Date of Graduation

5-2018

Document Type

Thesis

Degree Name

Bachelor of Science in Agricultural, Food and Life Sciences

Degree Level

Undergraduate

Department

Animal Science

Advisor

Rosenkrans, Charles F.

Reader

Powell, Jeremy G.

Second Reader

Rorie, Rick

Third Reader

Koltes, James E.

Abstract

Effects of Fescue Toxicosis on Whole Blood Gene Expression in Beef Cattle

The consumption of endophyte-infected tall fescue causes negative effects on the growth, reproduction, longevity, and overall health of beef cattle; this condition, termed fescue toxicosis by researchers and producers today, costs the United States over $1 billion in losses each year. To mitigate these production losses, it is important for producers to understand how fescue toxicosis affects gene expression and physiological pathways in beef cattle. This study examined the whole blood gene expression and affected pathways in beef cows grazing both endophyte-infected (toxic) tall fescue and (non-toxic) tall fescue. Animal model included 100 Hereford and Charolais cross bred beef cows of varying age and parity. Cows were allocated evenly by sire breed to two pasture types: toxic (n = 50) and non-toxic (n = 50). Whole blood samples were collected from cows via jugular venipuncture and stored at 4℃ for two days, then at -80℃ for approx. 7 months. Isolation of RNA was performed, and concentration and purity were analyzed before samples (n = 90) were sequenced. Statistical analysis was performed to ultimately identify 499 differentially expressed (DE) genes, which were then analyzed for involvement in specific gene expression pathways using ENSEMBL identification numbers and DAVID software. Gene expression pathways identified in this study were related to heat shock protein function, immune response, and hormone signaling pathways. The research of DE genes and expression pathways identified in this study that have not yet been discussed may help to further our understanding of the impact of fescue toxicosis, such as those involved in immune responses.

Keywords

fescue, gene expression, pathways, RNA-seq

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