United Auctions will have 230 pedigree Aberdeen Angus bulls up for auction at Stirling tomorrow, followed by 180 pedigree Limousin bulls on Wednesday.

A fortnight later it will be the turn of pedigree Simmental and Charolais bulls to go under the hammer.

The firm holds two important sales of pedigree bulls every year – one in October and the other in February. Last autumn's sale saw a pedigree Charolais bull break the breed's world record price with a hefty bid of 100,000gns, or £105,000. Earlier in the year, auctioneers Harrison and Hetherington broke another breed world record, that time for the Limousins, when they sold a bull for 120,000gns, or £132,000 in Carlisle last February.

Mind you, if you think those are big prices, spare a thought for the Texel ram lamb that made £231,000 at a sale in Lanark last August. Then there were the twin Blackface ram lambs that went for a total of £150,000 later on last year at an auction in Dalmally – one for £90,000 and the other for £60,000.

Big prices like those, that could buy houses or flats, are only paid for top animals and bear little resemblance to the comparatively modest prices most commercial pedigree animals fetch.

Imagine the thrill an auctioneer gets as his hammer falls on a record breaker, particularly when you remember that most of his life is spent cajoling bids out of canny or reluctant bidders. That's when many resort to guile and cunning. After all, a good auctioneer only needs one willing and unwary bidder to run something up to a good price.

Then there are all the standard phrases like "altering sorts, they'll go on and do", which is auctioneer speak for "ill-thriven, plain sorts", or "never been below a thousand feet" as a way of explaining why animals have not grown out or are thin.

I'm not saying auctioneers are dishonest, but it is their task to get the best price possible – partly to please the seller and get repeat business, but mainly to maximise the amount of commission for his firm.

Sometimes such tactics backfire and the auctioneer is left in possession of several pens of animals at the end of a poor day's selling. In such cases, he will graze them in a field adjacent to the market and sell them at the next sale.

One of my tasks as a farming journalist is to compile brief market reports to show price trends. Some auctioneers try to mislead me into thinking that a disastrous sale wasn't so bad by attempting to report only the leading prices and withholding the averages.

Having said all that, most auctioneers appear saintly when compared to some farmers, who have a whole raft of their own tricks up their sleeves.

Auctioneers may run bidders up, but farmers are just as capable of arranging for their friends to do it as well. Seasoned buyers have eyes as sharp as any auctioneer and easily spot when no-one else is bidding and they are being run up – but a couple of other farmers openly bidding is usually enough to reassure them.

Then there is the age-old wheeze involving luck pennies. That's where the seller traditionally spits on an old penny and gives it to the buyer to make the animals lucky. With the passage of time those pennies have been inflated to pounds, and several fivers or tenners now regularly change hands.

Some sellers of pedigree livestock take that practice to ridiculous extremes and, following a deal made prior to the sale, hand thousands of pounds in cash back to the purchaser.

That way he gives the illusion that his animal fetched more than it really did in the hope of enhancing the reputation of his herd or flock and increasing the value of future sales.

Subtler operators opt for a cashless form of the con. Instead of handing back cash they "retain" a half share in the animal that has been sold. While some of those deals are public knowledge by virtue of the auctioneer announcing it as a condition of the sale, or the new owner declaring that such a deal has been struck, others don't let on.

That way, while it appears that a sizeable sum has been bid, the reality is that the purchaser only paid half the bid price.

I could go on, but suffice to say that livestock auctions are not for the unwary.