The best stallions make the best broodmare sires. Buckpasser, Deputy Minister, and Mr. Prospector all earned top marks as the sires of champions and as leading sires before moving on to become superb broodmare sires.

A broodmare sire, however, has a time limit. The stallion has to generate a sufficient volume of producers to climb the ranks of that list, and by that time, the sire is frequently “getting along.” Then there is a time limit before the stallion’s daughters age out of the broodmare pool to the extent that he has no real chance to lead the list unless … like Double Jay, he has a daughter who produces a Horse of the Year like John Henry, who keeps on going forever.

malibu moon

Aging out of the population is what happened with Mr. P, who has no daughters consigned to the Keeneland January sale this year, but younger top broodmare sires are well represented this year.

Second to A.P. Indy on this year’s list of leading broodmare sires, Unbridled’s Song has 1,550 foals out of 17 crops, with his youngest being 2-year-olds. From those, the stallion has 322 dams of runners so far, and those numbers will increase rapidly as more of his daughters from large crops age into the broodmare production pool.

Unbridled’s Song is competing at the top of the tree with star sires like A.P. Indy (337 producing daughters), Storm Cat (381), Deputy Minister (228), and Seeking the Gold (272). Those are the top five American-based broodmare sires in 2015.

It is noteworthy that four of the five – A.P. Indy, Unbridled’s Song, Storm Cat, and Deputy Minister – were G1 winners at 2, but their performance thereafter runs the gamut. A.P. Indy won the Belmont Stakes and Breeders’ Cup Classic, was named Horse of the Year. Storm Cat did not train on due to problems with his feet and went to stud with little fanfare.

All of them, however, became undisputedly influential sires, and the stallions’ best qualities are being transmitted by their daughters too.

Looking down the list, relatively young broodmare sires with upward mobility include Distorted Humor (foal of 1993), Smart Strike and Mr. Greeley (both 1992), Pulpit (1994), and Giant’s Causeway (1997).

They fit the criteria of being both important sires and having an increasing number of daughters coming into production.

Another of this ilk is A.P. Indy’s son Malibu Moon, the sire of 2013 Kentucky Derby winner Orb. Already with 18 stakes to the credit of his daughters, Malibu Moon is still in the early days of his potential as a broodmare sire because he began in a regional program without the customary volume of foals in his early crops.

In 2015, the stallion had only 105 producers working for him, roughly 30 to 40 percent of the total that the top-ranking broodmare sires have. But with performers like Stellar Wind to represent his daughters, bigger things are on the way.