Seimi's small heart was smote. He was inconsolable. And then he was furious.
"That boy can plough," said a fellow farmer fiercely. "He knows more about working horses than they would ever know."
And then rebellion stirred amongst father and son. Seimi stayed by his dad's side as they walked slowly together behind their horses, Jack and Bobo, carefully carving out the land. Nobody stopped him.
"He's interested in ploughing - and this is how he's going to learn," said Eamon firmly.
At their small farm in Kilmaine, the McDonaghs have abandoned tractors for horses - 'progress' didn't turn out to be so good after all on a farm of their size.
"They're more efficient - the horses don't mess up the land like the tractors do," Eamon explained. There were just five or six farms left in Ireland where the old-style horse-drawn ploughs were maintained, he said, adding that he knew them all through the Irish Working Horse Association.
The ancient way had an admirer in President Michael D Higgins who lingered up at the fields far longer than he was probably required to, as he patted the horses and chatted with the farmers.
Both he and Sabina were sensibly clad in tweed against the distinctly autumnal chill. But the skies were blue and it was very pleasant up there, where all the 'real' work was happening, away from the crowds and the hum of machinery.
"It gives you a feeling of your own earthiness - there's something special about it," said Sabina - overheard as she chatted with one of the officials accompanying her on the rounds.
They met with JP Clarke from Sligo, resting for a moment atop his powder blue vintage tractor which has been in the family since 1952 and from which came a strangely soothing and nostalgic aroma of old petrol.
It was almost with a sense of regret that they left - but there was plenty more to see, beginning with the pony games as junior members of hunts around the country navigated the obstacle course with pluck and gusto.
Such a throng was beating its way to the Department of Arts, Heritage and the Gaeltacht that a fresh load of bark mulch had to be delivered to soak up the mud. And of course there was plenty of that - and while miraculously, the rain held off all day, wellies were still a must.
PJ Lynam, chairman of the Irish Ploughing Association, said they had everything from a spool of thread to a combine harvester.
"We have just about everything - and if you think of something else, we'll have it for you next year," he assured.
He wasn't joking. There was sushi. And even locally produced hot sauce.
PJ said the event - now in its final year in Laois, with a new destination yet to be unveiled - was worth well over €35m to the economy.
"If you only spent two minutes at every stand, it would take you seven days to go through it all," he added.
He wasn't joking about that either. Clocking up almost 15,000 steps as we trudged through the endless sea of people, it was no wonder there was mutiny amongst the ranks of some of the younger patrons.
If you listened carefully, at any one time you could hear about 25 simultaneous moans of "No, Mammy!" emanating from the crowd.
But there was serious business taking place here too - and some was definitely for the younger visitors.
Showing that sometimes the best ideas are those which you might think are the blindingly obvious, Padraic Cuddy from Roscommon was doing a brisk trade in miniature toy fields of artificial grass.
All children may have their toy farm animals, but they never have a proper backdrop for them, explained Padraic.
Being in the trade of artificial grass, he decided to knock up a basic field with hedges for his son Tommy (4) last Christmas.
When it proved to be such a big hit, Padraic knew he had a business idea in his hands.
And "The Field" became a reality just a few weeks ago when it got the crucial CE safety stamp and it is selling at the Ploughing Championships for €40.
Padraic is also in talks with Smyths Toys and he hopes to sell it in all its stores and across Europe - as well as the obvious market for Irish descendants in the US.
It even comes with toy land registry deeds for those who really want to feel part of home. "I'm absolutely delighted said Padraic, whose fields were getting a lot of interest yesterday.
Later, we moved to the outright dramatic, as Laois County Fire & Rescue Service demonstrated the perils of an old-fashioned chip pan fire. The service deals with about 20 such fires in Laois alone each year - with most, but not all, in the homes of elderly people, explained Station Manager James Brown.
There was an acrid smell of oil as it ignited, before the fire officers demonstrated the lethal 'what not to do' method - pouring water from a careful distance over the burning pot.
Instantly, a terrifying wall of flames puffed out towards the crowd which fled, shrieking in alarm.
Anne Smith from Glenbay, Co Kerry - there with children Mary Kate (8) and Roisin (10) - sheepishly admitted that the smoke alarm often goes off when she's cooking.
"But I never use a chip pan," she said.