20-09 Understanding how bovine respiratory disease risk factors promote development of pneumonia as a strategy to develop novel methods to prevent disease
Risk factors for bovine respiratory disease (BRD)— stress, virus infection, and adverse weather conditions—have been assumed to cause "immunosuppression" that predisposes to bacterial infection. Our recent data indicates an alternative, that these risk factors promote respiratory tract inflammation, which harmfully changes how the calf responds to subsequent bacterial infection of the respiratory tract. The distinction is important because it redirects strategies for disease prevention and risk assessment, thus aiming to minimize rather than enhance immune-inflammatory responses during this risk period.
This research focuses on inflammation during the early risk period before infection becomes established, whereas the later role of infection-induced inflammation in damaging lung tissue is already well-known. We have shown that inflammation in healthy calves arriving to feedlots leads to adverse disease outcomes. The next step is to evaluate how BRD risk factors promote inflammation within the respiratory tract. The approach involves comparison of controls to recently weaned and/or comingled beef calves, to identify evidence of excessive inflammatory responses and the biologic mechanisms underlying these abnormal responses. These advances are targeted to develop alternatives to antibiotics for disease prevention and more effective tools to assess BRD risk.
Thus, the proposed work addresses the research priorities of Animal Health, and specifically "Alternatives to antimicrobials for infection and disease management actively developing", "Calves are more robust, require less pharmaceutical intervention and regain optimal growth rates more quickly", "Develop management programs that utilize genetics, nutrition, welfare biosecurity and environmental management to produce robust cattle with reduced reliance on other treatments".
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