On January 18, 2009, Smarty Jones became a “grandpa” when his daughter Jonespartyofwon produced a filly in Pennsylvania. Since Jonespartyofwon isn’t even three full years old herself (she was foaled April 20, 2006), an immediate and predictable furor broke out on equine message boards across the country on the topic of breeding 2-year-old fillies. Many of the respondents characterized the practice as inhumane, comparing it to getting a young teenager pregnant. But is this comparison accurate?
Surprisingly, there is little relatively hard data on this issue on the Web, at least at sites not restricted to professional memberships. While studies have indicated that even yearling fillies do not seem to be endangered by pregnancy, other questions besides maternal mortality come to mind.
The most common objections usually raised to the breeding of a 2-year-old filly are that she may be stunted in her growth because of the physical demands of pregnancy; that she may not be mentally mature enough to bond with and raise her foal properly; and that such early breeding is somehow unnatural. But the “unnatural” argument does not seem to be supported. In feral herds, where equine behavior is not hampered by human conventions, 2-year-old fillies can and do get bred, provided they are cycling and receptive. Of course, not all are. Like 14- and 15-year-old girls, 2-year-old fillies vary in their physical maturity, and some do not cycle reliably, making breeding and conception less likely.
On the other hand, some fillies begin cycling regularly at a relatively young age and conceive readily if bred – sometimes a little too readily, as more than one owner of a “surprise!” foal can attest. A famous case is that of Amazing Philly, a foal of 2000 whose dam Speak Compelling was an early 3-year-old in training when the filly was born. The sire was never identified, but is believed to have probably been one of the colts stabled at the 1999 Barretts March sale of 2-year-olds in training at which Speak Compelling was sold.
As Speak Compelling went on to make 50 starts all told, winning five, and was comparable to her dam’s other foals in racing ability, she seems to be fair evidence that an early pregnancy need not compromise a filly’s athletic potential. And she probably isn’t atypical. According to information at the American Association of Equine Practitioners (AAEP) Web site, the first seven or eight months of pregnancy place only slight demands on the mare. Thus, assuming a normal growth rate, a filly bred at 22-24 months will probably have 98% or more of her growth already completed by the time she encounters the higher demands of late pregnancy, making marked stunting unlikely. (There is some anecdotal evidence that the type of filly that is likely to show early sexual maturity tends to be of the smaller, early-developing type physically as well, which may account for the persistent belief that an early pregnancy will stunt a filly.)
Whether a 2- or 3-year-old filly has the mental maturity to raise a foal is another question. The available evidence does seem to suggest that the experienced broodmare is more successful at raising foals, all other factors being equal, but evidence linking maternal age at the birth of a first foal to the probability of that foal’s survival seems more difficult to come by. Another question for further research might be whether the juvenile filly is more vulnerable to contracting sexually transmitted diseases than an older female, a difference known to exist in humans.
Regardless of the evidence (or lack of it) regarding the effects of early breeding on mare and foal, a good reason for thinking twice about breeding a 2-year-old is the question of whether she is the sort of filly that should be bred regardless of age. Virtually all Thoroughbred fillies sent to the breeding shed at 2 are unraced, which means that they have not been tested for racing performance. While a filly that was unable to race due to illness or accident may be worth considering if her conformation and pedigree are both good, a filly that was physically unable to withstand training is another question, and so is a filly that was taken out of training due to mental issues or a wicked case of the slows. A bad broodmare prospect is a bad broodmare prospect, regardless of age.
Despite its unpopularity, early breeding has had some good results. A search through the history books reveals that 1844 Two Thousand Guineas winner The Ugly Buck (GB) was produced by Monstrosity (GB) when she was just 3; likewise, the dam of the great foundation mare Queen Mary (GB), an unnamed daughter of Plenipotentiary (GB), was just 3 when her famous daughter was foaled. More recently, Silvery Swan was bred to Mr. Greeley as a 2-year-old and produced 2000 Cigar Mile Handicap (gr. I) winner El Corredor. She went on to prove that the early pregnancy had not depleted her resources as a producer by throwing 2001 Reeve Schley Jr. Stakes (gr. IIIT) winner Silver Tornado as her second foal and 2005 Haskell Invitational Handicap (gr. I) Roman Ruler as her fifth.
Based on the available evidence, is breeding a filly as a 2-year-old ever a good idea? For Silvery Swan and Monstrosity, the results justified the decision, but they cannot be taken as typical; after all, very few mares of any age produce multiple grade I winners or Classic winners. The best answer seems to be “it depends,” according to the overall maturity of the filly being considered. For a well-developed, healthy, sensible filly that would otherwise be a good broodmare prospect, the risks may be little if any more than for a 3- or 4-year-old. But when in doubt, it may be best to follow traditional wisdom and wait another year.
Smarty Jones, whose 3-year old daughter recently made him a "grandpa."
Anne M. Eberhardt