The Jockey Club today released Report of Mares Bred (RMB) statistics for the 2013 breeding season. Based on RMBs received through October 10, 2013, The Jockey Club reports that 1,698 stallions covered 34,174 mares in North America during 2013.

The annual statistics represent approximately 90% of the mares that eventually will be reported as bred in 2013. According to historical trends, The Jockey Club expects to receive RMBs representing an additional 3,000 to 4,000 mares bred during the 2013 breeding season.

The number of stallions declined 8.8% from the 1,861 reported at this time in 2012, and the number of mares bred fell 3.4% from the 35,391 reported at this time last year.

The number of stallions covering 100 or more mares increased by one, from 87 in 2012 to 88 in 2013. These stallions accounted for a greater percentage of the total mares reported bred this year — 34.0% of all mares bred in 2013 versus 31.9% of all mares bred in 2012 as reported at this time last year. RMB statistics for all reported stallions in 2013 are available through the Publications & Resources section of The Jockey Club’s website at jockeyclub.com.

Further book size analysis shows a 2.9% increase in the number of mares bred to stallions with a book size of 100 or more in 2013 when compared to 2012 as reported at this time last year; an 11.6% decrease in mares bred to stallions with a book size between 75 and 99; an 11.3% increase in mares bred to stallions with a book size between 50 and 74; a 15.9% decrease in mares bred to stallions with a book size between 25 and 49; and a 5.3% decrease in mares bred to stallions with a book size fewer than 25.

The stallion Into Mischief led all stallions with 210 mares bred in 2013. Rounding out the top five were Archarcharch, 187; Harlan’s Holiday, 187; Kitten’s Joy, 184; and Majestic Warrior, 176.

Kentucky traditionally leads North America in Thoroughbred breeding activity. During 2013, Kentucky’s 235 reported stallions covered 15,695 mares, or 45.9% of all of the mares reported bred in North America. The number of mares bred to Kentucky stallions increased 2.2% percent compared with the 15,361 reported at this time last year.

Of the top 10 states and provinces by number of mares reported bred in 2012, only Kentucky, Oklahoma, and Texas stallions covered more mares in 2013 than in 2012, 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 2013 through October 10:

In addition, it was announced yesterday that, for the first time, Report of Mares Bred information on stallions that bred mares in North America will be 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 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, among others. Additional information is available at jockeyclub.com.