Abstract: The previous studies demonstrate that the main functions of vitamin D （VD） are to promote bone growth and prevent rickets by regulating Ca ions. However, in recent years, it has been found that VD not only plays an important role in skeletal diseases, but also is closely associated with a variety of extra-skeletal diseases, including cardiovascular diseases, metabolic disorders, malignant tumors, allergic diseases, autoimmune diseases, reproductive diseases, etc. At present, although the researches on the biological functions of VD have become more and more comprehensive and in-depth, most of the them focus on humans and mice. There is limited information on extra-skeletal biological function of VD in different animals, such as cattle, pigs, dogs, cats and so on. Therefore, on the basis of consulting related literatures, this article summarizes the research advances of biological functions of VD on blood pressure, immune regulation, endocrine, endometrial and skeletal muscle, and so on, in hoping to provide a better understanding of biological functions of VD in extra-skeletal system of different animals.

Key words: vitamin D, blood pressure, endometrium, endocrine disease, immune regulation, skeletal muscle