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Home / Equine Research Bank / Animals (Basel) / Hair Cortisol Concentrations in Feral Horses and the Influen...
Animals : an open access journal from MDPI2023; 13(13); doi: 10.3390/ani13132133

Hair Cortisol Concentrations in Feral Horses and the Influence of Physiological and Social Factors.

Abstract: Cortisol is a glucocorticoid hormone produced during activation of the hypothalamic-pituitary-adrenal axis (HPA) in response to psychological or physiological demands. High amounts of circulating cortisol can be found in individuals experiencing energetically demanding physiological events, such as pregnancy, lactation, injury, or starvation, but, also, in individuals who may have less obvious HPA activation from social situations. The feral horse population on Sable Island (Nova Scotia, Canada) provides an opportunity to look at hair cortisol concentration (HCC) as a proxy for circulating cortisol concentration to better understand physiological correlates. The horse's complex social structure also allows us to look at how the population and group structure may influence HPA activation. Hair samples (n = 282) were analyzed from 113 females and 135 males. Females with dependent offspring (foals) had higher HCC than those females without dependent offspring (p = 0.005). Horses in poor body condition were also more likely to have higher HCC (females: p < 0.001, males: p = 0.028); females had greater variation in the body condition index (BCI), which also correlated with foal production. In general, the top-ranked models describing female cortisol levels included age, BCI, presence of a foal, as well as social measures such as harem size and the number of bachelors in the vicinity. The top model describing male cortisol levels included age, BCI, and year of collection only, and the number of bachelors in the home range appeared in subsequent, though still high-ranked, models. Among the variables not of direct interest, we found some significant results relating to hair color and hair texture. Differences in HCC patterns between feral and domestically kept horses (e.g., age and sex) are likely linked to periods of resource limitations, particularly for individuals experiencing energetically demanding processes such as reproduction, illness/parasitism, or related to experiencing the full range of social and reproductive behaviors.
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Publication Date: 2023-06-27 PubMed ID: 37443930PubMed Central: PMC10339936DOI: 10.3390/ani13132133Google Scholar: Lookup
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  • Journal Article

Summary

This research summary has been generated with artificial intelligence and may contain errors and omissions. Refer to the original study to confirm details provided. Submit correction.

This research paper discusses a study conducted on feral horses in Sable Island, Nova Scotia, Canada. The researchers studied the hair cortisol concentrations of these horses to understand how physiological and social factors influence their glucocorticoid hormone production.

Research Methodology and Objective

  • The researchers used hair cortisol concentration (HCC) as a measure for circulating cortisol concentration. Cortisol is a hormone produced in response to psychological or physiological stress.
  • A total of 282 hair samples were analyzed, collected from 113 female and 135 male horses.
  • The complex social structure of the feral horse populations was utilized to understand how population and group structures influence HPA activation.

Key Findings

  • Horses with dependent offspring or in poor body condition were more likely to have higher HCC. This might be due to the energetic demands of pregnancy, lactation, injury, or starvation.
  • In females, the top-ranked models for cortisol levels included age, body condition index, presence of a foal, harem size, and the number of bachelor horses in the vicinity.
  • On the other hand, the top model for male cortisol levels included age, body condition index, and year of collection, with the number of bachelor horses appearing in subsequent models.

Implications and Significance

  • The study provides insights into some of the influences on cortisol production in feral horses. This could have potential applications in understanding stress responses in other wild animal populations.
  • The authors suggest that differences in HCC patterns between feral and domestic horses, such as age and sex, could be linked to periods of resource limitations — in particular for reproduction and illness — or related to social and reproductive behaviors.

Additional Findings

  • The researchers also found significant results relating to hair color and hair texture, though these were not the primary focus of the study.

Cite This Article

APA
Medill SA, Janz DM, McLoughlin PD. (2023). Hair Cortisol Concentrations in Feral Horses and the Influence of Physiological and Social Factors. Animals (Basel), 13(13). https://doi.org/10.3390/ani13132133

Publication

Animals : an open access journal from MDPI
ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 13
Issue: 13

Researcher Affiliations

Medill, Sarah A
  • Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5C8, Canada.
Janz, David M
  • Department of Veterinary Biomedical Sciences, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
McLoughlin, Philip D
  • Department of Biology, University of Saskatchewan, Saskatoon, SK S7N 5C8, Canada.

Grant Funding

  • 371535-2009 / Natural Sciences and Engineering Research Council
  • 25046 / Canada Foundation for Innovation

Conflict of Interest Statement

The authors declare no conflict of interest.

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Citations

This article has been cited 1 times.
  1. Medill SA, Janz DM, McLoughlin PD. Hair Cortisol and Testosterone Concentrations in Relation to Maturity and Breeding Status of Male Feral Horses. Animals (Basel) 2023 Jun 27;13(13).
    doi: 10.3390/ani13132129pubmed: 37443926google scholar: lookup
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