Abstract   

    Sixty three faecal as well as blood samples from a group of 15 young Friesian calves under 2 months of age at Aber Farm Bangor, U.K. were collected on monthly basis and examined for the presence of Cryptosporidium oocysts and serum immunoglobulin G (IgG) antibodies, Twelve (19.23 %) were found positive with Cryptosporium species while in 5 (7.9 %) faecal samples both Cryptosporidium and Eimeria were present but 46 (73.0 %) samples were negative. In 9 out of 12 (75.0 %) cases where Cryptosporidium ocysts were present, a positive IF AT was observed while in 4 out of 5 (80.0 %) positives were seen in the presence of both Cryptosporium and Eimeria oocysts. In contrast only 6 out of 46 (13.1%) cases, a positive IFAT was also seen when no oocysts were recorded. Oocysts fluoresced brightly with positive serum samples and only faintly or not at all with the negative samples or the conjugate alone.

Key words: Friesian calves, Immunoglobulin G, Cryptosporidium oocysts.