Hot Horses, Hydration and Heatwaves

Hot Horses, Hydration and Heatwaves

Heat waves are becoming more frequent – that’s a scientific fact. Horses are particularly susceptible to heat stress (they heat up 10 times faster than we do) so we owe it to them to give our hot horses that extra care in extreme heat not only for their comfort, but for their health.

Like most living creatures horses have a natural way of coping with hot weather. They sweat up to 20 litres an hour in cool conditions and as much as 30 litres in hot, humid weather. The sweat evaporates cooling them down, but there are situations when this is not enough and the body temperature increases drastically causing heat stress, with dire consequences.


A normal body temperature for a horse is around 37 degrees C … if this increases to around 41 degrees the muscles literally begin to cook (denature) and can lead to hypotension, colic and kidney failure.

It’s a bit ironic that heat waves tend to happen during the season when horses are expected to perform at their best … in shows, eventing, endurance, racing and all the other equestrian events we so enjoy during the summer season.

A horse that is worked too hard on a hot day can become seriously overheated. Even just hanging out in the field on a hot day can make a horse overheat if there is no shade available, especially if he’s obese or has a shaggy, thick coat.

Excessive sweating itself can cause dehydration, depleting minerals and salts in the system which, if not replaced, could cause a metabolic crisis.


So how can you keep your hot horses healthy and happy?

The most important element you need is water. Firstly to be used in the most obvious way which would be the availability of plenty of clean, fresh water available to drink. On extremely hot days a horse should drink about 20 gallons of water a day, which will certainly keep horse owners busy, especially if you have a herd to care for.

To compensate for sweating add an electrolyte supplement to his diet and provide a salt block.

For hot horses that are not keen drinkers you can make up for it by adding water to feed supplements rather than feeding it dry, or use a product such as the amazing Horse Quencher to encourage him to drink.

Just like humans, horses also appreciate being cooled down with water on a hot day. If he enjoys it hose him down … let him loose to wallow in cool rivers and streams. Hot horses can be cooled by being wet down and scraped off repeatedly.


Did You Know?

Water makes up to 75% of the average horse’s body, an apple is 85% and a jellyfish is 95%. We are approx 50%....

In an average 450kg horse this 75% would equate to 70 gallons of water leaving him with only 199kg of bone and tissue.

Water, therefore to the horse is a very important commodity and, unfortunately, they can be difficult to keep hydrated when in hard work or just throughout the summer. Sadly horses are not like us, when they are thirsty they will not always drink!

Dehydration is serious causing fatigue, tying up and even colic. Just a 10% loss of water can cause a large decrease in performance. When you take into account that a horse working in hot weather can lose up to 15 litres of sweat per hour (compared to our 2 litres) and then add to this that he will not always drink even then; making him drink becomes crucial.

When horses sweat they lose equal amounts of salt and water, so therefore unlike humans who sweat mainly water and little salt, the horse’s body does not receive the required signals to stimulate the thirst mechanism. To encourage the horse to drink, therefore, we have 2 approaches:

1) Add salt or electrolytes to his water/feed or give them by syringe

2) Use Horse Quencher to make his water taste yummy and encourage him to drink.

There are many electrolytes on the market today, however, like all horse feed supplements they are all slightly different and contain a different combination of different ingredients.

Search our Electrolyte page for our favourite products


Don’t forget heat brings out flies and other insects, which come with their own dangers to horses. If your horse is susceptible to bites and skin conditions, make sure you keep him in during the times of the day (especially late evening) when insects are most active. Use insect repellents and fly rugs to keep him comfortable.

Poo pick frequently, keep stables clean and locate your stable waste as far away from the horses as possible.

Heat and high humidity also increase the activity of bacteria and viruses, and therefore increase the risk of infectious diseases in horses. Be vigilant for any sign of infection and call the vet if you are at all concerned.


The basic tasks that face horse owners in the heat are to keep him cool, hydrated and clean. Apart from the factors already mentioned, you can do the following:

Provide an area where your horse can get out of the direct sun … a field shelter, shade trees.
Keep exercise to a minimum and don’t work him too hard on extremely hot, humid days – keep tack to a minimum and enjoy some light riding.
Keep stables well ventilated … a fan is a great way not just to keep things cool, cut also to blow off insects.
Keep wounds clean, dry and protected.
Be vigilant and aware of how your horse is handling heat, and if you have any concerns consult your vet. Check his rectal temperature, watch for profuse sweating, rapid breathing and heart rate, droopy ears and general tiredness, lethargy and dehydration (use the pinch test).
If an activity makes your horse overheated guard against cooling him down too quickly – this could lead to muscle cramping.

Enjoy your horse in the summer, but when conditions become extreme go that extra mile to help him cope! Totally Tack is here to help … we’ve got all the products and advice you need to enjoy a cool summer, available online!