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Stamina and the Maternal Influence

Is Stamina Crucial to Future Success?

As long as there is horse racing, the debate will go on: What traits are most important in successful broodmares? There are those who are adamant about a mare’s female family, refusing to consider those without significant black-type on their catalog pages. Others rely on the mare’s race record, and some argue that confirmation is most important.

But what about the running style of prospective broodmares? Is there a difference between mares with early turn of foot and mares that require longer distances? Much of the current literature seems to focus on the importance of the dam’s ability to pass along stamina, theorizing that mares are more adept at passing along the genetic material required for stamina. Based on an analysis of graded stakes mares, we’ll attempt to shed some light on the topic.

Our study groups were derived from graded stakes results between 1992 and 1996 as a function of the distance raced. Four our purposes, sprinting-type mares included all mares who won or placed in a graded stakes that were run at six furlongs or less. Distance oriented mares included mares who won or placed in a graded stakes run at ten furlongs or longer.

These parameters produced a six furlong group of 81 mares and a ten furlong group of 79 mares. Interestingly, there was no overlap in the lists, meaning that no mare who had won or placed in a graded stakes at ten furlongs or greater had also won or placed in a graded event at six furlongs or less, and vice versa. In other words, the two populations were completely exclusive from one another.

Of the original 160 mares, 113 had produced at least one starter by the end of the 2001 racing season, 55 six furlong mares and 58 ten furlong mares. This yielded two study groups: 114 foals resulting from six furlong mares and 120 foals resulting from ten furlong mares.

Due to limited data availability, we understand that our sample size equates to a ‘pre-study’ of sorts. That is, our numbers preclude us from drawing concrete conclusions. Instead, our goal is to simply lay a foundation for further work and study.

Having said that, we found that the two study groups virtually mimicked each other in production. Results are itemized below:

10 Furlong Mares 6 Furlong Mares
Starters 120 114
Winners 88 (73.3%) 84 (73.6%)
Stakes Horses 25 (20.8%) 24 (21.1%)
Graded Stakes Horses 14 (11.6%) 11 (9.6%)
Earnings $13,422,015 $12,858,424
Avg. Earnings / Starter $111,850 $112,793

With the exception of ten furlong mares producing graded stakes horses at a slightly faster clip, the numbers fail to separate the two groups. With roughly 20% stakes horses from foals and 10% graded stakes horses from foals, the two groups reiterate the importance of racing class in broodmares, but fail to tell us which racing style should be sought out by bloodstock buyers.

And while these two groups were exclusive of one another, we suspect that many of the mares in the ten furlong group had the ability the sprint successfully, but were never pointed in that direction by their connections. A deeper investigation of the ten furlong mares, separating those with early speed from the plodders, might lead to more significant findings than what we found here. Our suspicions are that a disproportionate amount of the ten furlong mare’s successes were provided by those who had early tactical speed. It’s possible that the plodding distance mares are riding the coattails of the speed mares in the same ten furlong group. You can be sure that we will re-visit this topic in the coming months.

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Thoroughbred Review
  • About Jason Hall

    A lifelong student of bloodstock topics as well as being an active owner and breeder, Mr. Hall advocates the importance of empirical research to identify truth in breeding practices. His articles have appeared in such magazines as The Blood-Horse, Thoroughbred Times, The Mid-Atlantic Thoroughbred, The Texas Thoroughbred, The Homestretch, Illinois Racing News, Hoofbeats, The Louisiana Thoroughbred and El Caballista. Mr. Hall holds a degree in journalism from Boise State University.

  • Mariana Lopez

    An enthusiastic and dependable member of our team, Mariana specializes in data collection and interpretation for our statistical research projects.

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