Jockey Club mulls limiting stallions’ books to 140 mares

LEXINGTON, Ky. – The Jockey Club is considering a rule that would for the first time limit the number of mares that an individual stallion can cover during a North American breeding season beginning in 2021, a limitation that would have significant impacts on the breeding industry.

In a release issued Friday morning, The Jockey Club said that the rule was being considered because of concern over “the narrowing of the diversity of the Thoroughbred gene pool.” The release also noted that the organization “solicits and welcomes comments on the proposed rule from breeders, owners, and others with interests in the Thoroughbred breed and industry.”

If implemented, the rule would put a cap on the number of mares bred for the first time in history. The Jockey Club, which is the official registrar of the Thoroughbred breed in the U.S., has largely sat on the sidelines over the past 25 years as stallion books exploded well past the historical maximum of 60 mares, a cultural limit that held fast until the 1990s, when farms began honing the science of horse breeding and sought additional revenues through larger books.

“It’s one of those things that will definitely change how folks go about their business,” said Mark Toothaker, the sales manager at Spendthrift Farm, which stands five stallions that covered 140 mares or more in 2018, including Into Mischief, who led all stallions with 245 mares bred. “This will change everything.”

The rule being considered would limit stallions to 140 mares bred, and it would be phased in depending on the year in which a stallion first entered the breeding shed, The Jockey Club said. For horses entering stallion service in 2020, the 140 cap would first apply during the 2024 breeding season, the organization said. Stallions that had their first year of service this year would be capped starting with the 2023 breeding season, while stallions that entered service in 2018 would be capped in 2022. All other sires would be capped as of Jan. 1, 2021.

The release noted that in 2018, 43 stallions covered 140 or more mares, representing 27 percent of the entire population of mares bred. That stood in contrast to 2007, when 9.5 percent of mares bred were covered by stallions that had books larger than 140 mares.

That concentration has been impacted immensely by a sharp decline in the foal crop over the past 12 years. In 2007, the foal crop was 34,358, and it has since declined to an estimated 20,500 for the 2020 breeding season.

“The combination of these changes has resulted in a substantial increase in the percentage of foals produced by a discreet segment of stallions – signaling a worrisome concentration of the gene pool,” The Jockey Club said.

Limitations in the gene pool can have deleterious longterm effects on the biological health of an animal herd due to the impacts of inbreeding. Those limitations can also have commercial impacts if buyers have a surfeit of options when looking for a particular sire line or cross, leading to less individual demand on each of the horses possessing the desired lineage.

The phase-in approach is being considered because the value of a stallion is typically based on the amount of revenue the horse can produce during the first three years of its career. By imposing a cap on the number of mares bred, those valuations will change significantly. In classical economic analysis, that will also lead to upward pressure on stud prices at the top level of the business.

“There’s no question it will [put pressure on stallions fees],” Toothaker said. “The ones that are in demand will definitely see their fees go up.”

The Jockey Club announced that it was considering the cap just days before the Keeneland September yearling sale was set to begin. The sale draws the leading stallion managers in the world to the Keeneland sales grounds over two weeks of selling, and the topic is expected to be a major item of discussion there.

The specific rule under consideration states that the limit will apply to an “individual stallion per calendar year in North America,” which would seem to allow stallion managers to continue to ship horses to Southern Hemisphere locales without violating the cap. However, some stallion farms in the U.S. open their stallions to Southern Hemisphere mares who are shipped to the farms for breedings in the fall on the Southern Hemisphere season, and it was not immediately clear if those mares would count against the limit.

The Jockey Club did not immediately respond to a list of questions emailed to the organization.

Some farm managers who stand a number of sires who cover well in excess of 140 mares a year said on Friday morning that they would reserve comment until they had a better understanding of how the cap would impact the market and get further clarity on how the rule would be applied.

“We have no comment right now,” said Adrian Wallace, the nominations manager for Coolmore, which stands Cupid (223 mares bred in 2018), Practical Joke (220), Uncle Mo (179), and 2015 Triple Crown winner American Pharoah (180), among other stallions. “We’ll sit down and have a chat, see where we stand, and we’ll be having discussions about this throughout the sales.”