The idea that the allowance of Lasix is in the best interest of the horse is arguable, as you well know. There is nothing cruel about a horse losing its breath and slowing its running -- this is something we can all attest to personally -- and cases of extreme EIPH are quite rare. Those who do bleed heavily are said by ALL to NOT be helped by Lasix administration and should be retired from racing. But the side effects of Lasix may indeed be cruel including the loss of electrolytes given that potassium and calcium are responsible for many cellular process in the horse such as bone density. Given that our horses are making fewer and fewer starts since the allowance of Lasix, we could look at this being a cause. It can also be deemed cruel if we are breeding bleeding into the breed.
The bottom line is that we need far, far more research into Lasix and EIPH and the side effects of Lasix and alternative treatments for EIPH. For example, an interesting case can be made for changing our warm ups:
Enforce a specific warm-up regimen prior to each race. It shouldn’t have to come to this, but watching horse after horse walk/jog while their neck is wrenched towards a lead pony in the post parade is nauseating. How is 2 minutes of 10mph jogging with a heart rate of 120bpm supposed to prepare a horse’s circulatory system for an event consisting of 35+mph speeds and maximum heart rates near 230bpm? No wonder when firing from the gate that the pulmonary capillaries are caught sleeping and cannot keep up with the demands of rapidly increasing pressures from within.
To make matters worse, when a horse is asked to pick it up to a sprinting pace, his spleen contracts and shoots up to 30% more red blood cells into the mix, further thickening the blood and the associated high blood pressures. This is part of the ‘fight or flight’ response designed by nature to allow this animal of prey to escape his predators.
This splenic contraction needs to take place PRIOR to loading into the gate, not within the first few strides of a race. Nothing major, just a nice 1-2F in 13sec/furlong pace, finishing up with 5-7 minutes left before loading. Is your horse not behaviorally trained to pull this off without running off with the rider? Well then you have some extra work to do in the mornings until he is capable. Some will learn immediately, others will be a headache – that is the nature of the beast. He should be warming up in this manner prior to any training breeze as well for good measure.
How does this enforced warm-up address the two key causes of EIPH?
With the 30% additional red blood cells introduced into the horse’s system 5-7 minutes before post time, you are allowing millions of pulmonary capillaries quite a bit of time to adapt and stretch, a process called vasodilation. As it stands right now, that burst of blood volume is shot into the horse during the first few jumps from the gate, and he is then expected to continue for an additional 60-120 seconds at near full throttle. With a mandatory race-specific warm up, by the time a horse fires from the gate, he has had several minutes to adapt to the increased blood pressures from the splenic contraction while waiting to load.
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