This study demonstrated a clear benefit in vaccinating pigs subclinically infected with porcine circovirus type 2 (PCV2) with a one-dose PCV2 vaccine.
At weaning (3 weeks of age), 1427 pigs were vaccinated and 1431 were sham-inoculated with a placebo (0.9% physiological saline). After 33 days in the nursery, 528 pigs from each treatment group were moved into 48 pens in a commercial finisher barn, ensuring equal age of pigs across both treatments. Each pig was weighed on day 2 in the finisher barn and on day 88 (end of the study period).
The vaccinates had a 36-g-per-day advantage in daily gain and 4.6% less mortality than the unvaccinated pigs. More than twice as many vaccinates as unvaccinated pigs (40 versus 16, respectively) were marketed at the first shipment. Furthermore, carcass weight (95.0 kg versus 94.0 kg; P < .05), lean percent (60.52% versus 60.26%; P < .05) and carcass index (111.6 versus 111.1; P < .05) were all greater for the vaccinates. The mean loin depth was 65.1 mm for vaccinates and 63.3 mm for unvaccinated pigs (P < .05). The vaccinated pigs delivered a return on investment of $5.90 per pig over the unvaccinated pigs.
Young MG, Cunningham GL, Sanford SE. Circovirus vaccination in pigs with subclinical porcine circovirus type 2 infection complicated by ileitis. J Swine Health Prod. 2011;19(3):175?180.