The True Cost of Mastitis and the Benefits of Prevention

Introduction

Every Irish dairy farmer has had to deal with mastitis at some stage. It’s one of those problems that creeps into the yard year after year, a swollen udder, clots in the filter, a cow off her milk. Most farmers treat the case and move on, but what often goes unnoticed is the real scale of the loss. Mastitis doesn’t just mean a few days of antibiotics. It reduces yield, raises bulk tank somatic cell counts (SCC), increases culling rates, and can slash herd profits by thousands. When margins are already tight, this is a cost no farm can afford to carry.

How Widespread Is Mastitis?

Mastitis is more common than many admit. While two-thirds of Irish dairy herds keep their bulk tank SCC below 200,000 cells/ml, the remaining 35% are struggling with higher levels, and this points to ongoing udder health problems. A herd SCC above 200,000 is a clear red flag for subclinical mastitis, the type that doesn’t always show in the parlour but steadily eats into production.

Clinical mastitis cases, the ones that are obvious, are also widespread. On average, Irish herds experience between 40 and 65 cases per 100 cows each year. That means almost every second cow in a 100-cow herd could face at least one bout of mastitis over the season. Even in well-managed herds, flare-ups after calving or during damp housing periods are common. What this shows is simple: mastitis isn’t a rare headache, it’s part of the reality of dairy farming. The question is whether it’s being managed or allowed to drain profits.

The Real Cost to Farms

When you put numbers on mastitis, the impact is striking. A single clinical case costs in the region of €250–€300 once you include vet bills, treatments, milk thrown down the drain, and the reduced yield that follows. Multiply that by 20–30 cows in a year, and you’re talking €6,000–€9,000 gone before you even think about bulk tank penalties.

But the bigger cost is the one you don’t see, subclinical mastitis. This is where SCC is raised but cows don’t look sick. For a herd with an SCC between 300,000 and 400,000, the hidden loss can be as high as €18,600 in a 100-cow herd. That’s about €186 per cow, and it never shows up as a line item. It’s just litres that never make it into the tank.

When SCC tips towards 400,000, the financial hit becomes brutal. A herd that could be making over €31,000 in net profit can see that figure drop to just €12,000, all because of mastitis. That’s a loss of nearly €20,000 for no extra work, feed, or land. It’s simply money left on the table.

Why Prevention Makes Financial Sense

The positive side of the story is that mastitis prevention works, and it pays back quickly. Farmers who focus on prevention often see SCC drop, fewer clinical cases, and stronger milk cheques at the end of the month.

Take a 100-cow herd again. Spending €3,500–€4,000 a year on teat disinfectants, cubicle lime, bedding, and machine servicing might seem like another cost. But that spend protects against losses of €12,000–€15,000. In other words, for every euro invested in prevention, the farmer is getting at least three back in avoided losses. That’s a return better than almost any other investment on the farm.

Prevention also reduces stress. Every mastitis case means extra handling, record-keeping, and treatment — jobs that eat up time when labour is already stretched thin. Fewer sick cows free up hours for other jobs and reduce the risk of antibiotic residues in milk, which can trigger processor penalties and reputational damage.

What Works on Irish Farms

The building blocks of prevention are simple, but they only work when done consistently.

• Teat dipping before and after milking remains one of the cheapest and most effective steps. A few extra seconds per cow makes a big difference to infection rates.
• Milking machine servicing is often overlooked, yet vacuum levels, pulsation, and liner condition have a huge effect. A worn liner can spread mastitis across a whole row in one milking.
• Cubicle hygiene is critical during housing. Cows lying on damp or dirty beds are far more likely to pick up infections. Fresh bedding and regular liming are low-cost jobs that prevent expensive cases.
• Milk recording gives the data you need. Without it, high-SCC cows go unnoticed and continue to infect others. Identifying and managing repeat offenders is key to lowering the bulk tank SCC.
• Selective dry cow therapy (DCT) means using antibiotics only where needed, reducing costs and helping with antibiotic resistance targets. Combined with teat sealers, it sets cows up for a healthier next lactation.

These aren’t complicated or new ideas, but together they make the difference between a herd running at 150,000 SCC and one constantly battling penalties at 350,000.

The Payback in Real Numbers

Running the numbers paints the clearest picture.

• 20 clinical cases × €250 each = €5,000 lost.
• Subclinical mastitis losses = €7,000–€10,000.
• Total = €12,000–€15,000 lost annually.

Prevention costs:

• Hygiene products, bedding, liners, and servicing = €3,500–€4,000 annually.

So, by spending €4,000, a farm can avoid €15,000 in losses. That’s a three-to-one payback. On top of that, SCC reductions can bring processor bonuses, stronger cow longevity, and reduced labour.

Conclusion

Mastitis isn’t just an occasional hassle. It’s one of the biggest drains on profitability in Irish dairying, quietly stripping income from farms every year. With a third of herds still running high SCCs, the opportunity for improvement is clear.

The tools to tackle mastitis are straightforward and affordable. What matters is discipline and consistency in applying them. Every clinical case avoided, every SCC point reduced, is more milk in the tank and more money in the farmer’s pocket. At a time when margins are under pressure, mastitis prevention isn’t just about animal health, it’s about keeping Irish dairy farms profitable and sustainable for the long run.

*By Anne Hayden MSc., Founder, The Informed Farmer Consultancy.