I do not need to convince dairymen that milk is the most nutritionally complete food source, but I would like to make the point here that milk does not always provide adequate supplies of vitamins and minerals to the young calf.

For most beef producers in North America, the answer to the title of this article depends on the season. Vitamin D is not always an essential nutrient for cattle, as vitamin D3 (the main form of vitamin D utilized by cattle) is produced in their skin when exposed to the sun’s UVB rays – hence its nickname as the sunshine vitamin.

Vitamin D is typically recognized as being necessary for proper bone formation and maintaining calcium and phosphate in the body. Recent discoveries indicate that vitamin D also is required for the activation of critical innate immune defenses of cattle against microbial pathogens.