Many horses will find hot weather uncomfortable, but the good news is there is plenty we can do to help keep them cool and reduce the risk of dehydration and colic.
Horses can consume more than double their normal water intake in hot weather, so be prepared for this. A constant supply of clean and fresh water is essential to help prevent dehydration – buckets of water in the stable will become warm and possibly unpalatable if left to stand for too long.
Water has a key role in your horse’s digestive system. If your horse doesn’t have access to any or enough water it can increase the risk of colic. Water is an essential component in the digestive process. It is continually secreted into and reabsorbed from the gut. Changes in hydration can affect the digestive process and how food passes along the gut. This can lead to problems such as impaction colic. If the drinking supply is from a silty natural water source this could lead to sand colic.
Read more about colic here.
It is ideal to have more than one water source available in the field so that certain herd members aren’t prevented and chased away from drinking by other herd members. Keeping the water source away from a corner will help prevent a horse being ‘cornered’ by another horse.
You could also soak or steam your horse’s hay to help increase water intake. Remember to introduce soaked/steamed hay into the diet gradually to reduce the risk of colic. Feed soaked hay as soon possible after soaking and dispose of any uneaten soaked hay. Avoid soaking hay in direct sunlight and soaking for long periods of time in warm weather as it may encourage mould growth. It is recommended to soak hay for around 1-2 hours in warm conditions. However, if you normally soak your hay for longer periods speak to your vet or a qualified nutritionist if you have any concerns.
If appropriate, you could add a flavouring of mint or apple juice to your horse’s water to encourage them to drink.
If you cannot avoid travelling your horse in hot weather then try to travel as early or as late as possible to avoid the hottest part of the day and take more water with you than you think you will need. Remember some horses are fussy about drinking water away from home, so it could be essential to have a familiar supply.
Carrying plenty of water is also a vital part of being prepared if your vehicle was to break down with your horses on board. You could be stuck at the side of the road waiting for a recovery crew so water will be vital to help keep your horse cool and hydrated.
Read The British Grooms Association’s advice on Horse & Hound about what action you can take if caught up in motorway traffic.
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. 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 suddenly changing your horse’s management can increase the risk of colic.
If you are going to exercise your horse, it is best to do so either in the morning or evening when it is coolest. If exercising in the hotter weather take more breaks- horses can’t be expected to do as much in hot weather as at other times if they are not acclimatised to working for longer periods in hot weather. It takes 2-3 weeks of regular exercise in hot weather for a horse to acclimatise. Be mindful of your horse’s fitness as overweight horses may struggle more in hot weather and are at a higher risk of heat related illness.
Don’t forget to wear hi-viz if you are riding out. Even in bright sunshine patches of shade can make it difficult for drivers to spot horses on the road.
After riding make sure you cool the horse down properly. This can be achieved by continuously pouring cold water all over the horse’s body. Not scraping the water off the horse does not cause the skin temperature to rise and leaving water on the horse does not increase the horse’s temperature. More information on cooling your horse can be found in Dr David Marlin’s article.
If your horse has a thick coat (like a Cushing’s sufferer, for example) then he may need a clip to prevent him becoming too uncomfortable.
Flies are another hot weather menace. If you can keep your horse in during the day and out at night then his exposure to flies can be reduced. Thin, white fly sheets, fly masks and insect repellents can help greatly. The saliva from the bite of Culicoides midges and to a lesser extent the black fly can cause an allergic reaction in some horses resulting in the condition known as Sweet Itch (also known as Insect Bite Hypersensitivity). Intense rubbing of the mane and tail can ensue to the extent that some horses will rub themselves raw. Further information on Sweet Itch is available here.
Remove droppings frequently from the paddock and stable to avoid attracting flies and position the muck heap away from where the horse is kept where possible.
Sun cream isn’t just for humans! Remember horses with pink skin and grey or white hair are most susceptible to burning so sun protection is highly recommended, especially on pink noses.
Dehydration can occur when a horse loses more water (for example lost in sweat, breath, urine and droppings) than it takes in. Knowing what is normal for your horse is important so you know when your horse isn’t right. Signs of dehydration include:
- Dark urine/reduced urination
- Reduced amount of droppings
- Dry skin and mouth
- Thick, sticky saliva
- Dull eyes
- Gums that are dark in colour
As well as water, electrolytes are also lost in sweat, breath, urine and droppings. Electrolytes are salts and minerals that help with many different bodily functions such as making urine, digestion and muscle contraction and the major ones are sodium, potassium, chloride, calcium and magnesium.
A dehydrated horse can deteriorate quickly if not rehydrated. To help rehydrate a horse, electrolytes can be added to feed or water to help replace what has been lost. Ensure you follow the manufacturer’s recommendations on use and dose. If you do add to water make sure the horse doesn’t mind the taste as he may not drink anything at all- offer a bucket of plain water as well. Electrolytes can be fed daily for horses in medium work or above (eg competiting at affiliated level, eventing, polo, endurance etc) and not just during times of competition or dehydration. More information on electrolytes can be found in Dr David Marlin’s article.
Heat exhaustion can be a very serious condition and can occur if the horse is exposed/exercised in very hot or humid conditions and is often also suffering from dehydration. Signs of heat exhaustion may include signs of dehydration and potentially:
- Increased pulse and breathing rate
- Nostril flaring
- Increased rectal temperature
- Fast, shallow breathing (panting)
- Reduced urination
- An irregular heartbeat
- Decreased appetite and thirst
- Slow recovery after exercise
- Muscle spasms
- Reduced performance
- Decreased appetite
- A raised temperature
If your horse is showing signs of heat related illness contact your vet immediately, move him into the shade and 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 process to develop life threatening heat stroke. This may lead to the horse becoming unsteady on their feet (ataxia) and/or collapsing.
The hot weather may also affect grazing too as the sun will tend to bleach grass and dry it out; effectively your grazing has been made into hay! Although it may not look very green horses are likely to consume enough calories to sustain them as indeed they do from hay assuming that they are only in light work. But, the nutritional value of very sun dried grass maybe lower than conventionally made hay as the vitamins will have been oxidised and therefore a balancer maybe required to provide the horse with its vitamin and mineral requirement. A horse grazed on sun dried grass does not necessarily need additional forage assuming that it is not losing weight.
Before providing additional forage it is vital that you fat score (body condition score) the horse, as this will help determine whether they are getting enough calories from the grass. It is likely that they are not using as many calories compared to the winter when grass is generally not available. In addition because of the hot weather they might not be ridden as much as normal and of course they are not burning calories to stay warm.
Another way of monitoring if your horse is eating enough grass would be to monitor your horse’s poo! If you are collecting less than 1% of the horse’s bodyweight as droppings then the horse may need extra forage. Be extra careful if you own an overweight horse or a horse with an underlying disease such as Equine Metabolic Syndrome and rain is forecast. The combination of rain and sun will cause the grass to grow quickly which could increase the chances of laminitis assuming you let your horse eat too much. Be prepared to limit grazing if rain is on the horizon and introduce your horse slowly back to what will effectively be a very different forage compared to what they have been eating for the last few weeks.
Also, a bare paddock may mean that your horse will ingest more mud, soil or sand which could increase the likelihood of colic so you may need to feed additional forage to help prevent this. Remember to introduce any new forage gradually over 7-14 days to decrease the risk of colic. Read more about Colic here.
Compare grass growth in 2019 with the last two previous years by region.
Thanks to Dr Teresa Hollands, Senior Teaching Fellow (Veterinary Nutrition) at the University of Surrey for her assistance with the Grazing advice.