This study was performed in a farrow-to-finish farm located in Huesca Spain.

Signs related to M hyo infection during fattening, and associated with lung lesions at slaughter were present before the start of the trial.

A group of 532 healthy 3-week-old piglets was included in the study and allocated to the following treatment groups using randomization according to initial live weight and gender:

- T1 (n=169): CIRCOVAC + STELLAMUNE UNO
- T2 (n=169) : PORCILIS PCV + M+PAC
- T3 (n=169) vaccinated with CIRCOFLEX + MYCOFLEX
- Controls (n=25) kept unvaccinated.

Vaccines were administered at the same time but separately in T1 and T2 and mixed prior to administration in T3. Pigs were housed grouped by gender and apparent size. Pigs from the different groups were co-mingled in the fattening pens only.

Individual live weight was recorded at 3, 11 and 23 weeks of age (slaughter age). Mortality, treatments as well as lungs scores in at least 60% pigs per group were recorded. Serologies were performed to assess PCV2 and M hyo passages.

Results

At slaughter age, weights of the vaccinated pigs (T1, T2 or T3) were +3.4 to +4.9 kg higher than weights of non-vaccinated pigs (P<0.05).

Average daily gain from weaning-to-slaughter was +23 to +33 g/day higher than in controls (P<0.05). At 24 weeks of age, the weight of the pigs in groups T1 and T2 were +0.8 and +1.5 kg higher than those in T3 (p>0.05).

During fattening, growth of the pigs vaccinated with T3 was not statistically different than that of the non-vaccinated pigs (724 g/d vs. 700 g/d, P>0.05) contrary to the other vaccinated group (735 g/d and 740 g/d for T1 and T2 resp.).

Throughout the study, mortality and treatment rates in group T1 (5.3% and 36%, respectively) were numerically lower compared to the other vaccinated groups (both 7.7% and 42%). At the abattoir, there were numerically less lesions in the lungs of the pigs vaccinated with T1 and T2 than those vaccinated with T3 (P>0.05). PCV2 and M hyo natural challenge were confirmed serologically.

Circulation of SIV and PRRSv was also evidenced by additional investigations.

Discussion and conclusion

Under the conditions of the study, only separated administrations of PCV2 and M hyo vaccines provided improved results on ADWG against both a field PCV2 and M hyo challenge contrary to the other combination tested.

Presented at the 2015 European Symposium of Porcine Health Management

August 2015