Vitamin B-8 (Biotin)
Vitamin B-8, also known as biotin, is important for thyroid, skin, bone marrow, adrenal and nervous system health. Biotin also is helpful to your dog’s reproductive process and for aiding your dog in processing fats, carbohydrates and proteins. Good sources of biotin are corn and beef liver. Interestingly, raw eggs have an enzyme that depletes biotin so, if you feed your dog eggs, you should make sure the eggs are properly cooked. Long-term antibiotic use has also been associated with biotin deficiency in dogs. Symptoms of biotin deficiencies include hair and skin conditions, eye discharge, small litter size and sometimes diarrhea. If not treated, a biotin deficiency can also cause limb paralysis.

Vitamin C
Vitamin C, a water soluble vitamin, aids your dog’s immune system and development. Vitamin C is found in citrus fruits and vegetables. Vitamin C is often used to supplement large-breed puppies and nursing mothers. It has also been used with some success in reducing the effects of some conditions such as hip dysplasia and bladder stones. Too high doses of vitamin C can cause diarrhea (vitamin C is a natural laxative) and a bloated abdomen. In addition, a link has been suspected between too high doses of vitamin C and the occurrence of kidney stones.

Vitamin D
Vitamin D, a fat soluble vitamin, is essential for regulating the bloodstream’s calcium and phosphorous levels, bone formation and proper muscle and nerve function. Vitamin D sources include fish liver oil and sunlight. Vitamin D deficiency can cause rickets, a bone disorder with symptoms such as bowed legs, swollen joints and weakness. Too much vitamin D can create inappropriate amounts of calcium to be stored within your dog’s heart and other muscles. High doses of Vitamin D can also cause vomiting, diarrhea, hemorrhaging, excessive thirst, increased urination, lethargy, limping and bone pain.