Repeatability of ovine faecal oocyst counts in natural infections with Eimeria spp.

The repeatability of ovine faecal oocyst counts was studied in Merino of Arles and Romanov sheep over short (4 days) or longer periods (1 month). The repeatabilities over short periods ranged from 0.27 to 0.67 for total oocyst output, from 0.06 to 0.54 for Eimeria ovinoidalis and from 0.29 to 0.52 for E. parva counts. E. ovinoidalis had lower and more irregular repeatabilities than E. parva. Their repeatabilities ranged, respectively from 0.18 (E. ovinoidalis) to 0.22 (E. parva) for longer periods. The genetic share in the determination of magnitude of oocyst counts seems similar to that recorded for trichostrongylid egg counts.