Of the 14 known vitamins, only two (vitamins A and E) have absolute dietary requirements for dairy cows.

In a paper at eXtension, Bill Weiss, professor and dairy extension specialist at The Ohio State University, discusses vitamin nutrition research and recommendations for dairy cows. He looks at these key vitamins and/or compounds currently recognized as vitamins:

vitamin A

β-carotene

vitamin E

biotin

niacin

B-vitamins

choline

vitamin C

Read "Update on Vitamin Nutrition of Dairy Cows."