A spraying applicator device is not required for efficacy of a live intranasal respiratory vaccine in young calves, which improves user convenience.

Almost all bovine intranasal respiratory vaccines require a spraying device, but there are no published reports which prove the necessity of this. The objective of this investigation was to compare the efficacy of the Bovilis® INtranasal RSP™ Live vaccine when applied with or without an (intra)nasal spraying device. This vaccine contains live, attenuated strains of bovine respiratory syncytial virus (BRSV) and bovine parainfluenza virus type 3 (BPI3V) and is licensed to protect young cattle against respiratory infections with wild-type field isolates of these viruses. Two efficacy studies, for BRSV and BPI3V respectively, were performed in which the vaccine was administered using a spraying device or directly from the tip of a syringe as a liquid stream. Both BRSV-vaccinated groups showed a reduction of nasal shedding, BRSV titres in lung washings and clinical symptoms. The BPI3V vaccinated groups showed a significant reduction of nasal shedding and a non-significant reduction of clinical symptoms. Overall, in both studies, the groups in which vaccine was administered without the spraying device performed better than the groups with the spraying device, although this difference was not statistically significant. In conclusion, a spraying device to administer Bovilis® INtranasal RSP™ Live was not required and both application methods induced a protective immune response. This makes application more convenient and flexible for future users and animals.