Evaluation of Haemophilus parasuis control in the nursery using vaccination and controlled exposure

Methods: The experiments were performed in a multi-farm system experiencing high nursery mortality (> 4.8%) due to H parasuis infection. In Experiment 1, pigs were vaccinated at weaning using a commercially available, one-dose H parasuis vaccine. In Experiment 2, pigs were vaccinated at processing and at weaning with an autogenous vaccine. In Experiment 3, pigs were orally inoculated at processing using a bacterial suspension containing a total of 105-6 colony forming units per mL of three H parasuis strains prevalent in the studied herd. Experiments 1 and 2 were repeated five times (5 consecutive weeks of production), and Experiment 3 was repeated nine times.