Comparative study of vaccines in preventing respiratory disease in beef calves after weaning

Vaccines against infectious bovine rhinotracheitis (IBR), bovine viral diarrhea (BVD), bovine parainfluenza-3 (PI-3), and bacterin against Pasteurella hemolytica and P. multocida were studied to determine their effectiveness when given 30 days before weaning in preventing respiratory disease in beef calves after weaning. A total of 310 calves, 6 to 8 months old, were divided into 3 groups. Group I consisted of 51 calves vaccinated with a temperature sensitive mutant vaccine intranasally (IBR-PI-3 TSV2). The 56 calves in Group 2 received another intranasal vaccine containing a modified live virus (IBR-PI-3 IP). Calves in both groups received a modified live bovine virus diarrhea (BVD) virus vaccine 30 days before weaning, and a bacteria containing Clostridium chauvei-septicum, Pasteurella hemolytica, and P. multocida. The bacterin was given twice, 2 weeks apart before weaning. The remaining 207 calves were used as unvaccinated controls. All calves were treated at lest once after weaning for clinical respiratory illness. The only virus isolated was PI-3. The serologic response to the viral vaccines was good. There was some doubt as to the effectiveness of the PI-3 component because vaccinated calves were affected by this virus after weaning. Further studies are needed on PI-3 virus vaccine and the most effective vaccination schedule. Vaccination at the time of weaning may have been helpful in the present experiment in preventing clinical disease.