Ireland has a very positive story to tell when it comes to national udder health. CellCheck, the national mastitis control programme, was launched in 2011 in response to industry concern that bulk tank somatic cell counts had been slowly rising over the previous decade. Since then, the story has changed significantly.

The national bulk tank somatic cell count (SCC) has reduced from 272,000 cells/ml in 2009 to 183,000 cells/ml in 2018, which is a phenomenal achievement and one that the industry should be extremely proud of (Figure 1).

However, udder health requires constant effort to maintain and is not something to be complacent about. This is evidenced by the slight rise in SCC in 2018 – undoubtedly influenced by the extreme weather challenges that were encountered that year.

Through best practice, it is possible to maintain standards of udder health, even at times of adverse conditions such as during 2018. The winners of the CellCheck Milking for Quality awards are proof of this.

The SCC range of the 500 winners has narrowed year after year since the awards first started in 2014. In its first year, all winners had an SCC of 103,000 cells/ml or less, while by 2019 a winning SCC was 76,500 cells/ml or less, based on the previous year’s SCC data.

This improvement in udder health has also allowed farmers to increasingly adopt the “prevention is better than cure” approach, with a reduction in the numbers of mastitis treatments being used.

In the last decade, there has been a 34% reduction in the number of intramammary mastitis treatments used (per 100 cows) during lactation (Figure 3).

This more prudent use of antibiotic is vital if we are going to work collectively to tackle the growing challenge of antimicrobial resistance (AMR). It is well recognised that the use of antibiotics contributes to the development of antibiotic resistance.

In order to slow down the development of AMR and to protect antibiotics for human use, Europe recently introduced new veterinary medicine regulations that will be implemented in all member states from January 2022.

Expected changes

One of the expected changes, as a result of the new legislation, is that “blanket” dry cow therapy will no longer be acceptable.

In other words, antibiotics may be used at the end of lactation to treat cows where there is evidence of infection, but the use of dry cow antibiotics to prevent new infections over the dry period will not be an option.

In 2019, only 43% of Irish dairy herds participated in whole herd milk recording

Having individual cow information through milk recording is key to knowing which animals require antibiotic treatment at the end of the lactation, and this is one of the current constraints that we face in this country.

In 2019, only 43% of Irish dairy herds participated in whole herd milk recording.

Despite this limitation, there is already evidence of a move away from blanket dry cow therapy in Ireland, again made possible by the improvement in udder health in recent years.

Sales data show a 20% reduction in dry cow antibiotic treatments (per 100 cows) in the last three years (Figure 4).

However, change is not without risk.

Farmers can manage this risk with good dry cow management and hygiene – hygiene at drying off and the use of products such as internal teat sealant.

It is also essential that farmers engage with their vets in this process, which they can do through a CellCheck dry cow consult, with its Targeted Advisory Service on Animal Health funded through the Rural Development Plan 2014-2020.

So what does of all this progress mean for farmers? Well, the tangible benefit of better mastitis control is more profit.

In partnership with Teagasc, we recently completed an additional economic exercise and looked at the actual gains made from the annual reduction in bulk tank SCC

In the early days of the CellCheck programme, Teagasc completed a piece of economic research which quantified the potential gains to be made from reducing the average SCC of a dairy herd in Ireland.

In partnership with Teagasc, we recently completed an additional economic exercise and looked at the actual gains made from the annual reduction in bulk tank SCC.

When we look at the SCC profile of the national milk pool in 2017 and compare it to 2013, the improvement has been worth an extra 0.6c/l milk to the farmer. There are no longer just “potential gains to be made”, but tangible returns being captured.

Challenges

As an industry, we still need to recognise and respond to the ongoing and emerging challenges that we will inevitably face, such as increasing our engagement with milk recording and minimising the risk of antimicrobial resistance developing.

But let’s not forget that we have a good story to tell, and we should be proud of what has been achieved to date.

The longer it is left, the bigger the problem it will become as high-SCC cows could be shedding infection and passing it on to other cows

February and March can often be bad months for SCC. It’s important to get on top of it now, before it develops into a significant problem. The longer it is left, the bigger the problem it will become as high-SCC cows could be shedding infection and passing it on to other cows.

Solution

In all likelihood, there are a small number of cows contributing to the problem. Identifying these cows is the next challenge. There are three ways of doing this but all involve a fair degree of hardship.

The first is to milk-record the whole milking herd. As most herds have only between 50% and 70% calved now, it’s probably not very effective at gathering valuable data other than SCC and the effectiveness of the dry cow period for curing infections – valuable data all the same. However, it may take a week or 10 days between booking the recording, doing it and getting the results back.

This can be done in two ways – using the Californian Milk Test (CMT) and paddle, or using an electronic version that gives an SCC indication

Individually testing each cow for SCC on the farm is probably the most effective, if time-consuming, task. This can be done in two ways – using the Californian Milk Test (CMT) and paddle, or using an electronic version that gives an SCC indication.

Both methods involve testing samples from each quarter. For me, the CMT test is probably the way to go. It’s cheap, effective and you get a foolproof result instantly, but it is time-consuming and tiring to do a full herd at once, so you will need extra help.

When using the CMT test, have equal amounts of milk in each paddle cup. You can achieve this by tilting the paddle and letting the excess spill out.

The thicker the milk, the higher the SCC

Pour in the same amount of CMT solution as there is milk in each paddle cup. Swirl the paddle cup for about 10 seconds. Results should be obvious immediately. Any thickening of the milk or gelling is an indicator that the SCC in that quarter is high. The thicker the milk, the higher the SCC.

High-SCC cows should be treated. Talk to your vet about the best treatment options.

Some vets will suggest taking a sample of milk and getting it tested for the type of mastitis and a sensitivity test can be performed to identify which antibiotic will work best.

Regulator

The cause of high SCC is not always down to unhygienic housing conditions. Is the milking machine working correctly? Check that the vacuum pressure is correct. The vacuum regulator could be acting up resulting in the vacuum being out of kilter. Most milking machines require a vacuum of 48kPa.