Pedigree Theories and Selection Techniques
2. The Racecourse Test
For many, the racecourse test is the only valid selection system, especially when one considers that the Thoroughbred is the result of over three hundred years of selection for one trait, superior running ability. While racing styles have changed over the centuries, from four mile heat racing to dash racing, the victory still goes to the horse that crosses the finish line first, so to use breeding stock that has not proven itself in some way on the racecourse is defeating the purpose of the breed, the fastest and most efficient galloper in the entire equine world.
The racecourse test can prove different several things. First, victory is to the swift. Quite simply the horse that can cover the required distance in the shortest time is the winner. Proven speed in training is important, but proven speed in actual competition, under stress, is even more critical. A horse can demonstrate brilliant speed as a pacesetter, as a "one run" stretch runner, or as a horse with tactical bursts of speed at the push of a button. In fact, many consider the ability to accelerate, or "quicken" when called upon as key to what makes a superior racehorse and a valuable sire. In longer races, efficiency of stride becomes more important, but the ability to quicken remains a more desirable asset than the ability of a horse to gallop others into the ground. Tireless but non-brilliant horses like those are referred to as "plodders."
Second, victory is to the strongest. The horse that can run and win often shows superior strength, or "soundness" of muscle and bone, both of which are necessary to compete successfully. Superior atheletes recover quickly from a race and run back to form without excess coddling. They are also highly desirable as breeding stock since they are likely to pass on their good conformation and bone structure to their offspring. This makes them important members of a breeding population, providing strength and soundness where it may be lacking.
Third, victory is to the one that desires it most. The Thoroughbred is noted not only for its great athletic prowess, but for its competitive spirit and willingness to exert itself when called upon by its rider. This "will to win" is critical in a successful racehorse, and those that don't show it are labeled as cowardly, or roguish, or without heart. Gameness and courage have won as many races as sheer physical ability. This spirit is sometimes manifested as a dominant attitude that the horse exudes when it's in contact with others of its species. Observations indicate that a dominant individual can "psych out" its competition in the post parade or int he race itself. Man o' War had it, Ruffian had it, Seattle Slew had it, and anyone who watched Cigar swagger to the post oozing "macho" knows he had it, too.
The racecourse test is the only way to prove a horse's speed, strength, and spirit. This is why the best racehorses make the most desirable stallion prospects, and why they also generally become the best sires. Horses that fail this test, either because they are poor atheletes or lack the racing spirit, are usually poor candidates as breeding stock.
When an unproven racehorse becomes a good sire or broodmare, research usually indicates that he or she showed tremendous potential in training and was retired due to some untimely circumstance, usually an injury. Such horses usually also own above average pedigrees. It is very unusual to find an unproven, poorly-bred horse succeed as a stallion. See the next section "Proven versus Unproven" for more insight into this phenomenon.
A horse's individual race record measures the racecourse test. The combined and averaged records of all of a stallion's progeny is a fair way to access a stallion's success or failure as a sire. The most effective number in evaluating a stallion's progeny is the AEI or "Average Earnings Index" which takes the average earnings of all runners for a specific period (which gets a score of 1.00) and evaluates the stallion's average progeny earnings against that figure. A number below 1.00 is below average. A number above 1.00 is above average. Good stallions generally have an AEI of at least 1.50.
The AEI needs to be accompanied by the CI or "Comparative Index" which is the same average number but relating to all the mares this stallion was bred to. A CI takes all the offspring of the stallions mates and extracts the average earnings of their combined progeny. A stallion with a CI of 2.19 means that his mates (mares) produced offspring that averaged 2.19 times the average for the breed for the generation in question.
If a stallion's AEI is lower than his mares' CI, then it seems to hint that he's not producing the same quality of runners as these mares have produced. In other words, he's dragging down the quality of his mares. This is not a good thing. This can be forgiveable in a very young stallion who received outstanding mares to begin with. If only his first few crops have raced, than his progeny have not been tested fairly enough to guage the two. Top young stallions frequently have AEIs that may be over 1.50 but with CIs that are 2.0 or over. This means that they were bred to exceptional mares and are producing good runners, but nothing like the top runners their mates have already produced. It's hard to interpret that as a negative so early in a stallion's career. AEI and CI need to be looked at together and in relation to the stallion's number of years at stud.