Reading time 10 minutes

Summer heat: Temperatures above 30°C can be challenging for both riders and horses. What should you pay attention to so that everyone copes well during these hot days?

Firstly, it’s important to remember that horses are originally steppe animals and have a relatively high tolerance for both low and high temperatures. However, even a steppe horse will seek shade in the heat if possible. Particularly, very young and elderly horses may struggle with thermoregulation when it gets too hot. While foals often rest in the shade of their mother, older horses can suffer from age-related heart issues, making heat, humidity, and weather fluctuations more problematic for them. Even horses in their prime can be bothered by the heat, much like their owners. So, what should you consider?

1) Provide shade

Wild horses naturally seek out shaded areas during the hottest hours. Therefore, it’s essential to have trees or shelters in the pastures – even if they’re just stretched awnings – where the horses can take cover, especially at midday. If providing shade in the paddock isn’t possible, consider bringing the horses indoors during midday or, even better, allow them to stay in the paddock overnight and keep them in the shady stable during the day.

Most horses prefer having free access from the stable to the paddock anyway. In stables with such access, it is usually observed that the horses go out to graze in the early morning hours, return late morning before the intense heat sets in, and eat hay for a while. This helps them balance the fiber/nutrient ratio, which can be less favorable in pasture grass and sometimes leads to the well-known “pasture diarrhoea”. They then rest or doze in the shade of the stable during the midday period, and later, when the sun is not as hot, the herd goes back to the paddock to spend the evening grazing. Ideally, having pastures right next to the stable and ensuring this setup would be ideal. However, if that is not possible, bringing the horses indoors at midday and offering them hay in the stable can help prevent prolonged periods without roughage.

2) Ensure adequate water supply

Five bay horses drinking at a lake
© Juliaap / Adobe Stock

Horses regulate their body temperature quite well by sweating. This process leads to the loss of electrolytes, so it’s essential to ensure a good supply of minerals during hot weather, and water. Always have water available in the pasture. Large buckets made of hard plastic are preferable over common black mortar buckets, as the latter may contain carcinogenic plasticisers that can leach into the water. Alternatively, using bathtubs works well and they are easier to clean. A water barrel on wheels can also be a practical option. Regardless of the container used, it’s crucial to refill and clean them regularly. Warm, stagnant water can become a breeding ground for germs and insects.

If there’s a stream in the paddock, horses can drink from there. However, standing water like drainage ditches, ponds, or large puddles that persist after rainfall should be fenced off as they can become highly contaminated with germs and are not suitable as drinking water for horses.

3) Supply minerals

Apart from water, horses also lose electrolytes through sweating. These electrolytes include sodium, potassium, chloride, and magnesium, among others. While potassium is usually abundant in their basic diet, sodium, chloride, and sometimes magnesium can be limiting. To ensure proper mineral intake, horses should have access to a salt lick where they can replenish their sodium chloride (“common salt”, NaCl) needs themselves. Natural salt stones like mountain core or Himalayan salt are usually more popular with horses than the white pressed salt licks. You can hang the salt stone on a post or place it on the ground in a rain-protected area, such as the stable or under a large tree. You can also build a small “salt stone shelter” in the paddock or on the trail. Additionally, providing a good mineral feed regularly helps replenish magnesium and maintain overall mineral balance. Electrolyte supplements are usually only necessary during intense athletic training and competitions when horses sweat excessively. For regular sweating during hot weather or light exercise, a salt lick and mineral feed are sufficient.

4) Cool your horse down

On hot days, it’s best to ride in the morning and evening when the temperatures are more comfortable for both riders and horses. However, this isn’t always possible, and sometimes you have no choice but to work the horse during the day. In such cases, after work, hose the horse down with water – it’s as refreshing for them as a shower is for us. The water doesn’t have to be ice-cold; lukewarm water is often more comfortable for most horses. When hosing down, start at the hooves (!) and gradually work your way up. Pay equal attention to the front and hind legs, gently moving the water jet from the hooves upwards.

The reason for this approach is that the horse’s legs experience what are called “centralisation reactions”: when the legs cool down, “short circuits” between arteries and veins open up, diverting blood flow away from the extremities. This mechanism helps conserve heat during winter. However, if we spray the horse from top to bottom in the summer, the same reaction can occur. The blood pools in the legs, and it can no longer be efficiently transported towards the body. This can lead to not only stocked up legs but also delays in the regeneration of micro-traumas caused by riding. In the long term, this can contribute to tendon and ligament damage. Therefore, it’s crucial to remember to hose the horse from hoof to heart and do it slowly. Alternatively, you can also take your horse swimming in the nearest lake for a cooling experience.

5) Protect from flies

Three horses with flies on their heads
© Tom Goossens / Adobe Stock

Hot weather not only strains the heart and circulation but also leads to a resurgence of annoying insects in significant numbers. During the heat of the day, horseflies are particularly active, while in the evening, various types of mosquitoes swarm around, and flies can be a nuisance at any time of day. There are, of course, several fly sprays available in the market that claim to provide relief. However, there has been an ongoing “arms race” between insect and spray manufacturers for years. Some insects have developed immunity to these sprays and still bite. They pass this tolerance on to their offspring, rendering the fly repellents less effective year after year. DELETE Previously, cedar oil was quite effective in protecting against insects, but today it has lost its efficacy.

Fly sprays typically use various essential oils or chemical products. When selecting a spray, it is essential to ensure that it does not contain permethrin, as it not only acts against insects but can also harm horses by being absorbed into their bodies, having a neurotoxic effect and requiring detoxification through the liver. Horses with detoxification disorders (e.g., KPU) or increased liver stress can react sensitively to such substances. DEET falls into a similar category and can lead to severe health issues and equipment damage, as it can attack plastic. Natural products often include cinnamon oils, citronella oil, geraniol, catnip oil, eucalyptus oil, and various other mixtures of essential oils. When using essential oils, it is advisable to apply them in small quantities and preferably through spraying, as directly smearing them on the horse may cause sensitive skin reactions. DELETE

As alternatives to fly sprays, fly blankets, and fly masks (both with zebra patterns or regular ones) are available. Painting the horse with zebra stripes can also be effective. The compound eyes of insects struggle to understand the zebra stripes, causing the horses to appear blurred to the insects. However, insects can still perceive horses through their CO2 (breath) and butyric acid (sweat) receptors, especially during and after riding, as riders may know from painful experience.

Interestingly, horses with metabolic issues are more susceptible to insect attacks than healthy horses, as are horses with high blood sugar levels or insulin resistance. This could be due to the fact that such horses emit a different smell, making them appear more appealing to the insects. If your horse seems to attract horseflies and mosquitoes frequently, it’s worth considering your horse’s feed and metabolism.

6) Protect from sunburn

Horses with distinctive facial markings, such as light pigment spots around the eyes in breeds like Appaloosas or Knabstruppers, those with white nuzzles, or even lightly pigmented horses like Cremellos or Perlinos, are particularly prone to sunburn on their sensitive facial skin. This condition is usually identifiable by the formation of crusts, inflammation, and sometimes open and weeping areas on the skin. If you have a sensitive horse, it is essential to take precautionary measures. Using long fly masks can offer protection not only against insects but also shield the eye and nostril area from sunlight. If this solution is not feasible due to playful herd mates removing the fly masks while playing, you can alternatively apply baby sun cream with a high sun protection factor. Baby sun cream is generally well-tolerated by horses and allows them to stay in the sun for longer periods. It’s important to remember to reapply the sun cream every morning, especially considering that water-related activities (playing in the water bucket, sweating, bathing, hosing down) can wash it off.

A skewbald horse with pink nose at risk of sunburn
© lenkadan / Adobe Stock

Research has shown that certain feedstuffs can have a photosensitizing effect, meaning they increase the likelihood of sunburn. Besides the well-known St. John’s wort, commonly found in most domestic paddocks, this effect also extends to American hogweed, which can cause sensitizsation upon contact, even without being ingested. Wheat (often listed as wheat, wheat flakes, wheat semolina bran, or by-products of grain processing), commonly used in ready-to-eat horse feeds, also heightens the susceptibility to sunburn, making it advisable to avoid such feeds. Additionally, there are suspicions regarding the photosensitizing effects of alfalfa, so caution is also recommended in its use. Furthermore, it has been observed that horses with metabolic issues are more prone to sunburn compared to horses with a healthy metabolism. Therefore, in cases of suspicion, it is best to provide preventive sun protection in the form of baby sun cream or a fly mask before painful burns can occur.