Research

Background

Bovine respiratory disease (BRD) is usually caused by a combination of bacteria and viruses. Accounting for the majority of morbidity and mortality in Canadian feedlots, it results in major performance and economic losses. BRD is not limited to feedlots, as isolated cases or larger outbreaks can affect calves pre-weaning, representing the leading cause of antimicrobial use on cow-calf operations.

Vaccines are an important tool to help reduce the incidence of BRD at both feedlot and cow-calf levels. According to the 2025 Canadian Cow-Calf Adoption Rates and Performance Levels Report, the majority of cow-calf producers are using at least one vaccine that targets the viral pathogens that can contribute to BRD (e.g., IBR, BRSV, PI3, BVD), but fewer  producers (~56%) use a vaccine targeting the bacterial pathogens (e.g. Mannheimia haemolytica, Pasturella multocida, Histophilus somnus). Feedlot cattle are generally vaccinated on arrival to the feedlot, unless previous vaccination history is known.

Most BRD vaccines require a booster and careful handling. Some may not completely match currently circulating strains of viruses or bacteria. This project proposes to develop a single shot, intranasal, thermostable, bivalent vaccine (in this case against bovine alphaherpesvirus 1 and Mannheimia), but more importantly, to create a vaccine development platform that could be easily scaled to include other pathogens and be able to be updated regularly at a lower cost than traditional vaccine development.

Objectives

The objectives of this project are to:

• Formulate and characterize intransal self-amplifying RNA vaccines that do not require specific temperature control
• Evaluate both systemic and mucosal immune responses in calves
• Anlayze the efficacy of developed vaccines in a challenge model using bovine alphaherpesvirus 1 and Mannheimia haemolytica

Implications of the Research

If successful, this project represents a potentially enormous breakthrough in vaccine research and development. Current vaccines can take several years and hundreds of thousands of dollars (or more!) to develop. This vaccine platform could provide a very real advantage not only to cattle health, but to reduce research and development costs.