Horse Sweat – Why Does It Lather?

 Posted by on June 18, 2013  Health, Horses
Jun 182013

Horse Sweat Lathering

Anybody who has exercised a horse in hot weather will be familiar with their horses white frothy sweat. It can typically be seen where something rubs against the horses skin – it is most often seen underneath the saddle cloth (as shown in the picture) or sometimes on the neck where the reins rub against the horses neck. It’s fairly obvious that horses sweat to get rid of the heat generated by vigorous exercise but why does it lather into the frothy white stuff? …. After all we sweat as well and our sweat does not lather!

Horses are large flight animals that generate a lot of heat when they are running away from a potential threat. Large animals, such as horses, have a low surface to volume ratio which means that there is not enough surface area on their bodies to allow them to radiate enough heat to cool them down.

So horses need to dissipate heat when exercising and have evolved the ability to sweat – just like humans. Sweating in horses and humans works because liquid evaporating from the surface of the skin cools the body down. Sweat that just drips off does not actually cool the body down. Sweat must evaporate from the skin to cool the body. Human sweat is water with sodium, chloride and a bit of potassium.

Horses have a hairy waterproofed coat so human “water” sweat would not be able get through the waterproofed coat. Horses, have therefore evolved sweat which is very different to human sweat. Horse sweat contains a very high concentration of a detergent like protein called Latherin. The purpose of Latherin is to wet the hairs to allow water to flow through the hairs and get to the surface where it can evaporate and cool the horse. And it is Latherin that lathers when rubbed to give the characteristic white frothy sweat.

So next time your horse sweats “white” you will know that it is due to detergent like substance in their sweat that allows the sweat to get through their water proof coat. I am not sure if this knowledge will help you looking after your horse but it is interesting to know.


Author: Chris Atkin

Chris Atkin is a videographer specialising in high quality equine videos which are typically used to sell your horse, promote your stallion or equine business or as a memento of a big competition. Videos can be uploaded to YouTube and adverts can also be produced for broadcast on specialist equine satellite TV channels.

Videos: YouTube channel or Google+