In the old days it was believed that when snow was on the ground horses did not require an additional water source, but horses are not as efficient as cattle at obtaining full hydration from snow alone, so there should always be clean, fresh water available. That said, when water is also available there is generally nothing to worry about if your horse chooses to eat snow instead.

There have been documented cases of horses choosing to eat snow instead of drinking available water when the water is not pure. Assuming you provide your horse with water from the tap (the same source as you), you can assume there is nothing alarming to worry about. However, there is some evidence that water fluoridation by public authorities can lead to health defects in horses, and that those horses will tend to choose a water supply that lacks the additional fluoride. In fact, your home state of Minnesota actually has a very high level of water fluoridation. This might therefore be something for you to investigate further.

Horses seem to love snow, and will often become very excited when put out to pasture just after the first snow falls. However, snow brings with it some potential problems, not least the added potential of injury from hidden holes, slipping and general over-excitement. It’s also important to make sure that your horse is getting enough hay when the grass is inaccessible. In addition, when your horse spends a lot of time in snow it is important to monitor his hooves for build-up of snow/ice, specifically if they have shoes. Your farrier would be able to apply a special pad – "Snow Pads" – that are designed to prevent build up of snow in the shoe.