QUANTIFYING RISK-FACTORS OF COCCIDIOSIS IN BROILERS USING ON-FARM DATA-BASED ON A VETERINARY PRACTICE

A study was done to find and quantify risk factors for coccidiosis. Th e study population consisted of 4774 broiler flocks kept on 177 farms. Flocks were considered a case when at least one bird in the flock sho wed microscopic presence of oocysts in intestinal scrapings in a grow- out cycle. Other flocks were defined as controls. This was done for th ree types of Eimeria: Eimeria acervulina, Eimeria tenella and Eimeria maxima. Logistic regression was used to assess variables that influenc e the occurrence of Eimeria species. There were 49 variables, based on animal, flock or farm level. There was an enhanced risk of coccidiosi s due to environmental and management factors that increase the risk o f introducing contamination or that are related to hygienic measures. These include lack of use of overalls by visitors, a farmyard which is difficult to clean, bad hygienic status, personnel who might also be working on other farms, presence of other animals on the farm, and fee ding and drinking systems which are more difficult to clean. Also, the presence of other diseases on the farm and Eimeria species found in t he previous flock increased the risk of coccidiosis. (C) 1998 Elsevier Science B.V.