Video Proof of Why Thoroughbreds Bleed in the US and not in Japan
Click ‘play’ on both of the above videos simultaneously, and watch six horses in the post parade 5min prior to loading in Japan (top clip) and in the United States (bottom clip) over dirt last night on TVG – quite a difference, eh?
I have argued for years that an appropriate pre-race warmup prior to loading in the gate will eliminate or decrease the severity of bleeding in most racing stock without the use of a pharmaceutical diuretic such as Salix/Lasix.
The mechanism behind this concept is twofold: A single furlong at a 15sec clip (or a bit quicker) will cause the spleen to contract and shoot 30% more red blood cells into the bloodstream, thickening the blood and stressing the capillary walls. Slowing to a jog/walk soon afterwards allows these blood vessels time to stretch and dilate in order to decrease blood pressure, naturally. Otherwise this happens in the first few strides from the gate – albeit with no rest period to accomodate the newly thickened bloodflow. Bleeding ensues.
Briefly, EIPH or bleeding from the lungs in an exercising thoroughbred is the result of high blood pressures overwhelming the pulmonary capillaries and causing them to burst, leaking blood into the lungs themselves. There are two variables at play here: the viscosity of the blood itself, and the volume of capillaries present in lung tissues.
Firstly, as described above – the equine spleen is unlike the human version and serves as a reservoir of oxygen carrying red blood cells in horses, this is but one catalyst of the ‘fight or flight’ response found in animals of prey. Secondly, capillaries are tiny straw-like tubes that connect arteries and veins. Genetics determines how many a horse is born with, but conditioning determines how dense that capillary bed becomes: a horse’s arteries and veins are unaffected by the training environment, but exercise at 60-70% of maximum heart rate increases the number of capillaries.
Lasix works by inducing increased urination in a horse, resulting in a lower volume of water within the plasma component of the blood: lower blood volume then equals lower pressures throughout the circulatory system. However, as with any drug (human or equine) there are side effects.
Often enemies of Lasix cite the fact that Europeans do not allow the drug in their racing programs. However, this is not comparing apples to apples. Euros run overwhelmingly on turf or synthetic – and a relaxing 54sec half mile from the gate has little in common with the US style of 45sec in the first half mile over an unforgiving dirt surface.
Finally, with the above videos I am able to confirm what I have always suspected: in jurisdictions that prohibit raceday Lasix AND race on dirt – other interventions such as an extensive warm up are utilized to control the effects of EIPH.
Horses in Japan are trained trackside just like in the US – they don’t have access to hundreds of acres of rolling hillside to train over between efforts, as do the Euros. Yet, you see no lead ponies in the above post parade at Kyoto Racecourse as trainers have conditioned their horses in the mornings to behave appropriately during the big events even with this pre-race blowout.
A common, and valid, reason given by US trainers as to why they don’t practice such a pre-race warmup is that they cannot find riders who are able to consistently pull up the horse after a quick furlong, not in the mornings and not on raceday.
That is a lack of horsemanship on the part of the exercise rider that the trainer overcomes by veterinary intervention – yet opponents of Lasix are touted as ‘cruel to racehorses’ – what a crock.
Trainers out there unwilling to overcome ego and apply some science to the conditioning process be warned: if Lasix is ruled off – you are going to have to do what I just described in order to remain competitive. I recommend you do some experimentation now, practicing the above warm-up protocol before a training breeze – and you will be shocked how well your horse finishes up that breeze after a spleen-contracting furlong 3min before the real work begins.
Stretching and warming up in humans in order to prevent injury has been exposed as a fallacy, the real value in warming up aggressively is to improve performance during competition – this practice WILL buy you a few tenths of a second if you implement it correctly, even in the slowest horse in your barn, provided he is reasonably sound.
If you are based at KEE or CD give me a shout and I’ll come with my HR/GPS equipment, free of charge, and show you with numbers how this practice consistently improves performance.