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Home / Equine Research Bank / Equine Vet J / Cortisol and heart rate response of mares during the in-hand...
Equine veterinary journal2025; doi: 10.1111/evj.70083

Cortisol and heart rate response of mares during the in-hand breeding procedure with and without restraint.

Abstract: In-hand breeding involving restraint methods is likely the most common practice in the horse breeding industry worldwide. However, welfare issues that arise from such management have not been investigated in detail. Objective: (1) To investigate whether the mares show increased stress responses during in-hand breeding using (a) a lip twitch and (b) hobbles. (2) To evaluate if the use of restraint methods influences the mare's expression of oestrous behaviour. Methods: Intra-individual cross-over design. Methods: Six Franches-Montagnes stallions and 10 warmblood mares were used in these experiments. Each mare underwent standardised teasing and breeding sessions with and without one of the two restraint methods (morning and afternoon) on the day before ovulation. Salivary cortisol concentrations, continuous heart rate (HR) and heart rate variability (HRV) before, during and after the teasing and breeding sessions were measured as objective stress indicators. An ethogram was established to evaluate the behaviour during breeding. Results: Using the lip twitch increased cortisol concentrations (with twitch from 0.77 ± 0.07 to 1.20 ± 0.07 ng/mL vs. without twitch from 0.73 ± 0.07 ng/mL to 0.99 ± 0.07 ng/mL; p = 0.04), and the hobbles could not be applied to 2 out of the 10 mares in our study, as they did not tolerate this restraint method. Conclusions: The sample contained a small number of mares. Conclusions: Using a lip twitch in mares during in-hand breeding is accompanied by a slight degree of stress, while hobbles are tolerated very well or not at all by the mares.
© 2025 The Author(s). Equine Veterinary Journal published by John Wiley & Sons Ltd on behalf of EVJ Ltd.
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Publication Date: 2025-09-02 PubMed ID: 40891633DOI: 10.1111/evj.70083Google Scholar: Lookup
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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.

Overview

  • This study examined how two different restraint methods, a lip twitch and hobbles, affect stress levels and behavior in mares during in-hand breeding procedures.
  • It aimed to determine whether these restraint techniques cause stress and influence mares’ oestrous behaviors using physiological and behavioral measures.

Background and Purpose

  • In-hand breeding, where mares are physically restrained, is a common practice in horse breeding worldwide.
  • Despite its widespread use, how restraint affects the welfare, particularly stress levels, of mares has not been thoroughly studied.
  • The study focused on two main objectives:
    • To assess if using a lip twitch or hobbles during breeding induces increased stress responses in mares.
    • To evaluate whether these restraint methods alter how mares express behaviors associated with oestrus (the period of sexual receptivity).

Methods

  • The study utilized an intra-individual cross-over design, meaning each mare experienced both restrained and non-restrained breeding sessions to allow direct comparison within individuals.
  • Subjects:
    • Six Franches-Montagnes stallions and ten warmblood mares were involved.
    • Trials were conducted on the day before ovulation, a critical time for observing oestrous behavior and breeding responses.
  • Procedure:
    • Mares underwent standardized teasing (to stimulate oestrous behavior) and breeding sessions either with restraint (lip twitch or hobbles) or without restraint.
    • Two sessions were conducted on the same day: one in the morning and one in the afternoon.
  • Stress and behavior evaluation:
    • Salivary cortisol concentrations were measured as a biochemical marker of stress.
    • Heart rate (HR) and heart rate variability (HRV) were continuously monitored to assess physiological stress responses.
    • An ethogram (a catalog of specific behaviors) was used to quantify oestrous behavior during breeding.

Results

  • Use of the lip twitch restraint:
    • Significantly increased salivary cortisol levels from a baseline of approximately 0.77 ng/mL to 1.20 ng/mL, signaling increased physiological stress.
    • Without the twitch, cortisol also rose but to a lesser extent (from about 0.73 to 0.99 ng/mL).
    • The increase with lip twitch was statistically significant (p = 0.04), indicating a measurable effect on stress.
  • Use of hobbles:
    • Hobbles were either well tolerated or not tolerated at all by different mares—2 out of 10 mares refused to accept this form of restraint.
    • The study did not report a significant cortisol increase due to hobbles for the mares that tolerated it.
  • Effects on oestrous behavior:
    • The abstract does not detail specific findings related to behavior changes induced by restraints, suggesting either minimal effect or that the primary focus was on physiological stress markers.
  • Limitations:
    • The sample size was relatively small, especially considering only 10 mares were tested.
    • This limits broad generalizability but provides preliminary insight into restraint impacts on stress.

Conclusions

  • Applying a lip twitch to mares during in-hand breeding produces a measurable, though slight, increase in stress as indicated by cortisol increase.
  • Hobbles present a dichotomous response: mares either tolerate them very well or refuse them completely, indicating individual variation in acceptability.
  • These findings highlight welfare considerations in horse breeding management—lip twitches may raise stress levels modestly, and hobbles might cause behavioral issues in some mares.
  • The study emphasizes the need for careful choice and potentially individualized restraint methods to maintain mare welfare during breeding.

Cite This Article

APA
Atayde MF, Vidondo B, Bruckmaier R, Freymond SB, Sieme H, Rey-Kaeser R, Burger D. (2025). Cortisol and heart rate response of mares during the in-hand breeding procedure with and without restraint. Equine Vet J. https://doi.org/10.1111/evj.70083

Publication

Equine veterinary journal
ISSN: 2042-3306
NlmUniqueID: 0173320
Country: United States
Language: English

Researcher Affiliations

Atayde, Maria Fernanda
  • Swiss Institute of Equine Medicine, Vetsuisse Faculty University of Bern, Avenches, Switzerland.
Vidondo, Beatriz
  • Veterinary Public Health Institute, University of Bern, Liebefeld, Switzerland.
Bruckmaier, Rupert
  • Veterinary Physiology, Vetsuisse Faculty, University of Bern, Bern, Switzerland.
Freymond, Sabrina Briefer
  • Agroscope, Swiss National Stud Farm, Les Longs-Prés, Avenches, Switzerland.
Sieme, Harald
  • Clinic for Horses - Unit for Reproductive Medicine, University of Veterinary Medicine Hannover, Hannover, Germany.
Rey-Kaeser, Rebekka
  • Swiss Institute of Equine Medicine, Vetsuisse Faculty University of Bern, Avenches, Switzerland.
Burger, Dominik
  • Swiss Institute of Equine Medicine, Vetsuisse Faculty University of Bern, Avenches, Switzerland.

Grant Funding

  • Foundation Pro Pferd, Switzerland

References

This article includes 33 references
  1. Scoggin CF. Natural service: in‐hand breeding. In: Dascanio JJ, McCue PM, editors. Equine reproductive procedures. Hoboken, NJ: Wiley; 2014. p. 114–116.
  2. Merkt H, Bartmann CP, Bader H. Restraint of mares for mating. Pferdeheilkunde 2001;17(3):217–218.
    doi: 10.21836/pem20010303google scholar: lookup
  3. McDonnell S. Reproductive behavior of stallions and mares: reproductive behavior of stallions and mares: comparison of free‐running and domestic in‐hand breeding. Anim Reprod Sci 2000;60‐61:211–219.
    doi: 10.1016/s0378-4320(00)00136-6google scholar: lookup
  4. Campbell MLH, Sandøe P. Welfare in horse breeding. Vet Rec 2015;176(17):436–440.
    doi: 10.1136/vr.102814google scholar: lookup
  5. Oliveira RA, Aurich C. Aspects of breeding stallion management with specific focus on animal welfare. J Equine Vet Sci 2021;107:103773.
    doi: 10.1016/j.jevs.2021.103773google scholar: lookup
  6. Visser EK, van Reenen CG, van der Werf JTN, Schilder MBH, Knaap JH, Barneveld A. Heart rate and heart rate variability during a novel object test and a handling test in young horses. Physiol Behav 2002;76(2):289–296.
    doi: 10.1016/s0031-9384(02)00698-4google scholar: lookup
  7. von Borell E, Langbein J, Després G, Hansen S, Leterrier C, Marchant J. Heart rate variability as a measure of autonomic regulation of cardiac activity for assessing stress and welfare in farm animals—a review. Physiol Behav 2007;92(3):293–316.
    doi: 10.1016/j.physbeh.2007.01.007google scholar: lookup
  8. Peeters M, Sulon J, Beckers J-F, Ledoux D, Vandenheede M. Comparison between blood serum and salivary cortisol concentrations in horses using an adrenocorticotropic hormone challenge. Equine Vet J 2011;43(4):487–493.
    doi: 10.1111/j.2042-3306.2010.00294.xgoogle scholar: lookup
  9. Schönbom H, Kassens A, Hopster-Iversen C, Klewitz J, Piechotta M, Martinsson G. Influence of transrectal and transabdominal ultrasound examination on salivary cortisol, heart rate, and heart rate variability in mares. Theriogenology 2015;83(4):749–756.
    doi: 10.1016/j.theriogenology.2014.11.010google scholar: lookup
  10. Schmidt A, Biau S, Möstl E, Becker-Birck M, Morillon B, Aurich J. Changes in cortisol release and heart rate variability in sport horses during long‐distance road transport. Domest Anim Endocrinol 2010;38(3):179–189.
    doi: 10.1016/j.domaniend.2009.10.002google scholar: lookup
  11. von Lewinski M, Biau S, Erber R, Ille N, Aurich J, Faure JM. Cortisol release, heart rate and heart rate variability in the horse and its rider: different responses to training and performance. Vet J 2013;197(2):229–232.
    doi: 10.1016/j.tvjl.2012.12.025google scholar: lookup
  12. Peeters M, Closson C, Beckers J-F, Vandenheede M. Rider and horse salivary cortisol levels during competition and impact on performance. J Equine Vet Sci 2013;33(3):155–160.
    doi: 10.1016/j.jevs.2012.05.073google scholar: lookup
  13. Strzelec K, Kankofer M, Pietrzak S. Cortisol concentration in the saliva of horses subjected to different kinds of exercise. Acta Vet Brno 2011;80(1):101–105.
    doi: 10.2754/avb201180010101google scholar: lookup
  14. Strzelec K, Kędzierski W, Bereznowski A, Janczarek I, Bocian K, Radosz M. Salivary cortisol levels in horses and their riders during three‐day‐events. Bull Vet Inst Pulawy 2013;57(2):237–241.
    doi: 10.2478/bvip-2013-0042google scholar: lookup
  15. Strzelec K, Pietrzak S, Prochniak T, Janczarek I, Cywinska A, Bereznowski A. Salivary cortisol levels in horses and their junior riders during show jumping. Turk J Vet Anim Sci 2020;44(2):391–395.
    doi: 10.3906/vet-1908-17google scholar: lookup
  16. Bergfelt DR, Mann BG, Schwartz NB, Ginther OJ. Circulating concentrations of immunoreactive inhibin and FSH during the estrous cycle of mares. J Equine Vet Sci 1991;11(6):319–322.
    doi: 10.1016/s0737-0806(06)81280-3google scholar: lookup
  17. Figueiredo T, Paiva R, Kozicki LE, Kaercher F, Weiss RR, Santos IW. Induction of ovulation in quarter horse mares through the use of deslorelin acetate and human chorionic gonadotrophin (hCG). Braz Arch Biol Technol 2011;54(3):517–521.
    doi: 10.1590/s1516-89132011000300012google scholar: lookup
  18. Szijarto N. Physiological stress in mares during domestic breeding in relation to MHC‐linked social behaviors. 2021.
  19. Schmidt A, Möstl E, Wehnert C, Aurich J, Müller J, Aurich C. Cortisol release and heart rate variability in horses during road transport. Horm Behav 2010;57(2):209–215.
    doi: 10.1016/j.yhbeh.2009.11.003google scholar: lookup
  20. Scheidegger MD, Gerber V, Ramseyer A, Schüpbach‐Regula G, Bruckmaier RM, van der Kolk JH. Repeatability of the ACTH stimulation test as reflected by salivary cortisol response in healthy horses. Domest Anim Endocrinol 2016;57:43–47.
    doi: 10.1016/j.domaniend.2016.04.002google scholar: lookup
  21. Landers R. Computing interclass correlations (ICC) as estimates of interrater reliability in SPSS. 2015.
  22. Cicchetti DV. Multiple comparison methods: establishing guidelines for their valid application in neuropsychological research. J Clin Exp Neuropsychol 1994;16(1):155–161.
    doi: 10.1080/01688639408402625google scholar: lookup
  23. Yngvesson J, de Boussard E, Larsson M, Lundberg A. Loading horses (Equus caballus) onto trailers—behaviour of horses and horse owners during loading and habituating. Appl Anim Behav Sci 2016;184:59–65.
    doi: 10.1016/j.applanim.2016.08.008google scholar: lookup
  24. Waran N, Randle H. What we can measure, we can manage: the importance of using robust welfare indicators in equitation science. Appl Anim Behav Sci 2017;190:74–81.
    doi: 10.1016/j.applanim.2017.02.016google scholar: lookup
  25. Heleski CR, Shelle AC, Nielsen BD, Zanella AJ. Influence of housing on weanling horse behavior and subsequent welfare. Appl Anim Behav Sci 2002;78(2–4):291–302.
  26. Padalino B, Raidal SL, Knight P, Celi P, Jeffcott L, Muscatello G. Behaviour during transportation predicts stress response and lower airway contamination in horses. PLoS One 2018;13(3):e0194272.
    doi: 10.1371/journal.pone.0194272google scholar: lookup
  27. Torcivia C, McDonnell S. Equine discomfort ethogram. Animals (Basel) 2021;11(2):580.
    doi: 10.3390/ani11020580google scholar: lookup
  28. Dyson S. The ridden horse pain ethogram. Equine Vet Educ 2022;34(7):372–380.
    doi: 10.1111/eve.13468google scholar: lookup
  29. Blum S, Gisler J, Dalla Costa E, Montavon S, Spadavecchia C. Investigating conditioned pain modulation in horses: can the lip‐twitch be used as a conditioning stimulus?. Front Pain Res 2024;5:1463688.
    doi: 10.3389/fpain.2024.1463688google scholar: lookup
  30. Flakoll B, Ali AB, Saab CY. Twitching in veterinary procedures: how does this technique subdue horses?. J Vet Behav 2017;18:23–28.
    doi: 10.1016/j.jveb.2016.12.004google scholar: lookup
  31. Möstl E, Palme R. Hormones as indicators of stress. Domest Anim Endocrinol 2002;23:67–74.
  32. McLean AN, McGreevy PD. Horse‐training techniques that may defy the principles of learning theory and compromise welfare. J Vet Behav 2010;5(4):187–195.
    doi: 10.1016/j.jveb.2010.04.002google scholar: lookup
  33. Wulf M, Beythien E, Ille N, Aurich J, Aurich C. The stress response of 6‐month‐old horses to abrupt weaning is influenced by their sex. J Vet Behav 2018;23:19–24.
    doi: 10.1016/j.jveb.2017.10.010google scholar: lookup

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