Experimental bovine pneumonic pasteurellosis. II. Genesis and prevention

Area of Science:

• Veterinary Medicine
• Immunology
• Animal Health

Background:

• Bovid herpesvirus 1 (BoHV-1) infections cause significant respiratory disease in cattle.
• Co-infections with bacterial pathogens like Pasteurella haemolytica exacerbate BoHV-1-induced pneumonia.
• Stressors such as transportation can increase susceptibility to respiratory infections in calves.

Purpose of the Study:

• To evaluate the efficacy of intranasal vaccination against BoHV-1 in calves.
• To assess the impact of vaccination on susceptibility to secondary Pasteurella haemolytica challenge.
• To investigate the potential role of transport stress in BoHV-1 and P. haemolytica co-infection outcomes.

Main Methods:

• Two experiments involving crossbred Hereford calves were conducted.
• Calves were vaccinated intranasally with a commercial BoHV-1 vaccine or left unvaccinated.
• Animals were challenged with BoHV-1 and P. haemolytica aerosols, with some groups subjected to transportation stress.

Main Results:

• Vaccinated calves exhibited less extensive pulmonary lesions and significantly higher survival rates (6/8) compared to unvaccinated controls (0/8) in the first experiment.
• In the second experiment, all unvaccinated control calves developed pneumonia affecting all lung lobes, while vaccinated calves showed no pulmonary lesions.
• Three out of four control calves died from pneumonia, whereas none of the vaccinated calves died.

Conclusions:

• Intranasal vaccination against bovid herpesvirus 1 provides significant protection against subsequent challenge with both BoHV-1 and Pasteurella haemolytica.
• Vaccination markedly reduces the severity of pneumonia and improves survival rates in calves.
• The study highlights the protective effect of vaccination, even in the presence of stressors like transportation.