With much recent emphasis given to Vitamin D deficiency in humans, this article caught my attention. Turns out our four-legged friends have as much need for adequate vitamin D levels as we humans do. Did you know that horses with less than two hours of turnout time per day could be at risk for low vitamin D levels? I also learned that Vitamin D deficiency is the cause of Rickets disease in young horses. I had heard of that, but never knew what caused it.