Honors Theses and Capstones

Date of Award

Fall 2012

Project Type

Senior Honors Thesis

College or School



Molecular, Cellular and Biomedical Sciences

Program or Major


Degree Name

Bachelor of Science

First Advisor

Joanne Curran-Celentano


Interest in organic milk is increasing. By USDA Certified Organic standards, animals must be fed on pasture for a minimum of 120 days. Research indicates that various factors such as diet impact the nutritional quality and composition of milk. The objective of this study was to understand how feeding practices affected bovine plasma carotenoid concentrations over time. Plasma samples were collected from 9 cows fed on pasture at an organic dairy and from 9 cows fed total mixed ration (TMR) at a conventional dairy. Components were extracted from the plasma and separated via High Performance Liquid Chromatography. Results showed that plasma concentrations of lutein, zeaxanthin, β-cryptoxanthin, and β-carotene significantly changed from baseline at each dairy. The changes in plasma lutein, zeaxanthin, α-carotene, and β-carotene concentrations were also significantly different between dairies. Plasma lutein, zeaxanthin, α-carotene, and β-carotene concentrations were significantly higher in plasma from cows fed on pasture versus cows fed TMR. This suggests that diet and season affect the concentrations of measured components in plasma. These variations could influence the health of the animal and the nutrient composition of the resulting milk.