The Jockey Club today released Report of Mares Bred (RMB) statistics for the 2017 breeding season. Based on RMBs received through October 17, 2017, The Jockey Club reports that 1,342 stallions covered 31,863 mares in North America during 2017.

Based upon historical reporting trends, The Jockey Club estimates an additional 2,000 to 3,000 mares will be reported as bred during the 2017 breeding season.

The number of stallions declined 5.7% from the 1,423 reported at this time in 2016, and the number of mares bred decreased 5.6% from the 33,746 reported last year. The number of stallions covering 125 or more mares decreased from 64 in 2016 to 60 in 2017.

Further book size analysis shows a 3.3% decrease in the number of mares bred to stallions with a book size of 125 or more in 2017 when compared to 2016 as reported at this time last year; a 13.0% decrease in mares bred to stallions with a book size between 100 and 124; a 27.4% decrease in mares bred to stallions with a book size between 75 and 99; a 11.5% decrease in mares bred to stallions with a book size between 50 and 74; a 14.9% increase in mares bred to stallions with a book size between 25 and 49; and a 4.7% decrease in mares bred to stallions with a book size fewer than 25.

When comparing statistics based on reports received through the same day (October 17) from previous breeding seasons, the percentage of broodmares covered by large book size (125 or more) stallions increased from 19.3% in 2013 to approximately 29% in 2015 where it has remained over the past three seasons.

The proportion of stallions with book sizes of 125 or more mares grew from 2.6% in 2013 to 4.5% in 2015. It has remained constant at that rate over the past three breeding seasons.

Note: Statistics summarized as of October 17 of the breeding seasons indicated in the columns above; as reports of mares bred continue to be received, final statistics are subject to change.

RMB statistics for all reported stallions in 2017 are available through the Fact Book section of The Jockey Club’s website at jockeyclub.com.

The stallion Into Mischief led all stallions with 235 mares bred in 2017. Rounding out the top five by number of RMBs were Dialed In, 231; American Pharoah, 214; Uncle Mo, 204; and, Bodemeister, 192.

Kentucky traditionally leads North America in Thoroughbred breeding activity. During 2017, Kentucky’s 229 reported stallions covered 17,275 mares, or 54.2% of all of the mares reported bred in North America. The number of mares bred to Kentucky stallions decreased 2.7% percent compared with the 17,750 reported at this time last year.

Of the top 10 states and provinces by number of mares reported bred in 2017, Ontario, Pennsylvania and Indiana stallions covered more mares in 2017 than in 2016, as reported at this time last year. The following table shows the top 10 states and provinces ranked by number of mares reported bred in 2017:

Note: Each incident in which a mare was bred to more than one stallion and appeared on multiple RMBs is counted separately. As such, mares bred totals listed in the table above may differ slightly from counts of distinct mares bred.

In addition, Report of Mares Bred information on stallions that bred mares in North America is available through report 36P or a subscription service at equineline.com/ReportOfMaresBred.

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 americasbestracing.net. Additional information is available at jockeyclub.com.