title: Differences between female and castrated male lambs in susceptibility to natural, predominantly Teladorsagia circumcincta infection.
abstract: The difference between castrated male lambs and entire female lambs in susceptibility to gastrointestinal nematode infection was investigated in a flock of Scottish Blackface sheep. Castrated male lambs had higher faecal egg counts, higher body weights, lower parasite-specific plasma IgA activity and more adult nematodes. There were no detectable differences in the length of adult Teladorsagia circumcincta. Heavier egg shedding by males was associated with greater worm burdens. The difference in plasma IgA activity may have been a consequence of larger numbers of adult nematodes inhibiting the transfer of mucosal IgA to the plasma. At least part of the sex difference in egg production could be a consequence of males ingesting larger amounts of grass and hence numbers of infective larvae because of their larger size. The differences between castrated males and females contribute to the observed variation in nematode egg production in naturally infected lambs.
authors.affiliation: Department of Animal Medicine, Faculty of Veterinary Medicine, Tripoli University, PO Box 84575, Tripoli, Libya.
authors.forename: O
authors.initials: O
authors.lastname: Abuargob
authors.affiliation: Institute of Biodiversity, Animal Health and Comparative Medicine, Garscube Campus, University of Glasgow, Bearsden Road, Glasgow G61 1QH, United Kingdom. Electronic address: michael.stear@glasgow.ac.uk.
authors.forename: M J
authors.initials: MJ
authors.lastname: Stear
mesh_terms: D000818:Animals; D004198:Disease Susceptibility; D005243:Feces / Q000469:parasitology; D005260:Female; D005767:Gastrointestinal Diseases / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*; D007070:Immunoglobulin A / Q000097:blood; D008297:Male; D010270:Parasite Egg Count / Q000662:veterinary; D012737:Sex Factors; D012756:Sheep; D012757:Sheep Diseases / Q000453:epidemiology* / Q000276:immunology / Q000469:parasitology; D014251:Trichostrongyloidea / Q000276:immunology / Q000302:isolation & purification*; D014252:Trichostrongyloidiasis / Q000453:epidemiology / Q000469:parasitology / Q000662:veterinary*
chemical_list: D007070:Immunoglobulin A
keywords: Faecal egg counts; IgA; Nematode; Sex; Sheep; Teladorsagia circumcincta