A Comparison of serological responses when modified-live infectious bovine rhinotracheitis virus vaccine and Mannheimia haemolytica bacterin-toxoid are administered with needle-free versus conventional needle-based injection in yearling feedlot steers
Keywords:bacterial diseases, immune response, immunization, live vaccines, steers, vaccination
A total of 111 yearling feedlot steers were vaccinated with 5-way modified-live virus vaccine and Mannheimia haemolytica (MH) bacterin-toxoid, utilizing either needle-free or conventional needle-and-syringe injection techniques. Blood samples were collected from all steers at the time of vaccination and 21 days later, and serum was analyzed for antibody titers to infectious bovine rhinotracheitis (IBR) virus and M. haemolytica (MH) leukotoxin. Serological response to the IBR viral fraction of the 5-way viral vaccine was significantly higher (P=0.001) on day 21 following administration with needle-free injection, compared to conventional needle injection. Serological responses to the MH supernatant and cell-associated antigens were not statistically different (P=0.06) on day 21 following administration with needle-free injection, compared to conventional needle injection.