Activities of The Jockey ClubMatt Iuliano - Vice President, Registration Services, The Jockey Club
The Thoroughbred Breed Today
Matt Iuliano: Thank you, everyone, and good morning. Since the death of Eight Belles in the Kentucky Derby, we have all heard and read the remarkable array of opinion regarding Thoroughbred breeding and genetics. If we could pull common threads from this growing mound of material, two predominant messages emerge. The first is material that's been especially critical of particular sire lines due to a perception that certain sires have weakened the breed. The second is criticism of the increasing number of mares covered by the more commercially popular stallions.
I want to underscore the phrase "commercially popular" to recognize the marketplace as the prevailing force driving all decisions throughout the life cycle of the Thoroughbred: from the breeding shed, to the sales ring, to the racetrack and back to the breeding shed.
Comments that are critical of attributes of the Thoroughbred which result from market forces seem to implicate the market itself and challenge the market process for allocating resources among the participants. We have always subscribed to the theory that as long as the market is supplied with accurate and timely information, the value of a particular attribute is better determined by free enterprise as opposed to regulation.
With an abundance of opinion regarding the perception of a genetically weakened Thoroughbred, this morning I want to share with you the hard data and statistics we have been monitoring so we may separate the fact from fiction on this topic.
Let's start with a long-term review of the breeding statistics from 1965 to 2005.
Looking at the long-term trends in the foal crop and distinct sire count, a couple of things are worth comment here.
The first is the peak in the foal crop that occurred in the mid-1980s when registrations exceeded 50,000 foals. The second is the trend in the number of stallions that sired those foal crops. Up until 1994, these two populations moved in parallel. Afterward however, these two measures are not in concert as the number of foals ticked upward and the number of stallions began to trend downward, creating an increasing ratio of foals to sires.
Back in 1965, 18 stallions sired in excess of 30 foals each, with the majority of stallions producing 10 or fewer foals per year.
The next three decades saw tremendous growth: the number of stallions doubled and the foal crop nearly tripled in size to over 50,000 horses. In 1985, the number of stallions increased to over 7,000 and the average number of foals per stallion rose as well. With more stallions standing at stud and each on average producing more foals, the growth of the foal crop exceeded 7% annually in that 10-year time frame from 1975 to 1985.
After peaking in 1986, the number of stallions and foals trended downward. Average foal production per stallion, however, has continued to increase and stands at 10.5 foals per stallion in 2005.
So what began in 1965 with 18 stallions siring in excess of 30 foals each, has grown to 27 stallions siring over 100 foals each in 2005.
Now, the breeding statistics are fairly straightforward; the complexity arises when we analyze the foal crops and the pedigrees that result from them.
Comments heard frequently this spring have implicated the Thoroughbred pedigree as a contributing factor to the myriad of variables at work in horses in training.
In assisting the Thoroughbred Safety Committee, we developed a set of analytical tools for the pedigree to help us measure pedigree characteristics of horses at the racetrack.
Using a blank pedigree as a template, we analyzed all 31 sire positions present in a five-generation pedigree. We counted the total number of foals with common ancestors appearing within their pedigree, where those common ancestors were located, who they were and how they have changed over time through measurement of the 1965, 1985 and 2005 foal crops.
So between 1965 and 1985, the incidence of common ancestors within the 1st three generations actually declined by about 0.1% per year. Now remember, this is the period of time when stallion population and the foal crops were rapidly expanding.
From 1985 to 2005, these trends reversed and the incidence of common ancestors in the 1st three generations increased by 0.4% per year.
Overall in the 40 year study, the total proportion of the foal crop having a common ancestor appearing somewhere in the five-generation pedigree has increased by 2.88% or about 0.07% per year.
As part of our work with the Thoroughbred Safety Committee, we also studied the pedigrees from the 72,966 horses that started a race in 2007. From this group, we eliminated the older horses from consideration and focused instead on the 58,788 2- through 5-year-old starters.
Of these starters, we isolated the horses determined to have had a career-ending injury based upon our analysis of the chartcaller's detailed comments. Our objective was to study these pedigrees in light of all their contemporaries at the racetrack, and the foal crop as well, to see if we could identify any remarkable pedigree characteristics.
From the four principal crop years that make up the majority of racehorses, we couldn't identify any characteristic of the pedigree that distinguished horses with career-ending injuries from either their respective foal crop or horses that continued to race. Although the number of common ancestors in the 5th generation was approximately 2% higher, given an average generation interval of these horses somewhere in the 8- to 10-year range, this effect seems fairly remote.
Naturally, you will always find an occasional outlier whose common ancestors are found closer to the subject horse, and additionally, it could be argued that with horses entering the breeding shed earlier, the generation interval is decreasing, which would bring these effects closer to the subject horse over time. On average, however, we could not find any substantial differences among all horses in the foal crop, horses at the racetrack, and horses with career-ending injuries.
Next, we analyzed the data by the age of the horse. Although the 2-year-olds had more common ancestors in the 4th generation, as was the case for the 3-year-olds in the 3rd generation, no clear age-related trend emerged.
We are in the process of extending this analysis over multiple years beyond the 2007 racing season to determine if any temporal relationships exist, but at least based on the 58,788 pedigrees of starters we analyzed, nothing obvious emerged that would distinguish the horses with career ending-injuries to those horses that continued to race or their respective foal crops.
With data from the Equine Injury Database, we will be able to introduce additional layers of data to this analysis and produce more robust studies that consider the effects and interactions of the multiple variables that are likely at work here. With due haste, I would certainly encourage all racetrack operators who have not already done so to begin participating in the Equine Injury Database so we may improve our knowledge in these areas.
Finally, we repeated all these analyses, this time looking for particular sire lines in horses with career-ending injuries.
To gather these numbers, we tallied all the sires present in every pedigree position in every horse of racing age for the 2007 racing season. We then ranked those sires according how to many occurrences we counted for each and compared these results in the foal crop, in horses that raced without injury, and in horses that had career-ending injuries.
Some sires were more prevalent in the foal crop and in the population of starters as we would expect in a free market. We could not identify any sire line that was more or less prevalent in horses with career-ending injuries as compared to horses that continued to race or the entire foal crop, as well.
For example, 7.6% of all the sire pedigree positions of the '02 thru '05 foal crops combined have a sire that traces back to Native Dancer. Of all the horses at the racetrack in 2007 that did not have an injury, 7.9% of all the sire pedigree positions have a sire that traces back to Native Dancer. Of all horses that sustained a career-ending injury, a sire tracing back to Native Dancer appears in 7.4% of the sire pedigree positions.
Native Dancer, and for that matter, no sire line was disproportionately represented when compared to the population.
There were more Native Dancers in the pedigrees of horses with career-ending injuries because there were more Native Dancers at the racetrack and in the population as a whole, and the same could be concluded for the Bold Ruler lines and Northern Dancer lines and on down the list.
Thus, we can find no evidence in the 2007 racing data that we analyzed that an increased incidence of career-ending injury can be attributed to a particular sire line.
In summary, we are continuing to work through these data to compare results over multiple years. With the addition of data from the Equine Injury Database combined with our full array of pedigree and racing data, analysis of the multiple interacting variables that are at work should be available next year.
James L. Gagliano: Thank you, Matt, for that reportů