New Breeding Statistics Added to the Online Fact Book

June 8, 2023

Champion mare Covfefe with her 2022 Constitution colt (Photo courtesy of LNJ Foxwoods)

The Jockey Club Press Release

LEXINGTON, Ky.— In addition to the quarterly update to its Online Fact Book, The Jockey Club today announced two new pages to the Fact Book breeding section: Number of Unique Sires by Position in the Pedigree Top Line and Percent of Mares Bred Categorized by Stallion Book Size.

“As the Thoroughbred breed registry for the United States, Canada, and Puerto Rico, The Jockey Club strives to provide statistics that are valuable and that help shine a light on what is happening in our industry, especially with respect to breeding,” said Matt Iuliano, executive vice president and executive director of The Jockey Club.

The unique sires by position table shows the number of unique sires by position within the top line of the pedigree and enables users to drill down by year and generation. Those links provide stallion names and the number of registered Thoroughbreds for that generation’s sires on the top sire line pedigree for the registered foals of the specific year.

The percent stallions and mares bred statistics display how the number of stallions and mares have changed over time based on stallion book size.

Other updates to the Fact Book, which were announced in March, include Reports of Mares Bred statistics’ being sortable by stallion name, number of mares bred, and state, and the Breeding Statistics’ being sortable by year and then by stallion name, mares bred, reports received, live foals, percent of live foals, and state.

The online Fact Book is a statistical and informational guide to Thoroughbred breeding, racing, and auction sales in North America and is updated quarterly. It also features a directory of Canadian, international, national, and state organizations. Links to the Breeding Statistics report that is released by The Jockey Club each September and the Report of Mares Bred information that is published by The Jockey Club each October can be found in the Breeding section of the Fact Book.

The 2023 edition of the Fact Book is available in the Resources section of The Jockey Club website at

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. You can follow America’s Best Racing at Additional information is available at

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