By Andi Anderson
Vitamin A is a vital nutrient for young calf health, but newborn calves are born with very limited stores. Since little vitamin A is transferred from the cow during pregnancy, calves rely heavily on colostrum after birth. This makes the diet of cows during late gestation especially important.
Milk provides only small amounts of vitamin A, so colostrum is the primary source for calves during the first few months of life. Research indicates that late-gestation cows need between 75,000 and 90,000 IU of vitamin A daily.
However, vitamin A content in hay can vary greatly depending on forage type, harvest maturity, storage conditions, and the length of storage. Because of this variation, supplementation needs can range from minimal to nearly the full requirement.
One useful indicator is hay color. Greener hay typically contains higher levels of beta-carotene, which the body converts into vitamin A, while bleached or weathered hay often contains less.
Though not exact, color can provide farmers with a quick visual clue. To make this tool more reliable, Nebraska Extension developed reference hay samples with known vitamin A content for comparison.
Producers will have the chance to see these samples at upcoming Nebraska Extension events, including the GSL Open House on August 20, 2025, and Husker Harvest Days on September 9-11 at the “Big Red Building.” At these events, attendees can compare their hay visually, talk with experts about nutrition, and learn whether their cows may need extra vitamin A supplementation during the winter months.
In addition, Nebraska Extension is developing a tool that could estimate vitamin A levels from a picture of hay. To improve this research, they are inviting farmers to bring their hay samples to these events. By contributing, producers can help create better tools for beef nutrition management in the future.
Photo Credit: istock-simplycreativephotography
Categories: Michigan, Livestock