If you haven’t seen Dr. Susan Garlinghouse speak - you should take advantage of any opportunity to do so. She is at least as hilarious in person as she is on her website. At one point she called us a “tacky” crowd (which is apparently synomonous with “endurance”) and then mentioned that this being an endurance convention, she has probably seen most of us pee in the bushes and vice versa.
Oh too true, too true. And sometimes there aren’t even bushes.
The point of the seminar was Hydration of the endurance horse and cumulated with some electrolyte advice.
One point that was reiterated over and over and over was that there are long term effects on a horse. Think of the horse as a rubber band - you can stretch it repeatedly, but it produces micro damage that can accumulate and eventually lead to failure, OR you can stretch it REALLY far a couple of times, and then lead to failure. Horses are NOT 100% when they cross the finish line and we can not pretend it is. Going 100 miles or even 50 miles takes a certain toll on a horse - whether it is conditioned and not - and this seminar covered dehydration specifically. The bottom line is that EVERY horse needs consideration for it’s hydration and other physical needs after it crosses the finish line and in the hours and days afterwards. Just because you got that completion, or received all As at the finish doesn’t mean that your horse is as “good” as it came out of the pasture (in terms of hydration etc.).
Just a few numbers and facts to keep in mind:
- A 12% dehydrated horse is about to die. 6-7% usually has some other associated problems
- Dehydration under 5% can't be accurately identified without blood analysis
- Average endurance horse is 5% dehydrated whether its a 50 mile or a 100 mile. (Some interesting theories such as after 50 miles the thirst mechanisms finally catch up, or the coolness of the night/slowing down helps etc.)
- Having your horse's head to one side can affect the skin pinch test done during the vet checks. This was interesting because I think I’m very guilty of having the horse’s head tipped in towards the vet during the vet check, and I often get marked down for skin pinches, even when the rest of the parameters look good.
- Difference between tolerable dehydration and treatment is 2-3 gallons of water.
- The difference between tolerable dehydration and “about to die” is 8 gallons of water.
- Trailering loss is 0.8 gal per hour, 1% dehydrated per 90 min travel. Thus, 8 hour trip produces a horse that is 5% dedicated upon arrival (6.25 gallons low).
Another point that was addressed was the people that say “my horse will drink what it needs”, or “when it’s thirsty it will drink”. Actually, although the second statement may be true, depending on how you offer water, the first is definitely NOT true. Horses only voluntarily replace only about 2/3 of fluid deficit by drinking during the ride. Part of managing hydration of the endurance horse is getting that figure as close to 100% as possible.
Lots of factors were presented that won’t let your dehydrated horse “tank up” after getting to ride camp, the night before the ride. Here’s some that were new to me, or were good reminders:
-If at all possible, bring familiar water. At least for that first night.
-Provide BIG buckets. Horses will drink out of large buckets better, and keep the water level up so that they don't have dip into the bucket below eye level. The difference between having a large bucket versus a small bucket is the difference between being at the airport and only having a water fountain, versus a water bottle. Muck buckets are ideal for water buckets at rides. Clean is a must.
-Alfalfa. Although we were told in an earlier seminar (nutrition) about some of the problems with an alfalfa diet in terms of calcium and ammonia production/secretion, I didn’t connect the dots about a diet high in alfalfa impacting hydration until this seminar. High protein (alfalfa diets) need more water in order to excrete the excess protein. Horses fed a normal diet high in alfalfa are already at a disadvantage when it comes to hydration because of their need of additional water.
-The older horse has less fluid in their body than when they were younger, so the older horse is closer to the edge of dehydration than when he was younger.
It was mentioned that a higher heart rate at ride than at home is probably because of fluid losses. Thus, don't count on your horse having the same heart rate and recoveries at a ride that he does at home
Always try to feed wet foods - hay if possible. Never feed dry pellets.
OK - back to the numbers!
Cellular function is adversely affected at less than 2% dehydration. The result at this level is decreased sweat production (which will then increase heat load)
At 3% dehydration there is a 10% decrease in muscle strength, 8% decrease in muscle speed. How does this effect endurance horses? Think about a horse that is presented as tired, and stumbling. Do you think that it could be related to a decrease in muscle strength due to a very low level of dehydration? (remember - we can’t detect below 5% without a blood analysis!). Why do we care about muscle speed? Think of a tired horse that is tripping - do you want them to recover their footing quickly, so that you don’t need to check out the ground in an intimate fashion? Does any one still think that low levels of dehydration still doesn’t impact their horse’s endurance performance? Garlinghouse mentioned that dehydration will show up as lameness because the horses are going to be fatigued, stumble, hurt something etc.
So why don’t horses replace the fluid they are losing?
Horses have a lag of thirst response and an “apparent tolerance” for thirst in the horse (i.e. they are more tolerant of being thirsty than we are). One mechanism that was explained in the seminar is that horse sweat is the same saltiness as the blood.....so while the overall blood volume is less as the horse becomes dehydrated, the saltiness level of the blood doesn't change that fast. This can be compared to humans - whose blood gets saltier as they lose fluid. The little receptors that trigger the thirst response detect the change in this saltiness. Thus the response in the horse is slower and less selective. The adage of “don't wait to drink until you are thirst because then you are dehydrated” is even more true in the horse than in the human.
Presence of water in the mouth and esophagus shuts down the thirst response. I am familiar with this concept, which is why I'm adamant about not pushing other horses off the tanks or letting someone else do so to me. I will hang back and let my horse stand while waiting for a hole at the water trough, and then once I’m there, I am adamant about not letting other riders let their mounts say “hello” or do anything else that might cause my horse to stop drinking. I’m polite but firm. If you allow your horse to be pushed off the water or stop to drink to say hello to someone (which is just bad disease control as well….) your horse will drink less. Considering that under ideal circumstances your horse already will NOT replace fluid he is losing, this is probably less than ideal…..don’t do it to others, don’t let it happen to you. Better to wait 5 minutes until there’s less people at the trough than to “get in the thick of it”. Garlinghouse’s suggestion was to let the horse;s mouth go dry - don't use your water bottle to squirt water into the horses mouth, or drink out of small puddles. These sources provide the horse with minimal water that won’t significantly replace his losses. Better to not let him get his mouth wet (and thus shutting down his thirst response), and let him drink at a source where he can “drink his fill”.
In one study, aggressively elyting horses at a 36 mile ride caused them to voluntary replaced more of their fluid losses than the horses that were not elyted. Electrolyting causes the blood to get saltier (thus increasing thirst response) BUT electrolyzing is not without its risks. Some of the horses that were aggressively elyted had blood work with too high NaCl. Recommendation: don't try to replace ALL the horse’s elyte losses during ride - only a portion. This study tried to replace 50% of elyte losses, they recommend replacing 1/3 of losses in practical application.
Example of what that actually MEANS: Average loss of 2 oz per hour in ambient conditions. 4 oz in extremes conditions. .6-1 oz per hour of exercise. 51/2 to 8 oz in an average 50 mile ride.
Other electrolyte considerations from Garlinghouse:
-Smaller doses work better for horses that stop eating on larger doses.
-Elyte when watering, or even earlier than the water in the early part of the ride. Do what you can. Try to do more often than just at the vet check.
-Lots of problems to try and replace all electrolytes so don't try to do that. You can get arrhythmias by elyte too heavily.
-Don't give elytes to a horse that's already dehydrated and should be drinking and isnt. Can make problems worse. Example: your horse doesn’t usually drink on the first 10 mile loop, but is usually drinking by mile 20. When he isn’t drinking at mile 30 is NOT the time to start elyting.
Some cool trailering tips to minimize the dehydration effects described earlier: elyte before departure (Can give a huge big load here since you know he isn't dehydrated), and hang tub of sloppy mash in trailer that is high value. Mash should have milk shake consistency. Soak soak soak and then add some more water. Horse can consume a couple gallons this way and is MUCH better than having them eat dry hay in the trailer…..obviously need to get horse used to eating milkshake mashes at home….
Another option is to offer salty water first, before going to communal water trough. Have to start doing this at home (of course!). Here’s how to practice: bring a thirsty horse to the bucket and don't let them drink out of their water trough until they drink out of the salty bucket. Use the same bucket for the salty water each time. Start really dilute and work up. Recommendation for Enduramax was 1 oz per gallon (2 tablespoons) for ending concentration, thus start at 1/4 or 1/2 this level then increase over time.
You must be consistent about putting elytes in the food at home if that’s how you want to give them because the horse will start to refuse feed. Have to start building small and then build up over time (like the salty water). Get the horse to the point where they can tolerate a higher level of salt. At home can use just regular table salt (no iodine), don’t have to use electrolytes (because what makes the elytes taste salty is the NaCl in it, which is the taste aversion you are trying to overcome). However, make sure to test your horse with the ride elytes before the ride because it may taste a little different than the table salt and you don’t want anything weird to happen at the ride!!!!
And that’s it for my notes!!!! I hope that you found a little something or a little tidbit in this information that helps you during your season. I think I’m going to experiment with salty water, and offering wet mashes in the trailer instead of hay in the trailer. And you bet I’ll be paying attention to hydration this upcoming season!!!! I didn’t realize how low levels of dehydration produces significant physiological/performance effects and I’ll be making sure that the water I offer at the trailer is in a container that promotes drinking.
Back to paying attention in my animal welfare class. I have a couple more convention posts to put up: one more seminar to summarize, and then some product/vendor reviews.
PS - sorry about the font/formatting. I CANNOT get blogger to cooperate with me today, and even had to use a different browser to even ACCESS blogger :(