Field efficacy of two PCV2 and Mycoplasma hyopneumoniae vaccine combinations under Brazilian field conditions

The objective of this study was to investigate the efficacy of two combinations of vaccines against PCV2 and Mycoplasma hyopneumoniae (M hyo) under Brazilian field conditions.

This study was performed in a farrow-to-finish farm located in Minas-Gerais province, with a history of clinical PCVD and enzootic pneumonia during growing/finishing, and lack of homogeneity at slaughter time. A group of 896 healthy 3-week-old piglets was included in the study and allocated to the 4 treatment groups, using randomization according to sex and initial live weight. Pigs were administered CIRCOVAC®, Merial (0.5 mL) and SPRINTVAC®, Merial (2.0 mL) in groups T1 and T3 (VAC groups). Another PCV2 vaccine (1.0 mL) and another M hyo vaccine (1.0 mL) combination was tested in groups T2 and T4 (X groups). Vaccines were administered at weaning at the same time but separately in T1 and T2 and mixed prior to administration in T3 and T4. were housed in 7 pens of about 35 pigs until the end of the study. Individual bodyweights at 24, 64 and 148 days of age were recorded. Mortality and culling as well as pen feed consumption were assessed for the nursery period (24-64 days of age) and the fattening period (64-148 days of age). Coughing was recorded. Lungs in 80 pigs per group were inspected using Madec’s grid. Serology was performed in 10 pigs per group to assess PCV2 and M hyo circulation.

PCV2 and M hyo natural circulation were confirmed serologically. On average, weaning-to-slaughter (W-S) average daily weight gain (ADWG) in VAC groups was +17 g/day (p< 0.05) higher than in X groups. W-S ADWG was 827, 826 and 817,803 g/day in groups T1, T3 and T2, T4 respectively with a statistically better growth in T1 and T3 as compared to T4 (p< 0.05). Slaughter weights at 148 days in groups T1 and T3 were +3.2 and +3.0 kg higher than weights in group T4 (p< 0.05). Pigs in group T2 were 1.2 kg lighter than pigs in group T1 (p> 0.05). No difference in feed conversion ratio was observed. Throughout the study, mortality and culling rate was lower (p< 0.05): 5.4%, 6.7% vs 5.4%, 13.8% in groups T1, T3 vs T2, T4, respectively. Coughing index was significantly lower in T3 (1.1) as compared to X groups (T2: 1.94 and T4: 2.26) but not compared to T1 (1.42). At the abattoir, magnitude of the lesions was low whatever the group and no difference in prevalence (84 to 86%) was observed between VAC and X groups.

Under the conditions of the study, combining CIRCOVAC and SPRINTVAC either mixed prior to administration or injected separately provided comparable field protection against PCV2 and M hyo. In addition, mixing these very same products provided better protection than mixing the other combined products tested.

Disclosure of Interest: R. W. Pinheiro: None Declared, E. Bordin: None Declared, O. Merdy Conflict with: Merial S.A.S., F. Joisel Conflict with: Merial S.A.S.