US Jockey Club Rule Changes to Restrict Stallion Books

Media Release - Friday May 8

The Jockey Club board of stewards has announced that it has adopted a final rule limiting the annual breeding of individual stallions. The rule reflects The Jockey Club’s goal to preserve the health of the Thoroughbred breed for the long term and will apply prospectively to stallions born in 2020 or later. 

Effective today, The Jockey Club’s Principal Rules and Requirements of the American Studbook are amended by adding the following italicized language to the text of Rule 14C:

C. Based on the information on a completed Report of Mares Bred form, The Jockey Club will forward to the stallion owner, lessee or authorized agent a preprinted Service Certificate for each broodmare bred, including the name of the stallion, the name of the broodmare, the name of the dam of the broodmare, and the date of the last cover.

The total number of broodmares bred per individual stallion whose year of birth is 2020 or thereafter shall not exceed 140 per calendar year in the United States, Canada, and Puerto Rico. The Jockey Club shall limit the number of Stallion Service Certificates for such stallions to a maximum of 140 per calendar year.

When the stallion owner, lessee or authorized agent receives the preprinted Service Certificate, it should be examined for accuracy, signed by the stallion owner, lessee or authorized agent and forwarded to the breeder of the foal or submitted to The Jockey Club through Interactive Registration™ at www.registry.jockeyclub.com. The Service Certificate is required to register a foal. Service Certificates will not be issued unless a completed Report of Mares Bred form is on file at The Jockey Club and until genetic or re-DNA typing of the stallion has been completed (see Rule 5).

In an effort to illustrate the operation of the new rule, The Jockey Club offers the following examples of how it will be applied:

(1)  For stallions born in 2019 and earlier, there will be no limit to the number of mares reported bred in the United States, Canada, and Puerto Rico. The Jockey Club will issue stallion certificates for all mares bred by such stallions within the United States, Canada, and Puerto Rico during a calendar year.

(2)  For stallions born in 2020 and later, the maximum number of mares covered within the United States, Canada, and Puerto Rico in a calendar year will be 140. It would be a violation of Rule 14C for such a stallion to cover more than 140 mares within the United States, Canada, and Puerto Rico during a calendar year. The aforementioned limit will apply to all mares bred during a calendar year regardless of when The Jockey Club receives a Report of Mares bred (or any amendments or supplements thereto).

The Jockey Club will modify its Report of Mares Bred form and other related forms in recognition of the amendment to Rule 14. Stallion Service Certificates will be issued on the basis of first cover date in the order of mares listed on the Report of Mares Bred.

The Jockey Club is grateful for the many thoughtful comments in response to its September rule proposal. The stewards carefully considered those comments in formulating a rule that will promote diversity of the Thoroughbred gene pool and protect the long-term health of the breed. 

The Jockey Club will continue to maintain the Principal Rules and Requirements of the American Studbook in keeping with its mission to ensure the health of the Thoroughbred breed.

The Jockey Club, founded in 1894 and dedicated to the improvement of Thoroughbred breeding and racing, is the breed registry for North American Thoroughbreds. In fulfillment of its mission, The Jockey Club, directly or through subsidiaries, provides support and leadership on a wide range of important industry initiatives, and it serves the information and technology needs of owners, breeders, media, fans and farms. It is the sole funding source for America’s Best Racing, the broad-based fan development initiative for Thoroughbred racing.

Advertisment
More Reading...
Steve Davis Awarded NZTBA Personality of the Year
Bloodstock auctioneer and media personality Steve Davis has been honoured as the 2025 NZTBA Personality of the Year, in recognition of a lifetime of contribution to the New Zealand thoroughbred breeding industry.
Sires With Winners - Sunday July 27
Here is the full list of 54 stallions which had winners throughout Australasia today with winners and result details.
Juvenile Trial Watch – Rosehill
This will be the last Juvenile Trial Watch story for this season with all these youngsters to turn three on Friday and there was plenty of action with eight heats won by 2YOs and two more of this season’s G3 2YO’s North England and Memo stepping out against the older G1 stars.
Stallion Shares in Cool Aza Beel Offer Rare Opportunity via Magic Millions Virtual Sale
Breeders will have a timely chance to invest in one of Australia’s most exciting young stallions next week, with two individual stallion shares in Cool Aza Beel to be offered via the Magic Millions Virtual Sale on Tuesday, August 5.
Carrazzo Melbourne 'Sport of Kings' Tax Talk
It gives Baumgartners great pleasure to announce that the Paul Carrazzo’s “Sport of Kings” horse tax talk returns to Inglis Melbourne on Wednesday 13 August.
Fifth Winner For Hanseatic As Audio Pop Cam Wins
With four jumpouts under her belt, winning the last three, Tony and Calvin McEvoy's Hanseatic filly Audio Pop Cam was too good for her rivals, starting favourite to win the Unox Casa Maiden Plate (1100m) at Pakenham with ease.
New G1 Winner for Too Darn Hot
Fresh from siring two new stakes-winners in Europe on Saturday Too Darn Hot (GB) kept the momentum going on Sunday with a new Group I winner and Tornado Alert is a half-brother to Just Fine (IRE), winner of the Group I ATC The Metropolitan in 2023.
Consecutive Wins For Lucky Vega’s I’m Lucky Two
Off the back of an impressive two length victory over 1000m at Toowoomba at the end of June, the month between runs didn’t pose any issues as the Michael Nolan trained Lucky Vega (IRE) gelding I’m Lucky Two stepped out over 870m to win once again.
Closer Look at Written Tycoon – The Golden Crop Delivers
The sun might be setting on the stud career of Written Tycoon, but he’s not going into the twilight years quietly and is set to be crowned Champion Australian 3YO Sire this season, which is probably something predicted by many when he got the opportunity of a lifetime to cover at Arrowfield Stud for one season in 2020.
Beaufort Downs Celebrate Stakes Success with Platinum Diamond
A pedigree close to the hearts of Beaufort Downs has added another black-type strike to the North Canterbury farm’s roll of honour.