Allow me, if you will, to engage in a little thought experiment. It's late 2027, and a mid-term review is due on the nitrates derogation.

The good news is that Ireland successfully negotiated a renewal of the 220kg/ha derogation back in 2025. But now, less than two years later, Ireland's farmers are worried. And the Department of Agriculture is worried, as is the minister.

There's a fly in the ointment.

TB figures, which began to rise so alarmingly in 2023, have started to taper off this year. At least, the rate of increase has slowed down significantly.

That increase saw reactor numbers rise from 22,393 in 2022 to 28,901 in 2023, then rocket to 41,630 in 2024. This is not part of my thought experiment, these are the actual figures for those three years.

As cases surged toward 60,000 reactors in 2025, the minister introduced a significant tightening of restrictions. This included a lengthening of the minimum period a herd would be placed under restriction from 120 days - four months - to twice that. Six months now had to elapse between the first clear test in a restricted herd and the second test (this is one of the raft of proposals put forward by the Department at a recent TB forum meeting).

Reactor numbers

The effect was positive for reactor numbers. The number of extra cases, which had escalated from 5,000 to 13,000 to 19,000 in the years from 2023 to 2025, was reduced to just 7,000 extra cases in 2026, with testing in 2027 indicating the year end figure would be just 5,000 extra cases.

That still meant there were a total of 72,000 cases in 2027. These were extended across 10,000 herds. The new rules meant these herds were under restriction for much longer - a single case in the second check test means over a full year under restriction.

What has this got to do with nitrates?

A herd under restriction, unable to sell animals, has the organic nitrogen during its restricted period partially set aside. And now, with 7,000 dairy herds under restriction, many of them already availing of the derogation, this provision is having a serious effect on the national inventory for organic nitrogen. Brussels is seriously unhappy, other nations are accusing Ireland of utilising a loophole to disregard its commitments under the nitrates directive.

Ireland could lose its derogation, an unintended consequence of failing to prevent the rapid escalation of TB over the previous decade.

Knock-on effects

Perhaps you think that's a ridiculous flight of fancy. Perhaps it is. But everything to cause that sequence of events is currently in place. There are fears that reactor numbers could hit 60,000 cases this year. The Department has proposed a doubling of the restricted period, and a nitrates allowance is in place for restricted herds.

Of course, there other, more obvious knock-on effects. The cost of TB control is rocketing. Last year (2024, we're back in real-time) saw the Department of Agriculture spend over €100m on TB control for the first time. That figure will mushroom massively this year - not only will there be more reactor cattle to be compensated for, but the rise in beef prices means the compensation for each animal will also rise sharply.

So by 2027, if beef and milk prices stay high, heaven only knows how much of Exchequer funds will be spent on TB control.

The emotional cost takes its toll on morale and mental wellbeing.

Certainly enough to impinge on Government spending on other areas of farming. The next agri-environment scheme will be in gestation - it could be funding compromised post 2030 (the carbon tax funding is in place until then). Or perhaps TAMS, or the suckler cow programme, will see their budget affected. A fully domestically-funded scheme like the Straw Incorporation Scheme could be for the high-jump. The law of unintended consequences will surely be at play when it comes to funding of schemes.

And the direct cost to farmers of rampant bovine TB will be every bit as severe. The income loss associated with a breakdown can only be partially covered by Government supports. The loss of years, perhaps decades of breeding is very real but hard to quantify. And the emotional cost takes its toll on morale and mental wellbeing.

My colleague Noel Bardon breaks down the steady rise, which has accelerated into an alarming increase since 2023, here.

There are many different strands to be examined as to why TB is increasing, so many that there is plenty of room for disagreement as to the primary cause of Bovine TB, and the programme of action needed to stem the tide.

And disagreement is what we have. The Department of Agriculture and farmer representatives have never been further apart on this issue than they are now.

In fact, they have rarely been further apart on any issue, certainly not one of such fundamental importance to farming in this country.

Basically, the Department believes that it is bovine-to-bovine infection that is the primary cause, which must be tackled. Dairy expansion in particular has changed the playing field, with a 50% increase in dairy cows, which live in larger herds where infection is more likely to spread as cows spend hours daily together in collecting yards and parlours.

Farmers say that wildlife to bovine infection is a significant factor, and that the wildlife controls in place are totally inadequate, for deer and badgers. There isn't even agreement on population figures for either species, the IFA estimate for badger numbers is twice that of the Government.

'Wildlife must be tackled'

"We as farmers are prepared to accept pain on our part to bring TB under control. But if pain is inflicted on us, without tackling wildlife at the same time, that pain will be for nothing, because the cattle population will be re-infected with the disease by wildlife over and over again."

So said Wicklow dairy farmer Chris Fox at an ICMSA TB meeting on Wednesday night. Like any and all Wicklow cattle farmers, dairy, suckler or drystock, deer are a constant issue.

I can testify to deer herd expansion myself. Up to about 10 years ago, deer simply did not exist in our little part of the world. Now, they are a common sight. I tend to bring the sprayer out in the evening, partly because I work off-farm, and partly because the still of the evening offers excellent spraying conditions. There is also evidence building that spraying towards dusk is better for the insect population, as they have left crops at that hour, and returned to their resting and nesting places.

Anyway, when I am out spraying, as twilight settles in, I become extremely alert to the possibility of deer. Unlike rabbits or pheasants, who will vacate the area of a noisy tractor, deer are pretty unmoved by my arrival if they are grazing (and they always seem to be grazing - farmers from Kerry to Wicklow to Donegal would testify to the amount of grass deer eat, it's a significant economic loss for them). With a boom wingspan of 24 metres, I can easily hit a deer as I amble up the field. If I did, trust me, the sprayer would come out the worst from the collision.

My point is, deer are now an everyday part of life in Tombrack. Once, they would have been a novelty, and I'd have been photographing them. They have migrated down from the Wicklow border along the Ballingale river, which enters the Slaney on the next farm down from ours. The reason they have migrated is the same reason for most migration - necessity. The ever-expanding deer population in Wicklow is seeing small herds heading in all directions in search of pastures (or cropland) new. Which brings them into everyday contact with cattle.

Invasive species

One farmer at the TB meeting on Wednesday was pretty blunt in his appraisal of the control needed of the sika deer, the dominant species in Wicklow, and indeed across the country.

"Sika deer are like grey squirrels and Japanese knotweed - an invasive species" he said. "They are threatening the native red deer, they are a primary cause of TB infection, there is no natural control for them, and they must be eradicated. Not controlled, eradicated, from this country."

That's pretty strong talk. Another farmer spoke of how, for every three newly planted trees in Wicklow, two are eaten by Sika deer early in life, requiring repeated replanting.

Farmers were also highly critical of the current population control mechanism, which is restricted to shooting under licence of stags. "You can shoot 90% of the stags and it would have no effect on the birth rate," said one. "All you are doing is ensuring a good time for the remaining stags. They are actually only shooting a small percentage, so the point holds up even more."

Badgers are a much more vexed question. They are a protected species. There was a time when the extent of the badger population wasn't of particular importance, but then again, there was a time when TB was endemic in the bovine population.

At that time, TB was also a leading killer of people in Ireland. Between 1881 and 1891, it was estimated that over 1,000,000 people died in Ireland of tuberculosis. And we don't have to go back to Victorian times for evidence of how lethal this disease was - about 10,000 people died from TB in Ireland in the 1950s. And thousands more suffered permanent lung damage from the effects of the disease.

So for a time, badger numbers were controlled by farmers on the quiet. That is not an option in 2025, nor should it be. Hope that badger vaccination would be a solution is receding, as growing evidence suggests the control breaks down, that the vaccine has only a temporary effect.

Controlling the controllables

There are things every farmer can do. Raised water troughs will reduce the prospect of badgers contaminating the water. Perimeter fences on both sides of boundaries are necessary to keep neighbouring cattle from meeting for a nose or a nibble across a hedge, drain or fence. Biosecurity is vital - and that involves normal actions like disinfection for all visitors and when returning from another farm, or a factory or mart.

Marts are an unavoidable point of contact for cattle, minimising risk is the most that can be done.

There is growing evidence that genetics offer a way forward. As I mentioned here last month, ICBF ceo Sean Coughlan told a meeting I attended that there was a huge variation in the incidence of bovine TB from different bulls. The range was from as low as 4% of progeny being infected to as high as 30%. The Department is stressing the importance of utilising this information, and in this one, they are pushing an open door with farmers.

Other solutions may be harder to agree on. Martin Heydon may find that TB is becoming the first hot potato issue of his ministry.