A field efficacy trial of a trivalent vaccine containing porcine circovirus type 2a and 2b, and Mycoplasma hyopneumoniae in three herds.

BACKGROUND: This field trial was designed to evaluate the efficacy of a new trivalent vaccine containing porcine circovirus type 2a and 2b (PCV2a/b), and Mycoplasma hyopneumoniae at three independent locations. METHODS: Three farms were selected based on their history of PCV2 and M. hyopneumoniae co-infection. Each farm housed a total of 60, 3-day-old pigs that were randomly allocated to one of three treatment groups. Pigs were administered the trivalent vaccine intramuscularly with either a 1.0 ml dose at 3 and 24 days of age or a 2.0 ml dose at 21 days of age in accordance with the manufacturer's recommendations. RESULTS: Clinically, the average daily weight gain of the one-dose and two-dose vaccinated groups within all three farms was significantly higher (p < 0.05) than those of unvaccinated animals during the growing (70-112 days of age), finishing (112-175 days of age) and overall (3-175 days of age) stages of production. One-dose and two-dose vaccinated animals elicited neutralizing antibodies and interferon-γ-secreting cells (IFN-γ-SC), which reduced the amount of PCV2 in terms of blood load and reduced the severity of lymphoid lesions when compared with unvaccinated animals. Similarly, one-dose and two-dose vaccinated animals elicited IFN-γ-SC, which reduced the amount of M. hyopneumoniae in terms of laryngeal load and reduced the severity of lung lesions. CONCLUSIONS: The intramuscular administration of either one or two doses of trivalent vaccine was not significantly different in any of the evaluated parameters. The results of field trial demonstrated that the trivalent vaccine was efficacious in the protection of swine herds where PCV2d and M. hyopneumoniae were in active circulation.

Comparative Evaluation of Growth Performance between Bivalent and Trivalent Vaccines Containing Porcine Circovirus Type 2 (PCV2) and Mycoplasma hyopneumoniae in a Herd with Subclinical PCV2d Infection and Enzootic Pneumonia.

The present field trial compared two combined vaccines of porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae, each administered in herd with subclinical PCV2d infection and enzootic pneumonia. One vaccine was a bivalent containing PCV2a and M. hyopneumoniae and the other was a trivalent vaccine containing PCV2a and 2b (PCV2a/b), and M. hyopneumoniae. The defining difference between these two vaccines was the inclusion or absence of PCV2b antigen. A total of 480, 21day-old pigs were randomly allocated to one of four treatment groups (120 pigs per group, male = 60 and female = 60). These groups included; one-dose trivalent-vaccinated, two-dose trivalent-vaccinated, one-dose bivalent-vaccinated, and unvaccinated. The one- and two-dose trivalent vaccinated pigs exhibited significantly better growth performance when compared with those vaccinated with the bivalent vaccine. The one- and two-dose trivalent vaccinated pigs also reduced the amount of PCV2d loads in the blood and feces, and resulted in a lower M. hyopneumoniae load in the larynx when compared with one-dose bivalent vaccinated pigs. Statistical differences were not observed between the one- and two-dose trivalent-vaccinated groups in terms of growth performance, serology, amount of PCV2d loads in the blood and feces, amount of M. hyopneumoniae load in larynx, and pathological lesions. The results of the present study will provide swine practitioners and producer with comparative clinical field data to select the proper vaccine and vaccination regiment for herds suffering from subclinical PCV2d infection and enzootic pneumonia.