Before identifying what the most suitable mastitis control measures are in a herd, building an accurate picture of the situation is key.
Mastitis remains one of the largest ongoing challenges affecting the national dairy herd, but as industry pressure mounts around antibiotic use on-farm, controlling the disease is vital.
Speaking at an AHDB Dairyorganised event in Lanarkshire, veterinary consultant Dr James Breen told an audience that, with four of the six targets set around antibiotic use in the dairy sector directly relating to those used around mastitis control, getting a grip on mastitis incidence with a view to creating an effective ongoing control plan was increasingly important.
He said that, crucially, mastitis control did not warrant a generic approach and was very much herd-specific, in-line with what the situation was on a particular farm.
Dr Breen said: “Avoiding the need to treat mastitis in the first place, by preventing new infections and new cases, reduces the need for antibiotic use, but to work to that point there needs to be a ground-up approach.
“It involves building an understanding of the herd mastitis pattern, with a view to directing control measures in-line with what the farm data shows.
“Often, herd data around mastitis already exists in the form of milk recording information and records from on-farm software, so if we can measure it, we can paint a picture of what is going on and monitor and tweak in areas where it becomes clear work is needed.”
He highlighted the current annual average clinical mastitis incidence rate as 38 cases per 100 cows from herds monitored as part of the AHDB Dairy sentinel herds project, but said shifting focus from the headline rate to measuring and monitoring more sensitive data, such as new cases, was important.
“Measuring new cases, particularly those in the first 30 days of lactation, relates directly to infection picked up during the dry period and is one way to give a more accurate picture of what is going on. Headline rates can be distorted by recurrences or historic issues.”
He also said focusing on environmental factors when looking to reduce incidence rates was crucial.
With a background in dairy research including what is now the AHDB mastitis control plan, Dr Breen highlighted that in less than 10 per cent of data from more than 1,000 herds, contagious spread had been found to be the predominant pattern for mastitis incidence rates.
“When looking at patterns of mastitis levels, in terms of cell counts and clinical mastitis cases, herd environment management is key in more than 90 per cent of herds.
“But in many ways, this is much harder to manage and comes down to considering the bigger picture around consistent management. This can involve factors such as ventilation, bedding management, water quality and managing different groups as well as others through the year.”
Ahead of directing efforts and putting any kind of plan in place, determining the current mastitis pattern at herd level was crucially the starting point which can be done using existing herd data from on-farm software, milk recording data or other records.
Dr Breen highlighted a free tool, the AHDB mastitis pattern analysis tool, available via its website, which farmers and vets can access to convert mastitis and cell count data into a format which can produce a report on the pattern of mastitis infection on that unit.
Although tempting to start with sampling a few clinical cases, he said it was important these were done properly in an overall plan to yield their full benefit.
Building up a sample size of 10, by freezing samples if necessary, and sending for testing twice per year, was suggested as a starting point, as well as focusing sampling on a cross-section of clinical mastitis cases, to build up a picture of what was happening in the herd as whole.
“The challenge with bacteriology is that on its own it does not describe a pattern and tell you when the infections occurred.
“It will rarely produce a set of results which point to an obvious problem or variations which may have occurred over time, which arguably does not help pinpoint a starting point to control.”