Research was performed on grasslands of National Park „Warta Mouth” in a cattle herd. Individual feces samples from 277 cows and 167 calves were analyzed during the years 2004-2006 using McMaster method. The patterns of EPG level in cattle herd were different in three consecutive years of research due to month of the year, length of stay on the same area of pasture, animals category (suckler cows vs. calves) and efficacy of de-worming before grazing season. The top values in suckler cows reached 700 EPG in September 2004, while in 2005 peak was recorded in June (ca 600 EPG) and in 2006 year maximum value diminished to only 40 EPG in September. The pattern of EPG values in calves generally followed the EPG values in cows. The effect of pasture sward had significant impact on EPG in cattle. Abrupt drop in EPG values was observed when cattle was moved to Phalaris arundinacea - Glyceria aquatica pasture in June. This self cure might be caused by the action of chemical compounds such as alkaloids and glycosides of these two grasses.

37-47