The Sunshine Vitamin
Humans and dogs are remarkably similar in the creation of Vitamin D and this natural process begins with help from the sun, according to Doctor of Veterinary Medicine Demian Dressler’s Dog Cancer blog. Ultraviolet light, which cannot be seen by the human eye, is emitted from the sun initiating a physical response from the dog’s body. Most dogs naturally desire to be outside, even if only for 20 minutes, and this is where they soak up some rays to get Vitamin D production moving. This is the reason Vitamin D is often referred to as "The Sunshine Vitamin."
How it Works
The sun sends out ultraviolet light activating sterols which is cholesterol or body oils already present on the dog's fur. Due to a chemical reaction, the dog's body converts the cholesterol to cholecalciferol or Vitamin D3. The Vitamin D3 remains on the surface in the dog's fur. When a dog licks the fur, a natural grooming behavior, Vitamin D3 is then ingested orally. Activation of this chemical process only takes about 15 minutes in direct sunlight.
Take special care of dogs when exposed to sunlight. A duration of 15 to 20 minutes a few times a week is sufficient to maintain Vitamin D levels. Be sure the dog has access to water and is not tethered. A tethered dog often ends up in the sun because its gets wrapped around a tree or other stationery object. Short-snouted dogs such as pugs, shih tzus and bull dogs are more susceptible to the sun and get heat stroke easily.