No romance, here, for the champion racehorse. It is strictly business time for the start of the Australian thoroughbred breeding season on Monday.

This year for the first time Dundeel, better known to racegoers as It's A Dundeel, joins the ranks of other sires at stud, an industry that generates more than $300 million a year in stallion fees alone.

Horse breeders wanting Dundeel to "cover" their broodmares will pay $27,500 a season for the privilege.

Racing authorities around the world have banned artificial insemination, meaning that all the action must be done the old-fashioned way and only in spring. Stallions can cover up to four broodmares a day, depending on demand and powers of recovery.

Breeders pay anything from $1000 to hundreds of thousands of dollars to get their mare covered. Australia's most expensive sire, Coolmore Stud's Fastnet Rock, covered 212 mares at an advertised fee of $275,000 last year.

Although his fee is private for this season, it is expected he will cover about 200 mares at a cost of about $200,000, generating some $40 million for his owners.

Those stallions with a long line of mares are likely to have begun breeding shortly after midnight on Monday, as every minute counts in a season that lasts for little more than three months.

Last year 637 individual sires across the nation covered some 20,060 mares, and more than 13,500 foals are expected to be born this spring.

For Dundeel, the time to prove his value at Arrowfield Stud, outside Scone in the Hunter Valley, owned by Racing NSW chairman John Messara, is only short.

Stud manager Paul Messara said most speed stallions only had about three years (the time it takes for their first crop to race) to be judged on their progeny's success on the track. Sires with stamina bloodlines get a little longer.

"It's a judgment call [how long they get to prove themselves]," Mr Messara said. "There is a lot of money involved, with up to 42 shares in the stallion, because of that they don't get much time.

"However, if they are deemed successful, their yearlings sell for more money and breeding value goes up. Some horses are still breeding into their 20s, so you can see the potential."

The new stallion with the dearest fee this season, Zoustar, represents the dream of everybody who has owned a racehorse.

After being bought as a yearling for $140,000 and raced by a group of 12 owners, during which time he won $1.4 million in prizemoney, he was then sold for a reported $18 million for a career at stud.

Thoroughbred Breeders Australia chairman Basil Nolan said the size of the fees for stallions demonstrated the breeding industry's importance to the wider economy.

"This is a vitally important industry to Australia, especially in rural areas where these stud farms are based," he said. "The hundreds of millions generated in stallion fees is only one part of the economic input; there's also the thousands of people who work in the breeding industry, the agistment  fees paid by breeders and, of course, the money spent on buying the horses."

He added: "We are very fortunate to have one of the strongest breeding industries in the world, with Australian bred horses recognised across the globe for their speed and toughness."

For the records

- All foals and breeding stock have to be registered with the Australian Stud Book, which has been the official record keeper of the industry since 1878.

- The gestation period for a mare is about 11 months.

- There are 7922 breeders in Australia.

- About 4500 breeders own just one mare.