A comparison of growth performance and viral shedding in pigs vaccinated with porcine circovirus type 2 vaccines
This thesis is an investigation comparing the prevalence of porcine circovirus type 2 (PCV2)-viremia and growth performance in pigs vaccinated with either a one-dose or two-dose commercial PCV2 vaccine. Also, the suitability of nasal secretions, feces, and oral fluids, as a means to determine vaccine efficacy, were compared to blood samples. Overall, vaccinating against PCV2 improved the average daily gain of pigs compared to not vaccinating. In addition, while pigs vaccinated with the two-dose product had reduced growth in the nursery, they had reduced PCV2-viremia and increased average daily gain at the end of the grower-finisher phase compared to pigs in the one-dose group. Finally, the amount of PCV2 in the blood, nasal secretions, and oral fluids was highest in the control group, intermediate in the one-dose group, and lowest in the two-dose group, suggesting that nasal secretions and oral-fluid may be useful as indicators of vaccine efficacy.