Targeting a low somatic cell count post calving

Working with independent vet, James Breen (who divides his time between consultancy work with Map of Ag and teaching and research at the University of Nottingham), and following the principles of AHDB’s QuarterPRO programme, Adrian has seen some remarkable results.

“We had a bit of a hike in our somatic cell count (SCC) in 2019 after calving,” says Adrian. “In 2020 it was even worse, which is why we wanted to solve the problem for 2021.”

Gathering and understanding your data

For James Breen, it is important to start by examining the drivers of an increased bulk cell count. While bulk cell counts tell us about the proportion of the herd that are likely to be infected, they will be made up of uninfected cows, infected cows and chronically infected cows. Individual cow milk recording is therefore vital to understanding cell count infections in your herd and putting in place appropriate preventative measures

“We need to be looking at this data, even if cell count isn’t an issue,” says James. “We can still monitor trends in new high cell count infections and therefore have an early warning system in place. It is only by milk recording that we can take a step back and look at what is driving new infection rates and begin to think about preventing more new infections.”

James identifies key points when reviewing your data.

1. Are more than 10% of cows being reported with >200,000 cells/ml at the first test day after calving?
2. Are more than 1 in 12 cows being detected with clinical mastitis within 30 days after calving?

These are key markers for dry period infection patterns – the predominant infection pattern in a herd can be identified using the mastitis pattern analysis tool as part of AHDB’s QuarterPRO scheme. This will help us understand if a cow was already infected, what the infection pattern looks like and whether any changes in management have been successful.

Identifying solutions

In November 2020, James encouraged Adrian to begin milk recording again. Adrian imported this data into his own farm software and began to track the results of individual cows.

Reviewing the data available, James concluded that the dry cow period was likely to prove important to Adrian’s management plan. “If we have got cows that are above 200,000 cells/ml in their first milk recording post-calving, as we did at Ninezergh, the research evidence is that these are likely to be infections that the cow already had when she calved,” says James. “This immediately points us towards the dry period.”

Adrian said: “For the last five years we have used blanket treatments of antibiotics across the herd. We’d used sealants about eight years ago but had stopped. Back then, it was the tight milk price and you cut everything you could. We probably got away with it a bit.”

Traditionally, the dry cows at Ninezergh were rotationally grazed until three weeks before calving. Adrian and his team would then bring them in to a bare paddock where they would calve. However, as Adrian was improving his fertility management, his calving block was also getting tighter. And as a result, the numbers in the paddock at any one time was also increasing.

Working with Adrian’s own vet, Andrew Crutchley, Yan Farm Health, James and Adrian created a longer-term management plan. This was focussed on dry period management and aimed to reduce the risk of new infections.

James identified five key areas. “The research evidence around the effectiveness of internal sealants is very strong,” says James. “So the first thing I asked Adrian to do was to use these in all cows that were drying off. We also spoke about how important the hygienic infusion technique is and reviewed exactly what steps are required when drying-off.”

After treatment, Adrian and James looked at the importance of environmental factors to support the control programme. This included: ensuring that groups of dry cows spent no more than two weeks in any one area, bedding management for close to calving cows, and stocking density in the calving paddock.

For James, the combination of dry cow therapy and environmental management is vital. “It's no good us just focusing on using dry cow therapy hygienically, using internal teat sealants and then not thinking about where they're going to spend the next seven or eight weeks. We need to be clear about how susceptible these cows are.”

A preventative plan

Working with Andrew, a plan was implemented at Ninezergh. “Because we were a high cell count herd, Andrew set the threshold for antibiotic treatment quite low,” says Adrian. “45% of the herd were given the sealant only, while the remaining 65% also had antibiotics. The heifers were targeted slightly lower, so any heifer with a cell count above 120,000 in any of their last three recordings received antibiotics. For the cows, we set this number at 150,000.” It is expected that there will be more cows below this threshold and less need for treatment in subsequent years.

When it came to addressing the environmental factors, Adrian had to get creative. With limited options on farm, he repurposed a pre-existing building. “We built temporary cubicles within the existing pens and put rubber mats down on the slats to bring the cows in prior to calving,” says Adrian. “Each pen housed eight cows. At the end of the building was a straw pen, and the building itself was next to the calving paddock. We fed dry cow rolls rather than TMR and used the time we would previously have spent making the TMR in bedding the cows daily and maintaining the cubicles.

“Up until October, any cow we thought likely to calve in the next 24 to 48 hours would be removed from the pen and put in the calving paddock. We were able to really focus on the pens with those cows very close to calving, reducing the numbers in the calving paddock at any time. It all worked really well!” After October, any cows left to calve did so in the straw pen.

Positive results

Reviewing the data from Ninezergh tells an important story. “Comparing herd average data from October and November 2021 to the same period in 2020, the SCC is now much lower,” says James. “Looking at the data from November 2021, the dry cow period new infection rate is now zero – in other words none of the cows that were dried off below 200,000 cells/ml calved back in with a cell count above 200,000 cells/ml.”

Those cows entering the drying off period with an SCC above 200,000 cells/ml show a similar pattern. “87% of the cows that Adrian dried off above 200,000 come back in below 200,000 at first test,” says James.

For James, prevention is key. “We must prevent new infections. But that, in itself, is not simple. Where do the new infections come from? We do tend to assume that new infections come from other infected cows. For some herds, contagious infection patterns are important. But for a lot of herds, it's environmental infection.”

James is also quick to recognise that control plans must be targeted; one size does not fit all. “Each farm will have a different pathogen profile, different breeds, different milk yields and different environmental management plans. Mastitis control is about looking at your herd’s data at this particular time and designing a small set of control measures that are going to have the biggest impact.”

Adrian admits that he was sceptical of some of James’ suggestions initially. But the results speak for themselves. “We've never, in the history of me milking cows, had bulk cell counts in two figures. In November we had two of the four bulk counts in two figures. We had a 67 and 85. That's the result of following the advice we were given.”