That stylish nose ring. That macho stare. Does he have what it takes to be the new stud on the block?

The wind is whistling down from the snow-capped Moel Famau mountain range and a few blackbirds are warbling. But there is a worrying absence of Mozart wafting around the narrow lanes of Llanrhydd, a hamlet near Ruthin, north Wales.

The wind is whistling down from the snow-capped Moel Famau mountain range and a few blackbirds are warbling. But there is a worrying absence of Mozart wafting around the narrow lanes of Llanrhydd, a hamlet near Ruthin, north Wales.

Here lies the secretive home of Picston Shottle, a bull whose semen is the most sought after in Britain and is delivered up amid the strains of Wolfgang Amadeus, to get him in the mood for love.

The five-year-old Holstein Friesian's ability to sire superb calves at a rate of 200,000 shots of semen a year - almost double the output of an average, non-Mozart-loving bull - helped to raise the value of his owner's company, Genus plc, by around £50m last year.

However, all is not well. Picston is shattered and badly in need of a rest. The sound system is off and Picston's noisy, exertions at a metal contraption draped in cow hide have been reduced from five days a week to two.

While he rests, less than 30 miles away in Aldford, Cheshire, a young pretender is eyeing Picston's crown. He is Woodmarsh Conformer, another five-year-old Holstein Friesian. His breeders, the Duke of Westminster-owned Cogent, believe he will be next year's bull superstar.

"In any one year there is one popular bull," says Cogent's business development manager, Richard Williams.

"Last year it was a bull named Lucente. Now it's Picston Shottle. We'd hope to have something new this year. We are hoping that Conformer will be up at that level. But you have to wait for the daughters of bulls to start milking, so it's like looking into a crystal ball."

Prize bulls are a little like Premiership footballers. Many show potential at a young age, but very few make it to the top. Those that do are pampered, with little expense spared when it comes to keeping them in the best shape.

"For every 10 or 15 that go away, only one bull becomes a star," Mr Williams says. "The Shottles and Conformers can be one in a hundred bulls ... We are trying to find the cream."

It was sign of Picston's extraordinary value to the stock market that news of his downshifting sparked a flurry of stockbrokers' flash notes last week.

The champion procreator's whereabouts have remained a closely guarded secret, so precious is his semen to Genus's £100m share value. But The Independent on Sunday tracked Picston down last week to an unprepossessing collection of farm buildings.

This is the core of a remarkable multimillion-pound business: a chemical laboratory laden with test tubes, where Picston's semen is frozen into shots resembling drinking straws that sell for £40 a portion.

But what of the great beast himself? He was confined to reinforced pens, out of sight within the complex of corrugated shacks and breeze-block buildings. Genus's director, Mark Smith, has no intentionof allowinga glimpse of the ultimate ladies' man.

It transpires that Mr Smith's resistance is a blessing in disguise. A source at Genus discloses that Picston and his tempestuous cohorts will only tolerate the presence of the firm's staff in their pens.

"They get upset when they see strangers, and will snort and fret," says the source.

When it is work-time, a number of techniques are used to coax Picston out of a pen adorned with a deep bed of shavings and heat lamps, which keep him warm. A metal cow is in place at Llanrhydd, though it is apparently not to every bull's taste. Textbook techniques for semen collection involve several men with Marigolds on lurking beneath the "cow".

Genus insists that Picston is merely taking a break. "This bull has been working flat out for nine months," Suzanne Brocks, a spokeswoman, says. But in the farms around Llanrhydd, the old hands say every bull has his day.

Meanwhile, Conformer lies on his bed of straw, frolics in his sandpit - and waits.

BULL'S-EYE

• The first artificial insemination of a cow was in 1780, in Italy.
• Pedigree bulls have names such as Bocaddon Thunder, Donnah Randy Lumiere and Full Monty.
• Stud bulls are celebrities - Picston Shottle was called "the bovine world's answer to Barry White" and compared to Peter Stringfellow.
• Stud bulls can drink 15 gallons of water a day, and can smell a heifer five miles away.
• Robert Goodey, a semen collector, once said: "At dinner parties I have a good story to tell, but men don't like to think something's got one bigger than they have."