THE REPEATABILITY OF FECAL EGG COUNTS IN POLISH WRZOSOWKA SHEEP

The number of nematode eggs in the faeces was estimated in Polish Wrzo sowka sheep, in the spring and autumn of 1993 and again in 1994. The s heep had been naturally infected. The dominant species were Haemonchus contortus and Teladorsagia circumcincta, but Trichostrongylus spp., C ooperia curticei, Nematodirus spp. and Chabertia ovina were also prese nt. Anthelmintics were not used. Egg counts were skewed, with a range of 0-4100 eggs g(-1) (EPG); most sheep had egg counts below 100 EPG. E gg counts were approximately four times higher in spring than in autum n. Repeatability values within a season were all significant and posit ive. The repeatability of egg counts between seasons was estimated fro m the correlation between the mean transformed value in spring and in autumn, and was 0.52 in 1993 (P < 0.001) and 0.41 in 1994 (P < 0.05). The results show that animals with higher than average Values in sprin g are likely to have higher than average values in autumn, and suggest that similar mechanisms regulated egg counts in both seasons even tho ugh egg counts were much lower in autumn. (C) 1997 Published by Elsevi er Science B.V.