EFFECTS OF CHIROPRACTIC ON EQUINE GAIT KINEMATICS, HEART RATE, AND SERUM CORTISOL by JESSICA GLADNEY (Under the Direction of Kari Turner) ABSTRACT Study used 18 horses to determine how chiropractic affects riding sound horses over 8 weeks. Horses divided into Chiropractic (n=6), Riding (n=6), and Sedentary (n=6) group. Riding and Chiropractic group ridden 4 days per week. Sedentary horses unridden. Kinematics collected on Day 0, Day 2, Day 14, Day 28, Day 30, Day 42, and Day 56. Chiropractic group received chiropractic while Riding and Sedentary received grooming treatment on Day 1 and Day 29. Heart rate monitors placed on all horses during treatment. Serum cortisol collected on all PRE, MID, and POST treatment. At the trot, swing as a percentage of stride decreased in hind limbs on Day 56 compared to Day 28 (p=0.05), Day 14 (p=0.03), and Day 2 (p=0.02) in Chiropractic group. Cortisol is higher on Day 29 PRE vs. Day 1 PRE (P=0.03) in the Chiropractic group. Results show chiropractic minimally effects kinematics and increases PRE cortisol levels. INDEX WORDS: Chiropractic, Gait Kinematics, Heart rate, Serum Cortisol EFFECTS OF CHIROPRACTIC ON EQUINE GAIT KINEMATICS, HEART RATE, AND SERUM CORTISOL IN RIDING HORSES by JESSICA GLADNEY B.S., UGA, 2015 A Thesis Submitted to the Graduate Faculty of The University of Georgia in Partial Fulfillment of the Requirements for the Degree MASTER OF SCIENCE ATHENS, GEORGIA 2017 © 2017 Jessica Gladney All Rights Reserved EFFECTS OF CHIROPRACTIC ON EQUINE GAIT KINEMATICS, HEART RATE, AND SERUM CORTISOL by JESSICA GLADNEY Major Professor: Kari Turner Committee: Kylee Jo Duberstein Franklin West Electronic Version Approved: Suzanne Barbour Dean of the Graduate School The University of Georgia December 2017 ACKNOWLEDGEMENTS Committee: Dr. Kari Turner, Dr. Kylee Jo Duberstein, Dr. Franklin West UGA Livestock Arena Manager: Alexander Abrams Chiropractor: Dr. Dana Peroni DVM, Covered Bridge Equine Lameness Evaluation: Dr. Paige Williams DVM, Covered Bridge Equine Cortisol: Dr. Clay Lents, (who was found via Dr. Michael Azain) Undergraduate Researchers and Riders: Mary Cate Marchert, Marisa Bartholomew, Erin Jarboe, Madisen Gloeggler, Morgan Garrick, Jessica Simons, and Kaitlyn Gilroy This project would not be possible without every single one of the above names. Thank you, Thank you with all my heart. Thank you to every single one of my family and friends who encouraged me, supported me, and helped me along the way. iv TABLE OF CONTENTS Page ACKNOWLEDGEMENTS ........................................................................................................... iv LIST OF TABLES ........................................................................................................................ vii LIST OF FIGURES ..................................................................................................................... viii CHAPTER 1 INTRODUCTION .........................................................................................................1 Literature Cited ........................................................................................................3 2 REVIEW OF LITERATURE ........................................................................................4 Alternative Therapies ...............................................................................................4 Pain and Lameness ...................................................................................................7 Treating Pain and Lameness ....................................................................................9 Stress in Horses ........................................................................................................9 Biomechanics of the Horse ....................................................................................15 Gait and Back Kinematics .....................................................................................16 Literature Cited ......................................................................................................21 3 EFFECTS OF CHIROPRACTIC ON EQUINE GAIT KINEMATICS, HEART RATE, AND SERUM CORTISOL .............................................................................29 Abstract ..................................................................................................................30 Introduction ............................................................................................................32 Materials and Methods ...........................................................................................34 v Results ....................................................................................................................41 Discussion ..............................................................................................................48 Literature Cited ......................................................................................................51 4 CONCLUSIONS..........................................................................................................56 Literature Cited ......................................................................................................58 REFERENCES ..............................................................................................................................59 APPENDICES A Chiropractic Adjustment for Horses ............................................................................70 B Results Tables ..............................................................................................................71 vi LIST OF TABLES Page Table 1: AAEP Lameness Scale .....................................................................................................8 Table 2: Treatment*Day lsmeans of Cortisol .....................................................................................46 Table 3: Treatment*Day lsmeans of Heart Rate .................................................................................47 Table 4: Treatment*Day lsmeans of the Front Limb Measurements at the Walk ..................................71 Table 5: Treatment*Day lsmeans of the Back Limb Measurements at the Walk ...................................73 Table 6: Treatment*Day lsmeans of the Front Limb Measurements at the Trot ....................................74 Table 7: Treatment*Day lsmeans of the Back Limb Measurements at the Trot ....................................75 Table 8: Treatment*Day lsmeans of Suspension Time at the Trot .......................................................76 Table 9: Treatment*Day lsmeans of Stride Length at the Walk and Trot .............................................77 Table 10: Treatment lsmeans of Cortisol ...........................................................................................77 Table 11: Treatment lsmeans of AVG Heart Rate ..............................................................................78 Table 12: Treatment lsmeans of MAX Heart Rate .............................................................................78 Table 13: Treatment lsmeans of MIN Heart Rate ...............................................................................78 Table 14: Treatment lsmeans of Limb Measurements at the Walk .......................................................78 Table 15: Treatment lsmeans of Limb Measurements at the Trot ........................................................80 Table 16: Serum Cortisol by Horse and Group on Day 1 ....................................................................86 Table 17: Serum Cortisol by Horse and Group on Day 29 ..................................................................87 vii LIST OF FIGURES Page Figure 1: Walk and Trot of the Horse ............................................................................................16 Figure 2: Phases of the Trot ...........................................................................................................19 Figure 3.1: Treatment*Day Lsmeans of the Front Limbs at the Walk ..........................................41 Figure 3.2: Treatment*Day Lsmeans of the Hind Limbs at the Walk ...........................................42 Figure 4.1: Treatment*Day Lsmeans of the Front Limbs at the Trot ............................................43 Figure 4.2: Treatment*Day Lsmeans of the Hind Limbs at the Trot .............................................44 Figure 5: Stride Length of the Walk and Trot................................................................................45 Figure 6.1: Treatment*Day Lsmeans of the Front Limbs at the Trot ............................................82 Figure 6.2: Treatment*Day Lsmeans of the Front Limbs at the Trot ............................................82 Figure 7.1: Treatment*Day Lsmeans of the Hind Limbs at the Trot .............................................83 Figure 7.2: Treatment*Day Lsmeans of the Hind Limbs at the Trot .............................................83 Figure 8.1: Treatment*Day Lsmeans of the Front Limbs at the Walk ..........................................84 Figure 8.2: Treatment*Day Lsmeans of the Front Limbs at the Walk ..........................................84 Figure 9.1: Treatment*Day Lsmeans of the Hind Limbs at the Trot .............................................85 Figure 9.2: Treatment*Day Lsmeans of the Hind Limbs at the Trot .............................................85 viii CHAPTER 1 INTRODUCTION Lameness is the main cause of profit loss within the equine