The great statistical curmudgeon, like the groundhog, has reappeared from his burrow. This time, his target is the proportional success of progeny in regard to the age of broodmares and the birth rank of their foals.
If this seems a bit arcane, well it is. Most of the detailed topics we horse breeders evaluate are deep, dark, and difficult to parse. But they do provide information worthy of inspection and worth the time spent to digest it.
The views and analyses expressed below are the property of the GSC. Comments are welcome.
Age of Mares and Birth Rank
To the best of my knowledge, no one has ever performed an extensive analysis of the age of mares and birth rank using sales foals and their prices versus their results. I did something similar for one of the weekly publications, but it was yearlings only, best yearling sales only, and it was about 20 years ago (based on yearlings of 1980-1984, if I recall correctly). So the following survey of all weanlings, yearlings, and two-year-olds sold at public auction in North America in 1999-2002 was undertaken.
This is the same group I used for my study of the Rasmussen Factor on this website last August. Admittedly, the crop data is getting rather long in the tooth at this point. Many of those foals are now sires and dams of current stakes winners in their own right. But it really does not matter much what years you study because this is the sort of thing that does not change much over time.
Furthermore, some of these foals sold back in 1999-2002 are still racing and winning stakes.
Multiple G1 winner Commentator (a $45,000 weanling in 2001) was retired only last summer. He did win one stakes in 2009. Rumor Has It (a $250,000 weanling in 2001) won two stakes last summer at Arlington Park. And Trick of the North (a $8,586 yearling in 2002) won his first stakes, the British Columbia Premier’s Championship Stakes (bogus G3), at the age of eight last summer.
Let us begin by listing the best stakes winners among this group of sales foals. Table 1 does so. There you may see the 98 stakes winners (out of a total of 2,045) among this group who earned 2,000 or more Performance Points (my measure of how good a stakes winner is, see accompanying sidebar). They are sorted by birth rank and then by Performance Points.
The notation under Price might need some explaining. Commentator, for example, is listed as 01W45,000. That means he was sold as a weanling in 2001 for $45,000. If the stakes winner sold in more than one year, only the first year sold is listed. Xtra Heat, for example, sold as a weanling in 1998, as a yearling in 1999, and as a two-year-old in 2000. Since 1999 was the first year of this study, she is listed as 99Y4,700 (although her price of $5,000 as a two-year-old in 2000 is also incorporated into the results).
So you may see just by glancing at Table 1 which were the best foals of each birth rank sold among this group (age of mare is also listed in the last column). Commentator was the best first foal at 3,650. His dam Outsource was bred at two and produced him at the age of three.
Saint Liam was the best second foal at 6,357. Azeri was the best third foal at 9,380. Alkaased was the best fourth foal at 3,999. Orientate was the best fifth foal at 3,617. Peace Rules was the best sixth foal at 5,484. Honey Ryder was the best seventh foal at 5,384. Pleasantly Perfect was the best eighth foal at 9,890. Voodoo Dancer was the best ninth foal at 3,628. Financingavailable was the best 10th foal at 2,258. Extra Heat and Roses in May were the best 11th foals at 6,790 each. Imperial Gesture was the best 14th foal at 2,219. Stakes winners were found among 12th, 13th, 15th, 16th, and 17th foals as well, although not one of them was rated 2,000 or higher.
The top five were Pleasantly Perfect (eighth foal), Azeri (third foal), Ashado (7,931, third foal), and Xtra Heat and Roses in May (both 11th foals). Taking that at face value gives the nod to later foals of older mares.
On the other hand, 22 of these 98 stakes winners were third foals, followed by 14 second foals, and ten fourth foals. Four other groups (first, fifth, seventh, and eighth foals) had nine each. Taking that at face value gives the nod to early foals of younger mares.
You might be surprised to see only nine such stakes winners among first foals. First foals are always the largest group in any statistical study of birth rank. Since they are the largest group, they should have the highest number of best horses, but they do not.
The point here is that Table 1 was constructed merely to get the discussion started. The absolute number of best stakes winners matters much less than the proportion of such best stakes winners from foals. So I examined all 54,000+ weanlings, yearlings, and two-year-olds sold in North America in 1999-2002 and classified them by birth rank and age of mare and noted their prices and results.