Shedding course of bovine respiratory syncytial virus and bovine parainfluenza 3 virus in calves vaccinated intranasally

Shedding time of bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus 3 (BPIV3) in calves vaccinated intranasally with modified live Rispoval RS-PI3 vaccine was determined. Blood and nasal swabs were collected on selected days before and after vaccination. Antibodies against BRSV and BPIV3 were tested by Respiratory ELISA Pentakit and the viral RNA was detected by RT-PCR. Twenty eight days after administration of the vaccine, a marked increase of specific antibody titres to BRSV and BPIV3 was detected in vaccinated calves. All animals were RT-PCR positive both for BRSV and BPIV3. Both viruses were excreted with nasal discharges within 8 d after vaccination but the course of shedding in individual calves was variable.