The breakdown of Eight Belles in the Kentucky Derby this year and Barbaro in the Preakness last year started a lot of discussion about whether modern thoroughbreds are now bred for speed at an early age rather than durability.

The bloodhorse published a Stallion Durability List that ranks stallions by  the number of foals, the number of starters, the percentage of starters (which is how they are ranked) and then the average number of starts per offspring.  All the stallions listed have at least 100 foals on the ground.

The list has a special section on stallions whose progeny average more than 20 starts — certainly, those are sires that may pass along the durability gene to their offspring, making them good candidates for long and productive careers. Two points jump out to me when looking at the list: 1) the stallions whose foals have the highest average number of starts are not necessarily the ones with higher stud fees and 2) Mr. Prospector (shown to the right) is frequently listed in the breeding lines.

The stallion that tops the list is Demidoff ($3,000 stud fee) who descends from Mr. Prospector and Secretariat. Eight-two percent of his progeny make it to the track and they average 27.9 starts.

Interestingly, the stallions with the highest stud fees have foals with a very low average number of starts:

Giant’s Causeway ($300,000) progeny average 7.4 starts;

The progeny of Unbridled’s Song ($200,000), shown above, (which includes Eight Belles) average 11.1 starts;

Awesome Again ($150,000) progeny average 11.6 starts; and

Elusive Quality ($100,000) progeny average 11.7 starts.

Certainly, breeding is something to consider when evaluating thoroughbreds for post-racing careers, but it does make you wonder why the most expensive breeding stallions have progeny that race for such short careers.