Date of Graduation

5-2026

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Animal Science

Advisor/Mentor

Dr. Beth Kegley

Committee Member

Dr. Ken Coffee

Second Committee Member

Dr. Jeremy Powell

Abstract

Minerals are known to play a key role in the immune system, growth, and development of animals. An important part of a calf's life is receiving colostrum immediately after birth, which provides the calf with immunoglobulins and necessary nutrients that are required. Furthermore, the gestation period is another very important aspect of the calf's life where they can take in the necessary nutrition. This study compared how two different supplements fed during the gestation period ultimately affected the mineral concentrations of the colostrum, placenta, calf plasma, and cow liver. The supplements that were provided were a 1) control that provided the recommended concentrations of trace minerals, including zinc, from inorganic sources, and 2) a High-Zn supplement that added 360 mg of Zn/day from a Zn amino acid complex [Availa Zn, Zinpro, Eden Prairie, MN] an organic source of zinc. Eighty-Three Angus crossbred pregnant cows (age = 4.7 +/- 2 years and body weight = 531 =/- 84.4 kg, mean with standard deviation) were stratified by age, body weight, and sire of calf then assigned to one of four groups. These four groups were assigned randomly to one of the two experimental treatments being 1) a control with a level of Zn that met published requirements vs. 2) the increased concentration of Zn from an organic source (2 groups/treatment). Groups rotated pastures, and hay was offered when forage became limiting. Cows were offered grain mixtures (1.36 kg/cow offered 3 days/week) in which the experimental treatments were added. Cows began receiving treatments on day 162 of gestation and continued to receive the supplements until 30 days after the average calving date. For a more intensively sampled subset of cows (n = 8/group), once the calves were born the placenta was collected if possible, colostrum was collected, blood of the calf was collected 48 hours after birth, and liver biopsies were collected from the cows on days -2, 96, and 154 of the feeding period. Liver mineral concentrations were lower  than previously reported in other studies. However, even with the low values, there were no significant differences between the treatment groups.

Keywords

Zinc Supplementation, Gestation, Liver Tissue, Cattle Nutrition, Serum, Colostrum

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