Summer care | The British Horse Society

Increasing water intake

A constant supply of clean, fresh water is essential to help prevent dehydration.

A 500kg horse can drink between 20-30 litres (approximately 3-4 buckets) of water per day and this can increase to up to 50-60 litres (approximately 6-7 buckets) per day in hot weather.

Water has a key role in your horse’s digestive system, where it is continually secreted into and reabsorbed from the gut. Changes in hydration, by not having enough water, can cause disturbances to the digestive process and how food passes along the gut. This increases the risk of impaction colic which occurs when a firm ball of feed material blocks the intestine.

Soak hay

Introduce gradually to reduce the risk of colic and soak for at least six hours in cold water. Less time may be needed in warmer weather^1,2.

Water sources

Aim to have more than one water source available and where possible avoid corners of the field to prevent conflict.

Flavouring

Add a flavouring of mint or apple juice.

Change buckets daily

Change buckets in your stable daily to ensure freshness.

Water left too long can become unpalatable.

Use Enrichment

For example, cut up your horse’s fruit and veg. Pour on some water (or mix with some apple juice and water) and freeze to make a fruit/veg ice block. If feeding any new fruit and veg, it is extremely important to introduce new foods gradually over a period of 10-14 days to reduce the risk of colic. Ensure your horse has good dental health to help prevent the risk of choke. Always feed in moderation to ensure your horse continues to have a balanced diet. When introducing new enrichment always supervise your horse, and if you have any concerns, remove it.

Shelter

Shelter or shade is preferable in hot weather. If your horse is turned out, a field shelter provides the best protection from the sun. The shade provided by trees and hedges may provide a good substitute but remember that the shade will move with the sun, so there may be certain times of the day when it isn’t accessible to your horse. If natural shelter is used make yourself aware of poisonous trees and hedges which are unsafe for use around horses.

If you have the facilities, stabling horses through the hottest parts of the day, providing their stable remains cool, is an option to consider. However, inadequately ventilated stables can become uncomfortably hot and stuffy and your horse’s management must be changed gradually to reduce the risk of colic.

Flies

Flies are a hot weather menace! To help reduce your horse’s exposure:

Keep your horse in during the day and out at night
Use thin fly sheets and masks
Apply a fly repellent spray – always follow the manufacturers’ instructions and do not use on inflamed or broken skin
Remove droppings frequently from the paddock and stable
Position the muck heap away from where the horse is kept where possible.

Sun protection

Sun cream isn’t just for humans! Horses with pink skin and grey or white hair are most susceptible to burning so sun protection is highly recommended, especially on pink noses.

Watch

Looking after your horse in the sun

Grazing

The hot weather may affect your grazing, as the sun can dry out the grass, effectively turning your grazing into hay! This grass will still provide enough calories for your horse; however, the nutritional value may decrease. A low-calorie balancer or vitamin and mineral supplement may be required to ensure your horse is getting exactly what they need. A horse grazed on sun dried grass does not necessarily need additional forage assuming they are not losing weight. For horses in medium-hard work additional calories may be needed.

Assess the level of work your horse is in before providing additional forage, and fat score your horse to help assess whether they need any additional calories. Remember, your horse will not be burning as many calories through the summer, as they naturally would through the colder winter months to keep warm.

Be extra careful if you own an overweight horse or a horse with an underlying condition such as Equine Metabolic Syndrome or Cushing’s Disease and rain is forecast. The combination of rain and sun will cause the grass to grow quickly and if you let your horse eat too much, this could increase the chances of laminitis. Be prepared to limit grazing if rain is on the horizon and introduce your horse slowly back to what will be a very different forage compared to what they have been eating before the rain. 

If your horse is kept on a bare paddock be aware they could consume more soil or sand, increasing the risk of colic. You may need to feed additional forage to help prevent this. Introduce any new forage gradually over a minimum of 10-14 days. 

Identifying signs of heat-related illness

Recognising when your horse may be struggling in the heat, and taking the appropriate action, is vital in maintaining their health and welfare, especially in very hot or humid conditions. When the horse’s internal body temperature gets too high serious heat-related conditions can occur.

Dehydration

Dehydration can occur when a horse loses more water (for example lost in sweat, breath, urine and droppings) than it takes in. Signs of dehydration include¹:

Dark urine
Reduced urination
Skin slow to return to normal after being pinched
Very dry droppings
Reduced amount of droppings
Higher heart rate than normal
Lethargy and/or depression
Dry skin and mouth with thick saliva
Dull eyes
Longer capillary refill time- the time taken for gums to regain their healthy pink colour after pressure has been applied
Gums that are dark in colour - become redder rather than the healthy pink

A horse should not necessarily be considered dehydrated based on the observation of one sign. The more signs that are present the greater the chance that the horse is dehydrated and the greater the severity the dehydration is likely to be¹.

Heat Exhaustion and Heat Stroke

Heat exhaustion is a serious condition and can occur if the horse is exposed/exercised in very hot or humid conditions for long periods and is often also suffering from dehydration. Signs of heat exhaustion may include the signs of dehydration above and potentially:

Fast, shallow breathing (panting)
Nostril flaring
Increased rectal temperature, that does not, or very slowly returns to normal after a period of rest. The normal range is between 37.5-38.5°C.
An irregular heartbeat
Decreased appetite and thirst
Slow recovery after exercise
Muscle spasms
Reduced performance

If your horse is showing signs of heat related illness contact your vet immediately, move them into the shade and provide water to encourage them to drink. Start to cool the horse by continuously applying cold water all over the horse’s body until help arrives.

If not quickly and carefully managed, a horse suffering with heat exhaustion can progress to develop life threatening heat stroke, although this can sometimes appear suddenly without warning. Horses suffering from heat stroke can be very challenging and dangerous to manage as their behaviour can become aggressive and some signs may appear neurological, for example losing perception of where they are, with no regard for their handler.

If your horse begins to display bizarre bullish behaviour following substantial exercise on a hot day, they are most likely suffering from heat stroke. If not treated quickly and effectively it can cause damage to the kidneys, heart, lungs, brain or muscles, and in some cases can be fatal¹.

References

Rendle, D et al. (2018) Equine obesity: current perspectives. UK Vet Equine. Vol 2.
Furtado, T et al. (2018). When the grass is greener: The Equine Weight Management guide for every horse, every yard, and every owner. The University of Liverpool/ Horse Trust.

Thanks to Dr Teresa Hollands, Senior Teaching Fellow (Veterinary Nutrition) at the University of Surrey for her assistance with the grazing advice.

Horse care in hot weather