Intradermal vaccine application: effects on suckling piglet behaviour

Intradermal (i.d.) application of vaccines offers an improved hygienic standard compared to intramuscular (i.m.) injection. While previous studies confirmed similar immune responses in animals vaccinated i.d. and i.m., studies on consequences on animal behaviour are still lacking. Therefore, this study evaluated welfare aspects of i.d. and i.m. vaccination in suckling piglets.

The study was carried out in three batches in a commercial German pig farm. In the test group, 338 piglets were i.d. vaccinated with Porcilis® M Hyo ID ONCE with the IDAL injector (MSD Animal Health) on the 8th day of life. In the control group, 334 piglets were vaccinated i.m. according to standard farm procedures. On the following three days, the injection site was evaluated with regard to size of swelling and rubor. Piglets were weighed individually and body-temperature-measured one day before vaccination and eight days later. For ten days, starting two days before vaccination, continuous video recordings were performed in order to assess piglets’ resting, activity and suckling behaviour as indirect parameters of stress and pain. Six litters vaccinated i.d. and six control litters were observed. Video analyses via scan sampling in 5 minute-intervals concentrated on the day before vaccination, day of vaccination and day after vaccination. All data was statistically analysed using the software IBM SPSS Statistics, version 22.

Daily weight gain did not differ significantly between piglets vaccinated i.d. (247 g/d) and those vaccinated i.m. (258 g/d). There was no significant difference in body temperature between groups. On the first day after vaccination, test group piglets had more swellings than those in the control group. However, this difference disappeared by the seventh day after vaccination. On the day before vaccination, piglets in the test and control group differed significantly only in their standing behaviour (test group: 27.0% vs. control group: 20.1%). On the day of vaccination, piglets vaccinated i.d. lay significantly less frequently (70.2% vs 82.1%) and showed significantly more walking (14.0% vs. 11.7%) and suckling (46.0% vs. 35.6%) behaviour. On the day after vaccination, these effects were still observed for walking (18.1% vs. 17.2%) and suckling (48.4% vs. 36.4%).

Similar to other studies, piglets stressed or suffering pain show altered behaviour patterns, for instance less suckling activity. Therefore, the results of this study indicate a reduced degree of stress in suckling piglets after i.d. vaccination in comparison to i.m. vaccination.

Disclosure of Interest: None Declared.