Author ORCID Identifier:
Date of Graduation
7-2026
Document Type
Dissertation
Degree Name
Doctor of Philosophy in Animal Science (PhD)
Degree Level
Graduate
Department
Animal Science
Advisor/Mentor
Kegley, Elizabeth
Committee Member
Powell, Jeremy
Second Committee Member
Zhao, Jiangchao
Third Committee Member
Weimer, Shawna
Keywords
beef cattle; environment; microbiome; respiratory; thermal imaging
Abstract
Bovine respiratory disease (BRD) has persistently been the leading cause of morbidity of beef cattle in the United States. Season has been directly associated with respiratory disease incidence and is likely a proxy for weather conditions, which vary by geographical location. The nose is one of the first points of contact between the outside environment and inside the body. The nasal microbiome and its relationship with BRD have been heavily studied within beef cattle, but there are not yet any studies to determine if the environment within the nasal cavity has a role to play in this mechanism. This dissertation serves to understand the risk of the BRD complex by investigating the unknown relationships between the environment, nasal temperatures, and the nasal microbiome with BRD. The meta-analysis conducted supports prioritizing interventions for BRD, including metaphylactic programs and technological diagnostics which may be more effective in certain contexts. To investigate further, crossbred beef calves (n = 650) were purchased from regional auction markets and used for various 42-day receiving studies. When investigating environmental and phenotypic effects on BRD in calves, this study showed effects of castration status on arrival and minimal effects of ambient temperature. When introducing thermal imaging, nasal temperatures did not share a relationship with later BRD outbreaks but were positively correlated with rectal temperatures and ambient temperatures. To determine if thermal imaging could serve as a risk assessment or diagnostic tool for BRD in the receiving period, further investigation is warranted. The results from the microbiome study demonstrate that the microbiome within the nasal cavity of newly received beef calves contains detectable microbial and predicted functional signatures associated with respiratory health. Given its multifactorial nature, BRD requires a comprehensive approach for effective diagnosis and management, and the establishment of standardized diagnostic criteria would facilitate early intervention by enhancing the accuracy of diagnosis for BRD. To conclude, the basic features of BRD pathogenesis are relatively well understood, however the multiple factors involved create complex interactions between the environment, infectious agents, and the host, and will continue to challenge our understanding and management of BRD.
Citation
Cheek, R. A. (2026). Seasonality of Bovine Respiratory Disease Incidence, Nasal Temperatures, and the Nasal Microbiome in Receiving Beef Cattle: Understanding the Risk of the Bovine Respiratory Disease Complex. Graduate Theses and Dissertations Retrieved from https://scholarworks.uark.edu/etd/6389
