When horses exercise they burn up stored energy supplies, damaging muscletissue and losing water and electrolytes via sweat. After exercise it is important toreplenish these energy, water and electrolyte stores and provide protein for muscle repair.Failure to do so can result in reduced performance, muscle wastage and slow recovery times.What you feed, how you feed it and when it is fed all play a role in determining howeffectively you replace what your horse uses during moderate to high intensity exercise andhow quickly they will recover.

Replenish energy reserves
When a horse exercises, its muscles use glycogen (glucose that is stored by the muscles),fatty acids and some amino acids as fuel. During fast sprint type, high intensity work,muscles operate under anaerobic (no oxygen) conditions and primarily use glycogen as anenergy source. Under slower, low to moderate, intensity work the muscles will primarily burnfatty acids for energy under aerobic (oxygen using) conditions, saving muscle glycogensupplies for when it is needed for high intensity work.

If muscle glycogen supplies are depleted, the horse quickly becomes fatigued. Therefore itis important that after exercise, muscle glycogen supplies are replenished, otherwise thenext time the horse exercises it will start with less glycogen on board and will reach astate of fatigue faster.

The fastest way to replenish glycogen supplies in equine athletes is to feed a grain‐basedmeal following exercise. Grains contain starch, which is digested and absorbed as glucoseand this glucose is directly used to replenish glycogen supplies. The grains fed should becooked (either extruded, micronized, steam flaked or boiled) to maximise their smallintestinal digestibility (so more of the starch can be digested and absorbed as glucose).

A grain‐based meal should be fed within an hour of completing exercise. Once the horse hasreturned to a near normal respiration rate and started to cool down the meal can be fed. Ifthe horse has completed its exercise for the day it can be fed its normal morning or eveningfeed at this time. If you are still taking part in competition (for example you are at a vetcheck point in an endurance ride) you should limit the meal to 200 g of grain per kg ofbodyweight (or 0.2 lb per 100 lb of bodyweight) so that you don't induce a large increase inblood insulin levels (as discussed in Newsletter #16).

The horse's normal ration of hay and/or pasture should also be made available immediatelyfollowing exercise. If your horse cannot have grain in its diet or does not have grain aspart of its normal daily ration you must not use grain to replenish glycogen suppliesfollowing exercise. Instead, these horses should just receive their normal non‐grain ration.It may take these horses longer to recover from very heavy exercise and as such they may notbe capable of sustaining the workloads required for intense sports like horseracing,endurance and polo.

A note about overweight and lightly worked horses
If your horse is overweight or lightly worked it isn't necessary to replace glycogensupplies following work. The focus for overweight horses should be to burn calories and loseweight. Following exercise, their body will gradually replace any muscle glycogen that wasburnt during exercise using other sources of energy like propionate, a volatile fatty acidabsorbed from their hindgut that can be turned into glucose. Feeding grain after exercisewill only serve to slow weight loss progress and may even cause weight gain. Overweighthorses are also unlikely to exercise at an intensity that uses up any significant amount ofglycogen.

Likewise it is unnecessary to replenish glycogen supplies by feeding a grain meal followingexercise in horses that are only lightly worked or horses that are only worked a couple oftimes a week. These horses are unlikely to burn much glycogen and/or they have plenty oftime to easily replace what they did use before their next bout of exercise.

Look after the muscles During exercise a horse's muscles experience multiple little rips and tears that have to berepaired. The muscles also need to grow, strengthen and tone so they can cope with the workrequired of them. Ensuring crude protein and lysine requirements are met according to FeedXLwill mean your horse's muscles have access to plenty of amino acids to repair and grow,however supplying high quality protein in the form of whey protein concentrate immediatelyfollowing work (within the first 15 minutes of finishing exercise) may help lightly muscledhorses build muscle bulk faster. Whey protein provides rapidly absorbed amino acids thatfirst feed a horse's muscles, second signal to them to slow or stop the muscle breakdownprocess that occurs during and following exercise and finally, provides muscles with thebuilding blocks they need to grow and strengthen.

Dose rates of 10 to 20 grams per 100 kg of bodyweight of whey protein concentrate arecommonly used. There are also equine specific whey protein and other high proteinsupplements available for this purpose. Timing is critical for these supplements to beeffective; it must be given immediately after exercise (as opposed to giving it with thenext meal).

Rehydrate
There has been much debate over the years about when to allow a hot horse to drink waterfollowing exercise, with the common perception being that allowing a hot horse to drinkcauses colic. While you may wrestle with whether to let your horse drink immediatelyfollowing exercise I would urge you to use your common sense and knowledge of your ownhorse. If your horse wants to drink following exercise and doesn't seem to suffer any illeffects, then I would suggest allowing him to drink, as the positive effects of rehydrationwill be far greater than the benefits associated with not allowing a horse to drink until itis completely cooled. Drinking water will also help to lower a horse's core body temperaturefollowing exercise.

You should observe a few guidelines:
1. Offer cool water that is at a temperature that is comfortable for you to hold your handin (i.e. not too cold).
2. If you horse is a real guzzler, get him to take a few small breaks when drinking.

If you have observed your horse get colicky after a big drink then it would be wise to allowaccess to water gradually after exercise. But if your horse drinks with no ill effects thereis no reason to withhold water following exercise.

Research has also shown that giving slightly salty water (which you can makeby adding up to 9 grams of sodium chloride, which is common table salt, per litre to yourhorse's water) as the first water your horse has access to, followed by giving access toplain water aids in achieving high fluid intakes and faster rates of rehydration.

Replace electrolytes
When horses sweat they lose large amounts of the electrolyte minerals sodium, chloride andpotassium. They also lose smaller amounts of magnesium and calcium. These minerals lost insweat must be replaced to allow full rehydration and normal sweating and muscle function insubsequent bouts of exercise.

Ensuring that your horse's requirements for sodium, potassium and chloride are met accordingto FeedXL and making sure your horse has free access to a salt lick is adequate to ensureelectrolyte repletion on a daily basis. Under intense workloads (for example endurance) orwhen horses are working in very hot and humid conditions you may need to consider using aspecially designed electrolyte replacer for horses.

When selecting an electrolyte replacer for your horse, read the label of the availableelectrolyte supplements carefully. Be wary of products that contain less than 800 grams perkg of actual electrolytes (sodium, potassium, chloride, calcium and magnesium). Someproducts on the market are more than 50% 'filler' (usually dextrose or glucose) which is oflittle benefit to the horse as part of an electrolyte replacement program. Some glucose isnecessary for the effective absorption of sodium, but glucose should represent no more than10% of an electrolyte supplement.

The use of electrolyte replacers is a large and relatively complex topic that deserves adedicated FeedXL newsletter.

Summary
Failure to replace what a fit horse in moderate to high intensity work uses during a bout ofexercise will mean that the horse gradually becomes less and less able to complete the workrequired of it. Using a digestible cooked grain based feed in the first hour following thecompletion of exercise will restore muscle glycogen supplies. Feeding a high quality proteinsupplement like a whey protein concentrate within 15 minutes of the completion of exercisewill feed the muscles and allow them to repair and strengthen. Providing access to water,and initially slightly salty water following exercise will allow your horse to rehydrateitself. And finally, ensuring dietary requirements for the electrolyte minerals sodium,chloride and potassium are met according to FeedXL will allow your horse to replenishelectrolyte minerals lost during exercise as it eats its normal daily ration.

See Also:

Feeding BeforeExercise

Dr. Nerida Richards (PhD) is Australia's foremost expert in Horse Nutrition. This article iscourtesy of FeedXL DIY Diet Planner forHorses. If you would like be among the first to receive FeedXL newsletters thenplease consider subscribing to FeedXL.

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