The objective of this study was to evaluate the suitability of the Concentration McMaster technique in counting coccidia oocysts and to compare it with two others -McMaster method modified by Wetzel and Zajíček. A stock suspension containing Eimeria oocysts was prepared, from which five concentrations (20, 250, 500, 1,000 and 1,500) of oocysts were made. Each method was evaluated after the examination of 30 samples in five concentrations. Each sample was presented as a parasite negative fecal dropping into which a known number of oocysts were inoculated. When results of all three methods were compared, statistically significant differences (P<0.05) among them in each tested OPG concentration were found. The most diverse results (P<0.01) were provided by the Wetzel and Zajíček methods. The Wetzel method produced the least accurate results of all the evaluated methods and in all tested oocyst concentrations. This method was found inappropriate for counting coccidia oocysts in fecal droppings. The Zajíček and the Roepstorff and Nansen method produced oocyst counts similar to the true numbers. These two methods were then evaluated using poultry fecal droppings naturally infected by coccidial infection. Differences between these two methods were found in the repeatability of the obtained results rather than in the oocyst counts. Compared to the Zajíček method, the Roepstorff and Nansen method is faster, less laborious, and produces sensitive and reliable results with repeated measurements over time. For all these reasons the Concentration McMaster technique could be recommend for the detection and quantification of coccidia oocysts in bird droppings.

Key words: Eimeria, Fecal flotation, OPG, Parasite, Reliability, Sensitivity