The prevalence and intensity of helminth and coccidial infections in dairycattle in central Kenya

A survey of gastrointestinal parasite infections of young (< 6 months old), immature (6-12 months old) and adult (> 12 months old) dairy cattle on 16 farms in Kiambu District, Kenya was conducted during a dry season (Septembe r 1991 to January 1992) and during a wet season (March to July 1992). The s urvey was based on monthly coproparasitological examination of cohorts and worm counts in tracer calves. The effects of age, sex, farm and season on t he prevalence and intensity of helminth and coccidial infections were deter mined. Faecal egg and oocyst counts revealed that the overall prevalences w ere: strongyles (including trichostrongyles) (85.5%), liver flukes (Fasciol a gigantica) (34.0%), coccidia (30.9%) and tapeworms (9.6%). Eight species of the protozoan Eimeria were identified, the most prevalent species being E. bovis and E. zuernii. The most prevalent nematode genera were Haemonchus , Cooperia, Oesophagostomum and Trichostrongylus. Season, farm and age of t he animals had a significant (p < 0.05) influence on the intensity of infec tion with strongyles, liver flukes and coccidia, whereas the sex of the ani mals had no significant (p > 0.05) effect on the prevalence or intensity of infections. A higher intensity of infection with strongyles and coccidia w as found in the wet season than in the dry season (p < 0.05). The age-speci fic intensity was in the following order: for strongyles, immature animals of 6-12 months of age had the highest egg counts, followed by young calves and adults. Calves had significantly (p < 0.05) higher oocyst counts than i mmatures or adults. Liver fluke egg counts did not differ significant (p > 0.05) between immatures and adult cattle.