For different reasons kibble and raw food diets can each leave your dog deficient in certain trace minerals. Deficiency in vitamin A can lead to serious conditions especially blindness. Why Complex B instead of Vitamin B-12.
But sick cats may not be able to absorb enough of the B12 thats in their food. If your dog reaches terminal stage lacking B1 for about a month they will die within just a few days. This causes the deficiency of Vitamin D in the dog which can cause a lot of diseases and other consequences as well.
Vitamin D plays an indirect role in bone growth. Vitamin D Deficiency in Dogs Known as the sunshine vitamin because exposure to sunlight helps the body produce it naturally vitamin D is an essential vitamin for dogs which means the dogs own body does not produce a sufficient amount and therefore vitamin D must be included in the animals diet for the dog to maintain optimal health. Because dogs can store vitamin B12 in their kidneys and liver it is entirely possible for them to become B12 deficient but not show any signs for a while after.
Vitamin D comes in two sources.