In the current 2001 7th revised Dairy NRC, supplemental vitamin requirements for lactating dairy cows are listed for vitamin A, Vitamin D, and Vitamin E (75,000; 20,000; and 545 IU per head per day, resp.). In addition, production responses to 20 mg supplemental biotin and 50 g of rumen-protected choline were discussed in detail. Since that time, most research advances have been made in transition cows, with vitamin requirements for lactating cows in "set it and forget it" mode, especially with cows entering the lactation in good health status. However, supply disruptions in late 2017/early 2018 brought vitamin discussions and supplementation strategies to the forefront. Technol. advances include: herd status auditing, new product forms, and new understanding of modes of action beyond classical deficiency signs.