Factors Affecting the Efficacy of Free Choice Vitamin & Mineral Supplementation Programs

Authors

• Tanner K. Wansing, University of Nebraska-LincolnFollow

First Advisor

Mary E. Drewnoski

Committee Members

Kacie McCarthy, James MacDonald

Date of this Version

5-2026

Document Type

Thesis

Citation

A thesis presented to the faculty of the Graduate College at the University of Nebraska in partial fulfillment of requirements for the degree of Master of Science

Major: Animal Science

Under the supervision of Professor Mary E. Drewnoski

Lincoln, Nebraska, May 2026

Comments

Copyright 2026, Tanner K. Wansing. Used by permission

Abstract

While free choice vitamin and mineral supplements are widely used within the cow/calf sector, large knowledge gaps exist around the proper management of those supplements. This thesis discusses two factors affecting the efficacy of supplementation. The first interest was the stability of vitamin A when stored with a common free choice mineral supplement. This research addressed a critical data gap by generating information on vitamin A stability within the beef industry, as current data are predominantly based in the swine industry. Vitamin A was discovered to be stable until 4 months of storage regardless of storage conditions, whereas after 4 months of storage vitamin A degraded 3.82% per month. This indicates producers buying and storing large quantities of supplement may need to consider the time of purchase to ensure vitamin A supply matches requirements of differing production phases when supplemented. The second focus of this thesis evaluated the consumption of free choice supplements by grazing cow/calf pairs. Intakes of both cows and nursing calves were observed through nearly an entire yearly production cycle, encompassing a range of grazing systems and forage types. Smart feeder units captured intakes of individual animals, providing new insight into variability both within herds and within individual animals across varying management conditions. While individual cows remained consistent in a relative ranking system across different periods, average daily intakes varied greatly among the herd. Furthermore, the ability to capture both calf intake and concentrations of minerals provided novel evidence that supplement intake of nursing calves drives the liver status of those calves, and that intake availability to nursing calves is critical to properly fortify their bodily stores. Overall, the objective of this thesis is to deliver real world research that allows industry professionals to better understand the multitude of factors surrounding the stability of vitamin A and the variation of free choice intake that may affect the outcomes of a supplementation program. Where micronutrients are listed as halving a requirement based on physiological demand, many variables must be accounted for to determine proper supplementation levels to deliver adequate amounts to the grazing animal via free choice supplementation.

Advisor: Mary E. Drewnoski