CellCheck – the story so far

At the end of 2019, Animal Health Ireland (AHI) celebrated its 10th anniversary.

It was an opportunity to reflect on the progress that has been made over that time, in animal health in Irish cattle herds, both dairy and beef. AHI was established in 2009, as a not-for-profit organisation, tasked with providing the knowledge, education and coordination required to establish effective control programmes for non-regulated diseases of livestock. Its mission is to improve the sustainability, profitability and competitiveness of Irish farming and the agri-food sector though superior animal health. AHI has been, and continues to be, co-funded by industry and government which is a positive reflection of the value placed by the industry on AHI. Over the last decade several national programmes and project areas have developed, and indeed in the last 12 months AHI’s remit had broadened to include the pig sector.

One such programme is CellCheck, which is the national mastitis control programme, which launched in 2010. Development of CellCheck was guided by learnings and resources from Irish research and international mastitis control programmes, particularly Countdown Downunder from Australia (Brightling et al., 2009). CellCheck was established in response to industry concern that bulk tank somatic cell counts (SCC) had been slowly rising since the late 90’s (Berry et al., 2006).

It was also recognised that there was little or no coordinated approach to mastitis control at that time, often with inconsistent advice being given to farmers from various sources. In addition, while the impending abolition of quotas, which then came about in 2015, was recognised as an opportunity for Ireland, it was also accepted that it would present challenges for the industry. Ensuring optimal udder health and milk quality was one way that suppliers and processors could maximise profitability, remaining sustainable and competitive in challenging markets and times.

As with the other national programmes co-ordinated and led by AHI, CellCheck is supported by a Technical Working Group (TWG) and an Implementation Group (IG). The TWG is comprised of experts and experienced practitioners from a variety of fields who are tasked with drawing up factual resources, the development of decision-making tools, and the identification of areas for further research and development. By giving of their time free of charge, these experts enable AHI to access the technical resources required to develop its various programmes at a fraction of the true commercial cost of such expertise. The CellCheck Implementation Group plays a key role in the strategic direction and delivery of the CellCheck programme, as well as exploring and addressing the key industry challenges. The IG is composed of representatives from all industry stakeholder bodies. These individuals not only have an intimate working knowledge of their sectors, but also have a clear and strong mandate to articulate positions on behalf of their parent organisations and to engage robustly with the issues under consideration. In conjunction with the TWG, the IG is responsible for the development, implementation and monitoring of the programme.

Significant progress has been made in the udder health of the national herd, since the establishment of CellCheck. One of the most important activities within the CellCheck programme has been to establish a national SCC database. Since 2014, the Department of Agriculture, Food and Marine (DAFM) has been collecting bulk tank SCC data directly from the milk processors and co-ops. Currently, there are 16 milk purchasers submitting data to this central dataset, which accounts for over 95% of the national milk pool. This dataset has been invaluable in agreeing common industry targets and demonstrating progress in udder health nationally.

There has been a reduction in the national bulk tank somatic cell count (SCC) from 272,000 cells/mL in 2009, to 183,000 cells/mL in 2018 (Fig 1.).

Fig. 1 National annual average bulk tank SCC

In 2013, 39% of herds had an annual average SCC of 200,000 cells/ml or less, while in 2018, this had increased to 62%. Similar improvements were seen in the national milk pool, with the quantity of milk with an SCC<200,000 cells/mL increasing from 46% in 2013 to 65% in 2018 (Fig.2).

Fig. 2 Proportion of herds and milk volume with an SCC of 200,000 cells/mL or less (2013-2018)

Needless to say, standards of udder health are not something that we can become complacent about however, as we can see with the slight rise in bulk tank SCC and the decline in herds and milk volume with an SCC of 200,000 cells/mL or less, between 2017 and 2018. This was undoubtedly influenced by the extreme and unprecedented weather challenges that were encountered in Ireland in 2018. Preliminary analysis of the 2019 data indicates that this ‘hiccup’ has resolved, and udder health performance has returned to 2017 levels.

2019 was the 6th year of the CellCheck “Milking for Quality” awards. These awards are given to the 500 farmers with the best SCC results each year, based on the national SCC dataset. It is an opportunity to acknowledge and celebrate the excellent udder health performance on so many Irish dairy farms, with an annual national event attended by nearly 700 people! The SCC range of the 500 winners has narrowed year after year since the awards first started. In 2014, 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. The awards are based on the bulk tank SCC data from the previous year, and so it was interesting and inspiring to see that despite the adverse conditions of 2018, the SCC results showed that udder health can still be maintained, through best practice (Fig 3).

This national 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 (More et al., 2017). In the last decade there has been a 34% reduction in the number of mastitis treatments used (per 100 cows) during lactation (Fig 4).

Fig. 4 Intramammary antibiotic used during lactation, 2003-2018

So what does of all this progress mean for Irish farmers? Well the tangible benefit of better mastitis control is more profit. 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 (Geary et al., 2013). 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 looked at the SCC profile of the national milk pool in 2017 and compared it to 2013, the improvement has been worth an extra 0.6c/L milk to the farmer. No longer just ‘potential gains to be made’, but tangible returns being captured.

This progress has been achieved, not through new science, but by the industry working collectively and using science to inform their strategy and recommendations, and to develop the necessary resources. The “CellCheck Farm Guidelines for Mastitis Control” remain a fundamental part of the CellCheck programme, providing independent, evidence-based information, and providing clear, consistent messages. They are a practical management and advisory tool for farmers and service providers alike. To date, over 10,000 copies have been sold. Regular communications are also important, such as dissemination of the CellCheck Monthly Tip to farmers and service providers through multiple industry communication channels and newsletters, as well as the CellCheck website and monthly newsletter.

Development and delivery of training has played a key role in the CellCheck programme to date. Small group, face-to-face, peer learning has been identified as an effective way of transferring knowledge and skills. CellCheck Farmer Workshops enable and facilitate trained local service providers to engage with their farmers in the area of udder health, using prepared materials and tools. More than 250 workshops have been held to date for over 3,500 participating farmers. The objective of this workshop is to deliver best science & practice information around mastitis control to farmers, and to encourage the uptake of key best practices in everyday milking routines (Fig 5.). Multidisciplinary training, “SP2 Workshop Training”, was provided to service providers – vets, farm advisers, dairy co-op milk quality advisers and milking machine technicians – to deliver CellCheck Farmer Workshops, as part of a 4-person delivery team. To date, almost 500 service providers have been trained.

Fig. 5 CellCheck Farmer Workshop

To support capacity building and to monitor on-farm udder health performance, the CellCheck Farm Summary Report was developed by TWG members and ICBF. This report provides a clear overview of how a herd is performing in the area of mastitis control and udder health. It shows if a herd is on, above, or below target. It highlights the areas of excellence and directs farmers towards areas that may require further attention. The next stage of development is underway, which is of an interactive dashboard called the “Mastitis Investigation Tool”. This tool will allow the user to interrogate the milk recording and farm records to assist farm-specific mastitis problem solving and resolution.

A more prudent use of antibiotic is vital if we are going to work collectively to tackle the growing global challenge of antimicrobial resistance. One CellCheck activity in this area has been the establishment and promotion of a ‘CellCheck partner lab’ list. ‘CellCheck Partner Labs’ are those commercial laboratories that are successfully participating in a Proficiency Test scheme for mastitis bacterial identification, developed and delivered by DAFM. Hence, they are recognised as delivering mastitic milk sample services to an agreed standard and undergoing continual evaluation in this area. Participating laboratories also contribute results from commercial samples received into a central, anonymized database, which means that there is a more comprehensive understanding of the pathogens causing mastitis in Irish herds. The next focus of this work is to standardise the antimicrobial susceptibility testing done on mastitis pathogens and to collate the results to identify resistance patterns nationally.

As with many other countries, there is a growing focus on adopting selective drying off strategies instead of using blanket dry cow therapy. 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 Ireland. In 2019, only 43% of Irish dairy herds participated in whole herd milk recording. In order to improve the uptake of milk recording in Ireland, a CellCheck IG subgroup has worked on a strategic plan for the industry. One of the priority areas identified included challenging the ‘value perception’ around milk recording. To this end, a piece of quantitative research has recently been completed, which aims to identify and quantify the economic benefits at farm level from participating in milk recording, using Irish farm data. Another priority was to understand the obstacles to milk recording, which has commenced with an attitudinal survey of farmers delivered by a social science team.

Despite the limitation of milk recording, there is already evidence of a move away from blanket dry cow therapy in Ireland, again made possible by the continued improvement in udder health in recent years. Sales data show a 20% reduction in dry cow antibiotic treatments (per 100 cows) in the last 3 years (Fig 6).

Fig. 6 Intramammary antibiotic used at drying off, 2003-2018

However, it is recognised that change is not without risk. Farmers are encouraged to engage with their vets in advance of adopting a selective drying off strategy, in order to achieve the best possible outcomes and mitigate against the risk. Now in its second year, they can do this through a CellCheck Dry Cow Consult, which is part of the Targeted Advisory Service on Animal Health (TASAH) funded through the Rural Development Plan 2014-2020.  The purpose of the TASAH Dry Cow Consult is to enable farmers to engage with their vet to develop farm-specific selective dry cow strategies, where appropriate. Milk recording results and farm records are reviewed, as well as current practices when drying off cows, to help develop and plan these strategies. To be eligible to deliver a Dry Cow Consult, a veterinary practitioner must have completed CellCheck TASAH training, which has a particular focus on responsible antibiotic use at drying off, maximising udder health during drying off and the dry period and developing appropriate selective drying off strategies. This focus on drying off strategies and maximising udder health during drying off and the dry period was also supported by a series of 27 on-farm events around the country in Autumn 2018 and 2019. These on-farm events were organised and delivered in partnership with AHI stakeholders, ensuring that milk suppliers receive clear, consistent and united messages around best practice at drying off and responsible antibiotic use (Fig 7).

Speaker Frank O’Sullivan, AHI is pictured addressing a group at a Teagasc/Animal Health Ireland (AHI) CellCheck on farm event supported by Tipperary Co-op on the farm of Peter Hughes & Paul Maguire, Carron, near Tipperary Town. Photo O’Gorman Photography.

Ireland has an industry-agreed target, that by 2020, 75% of milk sold will have an SCC of 200,000 cells/mL or less. While much progress has been made towards this target, it continues to be challenging. As an industry we 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. However, udder health in Ireland is one of our positive animal health stories in recent years, informed by science and achieved through collaboration and collective action.

Text and pictures: Finola McCoy


Berry, D. P., O’Brien, B., O’Callaghan, E. J., Sullivan, K. O., & Meaney, W. J. (2006). Temporal trends in bulk tank somatic cell count and total bacterial count in Irish dairy herds during the past decade. Journal of Dairy Science,89 (10), 4083-4093.

Brightling, P. B., Dyson, R. D., Hope, A. F., & Penry, J. (2009). A national programme for mastitis control in Australia: Countdown Downunder. Irish Veterinary Journal62 (Suppl 4), S52.

Geary, U., Lopez-Villalobos, N., O'Brien, B., Garrick, D. J., & Shalloo, L. (2013). Examining the impact of mastitis on the profitability of the Irish dairy industry. Irish Journal of Agricultural and Food Research, 135-149.

More, S.J., Clegg, T.A., McCoy, F., 2017. The use of national-level data to describe trends in intramammary antimicrobial usage on Irish dairy farms from 2003 to 2015. Journal Dairy Science 100, 6400–6413. doi:10.3168/jds.2016-12068