title: Hair cortisol detection in dairy cattle by using EIA: protocol validation and correlation with faecal cortisol metabolites.
abstract: Hair may be a useful matrix to detect cumulative cortisol concentrations in studies of animal welfare and chronic stress. The aim of this study was to validate a protocol for cortisol detection in hair from dairy cattle by enzyme immunoassay (EIA). Seventeen adult Holstein-Friesian dairy cows were used during the milking period. Hair cortisol concentration was assessed in 25-day-old hair samples taken from the frontal region of the head, analysing black and white coloured hair separately. Concentrations of cortisol metabolites were determined in faeces collected twice a week during the same period of time. There was a high correlation between cortisol values in faeces and cortisol in white colour hair samples but such correlation was not significant with the black colour hair samples. The intra- and inter-assay coefficients of variation were 4.9% and 10.6%, respectively. The linearity showed R 2=0.98 and mean percentage error of -10.8 ± 1.55%. The extraction efficiency was 89.0 ± 23.52% and the parallelism test showed similar slopes. Cortisol detection in hair by using EIA seems to be a valid method to represent long-term circulating cortisol levels in dairy cattle.
authors.affiliation: 1Department of Animal and Food Science, Faculty of Veterinary,Universitat Autònoma de Barcelona,Edifici V,Campus UAB,08193 Bellaterra,Spain.
authors.forename: O
authors.initials: O
authors.lastname: Tallo-Parra
authors.affiliation: 1Department of Animal and Food Science, Faculty of Veterinary,Universitat Autònoma de Barcelona,Edifici V,Campus UAB,08193 Bellaterra,Spain.
authors.forename: X
authors.initials: X
authors.lastname: Manteca
authors.affiliation: 2Department of Animal Health and Anatomy, Faculty of Veterinary,Universitat Autònoma de Barcelona,Edifici V,Campus UAB,08193 Bellaterra,Spain.
authors.forename: M
authors.initials: M
authors.lastname: Sabes-Alsina
authors.affiliation: 2Department of Animal Health and Anatomy, Faculty of Veterinary,Universitat Autònoma de Barcelona,Edifici V,Campus UAB,08193 Bellaterra,Spain.
authors.forename: A
authors.initials: A
authors.lastname: Carbajal
authors.affiliation: 2Department of Animal Health and Anatomy, Faculty of Veterinary,Universitat Autònoma de Barcelona,Edifici V,Campus UAB,08193 Bellaterra,Spain.
authors.forename: M
authors.initials: M
authors.lastname: Lopez-Bejar
mesh_terms: D000827:Animal Welfare; D000818:Animals; D002417:Cattle / Q000378:metabolism*; D005243:Feces / Q000737:chemistry*; D005260:Female; D006197:Hair / Q000737:chemistry*; D006854:Hydrocortisone / Q000032:analysis*; D007124:Immunoenzyme Techniques / Q000662:veterinary*
chemical_list: D006854:Hydrocortisone
keywords: EIA; animal welfare; cortisol; dairy cattle; hair