LACK OF CORRELATION BETWEEN MICROSCOPIC LESION SCORES AND GROSS LESION SCORES IN COMMERCIALLY GROWN BROILERS EXAMINED FOR SMALL-INTESTINAL EIMERIA SPP COCCIDIOSIS

Comparisons were made between microscopic lesion scores (MLSs) and gro ss lesion scores (GLSs) in sections from small intestine of broilers d uring three routine coccidiosis screenings. The duodenal and jejunal G LS were determined and recorded by different evaluators. During each s creening, 2-cm sections of duodenum and jejunum were collected, and se ctions of intestine were then scored using a microscopic lesion scorin g system. No correlation between MLS and GLS was observed in duodenum in two out of three coccidiosis screenings, and no correlation was obs erved between MLS and GLS in jejunum in three out of three screenings. Our findings demonstrate that, if used alone in coccidiosis screening , GLSs can underestimate infections and may not provide a true represe ntation of the magnitude of Eimeria maxima infection within broiler fl ocks.