Solving The Myth of Washing Down Horses

Whilst the UK is in the midst of a heatwave, a discussion is going on about the best ways to cool horses down. Usually we don’t have this problem and almost any method is sufficient.

It makes me wonder how equestrians cope in hot climates. Would any readers from those countries care to enlighten me? I think I was told when I was in Dubai that the polo horses had air conditioned stables and were exercised very early in the morning. Horses from those climates also tend to be fine coated and thin skinned, unlike our hairy natives who are all struggling as the thermometer nudges thirty degrees Celsius.

Some people advocate hosing and scraping, others say to hose and let evaporation do the cooling down.

In fact, the best answer is to do a bit of both. Imagine you are standing next to a very sweaty horse. Quickly run the hose over him. Touch his side; the water is warm isn’t it?

Now comes the pseudo science part. By which I just mean I’m haphazarding a guess at the science but. Heat from the horse’s body transfers immediately to the water, so the water becomes the same temperature as the horse. The water then acts like an insulator (although scientists will say that water isn’t a particularly good insulator, some would say it’s enough of one in this case) so preventing the horse’s body from losing any more heat. At this point the horse can’t cool down until the water has evaporated.

Now, scrape the excess water off the horse and hose him again. Keep removing the warmed water until the water runs off cool. Now the horse’s surface temperature is returning to normal, but he still needs to continue cooling down. This happens when the cooler blood leaves the skin and goes to the hot muscles, so removing some heat from there.

It’s at this point that leaving cool water on the body to evaporate, mimicking the sweating process, is effective.
I found this explanation of why sweating cools you down:

Beads of sweat on your skin are in liquid form. When the water temperature rises, the molecules become more active and gain energy. When a molecule gains enough energy, it can break free from the bonds that hold the liquid together and transform into water vapor. This is evaporation. As the molecule evaporates, its energy — or heat — is removed from the sweat that remains on your body. This loss of energy cools the surface of your skin.

In the same way, water and sweat evaporating from the horse’s skin will cool them down. 

A friend told me that endurance riders advocate washing and scraping until the water runs cool off their backs and then leave the rest to evaporate. Which makes me feel better in my hosing the horses until the water feels cool against my hand, then scraping off excess and then turning them out to roll and dry out naturally. 

I found the following article about the cooling process followed at the Beijing Olympics – Read it here – which makes the valid point that if you continue to apply water to the horse’s body then warmed water will be displaced so cold water is always next to the skin and heat will displace to the water. So scraping excess water away can be replaced by just continuous hosing. This article also points out that to maximise the cooling effect of washing down it’s important to cover as much of their body as possible to increase the area that is being cooled, so don’t just wash the sweaty shoulders, wash all the neck and hindquarters too. 

6 thoughts on “Solving The Myth of Washing Down Horses

  1. Heather Holt Jun 20, 2017 / 11:27 pm

    There’s an excellent short article on this written by a vet who was associated with preparing for the Beijing Olympics. See link here:
    I live in a very hot climate and use my own comfort level to determine how my horse will cope in hot weather. If I’m struggling, I know he will! Most horses have a longish break over the hottest months.

    • therubbercurrycomb Jun 21, 2017 / 9:04 am

      Nice link, but it’s the same one that I put in… at least it should be! I’m going to go check ….

  2. Niamh Jun 21, 2017 / 9:40 am

    I live, ride and teach RDA in Hong Kong. All stables have fans and those horses which struggle live in the air conditioned section. Horse are clipped year round. We ride early for regular lessons, although RDA has to be later in the morning as it is within school hours. Horses are notworked between 12-2

    • therubbercurrycomb Jun 21, 2017 / 10:27 am

      Thanks for that info 😊 what types of horses do you have out there? This week I’ve been riding early and going home for a couple of hours over lunch and then teaching in the evening to try to avoid the heat but the forecast has predicted 5pm to be the hottest part of the day this week – global warming I guess

      • Niamh Jun 21, 2017 / 11:59 am

        Thank you for a great blog. Only discovered you very recently, wish I had found you AAAGES ago! Read every post.

        We have a mixture of horses out here. Most of the riding school horses are thoroughbreds, rehabilitated off the track out here. Bred in UK and Australia mostly. We also have some cobs and native types and quite a few German horses. Some small hairy/native ponies and quite fine ones too – the usual mix of riding school nags! We have to be very careful of a few, who are “dry coated” and really don’t sweat, so can become heat exhausted very quickly.

      • therubbercurrycomb Jun 21, 2017 / 4:45 pm

        Thank you 😊
        Sounds like a real mixture of them, I guess the hairy and natives are more likely to struggle in the heat but then clipping and acclimatising them will help them. Unlike us who aren’t used to the heat 🙈 I had Otis in for the vet today and he was standing there dripping sweat as he was examined – yuk! I think he enjoyed his shower afterwards anyway!

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