Many viruses, including bovine herpesvirus-1 (BHV-1), bovine respiratory syncytial virus (BRSV), parainfluenzavirus-3 (PI3), bovine coronavirus, bovine viral diarrhea virus and bovine reovirus, have been etiologically associated with respiratory disease in cattle. This review focuses on the pathogenesis of BHV-1 and BRSV, two very different agents that primarily cause disease in the upper and lower respiratory tract, respectively.

Advances over the last 20 years in immunology and molecular biology have provided many new tools for identifying the important antigens and new ways to achieve the appropriate immune responses to these antigens. These provide many more options to achieve the best immune response from deletion mutations, subunit antigens, vectors or DNA immunization. These tools are being adopted to screen, discover and produce the appropriate antigens and to deliver them by the optimal method and with novel adjuvants to achieve the appropriate immune response. These developments will result in vaccines for respiratory disease that are safer and more efficacious, and provide greater flexibility for use and administration.

Pharmacodynamics is limited with respect to its ability to provide precise predictions to guide therapy because of complications related to the bound versus unbound state of the agent, tissue versus plasma concentrations, drug degradation over time, variations among microorganisms, and factors associated with the specific environment at the infection site. Antimicrobial susceptibility testing is likewise imprecise when applied to an individual animal; however, it is valuable on an animal population basis.

Industry has made large investments into bovine respiratory disease (BRD) research historically, and will continue to do so, despite the apparent lack of progress, an uncertain regulatory environment, and increased competition for internal resources. Factors such as the growing demand for protein, and the ongoing consolidation and ‘technification’ of the beef sector globally suggest that the industry will continue to demand interventions that prevent disease, are more efficacious, can be easily administered, and positively affect meat quality. New products must also meet the regulatory requirements of safety and efficacy and anticipate the future needs of the numerous stakeholders in the global food chain. Two obstacles in meeting this challenge are the declining interest in food animal medicine, and BRD specifically, and the reluctance to accept new technology at the consumer level.

Despite numerous advances in bovine infectious disease research, bovine respiratory disease (BRD) remains a significant disease threat and a cause of tremendous loss. Renewed efforts and innovative strategies are required to build on the successes of the past to achieve the successes of tomorrow. Continued and improved support of BRD research will prove to be a worthwhile investment. To achieve better coordination and more efficient use of resources, the following supportive actions should be considered. There should be coordination of integrative teams through an over-arching agency (United States Department of Agriculture (USDA)) to provide peer review and priority review for available public research funds. This would include use of development grants (as seed and matching funding) available to public/private partnerships. Testing and validation of new procedures in production settings (providing more than cost analyses) should be strengthened. Publication of studies should be promoted and old links between clinicians, diagnosticians and basic researchers should be re-established. Sets of ‘best practices’ should be published. Programs to support both basic and applied research through graduate fellowships, residencies, workshops and start-up funding for young research scientists should be strengthened. Sustained funding to train the next generation of research investigators should be addressed as a critical need.