Theses and Dissertations

Issuing Body

Mississippi State University


Henry A. Paz

Committee Member

Jean Feugang

Committee Member

Shengfa Liao

Committee Member

Trent Smith

Date of Degree


Original embargo terms

Visible to MSU only for 6 months

Document Type

Graduate Thesis - Campus Access Only


Agricultural and Life Sciences

Degree Name

Master of Science


College of Agriculture and Life Sciences


Department of Animal and Dairy Sciences


Manure nitrogen in dairy cattle represents a substantial economic and environmental loss to the industry. Current strategies used to improve N efficiency (Neff) have shown limited progress and thus, warrant more effective approaches. Considering that the gastrointestinal bacterial community has been associated with various phenotypes of economic importance, the objective of this project was to evaluate the associations between the rumen and fecal bacteriomes and Neff phenotypes in dairy cows. Results showed similarities in the overall bacterial community composition and structure of cows differing in Neff. However, the relative abundance of specific bacterial ASV differed between low and high Neff cows. Furthermore, bacterial ASV strongly correlated with Neff could be involved in processes such as nutrient supply, performance, and feed efficiency. These suggest that the gastrointestinal bacterial community is a factor influencing Neff in dairy cows and specific bacterial members can potentially serve as markers of Neff phenotypes.