Clear blue skies, warm sunshine - it may brighten your mood but as the temperature rises it's necessary to consider the effect it may have on your horse's health.
Here's some advice on how your horse regulates his temperature and what you can do to help him stay cool.
Did you know that horses sweat 3-4 times more than humans?
And
Horses and humans are the only animals that sweat through the skin?
Your horse has his own in-built cooling and heating system called thermoregulation. This keeps his body temperature within a certain range. Sensitive nerves and receptors in the skin, abdomen, skeletal muscles and parts of the spinal cord send messages relating to body temperature to the hypothalamus – the thermoregulatory centre within the brain.
How your horse deals with heat
If you horse becomes too hot, through hot weather or exercise, he deals with it in 4 ways:
1. Evaporation. The is the most effective way for your horse to lose heat.
Sweat is secreted on to the skin, drawing heat from your horse as it evaporates. As the core temperature rises through either external temperature or exercise, blood flow to the skin increases. About 60% of heat carried in the blood is transferred to sweat and is subsequently lost as the moisture evaporates from the surface of the skin and thereby lowering body temperature.
The cooling effect of sweating is greatly reduced when it’s humid – this is when the atmospheric moisture reduces the efficiency of evaporation. In these conditions you must cool your horse down quickly with large amounts of cold water.
2. Convection. Air that passes over your horse’s body is heated by the skin and rises, this is replaced by cooler air – particularly if there is a breeze.
3. Radiation. Capillaries under the skin widen in a process known as vasodilation – this is when more blood transfers into the dermal regions. Some heat is then lost into the atmosphere.
Learn more about vasodilation, the circulatory system and vasodilation HERE.
4. Conduction. This is the transfer of heat from the body to cooler water, or to the ground if your horse is lying down. The cooler the water the more effectively conduction removes heat.
The role of electrolytes
When your horse sweats he will lose electrolytes and need to be replaced. His body fluid balance is carefully controlled by electrolytes – these manage the movement of water into and out of cells and in maintaining homeostasis – the transmission of nerve impulses, the healthy function of muscles, and the circulatory system.
Electrolytes are lost:
During training – sweating begins after 10 minutes of exercise.
In high temperatures and high humidity. You horse can lose 10-15 litres per hour!
Travelling long distances.
In urine.
Maintaining a healthy electrolyte balance
Make sure fresh water is available at all times.
Add electrolytes to feed.
Give your horse access to a salt lick. Sodium chloride (common table salt) is the most important electrolyte.
A deficiency in electrolytes can lead to:
Dehydration
Tying up
Fatigue
Lethargy
Constipation
Drop in performance
Top tips to help your horse in hot weather
Most horses will cope with hot weather but older horses or those with health conditions may not.
Bring your horse in out of the sun if he doesn’t have access to shade in his field. Brick or stone stables tend to be cooler whereas wooden stable can get very hot.
Avoid exercising during the hottest part of the day – ride first thing in the morning or late evening.
Make sure your horse always has access to clean water.
If your horse is stressed by the heat hose him off – it doesn’t have to be ice cold but it’s important to apply a lot of water to cool effectively. Allow your horse to dry naturally – DON’T scrape off the water. This can be done three or four times a day.
If your horse is on box rest consider getting him fan for his stable.
Learn to recognise the signs of heat exhaustion – very hot to touch, sweating all over, a lack of interest in his surroundings, unsteady on his feet, and/or deep and laboured breathing. If you’re in any doubt, cool your horse down by hosing him continuously all over his body until his breathing returns to normal.
This article contains extracts from Gillian's books Horse Anatomy for Performance and How Your Horse Moves