Analyze Diet
Animals : an open access journal from MDPI2017; 7(6); doi: 10.3390/ani7060041

Equine Welfare during Exercise: An Evaluation of Breathing, Breathlessness and Bridles.

Abstract: Horses engaged in strenuous exercise display physiological responses that approach the upper functional limits of key organ systems, in particular their cardiorespiratory systems. Maximum athletic performance is therefore vulnerable to factors that diminish these functional capacities, and such impairment might also lead to horses experiencing unpleasant respiratory sensations, i.e., breathlessness. The aim of this review is to use existing literature on equine cardiorespiratory physiology and athletic performance to evaluate the potential for various types of breathlessness to occur in exercising horses. In addition, we investigate the influence of management factors such as rein and bit use and of respiratory pathology on the likelihood and intensity of equine breathlessness occurring during exercise. In ridden horses, rein use that reduces the jowl angle, sometimes markedly, and conditions that partially obstruct the nasopharynx and/or larynx, impair airflow in the upper respiratory tract and lead to increased flow resistance. The associated upper airway pressure changes, transmitted to the lower airways, may have pathophysiological sequelae in the alveolae, which, in their turn, may increase airflow resistance in the lower airways and impede respiratory gas exchange. Other sequelae include decreases in respiratory minute volume and worsening of the hypoxaemia, hypercapnia and acidaemia commonly observed in healthy horses during strenuous exercise. These and other factors are implicated in the potential for ridden horses to experience three forms of breathlessness-"unpleasant respiratory effort", "air hunger" and "chest tightness"-which arise when there is a mismatch between a heightened ventilatory drive and the adequacy of the respiratory response. It is not known to what extent, if at all, such mismatches would occur in strenuously exercising horses unhampered by low jowl angles or by pathophysiological changes at any level of the respiratory tract. However, different combinations of the three types of breathlessness seem much more likely to occur when pathophysiological conditions significantly reduce maximal athletic performance. Finally, most horses exhibit clear behavioural evidence of aversion to a bit in their mouths, varying from the bit being a mild irritant to very painful. This in itself is a significant animal welfare issue that should be addressed. A further major point is the potential for bits to disrupt the maintenance of negative pressure in the oropharynx, which apparently acts to prevent the soft palate from rising and obstructing the nasopharynx. The untoward respiratory outcomes and poor athletic performance due to this and other obstructions are well established, and suggest the potential for affected animals to experience significant intensities of breathlessness. Bitless bridle use may reduce or eliminate such effects. However, direct comparisons of the cardiorespiratory dynamics and the extent of any respiratory pathophysiology in horses wearing bitted and bitless bridles have not been conducted. Such studies would be helpful in confirming, or otherwise, the claimed potential benefits of bitless bridle use.
Publication Date: 2017-05-26 PubMed ID: 28587125PubMed Central: PMC5483604DOI: 10.3390/ani7060041Google 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

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 explores the physiological responses of horses during strenuous exercise, focusing on the cardiorespiratory functions and potential experiences of breathlessness. The paper also evaluates the impact of management practices like rein use and bridles, as well as respiratory tract conditions on horse comfort and performance.

Understanding Cardiorespiratory Functions in Horses

  • The study critically reviews existing materials on equine cardiorespiratory physiology, aiming to determine the potential for various types of breathlessness to occur in horses during exercise.
  • Strenuous exercise brings a horse’s physiological responses, especially their cardiorespiratory system, to their upper functional limits. Any factors that diminish these functional capacities can impair the maximum athletic performance and may lead to unpleasant sensations like breathlessness.

The Impact of Rein and Bit Use

  • The use of reins that reduce the ‘jowl angle’ and any conditions that partially block the nasopharynx or larynx can disrupt airflow in the upper respiratory tract. This leads to increased flow resistance and potential discomfort for the horse.
  • Respiratory pathologies due to poor gear use can lead to a myriad of problems, including decreased respiratory minute volume and worsening of hypoxaemia, hypercapnia, and acidaemia. These conditions are common in active horses but may be exacerbated by inappropriate gear use.
  • Most horses show clear signs of aversion to a bit in their mouths, ranging from mild irritation to major pain. The bit can disrupt the maintenance of negative pressure in the oropharynx, preventing the soft palate from rising and obstructing the nasopharynx. This can lead to poor respiratory outcomes and subpar athletic performance.

The Benefits of Bitless Bridle Use

  • Using a bitless bridle may reduce or eliminate the adverse effects associated with bitted bridles. However, no concrete studies comparing the cardiorespiratory dynamics and respiratory pathophysiology between horses using bitted and bitless bridles have been conducted.
  • The research emphasizes the need for such comparative studies to confirm the potential benefits of bitless bridle use accurately.

Understanding the Notion of “Breathlessness”

  • The possibility of horses experiencing three different types of breathlessness—unpleasant respiratory effort, air hunger, and chest tightness—is discussed. These scenarios could occur when there is a mismatch between heightened ventilatory drive and the horse’s respiratory response.
  • Regarding horses involved in strenuous exercise unrestricted by low jowl angles or respiratory tract pathologies, it is still unclear the extent to which these mismatches might occur.
  • However, the combination of these breathlessness types is more likely to happen when certain pathological conditions significantly hamper maximal athletic performance.

Cite This Article

APA
Mellor DJ, Beausoleil NJ. (2017). Equine Welfare during Exercise: An Evaluation of Breathing, Breathlessness and Bridles. Animals (Basel), 7(6). https://doi.org/10.3390/ani7060041

Publication

ISSN: 2076-2615
NlmUniqueID: 101635614
Country: Switzerland
Language: English
Volume: 7
Issue: 6

Researcher Affiliations

Mellor, David J
  • Animal Welfare Science and Bioethics Centre, Institute of Veterinary, Animal and Biomedical Science, College of Sciences, Massey University, Palmerston North 4442, New Zealand. d.j.mellor@massey.ac.nz.
Beausoleil, Ngaio J
  • Animal Welfare Science and Bioethics Centre, Institute of Veterinary, Animal and Biomedical Science, College of Sciences, Massey University, Palmerston North 4442, New Zealand. n.j.beausoleil@massey.ac.nz.

Conflict of Interest Statement

The authors declare no conflict of interest.

References

This article includes 164 references
  1. Ramey DW. A historical survey of human-equine interactions.. .
  2. Barrey E. Genetic basis of equine performance.. .
  3. Hinchcliff KW. Exercise-induced pulmonary haemorrhage (EIPH). .
  4. Hinchcliff KW, Kaneps AJ, Geor RJ. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elsevier; New York, NY, USA: 2014.
  5. Beausoleil NJ, Mellor DJ. Introducing breathlessness as a significant animal welfare issue.. N. Z. Vet. J. 2015;63:44–51.
    doi: 10.1080/00480169.2014.940410pubmed: 25004795google scholar: lookup
  6. Fraser D, Duncan IJH. “Pleasures”, “pains” and animal welfare: Towards a natural history of affect.. Anim. Welfare 1998;7:383–396.
  7. Boissy A, Manteuffel G, Jensen MB, Moe RO, Spruijt B, Keeling LJ, Winckler C, Forkman B, Dimitrov I, Langbein J. Assessment of positive emotions in animals to improve their welfare.. Physiol. Behav. 2007;92:375–397.
    doi: 10.1016/j.physbeh.2007.02.003pubmed: 17428510google scholar: lookup
  8. Fraser D. Understanding Animal Welfare: The Science in Its Cultural Context.. Wiley-Blackwell; Oxford, UK: 2008.
  9. Yeates JW, Main DCJ. Assessment of positive welfare: A review.. Vet. J. 2008;175:293–300.
    doi: 10.1016/j.tvjl.2007.05.009pubmed: 17613265google scholar: lookup
  10. Kiley-Worthington M. Equine psychological needs and quality of life.. In: McIlwraith C.W., Rollin B.E., editors. Equine Welfare. Wiley-Blackwell; Chichester, UK: 2011. pp. 94–112.
  11. Green TC, Mellor DJ. Extending ideas about animal welfare assessment to include “quality of life” and related concepts.. N. Z. Vet. J. 2011;59:316–324.
    doi: 10.1080/00480169.2011.610283pubmed: 22040330google scholar: lookup
  12. Boissy A, Lee C. How assessing relationships between emotions and cognition can improve farm animal welfare.. Rev. Sci. Tech. Off. Int. Epizoot. 2014;33:103–110.
    doi: 10.20506/rst.33.1.2260pubmed: 25000782google scholar: lookup
  13. Broom DM. Animal Welfare in the European Union.. Policy Department C Citizens: Rights and Constitutional Affairs, Directorate General for Internal Policies, European Parliament; Brussels, Belgium: 2017.
  14. Mellor DJ. Updating animal welfare thinking: Moving beyond the “Five Freedoms” towards “A Life worth Living.. Animals 2016;6:21.
    doi: 10.3390/ani6030021pmc: PMC4810049pubmed: 27102171google scholar: lookup
  15. Gregory NG. Physiology and Behaviour of Animal Suffering.. Blackwell Science; Oxford, UK: 2004.
  16. Denton DA, McKinley MJ, Farrell M, Egan GF. The role of primordial emotions in the evolutionary origin of consciousness.. Conscious. Cognit. 2009 18:500–514.
  17. Vinuela-Fernandz I, Weary DM, Flecknell P. Pain.. In: Appleby M.C., Mench J., Olsson I.A., Hughes B.O., editors. Animal Welfare. 2nd ed. CABI; Oxford, UK: 2011. pp. 64–77.
  18. Art T, Scrteyn D, Lekeux P. Effect of exercise on the partitioning of equine respiratory resistance.. Equine Vet. J. 1988;20:268–273.
  19. Art T, Anderson I, Woakes AI, Roberts C, West PJ, Snow DH, Lekeux P. Mechanics of breathing during strenuous exercise in thoroughbred horses.. Respir. Physiol. 1990;82:279–294.
    doi: 10.1016/0034-5687(90)90098-Jpubmed: 2080318google scholar: lookup
  20. Ducharme NG, Hackett RP, Ainsworth DA, Erb HN, Shannon KJ. Repeatability and normal values for measurement of pharyngeal and tracheal pressures in exercising horses.. Am. J. Vet. Res. 1994;55:369–374.
    pubmed: 8192260
  21. Odeh M, Schnall R, Gavriely N, Oliven A. Dependency of upper airway patency on head position: The effect of muscle contraction.. Respir. Physiol. 1995;100:239–244.
    doi: 10.1016/0034-5687(94)00135-Mpubmed: 7481113google scholar: lookup
  22. Cook WR. Pathophysiology of bit control in the horse.. J. Equine Vet. Sci. 1999;19:196–204.
  23. Cehak A, Rohn K, Barton A, Stadler P, Ohnesorge B. Effect of head and neck position on pharyngeal diameter in horses.. Vet. Radiol. Ultrasound. 2010;51:491–497.
  24. Bayly WM, Grant BD, Breeze RG. Arterial blood gas tension and acid base balance during exercise in horses with pharyngeal lymphoid hyperplasia.. Equine Vet. J. 1984;16:435–438.
  25. Bayly WM, Hodgson DR, Schulz DA, Dempseu JA, Gollnick PD. Exercise-induced hypercapnia in the horse.. J. Appl. Physiol. 1989;67:1958–1966.
    pubmed: 2513313
  26. Butler PJ, Woakes AJ, Smale K, Roberts CA, Hillidge CJ, Snow DH, Marlin DJ. Respiratory and cardiovascular adjustments during exercise of increasing intensity and during recovery in thoroughbred racehorses.. J. Exp. Biol. 1993;179:159–180.
    pubmed: 8340728
  27. Tate LP, Corbett WT, Bishop BJ, Foreman JH. Blood gas tensions, acid-base status, heart rates and venous profiles in exercising horses with laryngeal hemiplegia before and after corrective surgery.. Vet. Surg. 1993;22:177–183.
  28. Durando MM, Martin BB, Hammer EJ, Langsam PP, Birks EK. Dynamic upper airway changes and arterial blood gas parameters during treadmill exercise. Equine Exercise Physiology 6.. Equine Vet. J. 2002;34:408–412.
  29. Art T, Bayly W. Lower airway function: Responses to exercise and training.. In: Hinchcliff K.W., Kaneps A.J., Geor R.J., editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elsevier; New York, NY, USA: 2014. pp. 587–603.
  30. Widdicombe J. Lung afferent activity: Implications for respiratory sensation.. Respir. Physiol. Neurobiol. 2009;167:2–8.
    doi: 10.1016/j.resp.2008.09.012pubmed: 18952010google scholar: lookup
  31. Couetil LL, Cardwell JM, Gerber V, Lavoie J-P, Leguillette R, Richard EA. Inflammatory airway disease of horses—Revised consensus statement.. J. Vet. Int. Med. 2016;30:503–515.
    doi: 10.1111/jvim.13824pmc: PMC4913592pubmed: 26806374google scholar: lookup
  32. Whitwell KE, Greet TRC. Collection and evaluation of tracheobronchial washes in the horse.. Equine Vet. J. 1984;16:499–508.
  33. Sweeney CR, Soma LR, Maxson AD, Thompson JE, Holcombe SJ, Spencer PA. Effects of furosemide on the racing times of Thoroughbreds.. Am. J. Vet. Res. 1990;51:772–778.
    pubmed: 2337276
  34. Lapointe JM, Vrins A, McCarvill E. A survey of exercise-induced pulmonary haemorrhage in Q standardbred racehorses.. Equine Vet. J. 1994;26:482–485.
  35. Poole DC, Erickson HH. Exercise-induced pulmonary hemorrhage: Where are we now?. VMRR 2016;7:133–148.
    doi: 10.2147/VMRR.S120421pmc: PMC6044800pubmed: 30050846google scholar: lookup
  36. Cook WR, Mills DS. Preliminary study of jointed snaffle vs. crossunder bitless bridles: Quantified comparison of behaviour in four horses.. Equine Vet. J. 2009;41:827–830.
    doi: 10.2746/042516409X472150pubmed: 20095234google scholar: lookup
  37. Quick JS, Warren-Smith AK. Preliminary investigations of horses’ (Equus caballus) responses to different bridles during foundation training.. J. Vet. Behav. 2009;4:169–176.
  38. Cook WR. An endoscopic test for bit-induced nasopharyngeal asphyxia as a cause of exercise-induced pulmonary haemorrhage in the horse.. Equine Vet. J. 2014;46:256–257.
    doi: 10.1111/evj.12205pubmed: 24548375google scholar: lookup
  39. Cook WR. Hypothesis article: Bit-induced asphyxia in the racehorse as a cause of sudden death.. Equine Vet. J. 2016;28:405–409.
    doi: 10.1111/eve.12455google scholar: lookup
  40. Lyle CH, Uzal FA, McGorum BC, Aida H, Blissitt KJ, Case JT, Charles JT, Gardner I, Horadagoda N, Kusano K. Sudden death in racing Thoroughbred horses: An international multicentre study of post mortem findings.. Equine Vet. J. 2011;43:324–331.
  41. Cook WR. A hypothetical, aetiological relationship between the horse’s bit, nasopharyngeal oedema and negative pressure pulmonary oedema.. Equine Vet. Educ. 2014;26:381–389.
    doi: 10.1111/eve.12196google scholar: lookup
  42. Cheetham J, Holcombe SJ, Ducharme NG. Upper airway function of normal horses during exercise.. In: Hinchcliff K.W., Kaneps A.J., Geor R.J., editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elsevier; New York, NY, USA: 2014. pp. 529–547.
  43. Cook WR. Some observations on form and function of the equine upper airway in health and disease, Part I: The pharynx.. Proc. AAEP 1981;27:355–392.
  44. Lane JG, Blandon B, Little DRM, Naylor JRJ, Franklin SH. Dynamic obstruction of the equine upper respiratory tract. Part 1. Observations during high-speed treadmill endoscopy in 600 Thoroughbred racehorses.. Equine Vet. J. 2006;38:393–399.
    doi: 10.2746/042516406778400583pubmed: 16986598google scholar: lookup
  45. Taylor CR, Malony GM, Welbel ER, Langman VA, Kamau JM, Seeherman HJ, Heglund NC. Design of the mammalian respiratory system.. Respir. Physiol. 1981;44:25–37.
    pubmed: 7232885
  46. Weber JM, Dobson GP, Parkhouse WS, Wheeldon D, Harman JC, Snow DH, Hochachka PW. Cardiac output and oxygen consumption in exercising Thoroughbred horses.. Am. J. Appl. Physiol. 1987;253:R890–R895.
    pubmed: 3425767
  47. Art T, Lekeux P. Training-induced modification of cardiorespiratory and ventilatory measurements in thoroughbred horses.. Equine Vet. J. 1993;25:532–536.
  48. Ducharme NG, Hackett RP, Gleed RD, Ainsworth DM, Erickson BK, Erb HN, Soderholm LV, Mitchell LM. Pulmonary capillary pressure in horses undergoing alternation to pleural pressure by imposition of upper airway resistive loads.. Equine Vet. J. 1999;30:27–33.
    pubmed: 10659217
  49. Wilson WD, Lofstedt J, Lakritz J. Abnormal respiratory noise (stridor). In: Smith B.P., editor. Large Animal Internal Medicine. 5th ed. Elsevier; St Louis, MI, USA: 2009. pp. 66–70.
  50. Gerring EL. Differential diagnosis of equine respiratory noises.. Practce 1985;7:109–117.
    doi: 10.1136/inpract.7.4.109pubmed: 4030112google scholar: lookup
  51. Petsche VM, Derksen FJ, Berney CE, Robinson NE. Effect of head position on upper airway function in exercising horses.. Equine Vet. J. 1995;18:18–22.
  52. Strand E, Fjordbakk CT, Holcombe SJ, Risberg A, Chalmers HJ. Effect of poll flexion and dynamic laryngeal collapse on tracheal pressure in Norwegian Coldblooded Trotter racehorses.. Equine Vet. J. 2009;41:59–64.
    doi: 10.2746/042516408X330392pubmed: 19301583google scholar: lookup
  53. Linford RL, O’Brien TR, Wheat JD, Meagher D. Radiographic assessment of epiglotic length and pharyngeal and laryngeal diameters in the thoroughbred.. Am. J. Vet. Res. 1983;44:1660–1666.
    pubmed: 6625319
  54. Allen KJ, Terron-Canedo N, Hillyer MH, Franklin SH. Equitation and exercise factors affecting dynamic upper respiratory tract function: A review illustrated by case reports.. Equine Vet. Educ. 2011;23:361–368.
  55. Go L-M, Barton AK, Ohnesorge B. Objective classification of different head and neck positions and their influence on the radiographic pharyngeal diameter in sport horses.. BMC Vet. Res. 2014;10:118.
    doi: 10.1186/1746-6148-10-118pmc: PMC4041040pubmed: 24886564google scholar: lookup
  56. Houghton Mifflin Company. The American Heritage® Science Dictionary.. Houghton Mifflin Company; Boston, MA, USA: 2017.
  57. . Poiseuille’s Law: IV Fluids, Open Anaesthesia.. 2017.
  58. Meyer H. “Rollkur”, “Hyperflexion” and “LDR”—The natural position of the head and neck of the horse and the modification by the rider.. Pferdeheilkunde 2010;26:388–413.
    doi: 10.21836/PEM20100309google scholar: lookup
  59. Zebisch A, May A, Reese S, Gehlen H. Effects of different head-neck positions on the larynges of ridden horses.. J. Anim. Physiol. Anim. Nutr. 2014;98:894–900.
    doi: 10.1111/jpn.12154pubmed: 24329611google scholar: lookup
  60. Zebisch A, May A, Reese S, Gehlen H. Effect of different head-neck positions on physical and psychological stress parameters in the ridden horse.. J. Anim. Physiol. Anim. Nutr. 2014;98:901–907.
    doi: 10.1111/jpn.12155pubmed: 24329719google scholar: lookup
  61. Sleutjens J, Smiet E, Van Weeren R, Van der Kolk J, Back W, Wijnberg I. Effect of head and neck position on intrathoracic pressure and arterial blood gas values in Dutch Warmblood riding horses during moderate exercise.. Am. J. Vet. Res. 2012;73:522–528.
    doi: 10.2460/ajvr.73.4.522pubmed: 22452499google scholar: lookup
  62. Cook WR. A solution to respiratory and other problems caused by the bit.. Pferdeheilkunde 2003;16:333–351.
    doi: 10.21836/PEM20000401google scholar: lookup
  63. Carey C, Moriarty SH, Brennan R. The impact of bitted and bitless bridles on the Therapeutic Riding Horse; Proceedings of the 12th International Equitation Science Conference on Understanding Horses to Improve Training and Performance; Wagga Wagga, Australia.. 22–25 November 2016; p. 99.
  64. Franklin SH, Naylor JR, Lane JG. Videoendoscopic evaluation of the upper respiratory tract in 93 sport horses during exercise testing on a high-speed treadmill.. Equine Vet. J. 2006;36:540–545.
  65. Fjordbakk CT, Strand E, Hanche-Olsen S. Surgical and conservative management of bilateral dynamic laryngeal collapse associated with poll flexion in harness race horses.. Vet. Surg. 2008;37:501–507.
  66. Franklin SH, Allen KJ. Assessment of dynamic upper respiratory tract function in the equine athlete.. Equine Vet. Educ. 2017;29:92–103.
    doi: 10.1111/eve.12432google scholar: lookup
  67. Parente EJ, Martin BB, Tulleners EP, Ros MW. Dorsal displacement of the soft palate in 92 horses during high-speed treadmill examination (1993–1998). Vet. Surg. 2002;31:507–512.
    doi: 10.1053/jvet.2002.36009pubmed: 12415518google scholar: lookup
  68. Allen KJ, Christley RM, Birchall MA, Franklin SH. A systematic review of the efficacy of interventions for dynamic intermittent dorsal displacement of the soft palate.. Equine Vet. J. 2012;44:259–266.
  69. Allen KJ, Franklin S. Characteristics of palatal instability in Thoroughbred racehorses and their association with the development of dorsal displacement of the soft palate.. Equine Vet. J. 2013;45:454–459.
    doi: 10.1111/evj.12004pubmed: 23294046google scholar: lookup
  70. Ducharme NG, Cheetham J. Abnormalities of the upper airway.. In: Hinchcliff K.W., Kaneps A.J., Geor R.J., editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elsevier; New York, NY, USA: 2014. pp. 549–586.
  71. Kannegieter NJ, Dore ML. Endoscopy of the upper respiratory tract during treadmill exercise: A clinical study of 100 horses.. Aust. Vet. J. 1995;72:101–107.
  72. Franklin SH, Burn JF, Allen KJ. Clinical trials using a telemetric endoscope for use during over-ground exercise: A preliminary study.. Equine Vet. J. 2008;40:712–715.
    doi: 10.2746/042516408X363783pubmed: 19165944google scholar: lookup
  73. Strand E, Fjordbakk CT, Sundberg L, Spangen H, Lunde H, Hanche-Olsen S. Relative prevalence of upper respiratory tract obstructive disorders in two breeds of harness racehorses (185 cases: 1998–2006). Equine Vet. J. 2012;44:518–523.
  74. Ahern TJ. Pharyngeal dysfunction during exercise.. J. Equine Vet. Sci. 1999;19:226–231.
  75. Boyle AG, Martin BB, Davidson EJ, Durando MM, Birks EK. Dynamic pharyngeal collapse in racehorses.. Equine Exerc. Physiol. 2006;36:546–550.
  76. Smith CM, Taylor RJ, Dixon PM. Unilateral displacement of the roof of the nasopharynx as a cause of stridor in a poney.. Vet. Rec. 1994;134:140–141.
    doi: 10.1136/vr.134.6.140pubmed: 8171784google scholar: lookup
  77. Strand E, Skjerve E. Complex dynamic upper airway collapse: Association between abnormalities in 99 harness racehorses with one or more dynamic disorders.. Equine Vet. J. 2012;44:524–528.
  78. Strand E, Hanche-Olsen S, Grøvold AMR, Mellum CN. Dynamic bilateral arytenoid and vocal fold collapse associated with head flexion in 5 Norwegian Coldblooded Trotter racehorses.. Equine Vet. Educ. 2004;16:242–250.
  79. Votion D. Metabolic responses to exercise and training.. In: Hinchcliff K.W., Kaneps A.J., Geor R.J., editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elseier; New York, NY, USA: 2014. pp. 747–767.
  80. Duffin J. The chemoreflex control of breathing.. Can. J. Anaesth. 1990;37:933–942.
    doi: 10.1007/BF03006641pubmed: 2123750google scholar: lookup
  81. Wagner PD, Gillespie JR, Landgren GL, Fedde MR, Jones BW, DeBowes RM, Pieschl RL, Erickson HH. Mechanisms of exercise-induced hypoxemia in horses.. J. Appl. Physiol. 1989;66:1227–1233.
    pubmed: 2496088
  82. Parks CM, Manohar M. Blood-gas tensions and acid-base status in ponies during treadmill exercise.. Am. J. Vet. Res. 1984;45:15–19.
    pubmed: 6422805
  83. Katz LM, Bayly WM, Roeder MJ, Kingston JK, Hines MT. Effects of training on maximum oxygen consumption of ponies.. Am. J. Vet. Res. 2000;61:986–991.
    doi: 10.2460/ajvr.2000.61.986pubmed: 10951995google scholar: lookup
  84. Katz LM, Bayly WM, Hines MT, Sides RH. Ventilatory responses of ponies and horses to exercise.. Equine Comp. Exerc. Physiol. 2005;2:229–240.
    doi: 10.1079/ECP200570google scholar: lookup
  85. Franklin SH, Van Erck-Westergren E, Bayly WM. Respiratory responses to exercise in the horse.. Equine Vet. J. 2012;44:726–732.
  86. Curtis RA, Kusano K, Evans DL. Observations on respiratory flow strategies during and after intense treadmill exercise to fatigue in thoroughbred racehorses.. Equine Vet. J. 2006;36:567–572.
  87. Padilla DJ, McDonough P, Kindig CA, Erickson HH, Poole DC. Ventilatory dynamics and control of blood gases after maximal exercise in the Thoroughbred horse.. J. Appl. Physiol. 2004;96:2187–2193.
  88. Thiel M, Tolkmitt G, Hoernicke H. Equine Exercise Physiology.. 2. ICEEP Publications; Davis, CA, USA: 1987. Body temperature changes in horses during riding: Time course and effects on heart rate and respiratory frequency; pp. 183–193.
  89. Hodgson DR, Davis RE, McConaghy FF. Thermoregulation in the horse in response to exercise.. Br. Vet. J. 1994;150:219–235.
    doi: 10.1016/S0007-1935(05)80003-Xpubmed: 8044664google scholar: lookup
  90. Foreman JH. Thermoregulation in the horse exercising under hot and humid conditions.. Pferdeheilkunde 1996;12:405–408.
  91. Jackson JA, Ducharme NG, Hackett RP, Rehder RS, Ainsworth DM, Shannon KJ, Erickson BK, Erb HN, Jansson N, Soderholm LV. Effects of airway obstruction on transmural pulmonary artery pressure in exercising horses.. Am. J. Vet. Res. 1997;58:897–903.
    pubmed: 9256978
  92. Cook WR, Williams RM, Kirker-Head CA, Verbridge DJ. Upper airway obstruction (partial asphyxia) as the possible cause of exercise-induced pulmonary haemorrhage in the horse: An hypothesis.. Equine Vet. Sci. 1988;8:11–26.
  93. Gunson DE, Sweeney CR, Soma LR. Sudden death attributable to exercise-induced pulmonary hemorrhage in racehorses: Nine cases (1981–1983). JAVMA 1988;193:102–106.
    pubmed: 3417520
  94. Hinchcliff KW, Couetil LL, Knight PK, Morley PS, Robinson NE, Sweeney CR, Van Ercj E. Exercise induced pulmonary haemorrhage in horses: American College of Veterinary Internal Medicine consensus statement.. J. Vet. Intern. Med. 2015;29:743–758.
    doi: 10.1111/jvim.12593pmc: PMC4895427pubmed: 25996660google scholar: lookup
  95. Hackett RP, Ducharme NG, Ainsworth DM, Erickson BK, Erb HN, Soderholm L, Thorson LM. Effects of extrathoracic airway obstruction on intrathoracic pressure and pulmonary artery pressure in exercising horses.. Am. J. Vet. Res. 1999;60:485–494.
    pubmed: 10211694
  96. West JB, Mathieu-Costello O, Jones JH, Birks EK, Logemann RB, Pascoe JR, Tyler WS. Stress failure of pulmonary capillaries in racehorses with exercise-induced pulmonary hemorrhage.. J. Appl. Physiol. 1993;75:1097–1109.
    pubmed: 8226517
  97. Deepika K, Barrocas QM, Fonseca JJ, Bikasi GB. Negative pressure pulmonary edema after acute upper airway obstruction.. J. Clin. Anaesth. 1997;9:403–408.
    doi: 10.1016/S0952-8180(97)00070-6pubmed: 9257208google scholar: lookup
  98. Bhaskar B, Fraser JF. Negative pressure pulmonary oedema revisited: Pathophysiology and review of management.. Saudi J. Anaesth. 2011;5:308–313.
    doi: 10.4103/1658-354X.84108pmc: PMC3168351pubmed: 21957413google scholar: lookup
  99. Abrahamsen EJ, Bohanon TC, Bednarski RM, Hubbell JAE, Muir WW. Bilateral arytenoid cartilage paralysis after inhalation anaesthesia in a horse.. J. Am. Vet. Med. Assoc. 1990;197:1363–1365.
    pubmed: 2266056
  100. Lang SA, Duncan PG, Shephard DAE, Ha HC. Pulmonary oedema associated with airway obstruction.. Can. J. Anaesth. 1990;37:210–218.
    doi: 10.1007/BF03005472pubmed: 2178789google scholar: lookup
  101. Dixon PM, Railton DI, McGorum BC. Temporary bilateral laryngeal paralysis in a horse associated with general anaesthesia and post anaesthetic myositis.. Vet. Rec. 1993;132:29–32.
    doi: 10.1136/vr.132.2.29pubmed: 8442333google scholar: lookup
  102. Kollias-Baker CA, Pipers FS, Heard D, Seeherman H. Pulmonary edema associated with transient airway obstruction in three horses.. JAVMA 1993;202:1116–1118.
    pubmed: 8473226
  103. Tute AS, Wilkins PA, Gleed RD, Credille KM, Murphy DJ, Ducharme NG. Negative pressure pulmonary edema as a post-anesthetic complication associated with upper airway obstruction in a horse.. Vet. Surg. 1996;25:519–523.
    pubmed: 8923732
  104. Senior M. Postanaesthetic pulmonary oedema in horses: A review.. Vet. Anaes. Analg. 2005;32:193–200.
    pubmed: 16008716
  105. Wilson RC, Jones PW. Long-term reproducibility of Borg scale estimates of breathlessness during exercise.. Clin. Sci. Lond. 1991;80:309–312.
    doi: 10.1042/cs0800309pubmed: 1851065google scholar: lookup
  106. Holcombe SJ, Derksen FJ, Stick JA, Robinson NE. Effect of nasal occlusion on tracheal and pharyngeal pressures in horses.. Am. J. Vet. Res. 1996;57:1258–1260.
    pubmed: 8874716
  107. Leclere M, Lavoie-Lamoureux A, Lavoie J-P. Heaves, an asthma-like disease of horses.. Respirology 2011;16:1027–1046.
  108. Bullone M, Lavoie J-P. Asthma, “of horses and men”–how can equine heaves help us better understand human asthma immunopathology and its functional consequences?. Mol. Immunol. 2015;66:97–105.
    doi: 10.1016/j.molimm.2014.12.005pubmed: 25547716google scholar: lookup
  109. Couetil LL, Denicola DB. Blood gas, plasma lactate and bronchoalveolar lavage cytology analyses in racehorses with respiratory disease.. Equine Vet. J. Suppl. 1999;30:77–82.
  110. Sanchez A, Couetil LL, Ward MP, Clark SP. Effect of airway disease on blood gas exchange in racehorses.. J. Vet. Intern. Med. 2005;19:87–92.
  111. Courouce-Malblanc A, Deniau V, Rossignol F, Corde R, Leleu C, Maillard K, Pitel P-H, Pronost S, Fortier G. Physiological measurements and prevalence of lower airway diseases in Trotters with dorsal displacement of the soft palate.. Equine Vet. J. Suppl. 2010;38:246–255.
  112. Parshall MB, Schwartzstein RM, Adams L, Banzett RB, Manning HL, Bourbeau J, Calverley PM, Gift AG, Harver A, Lareau S. An official American Thoracic Society statement: Update on the mechanisms, assessment, and management of dyspnea.. Am. J. Respir. Crit. Care Med. 2012;185:435–452.
    doi: 10.1164/rccm.201111-2042STpmc: PMC5448624pubmed: 22336677google scholar: lookup
  113. Corfield DR, Murphy K, Guz A. Does the motor cortical control of the diaphragm “bypass” the brain stem respiratory centres in man?. Respir. Physiol. 1998;114:109–117.
    doi: 10.1016/S0034-5687(98)00083-8pubmed: 9865585google scholar: lookup
  114. Bianchi AL, Denavit-Saubie M, Champagnat J. Central control of breathing in mammals: Neuronal circuitry, membrane properties, and neurotransmitters.. Physiol. Rev. 1995;75:1–45.
    pubmed: 7831394
  115. Buchanan GF, Richerson GB. Role of chemoreceptors in mediating dyspnea.. Respir. Physiol. Neurobiol. 2009;167:9–19.
    doi: 10.1016/j.resp.2008.12.002pmc: PMC4486073pubmed: 19118647google scholar: lookup
  116. Jensen D, Ofir D, O’Donnell DE. Effects of pregnancy, obesity and aging on the intensity of perceived breathlessness during exercise in healthy humans.. Respir. Physiol. Neurobiol. 2009;167:87–100.
    doi: 10.1016/j.resp.2009.01.011pubmed: 19450766google scholar: lookup
  117. El-Manshawi A, Killian KJ, Summers E, Jones NL. Breathlessness during exercise with and without resistive loading.. J. Appl. Physiol. 1986;61:896–905.
    pubmed: 3759774
  118. Gandevia SC. Roles for perceived voluntary motor commands in motor control.. Trends Neurosci. 1987;10:81–85.
  119. Manning HL, Schwartzstein RM. Pathophysiology of dyspnea.. N. Engl. J. Med. 1995;333:1547–1553.
    pubmed: 7477171
  120. Prabhakar NR, Peng Y-J. Peripheral chemoreceptors in health and disease.. J. Appl. Physiol. 2004;96:359–366.
  121. O’Donnell DE, Ora J, Webb KA, Laveneziana P, Jensen D. Mechanisms of activity-related dyspnea in pulmonary diseases.. Respir. Physiol. Neurobiol. 2009;167:116–132.
    doi: 10.1016/j.resp.2009.01.010pubmed: 19450767google scholar: lookup
  122. Lindinger MI, Heigenhauser GJF. Effects of gas exchange on acid-base balance.. Compreh. Physiol. 2012;2:2203–2254.
    pubmed: 23723036
  123. Banzett RB, Pedersen SH, Schwartzstein RM, Lansing RW. The affective dimension of laboratory dyspnea: Air hunger is more unpleasant than work/effort.. Am. J. Respir. Crit. Care Med. 2008;177:1384–1390.
    doi: 10.1164/rccm.200711-1675OCpmc: PMC2427058pubmed: 18369200google scholar: lookup
  124. Lansing RW, Gracely RH, Banzett RB. The multiple dimensions of dyspnea: Review and hypotheses.. Respir. Physiol. Neurobiol. 2009;167:53–60.
    doi: 10.1016/j.resp.2008.07.012pmc: PMC2763422pubmed: 18706531google scholar: lookup
  125. Booth S, Adams L. The shuttle walking test: A reproducible method for evaluating the impact of shortness of breath on functional capacity in patients with advanced cancer.. Thorax 2001;56:146–150.
    doi: 10.1136/thorax.56.2.146pmc: PMC1745995pubmed: 11209105google scholar: lookup
  126. Australian Lung Foundation. Better Living with Chronic Obstructive Pulmonary Disease: A Patient Guide.. 2nd ed. The Queensland Government; Queensland, Australia: 2012.
  127. Johnson BD, Saupe KW, Dempsey JA. Mechanical constraints on exercise hyperpnea in endurance athletes.. J. Appl. Physiol. 1992;73:874–886.
    pubmed: 1400051
  128. Reinero CR. Advances in the understanding of pathogenesis, and diagnostics and therapeutics for feline allergic asthma.. Vet. Rec. 2011;190:28–33.
    doi: 10.1016/j.tvjl.2010.09.022pubmed: 21036078google scholar: lookup
  129. Undem BJ, Nassenstein C. Airway nerves and dyspnea associated with inflammatory airway disease.. Respir. Physiol. Neurobiol. 2009;167:36–44.
    doi: 10.1016/j.resp.2008.11.012pubmed: 19135556google scholar: lookup
  130. Waran N, McGreevy PD, Casey R. Training methods and horse welfare.. In: Waran N., editor. The Welfare of Horses. Boston Kluwer Academic Publishers; Dordrecht, Netherlands: 2002. pp. 151–180.
  131. Duberstein KJ, Johnson EL. Bits 101. University of Georgia Bulletin 1379; University of Georgia; Athens, GA, USA: 2014. pp. 1–6.
  132. McGreevy P, McLean A. Behavioral problems with the ridden horse.. In: Mills DS, McDonnell SM, editors. The Domestic Horse: The Origins, Development, and Management of Its Behavior. Cambridge University Press; Cambridge, UK: 2005. pp. 196–211.
  133. Van Lancker S, Van der Broeck W, Simoens P. Incidence and morphology of bone irregularities of the equine interdental space (bars of the mouth). Equine Vet. Educ. 2007;19:103–106.
    doi: 10.2746/095777307X179882google scholar: lookup
  134. Cook WR. Damage by the bit to the equine interdental space and second lower premolar.. Equine Vet. J. 2011;23:355–360.
  135. Mata F, Johnson C, Bishop C. A cross-sectional epidemiological study of prevalence and severity of bit-induced oral trauma in polo ponies and racehorses.. J. Appl. Anim. Welf. Sci. 2015;18:259–268.
    doi: 10.1080/10888705.2015.1004407pubmed: 25679445google scholar: lookup
  136. Black JB, Frisbie D. Welfare concerns in the training and competition of cutting, reining and reined cow horses.. In: McIlwraith C.W., Rollin B.E., editors. Equine Welfare. Wiley-Blackwell; Chichester, UK: 2011. pp. 302–317.
  137. Fenner K, Yoon S, White P, Starling M, McGreevy P. The effect of noseband tightening on horses’ behaviour, eye temperature, and cardiac responses.. PLoS ONE 2016;11.
  138. . American Quarter Horse Association Rule Book, Rule 44(h,k). AQHA; Amarillo, TX, USA: 2009.
  139. Leitch M. Welfare in the discipline of dressage.. In: McIlwraith C.W., Rollin B.E., editors. Equine Welfare. Wiley-Blackwell; Chichester, UK: 2011. pp. 332–340.
  140. AWA NZ. Animal Welfare Act 1999 and Animal Welfare Amendment Act 2015 No. 2.. Government of New Zealand; Wellington, New Zealand: 1999.
  141. Cook WR. Bit-induced asphyxia: Elevation and dorsal displacement of the soft palate at exercise.. J. Equine Vet. Sci. 2002;20:7–14.
  142. Hanson F, Cook R. The Bedouin bridle rediscovered: A welfare, safety and performance enhancer.. Horse’s Hoof 2015 60:1–8.
  143. Cook WR. Bit-induced pain: a cause of fear, flight, fight and facial neuralgia in the horse.. Pferdeheilkunde 2003;19:1–8.
    doi: 10.21836/PEM20030111google scholar: lookup
  144. Dugdale D, Greenwood R. Some observations on conservative techniques for treatment of laryngopalatal displacement.. Equine Vet. Educ. 1993;5:177–180.
  145. Franklin SH, Naylor JR, Lane JG. The effect of a tongue-tie in horses with dorsal displacement of the soft palate.. Equine Vet. J. 2002;34:430–433.
  146. Franklin S, Allen K. Laboratory exercise testing.. In: Hinchcliff K.W., Kaneps A.J., Geor R.J., editors. Equine Sports Medicine and Surgery: Basic and Clinical Sciences of the Equine Athlete. 2nd ed. Elsevier; New York, NY, USA: 2014. pp. 11–24.
  147. Tabernaberri C, Cooper C, Clemence J. Transition to a bitless bridle.. Australian Associated Press (AAP); Equine Veterinarians Australia (EVA); Sydney, Australia: 2011. pp. 62–69. October/November.
  148. McGreevy PD, Corken RA, Salvin H, Black CM. Whip use by jockeys in a sample of Australian thoroughbred races—An observational study.. PLoS ONE 2012;7:e33398.
  149. Hood J, McDonald C, Wilson B, McManus P, McGreevy P. Whip rule breaches in major Australian racing jurisdictions: Welfare and regulatory implications.. Animals 2017;7.
    doi: 10.3390/ani7010004pmc: PMC5295154pubmed: 28275207google scholar: lookup
  150. British Horseracing Authority. Responsible Regulation: A Review of the Use of the Whip in Horseracing.. British Horseracing Authority; London, UK: 2011.
  151. Evans D, McGreevy P. An investigation of racing performance and whip use by jockeys in Thoroughbred races.. PLoS ONE 2011;6:e15622.
  152. Travers CW, Guthrie AJ, Lund RJ. Characterization of a standard exercise to fatigue test in Thoroughbred horse.. Pferdeheikunde 1996;12:463–465.
  153. Flaminio MJB, Gaighan EM, Gillespie JR. Exercise intolerance in endurance horses.. Vet. Clin. N. Am. Equine Pract. 1996;12:565–580.
    doi: 10.1016/S0749-0739(17)30273-0pubmed: 8938962google scholar: lookup
  154. Valberg SJ. Muscular causes of exercise intolerance in horses.. Vet. Clin. N. Am. Equine Prac. 1996;12:495–515.
    doi: 10.1016/S0749-0739(17)30269-9pubmed: 8938958google scholar: lookup
  155. Noakes TD. Fatigue is a brain-derived emotion that regulates the exercise behaviour to ensure the protection of whole body homeostasis.. Front. Physiol. 2012 3:82.
  156. Parente EJ. Testing methods for exercise intolerance in horses.. Vet. Clin. N. Am. Equine Pract. 1996;12:421–433.
    doi: 10.1016/S0749-0739(17)30265-1pubmed: 8938954google scholar: lookup
  157. Fraser D, Weary DM, Pajor EA, Milligan BN. A scientific conception of animal welfare that reflects ethical concerns.. Anim. Welf. 1997;6:187–205.
  158. Fraser D. Assessing animal welfare at the farm and group level: The interplay of science and values.. Anim. Welf. 2003;12:433–443.
  159. Fraser D. Understanding Animal Welfare: The Science in its Cultural Constext.. Wiley-Blackwell; Oxford, UK: 2008.
  160. Lund V. Natural living—A precondition for animal welfare in organic farming.. Livest. Sci. 2006;100:71–83.
  161. Mellor DJ. Positive animal welfare states and promoting environment-focused and animal-animal interactive behaviours.. N. Z. Vet. J. 2015;63:9–16.
    doi: 10.1080/00480169.2014.926800pubmed: 24875367google scholar: lookup
  162. Mellor DJ. Positive welfare states and reference standards for welfare assessment.. N. Z. Vet. J. 2015;63:17–23.
    doi: 10.1080/00480169.2014.926802pubmed: 24875152google scholar: lookup
  163. Mill JM, Ward WR. Lameness in dairy cows and farmers’ knowledge, training and awareness.. Vet. Rec. 1994;134:162–164.
    doi: 10.1136/vr.134.7.162pubmed: 8160329google scholar: lookup
  164. Packer RMA, Hendricks A, Burn CC. Do dog owners perceive the clinical signs related to conformational inherited disorders as “normal” for the breed? A potential constraint to improving canine welfare.. Anim. Welf. 2012;21:81–93.

Citations

This article has been cited 18 times.
  1. Uldahl M, Mellor DJ. Regulatory Integrity and Welfare in Horse Sport: A Constructively Critical Perspective. Animals (Basel) 2025 Jun 30;15(13).
    doi: 10.3390/ani15131934pubmed: 40646833google scholar: lookup
  2. Galotti A, Eisersiö M, Yngvesson J, Lanatà A, Maglieri V, Palagi E, Baragli P. Rein tension and heart rate variability in horses: an experiment on experience. J Anim Sci 2025 Jan 4;103.
    doi: 10.1093/jas/skaf146pubmed: 40331242google scholar: lookup
  3. Mellor DJ, Uldahl DM. Translating Ethical Principles into Law, Regulations and Workable Animal Welfare Practices. Animals (Basel) 2025 Mar 13;15(6).
    doi: 10.3390/ani15060821pubmed: 40150350google scholar: lookup
  4. König von Borstel U, Kienapfel K, McLean A, Wilkins C, McGreevy P. Hyperflexing the horse's neck: a systematic review and meta-analysis. Sci Rep 2024 Oct 2;14(1):22886.
    doi: 10.1038/s41598-024-72766-5pubmed: 39358404google scholar: lookup
  5. Mańkowska A, Witkowska D. The Most Common Environmental Risk Factors for Equine Asthma-A Narrative Review. Animals (Basel) 2024 Jul 14;14(14).
    doi: 10.3390/ani14142062pubmed: 39061524google scholar: lookup
  6. Bini de Lima AC, Sebastião da Fé VC, Palermo Hernandes MS, Oliveira Dos Santos VM. Olfactory Stimulation as Environmental Enrichment for Domestic Horses-A Review. Animals (Basel) 2023 Oct 12;13(20).
    doi: 10.3390/ani13203180pubmed: 37893904google scholar: lookup
  7. Tilley P, Simões J, Sales Luis JP. Effects of a 15° Variation in Poll Flexion during Riding on the Respiratory Systems and Behaviour of High-Level Dressage and Show-Jumping Horses. Animals (Basel) 2023 May 22;13(10).
    doi: 10.3390/ani13101714pubmed: 37238147google scholar: lookup
  8. Harvey AM, Beausoleil NJ, Ramp D, Mellor DJ. Mental Experiences in Wild Animals: Scientifically Validating Measurable Welfare Indicators in Free-Roaming Horses. Animals (Basel) 2023 Apr 28;13(9).
    doi: 10.3390/ani13091507pubmed: 37174544google scholar: lookup
  9. Seck M, Jobling R, Brown AF. Trialling Locally Made, Low-Cost Bits to Improve Bit-Related Welfare Problems in Cart Horses: Findings from a Study in Senegal. Animals (Basel) 2022 Dec 20;13(1).
    doi: 10.3390/ani13010002pubmed: 36611612google scholar: lookup
  10. Matsumoto T, Okumura S, Hirata S. Non-contact respiratory measurement in a horse in standing position using millimeter-wave array radar. J Vet Med Sci 2022 Sep 21;84(10):1340-1344.
    doi: 10.1292/jvms.22-0238pubmed: 35944981google scholar: lookup
  11. Fitzharris LE, Hezzell MJ, McConnell AK, Allen KJ. Training the equine respiratory muscles: Inspiratory muscle strength. Equine Vet J 2023 Mar;55(2):306-314.
    doi: 10.1111/evj.13606pubmed: 35711132google scholar: lookup
  12. Holmes TQ, Brown AF. Champing at the Bit for Improvements: A Review of Equine Welfare in Equestrian Sports in the United Kingdom. Animals (Basel) 2022 May 5;12(9).
    doi: 10.3390/ani12091186pubmed: 35565612google scholar: lookup
  13. Mellor DJ, Beausoleil NJ, Littlewood KE, McLean AN, McGreevy PD, Jones B, Wilkins C. The 2020 Five Domains Model: Including Human-Animal Interactions in Assessments of Animal Welfare. Animals (Basel) 2020 Oct 14;10(10).
    doi: 10.3390/ani10101870pubmed: 33066335google scholar: lookup
  14. Bergmann IM. Naturalness and the Legitimacy of Thoroughbred Racing: A Photo-Elicitation Study with Industry and Animal Advocacy Informants. Animals (Basel) 2020 Aug 26;10(9).
    doi: 10.3390/ani10091513pubmed: 32859112google scholar: lookup
  15. Mellor DJ. Mouth Pain in Horses: Physiological Foundations, Behavioural Indices, Welfare Implications, and a Suggested Solution. Animals (Basel) 2020 Mar 29;10(4).
    doi: 10.3390/ani10040572pubmed: 32235343google scholar: lookup
  16. Tarazona AM, Ceballos MC, Broom DM. Human Relationships with Domestic and Other Animals: One Health, One Welfare, One Biology. Animals (Basel) 2019 Dec 24;10(1).
    doi: 10.3390/ani10010043pubmed: 31878310google scholar: lookup
  17. Mellor DJ. Welfare-aligned Sentience: Enhanced Capacities to Experience, Interact, Anticipate, Choose and Survive. Animals (Basel) 2019 Jul 13;9(7).
    doi: 10.3390/ani9070440pubmed: 31337042google scholar: lookup
  18. Mellor DJ. Operational Details of the Five Domains Model and Its Key Applications to the Assessment and Management of Animal Welfare. Animals (Basel) 2017 Aug 9;7(8).
    doi: 10.3390/ani7080060pubmed: 28792485google scholar: lookup