Price Doesn’t Reflect Earnings
Paying top price to breed your thoroughbred mare to a racehorse stallion doesn't necessarily mean you're buying the best genes for a fast foal. More expensive stallions are not consistently producing progeny with the highest earnings on racetracks, researchers have found.
Scientists at University of Edinburgh in the United Kingdom gathered data and crunched numbers to see whether breeders get what they pay for in stud fees. The researchers discovered that higher stud fees don't reflect better genes for winning prize money in horse races. The bottom-line from this study, according to its authors, is don't rely on the magnitude of stud fees for measuring a stallion's genetic ability to produce high-earning racehorses.
These findings are based on data from 550 stallions standing in the UK and United States and their stud fees charged between 2001 and 2007. The highest fee encountered for a breeding was $500,000 US.
The pedigrees for nearly 4500 offspring were also analyzed. Fillies, for instance, earned anywhere from $58,000 to $140,000.
Where the numbers do reveal a link is between a horse's pedigree and its lifetime prize winnings. So it's possible for breeders to select for genes that influence a horse's total race earnings.
Nevertheless, the study's authors acknowledge that good genes account for only a small part of a racehorse's success. Most of the influence comes from the horse's training, its injuries and jockeys, and which races it runs. These environmental factors determine over 90% of the variation occurring among horses in their overall track earnings.
Alastair J. Wilson and Andrew Rambaut. 2008. Breeding racehorses: what price good genes? Biology Letters. 4(2): 173-175.