Breeding out the usefulness?

In the wake of Barbaro’s injury in Saturday’s Preakness, this article asks whether modern breeding and training practices have so weakened Thoroughbreds that we may not see another Triple Crown winner anytime soon. If so, this is only the most high-profile example of something which has been going on for a long time, and not just in TBs. Horse races in the 18th and 19th centuries were much longer, i.e. heats of 3 to five miles. A 3 y.o. horse is actually quite young, comparable to a person in their early teens; a horse isn’t fully mature until it’s about six–older if it’s a particularly large one. The growth plates harden into bone from the ground up, as it were; the ones in the spine and pelvis mature last. It isn’t just TBs either; quarter horses are ridden in futurities (horse shows, not racing) as young as two, which means they’re started under saddle as long yearlings. They break down early too. Why? $$$$$  The big TB stakes races are for 3 y.o.s; if they do well, they can be retired to the breeding shed early and also their sires (rarely their dams) see their value go up as producers. They’re raced and shown young to maximize the investment as fast as possible. You’re looking at 11 months gestation, then a year or two of training; there’s a lot of money at stake and you want to see results early. The punters aren’t going to sit still through heats of three and four miles either; where those races are still run, they are the province of stronger, mature animals. It isn’t cruel to run a fit horse that distance either (note the adjective); endurance horses can cover 100+ miles in 24 hours and still be hard to slow down at the end of it. They sure aren’t thoroughbreds though.

Taking a broader view, it’s not uncommon for the function to be bred out of the horse for the sake of form. Take the QH halter industry, where the fashion is for huge, muscly horses with tiny feet, which are prone to navicular disease, laminitis, and other forms of unsoundness; the babies are fed a lot of grain early to bulk up, almost like prize steers. More insidiously, you can get this overmuscled look quite easily–with HYPP, aka Hyperkalemic periodic paralysis:

Hyperkalemic periodic paralysis (HYPP), also known as Impressive Syndrome, is an inherited autosomal dominant disorder which affects sodium channels in muscle cells and the ability to regulate potassium levels in the blood of horses. This inherited disease is characterized by uncontrollable muscle twitching and substantial muscle weakness or paralysis among affected horses. HYPP is a dominant disorder; therefore heterozygotes bred to genotypically normal horses will still likely produce clinically affected offspring 50% of the time.

The disease is most common in the bloodline of the famous Appendix American Quarter Horse stallion Impressive, who has over 55,000 living descendants as of 2003. Although the disease is primarily limited to the American Quarter Horse breed and closely related breeds such as American Paint Horses and Appaloosas at this time, cross-breeding has begun to extend it to grade horses and ponies. The spread of the disease is perpetuated by the favorable judgings given to diseased horses in showing, due in part to involuntary muscle twitching which helps to build large, bulky muscles that judges favor.

Why are HYPP carriers still being rewarded in the show ring, then, encouraging their owners to breed them on and perpetuate the syndrome? There are many QH owners, breeders and trainers who would like to see N/H horses (carrying one HYPP gene nd thus can pass it on to 50% of offspring) made ineligible for registration; currently horses which are H/H (homozygous for HYPP) will be ineligible for registration as of January 2007. While this will help, it still won’t eliminate the disease from the gene pool completely, and if these horses have an edge in the show ring, is there really any incentive to breed it out?! What people won’t do for a damned ribbon.

(QHs, especially those in certain cutting lines, can also inherit a skin malady called HERDA, but compared to HYPP it is quite rare)

Other breeds have had their problems; the Foundation Morgan Horse movement was founded in an effort to save rare, pure bloodlines without the popular “show lines”, which have been found to contain legal and illegal crosses to Saddlebreds and Hackneys in an effort to produce high-stepping gaits and “hooky” Loch Ness monster necks for the show ring. Over 2/3 of Morgans now trace back to Upwey Ben Don and Upwey King Peavine. These Saddlebred crosses were legal at the time under the registry rules, but many, many breeders concentrate that blood until the original type is all but lost. The Chantilly Lace fiasco arose when it was discovered that false papers were used to cover up the use of Saddlebred mares. FCF Rhythm Nation was actually crowned Grand Champion Morgan Stallion (one of the judges was his breeder!) and it was later discovered that he was out of a Saddlebred mare! Now, I have nothing against Saddlebreds, or saddleseat, but saddleseat is, for most riders, very “fringey”; the average horse owner shows in Western classes, or hunter/jumper, dressage, competitive trail, etc.; a “saddley” horse isn’t going to appeal to a broad range of buyers, nor will it attract many new people to the breed. High action, flat croups and Nessie necks are not part of the Morgan standard, and the breed did not need this sort of “improvement”. Sadly, this has really split the Morgan breed into “show people” and “traditionalists”, with the former sticking with their version of glamour and the latter scrambling to preserve the old lines while they can.

A German shepherd with floppy ears, short face and a curly coat may be a fine pet but it isn’t much of a German shepherd any more; a horse which is deliberately bred to be unsound or a betrayal of its genetic heritage may be profitable in the short run, but it isn’t doing the animal any favours, and the damage done to the gene pool in the long run can be irrevocable. Let us hope that Barbaro recovers and can go on to a fine career in the breeding shed; let us also hope that he was injured as the result of an unfortunate accident and not a congenitally weak leg, lest the gene pool again be the loser in the long run.

NB: definitely see Dr. Deb Bennett’s excellent article on conformation, growth, and the history of horse racing.

Update: check out this article from The Sporting News, Barbaro’s Injury Forces Racing To Examine Itself as well as my followup post on this topic.