Hydration for Performance… Is your horse hydrated enough? (January 2015)


We all know that our horses need to be hydrated to perform well. But how do you know if your horse is hydrated enough? In my work as a McTimoney Animal Therapist, I have come across cases where mild dehydration is playing a part in the build up of tension and muscle soreness in the performance horses I have seen. As well as addressing the specific musculoskeletal imbalances I am trained to correct, aftercare advice includes a discussion on how the horse may be encouraged to hydrate fully. I thought that as many of you will be thinking ahead to the 2015 season, this might be a good time to throw some ideas around with you as well.

Correct hydration is necessary for optimal performance in terms of muscle function and heat balance within the body. So surely the topic of hydration is most pertinent in the hot summer months, when higher temperatures and humidity result in faster dehydration in our horses when out competing or riding at home? To an extent, yes it is more important in the summer months as the role of water in the removal of heat from the body and muscles accelerates the rate of dehydration in the warmer temperatures, but mild dehydration can be an overlooked factor in the winter months of training too.

Horses which sweat a lot through intensity of work or excitement will lose fluid, yet whereas in the hotter months a horse led to water will tend to drink, the colder ambient temperature can put horses off drinking cold water even when they need to. A horse which has got cold and is shivering will not drink cold water so the easiest way to encourage uptake of fluid is to get the rugs on and some sloppy feed in first. (If your horse is seriously dehydrated then veterinary intervention may be necessary.)

Hydration is easily monitored by pinching the skin gently at the base of neck and timing how quickly it recoils to normal tension again. A recoil time of less than one second is considered normal for the hydrated horse, more than one second indicates that the horse needs to take on more water. However, older horses in their twenties or beyond, often have less elasticity in their skin so may give a false positive result for dehydration, as their skin naturally takes longer than a second to recoil back to normal.

This is only a guide though, and every horse is an individual. Certainly, the cases I have seen which responded to a greater focus on hydration and fluid uptake, were not obviously dehydrated at the time of assessment and treatment for muscle tension and skeletal asymmetry. So what were the clues?

Firstly a consistent whole body increase in tone beyond that expected for the stage of training. Usually a horse will develop specific areas of tension and soreness relating to whatever the causal factor might be, so for example a horse with a poorly fitting saddle will have greater soreness in the paravertebral back muscles where the saddle has been pinching or moving. A high tone and lack of ‘bounce’ in the muscles throughout the body can result from high intensity training but may also indicate reduced hydration in the muscles, making them feel tighter and ultimately this means they are less powerful and more likely to tire sooner.

Another clue the rider might notice is a reduction in stamina, where their horse seems to tire sooner than expected for the stage of training. Alternatively the horse may feel ‘flat’ to ride or lack enthusiasm where he or she used to be keen to go. These can also be symptoms of other conditions including systemic illness, so monitor your horse and discuss these symptoms with your vet if in doubt. If no other reason can be found, it is possible that your horse will respond to a higher level of hydration.

“You can lead a horse to water, but you can’t make him drink…”

As mentioned earlier, it isn’t always easy to get your horse to take on more water, particularly when the weather is cold. However, there are simple ways to increase fluid intake and in many cases, horses will learn to drink more as time goes on. A very simple way to improve water uptake is to introduce salt to your horse’s diet, or use an electrolyte in the water supply. A salt lick in the stable is unlikely to be enough for most horses in work. Horses can tolerate up to 100g table salt per day although if you try to give your horse that much straight away, he or she will probably say you are trying to poison them! Start with 25g in one feed each day and slowly increase the amount over a period of two or more weeks. For most horses working up to an hour schooling or hacking five times a week, just 50g salt may be enough. But if you working at a higher intensity such as up gallops or training for endurance then up to 100g is preferable.

Another way to increase water uptake is to use something your horse likes in his water bucket such as carrots, apple juice or a handful of feed so your horse learns to drink in order to get to the feed he or she wants. Or you can turn your horse’s feed into soup by adding water to his or her feed bowl making the mixture as liquid as you can.

Too much of a good thing?

You would think that it wouldn’t hurt to drink too much water, but if your horse is drinking a lot more and urinating very frequently, then it is possible that an underlying condition needs diagnosis from your vet. While water intoxication does occur in humans, mostly publicised in marathon runners, it is unlikely that your horse will ‘over-drink’ unless there is another cause so if you suspect your horse is drinking a lot more than previously, then ask your vet about this.