Black Beauty - Cold water and Illness?

In the movie Black Beauty, there is a scene when after running through a storm all night, Beauty (the horse) is taken care of by the inexperienced stable boy Joe.  Beauty is in his stall, wet and steaming.  Joe refuses to cover Beauty with a blanket thinking he is too hot,  and then proceeds to give him cold water to drink. The next day, Beauty is found lying down and in pain.

Cold Water Myth
This scene may confuse general audiences and horse owners because it implies the cold water - "felt like a kick in the guts" -  is what made Beauty sick. It's still a commonly held belief that if you give a horse ice cold water, especially after a heavy workout, it will colic. However, this is untrue. It's not that the water being cold will make horses sick, it's that horses do not generally like to drink ice cold water.  Drinking cold water is uncomfortable on a horse's stomach making the horse tend not to want to drink much even if it's thirsty. People then draw to the conclusion that cold water makes horses sick when actually the sickness is likely brought on by the lack of enough fluids in the horses' systems.  During very cold winter months, horses are in greater danger of becoming dehydrated because they won't drink as much water if it's nearly frozen, which can lead to colic, hypothermia, and other illness.

Hypothermia and Dehydration
This movie is based off a novel by the same name by Ann Sewell, and she describes more of Beauty's symptoms. Here is an excerpt from the book after the hard ride: I was glad to get home, my legs shook under me, and I could only stand and pant. I had not a dry hair on my body, the water ran down my legs, and I steamed all over....He [Joe] rubbed my legs and my chest, but he did not put my warm cloth on me; he thought I was so hot I would not like it. He then gave me a pail full of water to drink; it was cold and very good, and I drank it all; then he gave me some hay and some corn, and thinking he had done right, he went away.  Soon I began to shake and tremble, and turned deadly cold, my legs ached, my loins ached, by chest ached, and I felt sore all over. 
 
After a horse goes through a strenuous workout, it needs to be walked to help dissipate the excess heat produced by its muscles. Sweating and breathing both release heat from the body to help the horse's core temperature return to normal. If the stored heat is not properly released, it can become trapped in the horse's muscles and its core which can lead to colic and "tying up" aka rhabdomyolysis - a condition of muscle stiffness, pain, and trembling.  At the same time, when a horse is being cooled down, it needs to replace all those lost fluids. Dehydration reduces blood flow to the muscles and organs, which can cause the core temperature to drop and make the horse hypothermic. 

Proper Cool Down and Hydration
Two things that Joe did incorrectly with Beauty is he did not cool him down properly and he did not hydrate him enough.  If your horse has had a hard workout, let it walk until it's breathing normally and not sweating. Also, let it drink. Make sure the water is a comfortable temperature (not ice cold) so the horse will want to drink enough.  Keeping a horse from water while cooling it down may make it more difficult for its body to circulate blood properly and return back to a normal core temperature.  Also, after only the horse is properly cooled and dry can a rug be placed on it. Trapped sweat can make the horse cold later on and also lead to skin problems. 

It seems to be a divisive issue in the equitation community on when to let a horse drink after a hard work out.  If you own a horse, what do you do after  a hard work out? Do you let your horse drink water immediately or do you wait?

Horses drinking from a stone trough. Painting by Enrico Coleman. [Public Domain]