The Bloody Side of Breeding
Horse Racing came under considerable scrutiny this month over the subject of medication. Most racehorses are given, amongst numerous painkillers, a drug known as furosemide. Furosemide is used to prevent what is commonly known as “bleeding” (Equine Internal Pulmonary Hemorrhage). The drug works by removing all of the excess water in a horse’s body. Without the liquid, required in the formation of blood, horses are less likely to form and pop blood vessels (bleed).
Bleeding must be prevented because it influences a horse’s performance. Bleeding can block a horse’s airways, making it difficult for him to breathe, as well as prompting him to run with his head high in the air, as though he is drowning and trying to get his head above water. Bleeding can also in some cases prove fatal. It is estimated that ? of all sudden racing deaths are caused by EIPH.
While Lasix does help with bleeding, it also hurts the horse. By flushing out all that fluid, furosemide dehydrates the horse, making the horse more tired and for that reason making it harder to run the horse back in another race quickly. It should be noted, however, that prior to the use of Lasix, it was commonplace to deprive a racehorse of both food and drink a day or even two days before a race. Despite these risks, the vast majority of trainers worldwide use the drug on their horses. While they are not permitted to race on it abroad, they still use it frequently in morning gallops. The use of Lasix remains a controversial topic, now more than ever. What is not so controversial is the source of Lasix; bleeding.
A severe case of EIPH
Most if not all bleeding is induced by a horse undergoing strenuous physical exercise, such as racing. It is possible, however, that some horses are more prone to bleed than others, based on their genetics.
I recently published a piece on the major sire lines of the Thoroughbred. You can read that here. The Darley Arabian, whose line is by far the most prosperous in the world, sired a horse by the name of Bartlett’s Childers (pictured in article photo) in 1715. Nicknamed “Bleeding Childers”, this stallion was instrumental in the fame of the Darley Arabian as he was the great grandsire of the undefeated second tier foundation sire, Eclipse.
Bartlett’s horse was nicknamed Bleeding Childers for his tendency to bleed out of his nose (most horses do not bleed badly enough for fluid to emanate from their nostrils, but rather it is contained in their trachea). Bartlett’s Childers never made it into a race.
It was found that the progeny of Bartlett’s Childers were more likely to bleed when they raced, the same thing that probably kept him off of the racecourse. As Bartlett’s Childers was found so much in pedigrees of top stallions, a tendency to bleed spread among the Thoroughbred breed.
The Australian Stud was not satisfied with this wive’s tale, and they published their own study that found that the tendency to bleed is a genetic trait. With this information, they have now banned any horse that bled or raced on an antiEIPH drug (such as Lasix). They attempt to breed the bleeding out of their horses.
Things don’t look quite as promising for American horses, though. Of the 25 leading stallions in America, 24 descended directly via their male line from Bleeding Childers, and all stallions listed descended from Bleeding Childers in some way. It should also be noticed that all of the top 25 leading stallions used Lasix or another antiEIPH medication.
That being said, don’t give up hope just yet! Recently a multitude of tracks across the country adopted medication reform that, with recent prompting by PETA, could put more focus on the breeding of bleeding.
Written by Colin K.