Prevalence of subclinical coccidiosis in broiler-chicken farms in the municipality of Mashhad, Khorasan, Iran.

A survey of the prevalence of subclinical coccidiosis in broiler-chickens was conducted in the municipality of Mashhad, Khorasan, Iran. Eighty-four chicken farms were randomly selected; from each farm, five birds per 106th week of age.6th week of age. The farm-level prevalence of subclinical coccidiosis was 38% (95% CI: 48 .47%). Uni- and multi-variable associations were tested between each va riable. An increased risk of infection in the broiler was associated wi th the larger farm, with older chickens, and if the chicken farm were sa mpled in the winter or spring, using coccidiostat in the food was not as sociated. The peak oocyst score in the litter occurred at >6th week age . Most farms (97%) had E. acervulina; (41%) had E. maxima and (12%) had E. tenella.