As pork producers moved away from concrete floors in the farrowing room, many assumed that coccidia,
a protozoan parasite which typically causes mild diarrhea in piglets at one to three weeks of age, had disappeared or diminished in importance. Not so. In a study conducted on 50 Ontario farms from May to August 2006, researchers found coccidia oocysts in feces from piglets aged from seven to 21 days on 70 per cent of the farms. Litters with coccidia were four times more likely to have diarrhea. Even in litters without diarrhea, coccidia were detected in 24 per cent of fecal samples. While the infection may cause reduced growth rates, it seldom results in serious illness or death.