EXPERIMENTALLY INDUCED PORCINE COCCIDIOSIS

Two controlled field experiments in which the performance of groups of pigs were studied following daily exposures to large numbers of mixed sporulated coccidial oocysts are reported. Comparisons between control and principal groups were made on the basis of faecal oocyst counts (OPG) and body weight gains. On the basis of oocyst counts, experimentally in fected principals in both experiments developed substantial oocyst populations which reached a peak on the 9th day of infection and declined steadily. Therefore, environmental controls did not develop oocysts. Controls gained more weight on the average than the infected principals during the experiments. Microscopic examination of intestinal tissue sections from an infected principal that died on day 22 revealed the presence of several large cystic bodies in the mucosa of the caecum and large colon. It is suggested that these structures could be schizonts.