Respiratory Efficacy of a Multivalent Marker Vaccine Against Bovine Viral Diarrhoea Virus Types 1 and 2, Infectious Bovine Rhinotracheitis Virus, Bovine Respiratory Syncytial Virus, and Bovine Parainfluenza-3 Virus in Young Calves

<b>Background/Objectives</b>: A new multivalent vaccine (DIVENCE^® PENTA), containing Bovine viral diarrhoea virus (BVDV) types 1 and 2 recombinant proteins, live gE/tk double gene deleted Bovine Herpesvirus type 1 (BoHV-1 or IBR), live attenuated Bovine respiratory syncytial virus (BRSV) and inactivated parainfluenza-3 virus (PI-3) has been designed to protect cattle against the main viral pathogens associated with Bovine respiratory disease (BRD). The aim of this study was to demonstrate the efficacy of DIVENCE^® PENTA against experimental infections with BVDV-1, BVDV-2, IBR, BRSV and PI-3 in young calves. <b>Methods</b>: Ten-week-old calves were given two intramuscular doses three weeks apart. The efficacy was evaluated by means of an experimental challenge three weeks after vaccination. Serology, clinical signs, rectal temperature, white blood cell count, viral shedding and lung lesions were monitored after the challenge. <b>Results/Conclusions</b>: The results demonstrated a significant sparing of BRD in calves vaccinated with DIVENCE^® PENTA, as evidenced by fewer clinical signs, lower rectal temperatures, reduced viral shedding and less severe pulmonary lesions compared to control animals. A significant reduction in hyperthermia, leukopenia and viraemia post-challenge was also observed, highlighting the efficacy of the multivalent vaccine against BVDV types 1 and 2, IBR, BRSV and PI-3 in young calves.