Page 90 - March 2016

“There are always consequences when using medication. I don’t think very many people understood how toxic some of the side effects were...”
“I feel that many soundness problems are human-caused by our practices of over-medi- cating these horses and causing them to flush too much calcium from the body. Our horses (that are running without these medications) stay a lot sounder. They don’t bleed and they don’t dehydrate as readily. Eoin runs very few horses on Lasix anymore. The only ones he uses it on are those with owners who strongly feel they are giving up a competitive edge if they don’t use it. We’ve determined that Lasix probably hinders more horses than it helps, and we’re not sure that it even helps any of them,” he says.
“In the early days of Lasix use (before the four-hour rule), trainers gave it closer to race time, within an hour or two. In that situation, there was probably a little less dehydration dur- ing the race (the effects were not yet complete) and perhaps some benefit from weight loss,
so it may have been performance-enhancing. State regulators recognized this, and that’s why administration time was pushed back to four hours to offset that advantage,” says Casner.
“People still believe in it, but the only sci- ence that has been done on it has been done on treadmills in which the heart rate doesn’t get anywhere near what it does at racing speed, so we really don’t know how it affects the run- ning horse.” Horses’ heart rates can reach 240 beats per minute (four times per second) and anything that disrupts cardiac electrolytes will impair optimum contraction. We tend to hin- der our horses more than help them when we use medications like NSAIDs and Lasix that often contribute to serious dehydration.
“Most of the time, the medication is to get them through the vet check before the race, and that’s why trainers give it the night before. The vet comes by and the horse is moving well, and by race time the effect is gone,” he says.
“A little knowledge is a dangerous thing, and that’s what’s happened over the past 25 years. Use of these medications has become so instilled into the culture of horse racing that people just cannot believe that horses can run without it—even though they do overseas. People here rationalize that by say- ing those horses run on turf or at a slower pace, etc., and make a lot of excuses. A lot of American horses have gone to Dubai, however, and performed nicely without medication,” he says.
“A few trainers in the U.S. are now run- ning their horses here without it. We had two Breeders Cup winners this year that ran with- out medications and set track records.”
Horses ran races for decades without it and performed well, and at a higher level than they are now. “I look at the races run by Secretariat, Seattle Slew, Affirmed, Alydar, etc. We had more Triple Crown winners back then,” says Casner.
Dehydration is generally not a problem as long as horses have a chance to drink and make up the loss. Endurance riders and ranchers who
use horses for long days out in the heat know that they
Racehorses sweat
a lot and their heart
rate can reach 240
beats per minute.
When medications are added that alter the levels of electrolytes, such as calcium and potassium, the heartbeat can be disrupted. The horse’s body will shift calcium from bones to wherever it is needed, but efforts to replenish electrolytes that have been flushed from the cells can take quite a while to be restored
at intracellular levels
need to let those horses drink every chance they get. If horses can stay hydrated, they are ready to go again the next day. They don’t get days off.
The big problems come when we use horses hard in the heat. They sweat a lot and we
skew things with medications. “A physiologist told me that a person can ‘jug’ a horse with electrolytes after a race in an effort to restore calcium, potassium, etc., that has been flushed out of the cells. You can give them ‘jugs’ and restore the extra-cellular levels, but it takes 30 days to restore intracellular potassium after it is severely depleted,” he says.
“Every time we give Lasix, we flush a
lot of calcium from the body cells and the only way that can be restored quickly (for that horse to continue to have proper muscle contractions, cardiac function and nerve transmission), is by pulling it from the bones,” explains Casner. The body has this wonderful mechanism to shift calcium from the bones to wherever it is needed. Lactating cows and broodmares do this to produce milk when dietary sources of calcium are inadequate. The body can rely on calcium stores within the bones for immediate use, but it takes quite a while to restore it.
88 SPEEDHORSE, March 2016
Dehydration is generally not a problem as long as a horse can drink plenty of water and make up the loss
EQUINE HEALTH