BACK TO QUEBEC CITY 2002 TITLES
Impact of timing of vaccination
against Mycoplasma hyopneumoniae on the behavioural and physiological reactions
of
piglets
V. Dufour1,2, R. Bergeron1
and S. Robert2
1Laval University, Sainte-Foy,
Canada; 2Dairy and Swine Research and Development Centre, Lennoxville,
Canada
The objective of this study was to determine whether vaccination is more stressful for piglets when combined with transportation to the fattening unit. Three groups of 64 early-weaned piglets were compared: no vaccination (T1); vaccination at 58 d of age (T2); and vaccination at 65 d of age (T3), 60 min before transportation to the fattening unit. In the nursery (16 to 65 d of age), each treatment consisted of 8 pens of 8 piglets distributed in 4 rooms. A human approach test (HAT) was done to evaluate individually the reactions of 72 piglets (3 piglets/pen) to unknown humans at 4 different times (d 36, 61, 68 and 94). During transfer to the fattening unit (day 65), heart rate was continuously recorded with heart rate monitors on 24 piglets and the ease of handling was evaluated by the time taken to empty the pens and to move the groups from the pen to the truck. Blood samples were taken from 72 piglets on d 18 and 65 (after transport) to determine the neutrophil/lymphocyte ratio (N/L). HAT tests showed that the latency to enter an area of 0.5 m around the experimenter decreased over time, except at d 68 (72h after transport) where the latency was higher than at d 61 (cubic effect of time; P<0.001). Treatments did not affect the reaction of piglets during HAT tests. T3 piglets had a lower heart rate than T2 (mean±SE: 180±4.6 vs 194±3.5 bpm) during transfer from the pen to the truck (P<0.05). However, the ease of handling, and the heart rate during transport (174±3.4 bpm) were not affected by treatments. The N/L ratio was similar in the three groups at d 18 but was higher in T3 (2.7±0.2) than in T1 (1.5±0.2) and T2 (1.5±0.2) at d 65 (P<0.01). In conclusion, combining vaccination with transportation (T3) had no effect on piglets' behaviour, as compared with vaccination one week before transport (T2) or no vaccination (T1). However, T3 piglets showed physiological changes that could be either due to an immune response to vaccination or to a stress reaction to transportation.