title: Variation and covariation in strongyle infection in East African shorthorn zebu calves.
abstract: Parasite burden varies widely between individuals within a population, and can covary with multiple aspects of individual phenotype. Here we investigate the sources of variation in faecal strongyle eggs counts, and its association with body weight and a suite of haematological measures, in a cohort of indigenous zebu calves in Western Kenya, using relatedness matrices reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h(2) = 23.9%, s.e. = 11.8%) and we also found heritability of white blood cell counts (WBC) (h(2) = 27.6%, s.e. = 10.6%). All the traits investigated showed negative phenotypic covariances with strongyle egg count throughout the first year: high worm counts were associated with low values of WBC, red blood cell count, total serum protein and absolute eosinophil count. Furthermore, calf body weight at 1 week old was a significant predictor of strongyle EPG at 16-51 weeks, with smaller calves having a higher strongyle egg count later in life. Our results indicate a genetic basis to strongyle EPG in this population, and also reveal consistently strong negative associations between strongyle infection and other important aspects of the multivariate phenotype.
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories,Kings Buildings, West Mains Road, Edinburgh EH9 3JT,UK.
authors.forename: R
authors.initials: R
authors.lastname: Callaby
authors.affiliation: School of Life Sciences, University of Nottingham,University Park, Nottingham NG7 2RD,UK.
authors.forename: O
authors.initials: O
authors.lastname: Hanotte
authors.affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science,University of Pretoria,Private bag X04, Onderstepoort,South Africa.
authors.forename: I
authors.initials: I
authors.lastname: Conradie Van Wyk
authors.affiliation: International Livestock Research Institute,P.O. Box 30709, Nairobi 00100,Kenya.
authors.forename: H
authors.initials: H
authors.lastname: Kiara
authors.affiliation: International Livestock Research Institute,P.O. Box 30709, Nairobi 00100,Kenya.
authors.forename: P
authors.initials: P
authors.lastname: Toye
authors.affiliation: African Union - Interafrican Bureau for Animal Resources (AU-IBAR),Kenindia Business Park building, Museum Hill, Westlands Road, P.O Box 30786, 00100 Nairobi,Kenya.
authors.forename: M N
authors.initials: MN
authors.lastname: Mbole-Kariuki
authors.affiliation: The Farm Animal Practice, The University of Edinburgh,Easter Bush, Edinburgh EH25 9RG,UK.
authors.forename: A
authors.initials: A
authors.lastname: Jennings
authors.affiliation: Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories,Kings Buildings, West Mains Road, Edinburgh EH9 3JT,UK.
authors.forename: S M
authors.initials: SM
authors.lastname: Thumbi
authors.affiliation: Department of Veterinary Tropical Diseases, Faculty of Veterinary Science,University of Pretoria,Private bag X04, Onderstepoort,South Africa.
authors.forename: J A W
authors.initials: JA
authors.lastname: Coetzer
authors.affiliation: The Roslin Institute, Easter Bush, University of Edinburgh,Roslin, Midlothian EH25 9RG,UK.
authors.forename: B M
authors.initials: BM
authors.lastname: de C Bronsvoort
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories,Kings Buildings, West Mains Road, Edinburgh EH9 3JT,UK.
authors.forename: S A
authors.initials: SA
authors.lastname: Knott
authors.affiliation: Institute of Evolutionary Biology, University of Edinburgh, Ashworth Laboratories,Kings Buildings, West Mains Road, Edinburgh EH9 3JT,UK.
authors.forename: M E J
authors.initials: ME
authors.lastname: Woolhouse
authors.affiliation: Division of Evolution, Ecology & Genetics,Research School of Biology, The Australian National University,Canberra, ACT 0200,Australia.
authors.forename: L E B
authors.initials: LE
authors.lastname: Kruuk
mesh_terms: D000818:Animals; D001724:Birth Weight; D001798:Blood Proteins / Q000032:analysis; D002417:Cattle; D002418:Cattle Diseases / Q000097:blood / Q000235:genetics / Q000469:parasitology*; D016000:Cluster Analysis; D004906:Erythrocyte Count / Q000662:veterinary; D005243:Feces / Q000469:parasitology; D005838:Genotype; D007630:Kenya; D007958:Leukocyte Count / Q000662:veterinary; D010270:Parasite Egg Count / Q000662:veterinary; D020641:Polymorphism, Single Nucleotide; D017206:Strongylida Infections / Q000097:blood / Q000235:genetics / Q000469:parasitology / Q000662:veterinary*; D013323:Strongylus / Q000502:physiology*; D015430:Weight Gain
chemical_list: D001798:Blood Proteins
keywords: haematology