

Hot weather earlier this summer is likely to be to blame for some cases, with cows gathering together in shaded parts of fields and then lying in muck and becoming contaminated.

“And while analysis may seem an extra hassle, without taking the time to find out what is causing problems it is impossible to improve cell counts and improve milk quality,” adds Mr Biggs.