A comparison between the equine and bovine hypothalamus-pituitary-adrenocortical axis.
Abstract: In this review, we address the function of the hypothalamus-pituitary-adrenocortical (HPA) axis with special emphasis on the comparison between the bovine and equine species. The pars intermedia of the pituitary gland is particularly well developed in horses and cattle. However, its function is not well appreciated in cattle yet. The Wulzen's cone of the adenohypophysis is a special feature of ruminants. Total basal cortisol concentration is much higher in horses than that in cows with similar free cortisol fractions. Corticotropin-releasing factor (CRF) concentrations in equine pituitary venous blood are lower compared with other species, whereas plasma ACTH concentrations in cows are higher than those in horses. A CRF challenge test induced a more pronounced cortisol response in horses compared with cattle, whereas regarding ACTH challenge testing, the opposite seems true. Based on data from literature, the bovine species is characterized by relatively high basal blood CRF and ACTH and low cortisol and glucose concentrations. Obviously, further lowering of blood cortisol in cattle is easily prevented by the high sensitivity to ACTH, and as a consequence, subsequent increased gluconeogenesis prevents imminent hypoglycemia. Hypoglycemia is less likely in horses given their high muscle glycogen content and their relatively high cortisol concentration. When assessing HPA axis reactivity, response patterns to exogenous ACTH or CRH might be used as a reliable indicator of animal welfare status in cows and horses, respectively, although it is emphasized that considerable caution should be exercised in using measures of HPA activity solely to assess animal welfare.
Copyright © 2016 Elsevier Inc. All rights reserved.
Publication Date: 2016-06-28 PubMed ID: 27345307DOI: 10.1016/j.domaniend.2016.02.008Google Scholar: Lookup
The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
- Review
- Research Support
- Non-U.S. Gov't
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.
The research article compares the hypothalamus-pituitary-adrenocortical (HPA) axis in equine and bovine species, particularly noting differences in anatomical features, hormone concentrations, and response patterns to certain tests.
Species Comparative Analysis
- The authors first note that the pars intermedia of the pituitary gland is quite developed in both species, but its function in cattle isn’t as well understood.
- Ruminants, like cows, have a unique feature known as the Wulzen’s cone in the adenohypophysis. This feature does not exist in horses.
- Basal cortisol concentration, a stress hormone is higher in horses compared to cows, but free cortisol fractions, the form that actually interacts with body cells, are similar in both species.
Hormone Concentration Differences
- Comparing hormone levels, the corticotropin-releasing factor (CRF), which triggers cortisol release, is lower in the blood from the horse’s pituitary compared to other species.
- In contrast, cows have higher levels of Adrenocorticotropic hormone (ACTH), which also stimulates cortisol production, than horses.
Response to Stimuli
- When given a CRF challenge test, which measures the responsiveness of the HPA axis, horses exhibited a more marked cortisol response than cows. In an ACTH challenge test, cows reacted more strongly than horses.
- From data gathered from literature, cows typically have an unusually high basal level of CRF and ACTH, but low levels of cortisol and glucose. According to the authors, this might be a protective mechanism: cows can quickly increase cortisol production (and thus blood sugar levels) due to their high sensitivity to ACTH, thereby preventing hypoglycemia, a severe drop in blood sugar levels.
- Horses are at a lower risk of hypoglycemia due to their high muscle glycogen content and higher cortisol levels.
Animal Welfare Assessment
- Finally, the authors propose using the HPA axis response patterns to tests as indicators of animal welfare, with ACTH tests being more reliable for cows and CRF tests for horses. However, they caution against using these measures alone to evaluate animal welfare, as the HPA axis reactions can be influenced by several factors.
Cite This Article
APA
van der Kolk JH, Fouché N, Gross JJ, Gerber V, Bruckmaier RM.
(2016).
A comparison between the equine and bovine hypothalamus-pituitary-adrenocortical axis.
Domest Anim Endocrinol, 56 Suppl, S101-S111.
https://doi.org/10.1016/j.domaniend.2016.02.008 Publication
Researcher Affiliations
- Department of Clinical Veterinary Medicine, Swiss Institute for Equine Medicine (ISME), Vetsuisse Faculty, University of Bern and Agroscope, Bern 3012, Switzerland. Electronic address: johannes.vanderkolk@vetsuisse.unibe.ch.
- Department of Clinical Veterinary Medicine, Swiss Institute for Equine Medicine (ISME), Vetsuisse Faculty, University of Bern and Agroscope, Bern 3012, Switzerland.
- Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
- Department of Clinical Veterinary Medicine, Swiss Institute for Equine Medicine (ISME), Vetsuisse Faculty, University of Bern and Agroscope, Bern 3012, Switzerland.
- Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern 3012, Switzerland.
MeSH Terms
- Animals
- Cattle / physiology
- Horses / physiology
- Hypothalamo-Hypophyseal System / physiology
- Pituitary-Adrenal System / physiology
Citations
This article has been cited 3 times.- Contalbrigo L, Borgi M, De Santis M, Collacchi B, Tuozzi A, Toson M, Redaelli V, Odore R, Vercelli C, Stefani A, Luzi F, Valle E, Cirulli F. Equine-Assisted Interventions (EAIs) for Children with Autism Spectrum Disorders (ASD): Behavioural and Physiological Indices of Stress in Domestic Horses (Equus caballus) during Riding Sessions. Animals (Basel) 2021 May 27;11(6).
- Schwinn AC, Sauer FJ, Gerber V, Bruckmaier RM, Gross JJ. Free and bound cortisol in plasma and saliva during ACTH challenge in dairy cows and horses. J Anim Sci 2018 Feb 15;96(1):76-84.
- Zhang Q, Yang L, Li Y, Gu P, Si R, Zhu L, Zhang W. Heat stress affects dairy cow performance via oxidative stress, hypothalamic-pituitary-adrenal axis, gut microbiota, and multi-dimensional mitigation. Front Vet Sci 2025;12:1686241.
Use Nutrition Calculator
Check if your horse's diet meets their nutrition requirements with our easy-to-use tool Check your horse's diet with our easy-to-use tool
Talk to a Nutritionist
Discuss your horse's feeding plan with our experts over a free phone consultation Discuss your horse's diet over a phone consultation
Submit Diet Evaluation
Get a customized feeding plan for your horse formulated by our equine nutritionists Get a custom feeding plan formulated by our nutritionists
