title: Seasonal variation in resistance of calves to experimental infections with Cooperia oncophora.
abstract: Over a period of nine years, ten experiments were conducted on Cooperia oncophora infections in calves. A total of 327 calves were infected, each with a single dose of 100 000 infective larvae. The large variation between experiments in the faecal egg output of calves appeared to be related to the time of year at infection. Calves infected in the Spring showed significantly higher peak egg counts than calves infected during the rest of the year. Most of the variation in worm length was explained by the age of infection.
mesh_terms: D000818:Animals; D001699:Biometry; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology*; D005243:Feces / Q000469:parasitology; D005260:Female; D008297:Male; D009349:Nematode Infections / Q000469:parasitology / Q000662:veterinary*; D010270:Parasite Egg Count / Q000662:veterinary; D012621:Seasons; D013320:Strongyloidea / Q000033:anatomy & histology