Two clinical challenge studies tested the efficacy of the Circo/MycoGard® vaccine. The first study compared Circo/MycoGard® and another commercial vaccine after a seeder pig PCV2d/PRRSV174 challenge. The second study compared Circo/MycoGard® to another commercial vaccine after an individual pig PCV2d/PRRSV174 challenge.
The first study, conducted by Pipestone Applied Research at a commercial wean-to-finish facility in Minnesota, assigned a total of 1,920 pigs to three treatment groups, which were randomly allocated by litter and weight at weaning. At processing, all study pigs were vaccinated with 2 mL of Ingelvac PRRSV®MLV according to label. At weaning, the first group received 1 mL of Circo/MycoGard®, the second group received 2 mL of CircoFLEX®/MycoFLEX®, and the third group received 1 mL of saline. Additionally, 240 pigs were enrolled as seeders and were not vaccinated for PCV2.
The sow farm was recently repopulated. It was negative for PRRSV, PEDV and Mycoplasma hyopneumoniae, as well as positive for PCV2. Each pen contained all treatment groups selected equally and randomly. The challenge was administered at four weeks post vaccination. Processing fluids were collected from the selected farrowing group, and serum was collected from 80 pigs/trt and 28 seeders at weaning and challenge.
The second study, which was conducted by Swine Services Unlimited, Inc. (SSUI) at a commercial wean-to-finish facility in Minnesota, treated a total of 288 pigs. These were also randomly allocated by litter and weight at weaning and assigned to three different treatment groups. At weaning, the first group received 1 mL of Circo/MycoGard®, the second group received 2 mL of Circumvent® PCV-M G2, and the third group received 1 mL of saline.
The sow farm was negative for PRRSV, PEDV and Mhp, and positive for PCV2 and recently repopulated. Due to finishing space considerations, half of the pigs were randomly selected at challenge for removal at 10 weeks post vaccination. The challenge was administered at four weeks post vaccination. Processing fluid was collected from the selected farrowing group, and serum was collected from all pigs at weaning and challenge.
In both studies, PCV2d was inoculated both IN (2 mL, 1 mL/nostril) and IM (1 mL), and PRRSV174 was inoculated IM (2 mL).
The results of both the Pipestone study and the SSUI study provided the same conclusion —Circo/MycoGard® is equivalent to competitor performance and outperformed the non-vaccinated group. In both studies the percentage of primary market pigs and light culls was equivalent for both vaccines, and the non-vaccinated group underperformed both vaccinated groups. Additionally, final weight distribution was equivalent among vaccinates with non-vaccinates having significantly lighter weight variation. Primary market pigs and light culls analysis were based on the number of pigs alive at the end of the study.
In the Pipestone study, wean-to-finish performance analysis was adjusted by parity, sex, days on feed and weaning weight in SAS and R1.
Processing fluids collected from the Pipestone study tested PCV2 PCR negative. Serum samples tested 0% (0/268) and 1% (3/250) PCV2 PCR positive at weaning and challenge, respectively. One ORF2 sequence at challenge was classified as PCV2d. Tissues were collected at approximately two weeks after challenge from dead or euthanized pigs to confirm challenge.
Processing fluids collected from the SSUI study from the selected farrowing group tested PCV2 PCR negative. Serum samples tested 5% (15/288) and 22% (64/288) PCV2 PCR positive at weaning and challenge, respectively. ORF2 sequences were classified as PCV2a at weaning and PCV2e at challenge. Challenge was confirmed by PRRSV and PCV2 lesions, PCR and IHC in tissues. Tissues were collected at approximately two weeks after challenge from dead or euthanized pigs to confirm challenge.
Vaccine performance in both studies were equivalent with no statistical difference, against PCV2d/PRRS174 pig challenge. Non-vaccinated pigs underperformed vaccinated pigs.
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