UCalgary researcher Dr. Renaud Léguillette shares fascinating insights from his work with world class competitive horses, including Spruce Meadows show jumpers and Calgary Stampede rodeo and chuckwagon horses. Renaud covers early disease detection and treatment, fitness assessments and preventative care strategies to optimize the health and success of performance horses. Find out how horse owners and caregivers help equine athletes achieve higher, faster, stronger. Learn more at ucalgary.ca/explore/equinesports

1. Powering Performance Horses:
Keeping Equine Athletes in Top Form
Renaud Léguillette
Calgary Chair in Equine Sports Medicine
Associate Professor, Faculty of Veterinary Medicine (UCVM)

2. Equine Sports Medicine:
What do we know about horse
athletes

3. Welcome
 Webinar series by University of Calgary scholars
 Information presented is a summary of the
scholars’ research

4. Renaud Léguillette, UCVM
Training
 DVM: Paris, France, Maisons-Alfort Vet.
School (ENVA)
 Clinical training/ specialty boards:
University of Montreal (internship/
residency: Equine internal medicine)
 Equine Sports Medicine and Rehabilitation
specialty boards (new college)
 MSc: equine asthma
 PhD: McGill University, Meakins-Christie
Laboratories on bronchial smooth muscle
in human asthma

5. Presentation objectives
 Introduction to the incredible exercise physiology
of horse athletes: How do they do it?
 What are the limiting factors?
 What can go wrong: Throat, lungs, heart
 How do we treat and help these horses?

6. All sorts of efforts:
Fast, Up, Sideways, Pulling …

7. How do these equine athletes do it?
 Incredibly efficient in their movements
 Can take-up a lot of oxygen (O2) from the air (respiratory)
 And can deliver O2 to the muscles (cardiac)
 Self “blood doping” system (O2 transportation)
 Incredibly tolerant to running anaerobic (without O2)

8. Horse locomotor apparatus:
Built to run!
 Muscle mass is UP: Less inertia/ Less energy lost moving the mass
Equine limb Human limb

9.  Pulleys/ Spring system of the tendons and ligaments:
Passive accumulation of energy in extension returned in
flexion
Horse locomotor apparatus:
Built to run!

10.  Pulleys/ Spring system of the tendons and ligaments:
Passive accumulation of energy in extension returned in
flexion
Horse locomotor apparatus:
Built to run!

11. Incredible Respiratory System
35-50 /min 100-180 /min
100-200 L/min >1500L/min
Max:
Fig. by Shannon Massie

12. Respiratory: Giant lungs
Modified from: Encyclopedie du Cheval, 1903

13. Incredible Cardiac System
70 bpm 35 bpm
220-age bpm 220-240 bpm
20-30 L/min 250-450 L/min
Resting:
Max:

14. Self “Blood Doping”
 Spleen contraction: “Self blood dopping”
12L of blood with 80% red blood cells (RBCs)
• Hematocrit (% RBCs) rest: 32%
• Hematocrit (% RBCs) exercise: 65%

15. Results: Incredible O2 consumption
 VO2max: Per Kg
Average person Average horse
40-50 ml/kg/min >150 ml/kg/min
 Elite human athlete ~80ml/kg/min Racehorse >200ml/kg/min
 Human record 97.5ml/kg/min (18 yo Norwegian cyclist in 2012)

16. What is the limiting factor?
The respiratory system!
 Horses are hypoxic at maximal speed:
“Diffusion limitation”:
• Very low PaO2: 70 mmHg (vs 92-99 mmHg at rest)
• Blood “flows too quickly” in the lungs
 Horses are hypercapneic at maximal speed:
“Ventilation limitation”:
• Increased PaCO2: 50+ mmHg (vs 44 mmHg at rest)
• Locomotory:respiratory coupling.

17. Resistance to airflow
‘Bottleneck’:
Nose/ Throat
‘Soccer field’:
Lungs/ Alveoli
Lower Airways
‘Pipe’:
Trachea
Turbulence:
- Increased velocity
- Decreased diameter

18. Respiratory: Upper airways project

19. Exhalation Max/Running Rest
Exhalation Max/Running Inhalation
Flow
WeightedVelocity
Respiratory: Upper airways project

20. Respiratory: Upper airways project

21. What can go wrong?
 Upper airways: Throat
 Lower airways: Lung
 Cardiac

22. What can go wrong?
 Upper airways: Throat

23. We assess the upper airways with a camera:
Endoscopy
 Static obstructions: Endoscopy at rest
 Challenge of the dynamic obstructions:
• Only happen during exercise when high flows
• Completely normal at rest
What can go wrong?
Upper Airways

24. Endoscopy during exercise?
Older option:
High speed treadmill

25. Dynamic upper airways endoscopy
 DRS: Dynamic Respiratory Scope:
• First in Canada 5 years ago
• Contribution from Equine Foundation of Canada (Eldon Bienert)

26. DRS: In the field, for all disciplines

27. Dynamic obstructions
 DRS movie:
• Dorsal displacement of soft palate
• Laryngeal hemiplegia
• Axial deviation of arytenoepiglotic folds
• Retroversion of epiglottis
• Pharyngeal collapse

28. How do we help with these
problems?
 Often a throat surgery (often general anesthesia)
 Now options of laser surgeries (standing sedation)
 Management (stress, bits, other problems)

29. What can go wrong?
 Upper airways: Throat
 Lower airways: Lung

30. What can go wrong?
Lungs: “Asthma”
“Equine Asthma”
Two non-infectious Diseases
Mild Severe
Inflammatory Airway Disease “Heaves”
(IAD) Recurrent Airway Obstruction
(RAO)
Coughing Labored breathing AT REST
Mucus/ nasal discharge Coughing
Decreased performance Severe: Not ridable

31. Horse asthma: Is it common in AB?
66
17 17
0
10
20
30
40
50
60
70
Moderate Airway Inflammation Severe Airway Inflammation Normal
Percentage
Moderate Severe Normal
Percentage
66%
17% 17%

32. Equine screening tools:
Questionnaire
 Horse owners are very reliable
to detect clinical signs
 Questionnaires are focusing
on clinical signs at rest

33.  To detect Severe or moderate Inflammation: Did the
horse cough in the past? (sensitivity = 0.97)
 COUGH is the key respiratory sign
Equine screening tools:
COUGH
 Questionnaires are helpful to identify respiratory
problems but not good to differentiate Moderate vs
Severe Inflammation.

34. How to diagnose
lung inflammation/ asthma?
 Bronchoalveolar lavage (BAL)

35. How to diagnose
lung inflammation/ asthma?

36. “Cellular phenotypes”
in horse asthma

37. Equine mild asthma:
Immune system response
Cytokines (Immune mediators) identified in BAL: Difference between mast
cells and neutrophils mild asthma horses

38.  Bronchoprovocation tests:
Histamine challenge to measure
the dose of histamine inducing
bronchoconstriction
How to document lung asthma in
research?
0
20
40
60
Day 0 Day 7 Day 15
Reactivity(%mg/ml)
*** *
Flow
Pressure
AmplificationAnalysisPrinting
Record

39. How to treat
lung inflammation/asthma?
 The key is NOT to treat asthma
 But to PREVENT exposure to dust/ allergens

40. Round hay bales -
“Digging” problem
 Round hay bales:
2 times more likely to have
severe asthma
58
34
4142
66
59
0
10
20
30
40
50
60
70
RAO IAD Normal
Percentage
Round Hay Bales vs Square Hay Bales
Round…
Square…

41. How to prevent
lung inflammation/asthma?

42. How to treat
lung inflammation/asthma?
 Treatments to decrease inflammation
 Treatments to “open” the bronchi and decrease mucus

43. Systemic corticosteroids:
Dexamethasone
Most effective to less effective:
• Dexamethasone:
• high doses, then taper down, but keep for LONG term
• Isoflupredone (Predef 2X):
• IM injections
• Prednisolone:
• NOT prednisone (poor bioavailability)

44. Inhaled corticosteroids: Devices
Discontinued:
Lower efficiency

45. Effects of inhaled steroids
on airway hypersensitivity
Fluticasone: Black
Dexamethasone: White

46. What can go wrong?
 Upper airways: Throat
 Lower airways: Lung
• Asthma
• “Bleeders” EIPH

47. “Bleeders”:
Exercise induced pulmonary hemorrhage (EIPH)
 What is it?
• Horses can bleed from their lungs with high intensity exercise.
• Common in horses racing at high speeds (up to 80%)
• Often paired with poor athletic performance
 How does it work? Not entirely sure
• Transmural stress and capillary walls ruptures
Pulmonary
Artery
hypertension
Aveoli
“vacuum”

48. Hemosiderophages
 BAL: Anytime (days) post race
How do you diagnose EIPH?

49. How do you diagnose EIPH?
 Endoscopy: 30+ mins post exercise

50. Study results: Barrel Racers: EIPH
 170 endoscopies
 >45% EIPH in tested Barrel racers
 Only 5/ 77 EIPH had blood at nostrils:
Mostly internal bleeding

51. How can we treat EIPH?
 No cure: Preventive measures. Active research field!
 Treat lung inflammation
 Decrease blood pressure
 Decrease “vacuum” in lungs

52. What can go wrong?
 Upper airways: Throat
 Lower airways: Lung
 Cardiac

53. Electrocardiograms (ECG) during
exercise in horses
 Electrical activity of the heart
 No studies published on racing ECGs: Challenging technique

54. What can go wrong?
Arrhythmias during exercise
 Ventricular premature contraction (VPC)
 An early beat originating from the ventricle

55. Chuckwagons study
 13 teams
 148 horses
 377 ECGs

56.  Same prevalence as
other disciplines
 VPCs are rare
during racing
Chuckwagons study

57. Can we detect and prevent
cardiac problems?
 Goal: Find a marker of cardiac damage BEFORE racing
 Validation of a new high sensitivity troponin assay
 Collaboration with Dr. Seiden-Long (CLS)
Normal
Racehorses

58. Test to diagnose cardiac problem
post event
 High sensitivity troponin after competition or clinical
signs
 3-6hrs post is the best blood sampling time
 No correlation with age

59. What did we learn?
 Horses have incredible adaptations to run. Their limiting factor
is the respiratory system
 Any nose or throat problem will affect airflow and athletic
capacity
 Many horses have mild asthma, a few have severe asthma
 Many high level horses have lung bleeding
 Severe cardiac electrical problems are very rare
 We have validated markers of cardiac muscle damage

60. Where do we go from now?
 Technologies in the field. Field studies
 We needed a portable system to measure VO2max and
just got it developed!
 Critical to assess fitness
 Critical to develop better & safer training protocols
 Critical to test training options like water treadmill
 We (and others) are working on the prevention of EIPH

61. Technology

62. Dr. Bayly’s mask/collaboration:

64. Thank you
 Horse owners for volunteering their horses in our
field studies.
 Calgary Stampede
 Events organizers
 Linda Atkinson
 Students and trainees:
• Summer students
• Graduate students
• Resident/ Interns

65. Upcoming webinars
 Our Brains and Fatigue, October 4, 12-1 p.m. MST
 No Pain No Gain? The Sociology of Sports, October
6, 12-1 p.m. MST
 The Race to Prevent Running Injuries, October 11,
12-1 p.m. MST
 Inside the Mind of an Olympian, October 13, 12-1
p.m. MST
 Knocking Out Concussions in Sports, October 20,
10-11 a.m. MST

66. Thank you
Sign up for other UCalgary webinars,
download our eBooks,
and watch videos on the outcomes of our
scholars’ research at
ucalgary.ca/explore/collections

67. Other webinar topics
For ideas on other UCalgary webinar topics,
please email us at
exploreucalgary@ucalgary.ca