December 2025 in “Biology Bulletin Reviews” This research review highlights how hair cortisol concentration can reflect the activation of the stress-response system in farm, domestic, and wild animals, noting it correlates with factors like species, sex, age, and environmental conditions, which may influence stress and adaptation.
10 citations
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September 2019 in “Frontiers in Veterinary Science” This study found that older steers had higher hair cortisol concentrations compared to younger steers, suggesting age affects chronic stress biomarkers in beef cattle.
21 citations
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January 2020 in “Conservation Physiology” This study found that cortisol concentrations were significantly higher in hair samples with follicles compared to those without, suggesting potential confounding in stress assessments using different hair sampling methods.
22 citations
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May 2019 in “Animals” In this study, researchers found that high hair cortisol levels, indicating stress in cows, were associated with certain shelter and cow-level conditions such as unclean environments and physical injuries.
69 citations
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May 2016 in “General and Comparative Endocrinology” This study found that hair cortisol concentrations in sheep were significantly increased by extensive brushing or dexamethasone treatment, suggesting that external factors may affect its reliability as a chronic stress measure.