It's an annual, all-day event held in a local hotel, which at one time was restricted to shepherds.
My friend was telling me how times have changed. And, with so few shepherds left, other rural workers like cattlemen and fencers are now allowed to attend.
Large numbers of sheep have been cleared from Scotland's hills to make way for trees, deer and grouse. The decline in the national flock has also been aided by the lack of profitability in recent years and the various financial incentives of environmental schemes aimed at reducing grazing pressure on our hills and moors.
Then there are modern systems of sheep husbandry and the advent of the ATV, those little four-wheel motor vehicles that allow shepherds to cover more ground in a fraction of the time it takes them on foot.
Nowadays, a shepherd is expected to look after at least 1000 ewes, although his father's generation might well have tended less than half that number.
Put simply, there are a lot less ewes on the Scottish hills, and the flocks that remain are being tended by disproportionately less shepherds.
The Sanquhar herds' fair was originally a hiring fair held on Candlemass (February 2). On that day, the street was filled with strapping, stalwart men clad in home-made clothes, the black and white plaid being universally worn. It was either folded carefully and thrown over the shoulder, or worn round the body so as to cover it completely down to the knees, just as it suited the wearer, or as the state of the weather demanded.
Each shepherd carried a stylish, homemade crook and at his heels was his inseparable companion, the faithful collie.
After they had made their bargain with the farmers for another term of employment, they held a great celebration in the town.
Over the years the fair evolved and the herds also used their annual get-together to sort out stray sheep. Those strays without marks and brands, whose ownership could not be proved, were sold and the money given to the local poor folk. Times move on, and today's fairs are simply social gatherings that revolve round a carpet bowling match.
Before the advent of the motor car, shepherds didn't get out so often, because they tended to live in remote and isolated places. So when they did come down from the hills, they knew how to make the most of it and enjoy themselves.
For some, it was the first time they had met their herding pals since the cast ram sales in early January, or even the autumn sales, so the crack at the bar was always animated.
It seems that this year's match was won by a pair of non-shepherds – a cattleman and a fencer. As my friend said: "Only half of the 45 present were full-time or retired herds when at one time there would have been close on a hundred full-time herds present."
Sanquhar has an old Council House or Tolbooth that was built in 1735 and protrudes into the High Street, reducing the flow of traffic to a single lane.
One absurd story from the 1930s involved four "weel-kent, but fu" local herds who decided to move that ancient edifice back a bit so that it wouldn't obstruct the road.
Taking off their jackets and rolling up their sleeves, each herd took a corner of the building and, on the count of three, managed to lift the Tolbooth and place it on the chosen spot. That was when they realised they had set it down on top of their jackets and had to go to the bother of lifting it again and setting it down on its original site in order to recover their clothes.
Of course, that is not the only far-fetched tale to emanate from the Sanquhar herds' fair – just one of the more memorable ones.
Now that they have recovered from their big day-and-night out, those few shepherds who were at it will have to knuckle down to some hard work in the run up to the lambing. Pregnant ewes need to be vaccinated, dosed and dipped for ticks, while leaner ones will need to be drawn off for special attention.
Then, of course, there will be all those long, hard hours doing the actual lambing itself.
Still, as they go about their spring work they can always think back to the fun and capers at the herds' fair.