Impact of Corticoid Treatments Concurrently Injected with PCV2, Mycoplasma hyopneumoniae Vaccines in Weaners16 October 2015
Dexamethasone is widely used in pig practice. Immunosuppression is frequently mentioned in the contraindication section of Summary of Product Characteristics. On the other hand few papers have been published on the topic, regarding pigs, write P. Tessier et al, Merial.
The objective of this trial was to investigate the impact of injections of dexamethasone salts (phosphate and acetate) at the time of 2 usual piglet vaccinations (M hyo and PCV-2) in field conditions.
Materials and Methods
A farrow-to-finish operation with 160 sows was selected by the practitioner. Management of sows is done in 4 batches running every 5 weeks. 60 piglets randomly selected from 20 litters have been allocated to 3 treatment groups at the age of 19 days. Ear tags with three different colours are applied the same day.
Following weaning and transfer to the subsequent unit, piglets are vaccinated against PCV-2 and Mycoplasma hyopneumoniae using 2 separate syringes (Porcilis® PCV and Suvaxyn® M hyo Mono) at the age of 28 days.
The control group receives 0.5 ml of isotonic glucose i.m., while the Solution group receives 0.5 ml of Dexamethasone phosphate i.m. and the Suspension group, 0.5 ml of Dexamethasone acetate i.m. Bleeding occurs on three dates at the age of 19 days (allocation), 49 days (3 weeks post-vaccination) and 84 days (9 weeks post-vaccination).
The blood are delivered to the diagnostic laboratory a few hours after collection and sera are centrifugated then processed with kits (M hyo ELISA DAKO and SERELISA PCV-2 Synbiotics).
Statistical analysis is performed with SYSTAT (Wilkinson, L., SYSTAT: The system for statistics. Evanston, IL: SYSTAT, Inc.), version 12.0 for Windows.
The amount of corticoids injected was 3 to 6 times the recommended dosage of the label. Before treatment all 3 groups were comparable for M hyo or PCV-2 antibodies (p= 0.799 and 0.601 respectively), with a high level of maternal antibodies.
At 7 weeks of age no statistical difference was noted for both vaccines, a huge decrease of maternally derived antibodies was noted.
At 12 weeks of age no difference was observed for PCV but for M hyo, if there was no statistically significant difference in prevalence, the OD titers of the Control group were significantly higher than both treatment groups. No circulation of wild PCV had occurred yet, but some circulation of Mycoplasma hyopneumoniae may have started.
These first results call for additional work, notably investigation on impact on Cell mediated Immunity.
K. P. Flaming, B. L. Goff, D. E. Frank, J. A. Roth, Comp Haematol lnt (1994) 4:218-225
Presented at the 2015 European Symposium of Porcine Health Management