DOCSLIB.ORG

Nigelperkins Phdthesis.Pdf (2293

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Nigelperkins Phdthesis.Pdf (2293 Epidemiology of health and performance in New Zealand racehorses A thesis presented In partial fulfilment of the requirements for the degree of Doctor of Philosophy in Veterinary Epidemiology at Massey University, Palmerston North, New Zealand Nigel Ross Perkins 2005 ii iii iv v Abstract: The aim of this research was to describe training and racing patterns, and causes of wastage in New Zealand Thoroughbred racehorses. Two separate studies were performed. The first involved analysis of data from before and after construction of a new training track at the Matamata Racing Club. Comparisons of measures of performance failed to detect any adverse impact that could be attributed to the new track. The second involved a longitudinal study over a 34-month period, and that involved 1,571 horses. Duration of training preparations and spell periods were associated with horse age, and with the reason for ending a training preparation. Most horses began a training preparation doing slow work and then progressively advanced to a first start. Incidence rates were estimated for starts per 100 training-days, and other summary measures were estimated including training-days to first start, and between successive starts. A total of 834 musculoskeletal injuries (MSI) were observed, resulting in either a spell period, retirement, or death of the horse. There were 165 respiratory disease events, and 58 conditions involving other body systems. Multivariate statistical models were used to explore risk factors for different types of MSI. Older horses were at higher risk of lower limb MSI, and injury to either the superficial digital flexor tendon (SDFT) or suspensory apparatus (SA), while they were at lower risk of shin soreness and other conditions. Male horses had higher risk of tendon and ligament injury than females. Lower risk of injury was observed in Autumn and Winter months compared with December, and in the 1999-2000 year relative to 1997-1998. Measures of cumulative exercise intensity showed a complex relationship with risk of injury that varied with type of injury. The risk of SDFT and SA injury was higher for those preparations without starts, while that for shin soreness was increased after the first start. For lameness conditions other than shin soreness or injury to the SDFT, the hazard was increased after the first start in a preparation, but the magnitude of effect was dependent on the number of days from the beginning of a preparation to the first start. vi vii Acknowledgements A large number of people contributed towards various stages of this project and I am grateful to them all for their support. The New Zealand Equine Research Foundation provided funding and encouragement. New Zealand Thoroughbred Racing staff and regional racetrack management staff, provided assistance. A special thank you is due to Ms Dagmar Fikken who was employed as a technician to assist in the collection of data, and to Glenda who helped so much with the Matamata end of the project. Thank you to the large number of veterinarians, trainers, and stable staff, who helped in so many ways to make this project possible, not the least of which was giving up their time on a regular basis to allow myself, Dagmar, or Glenda to ask questions and fill out forms. A special thank you to my supervisors, Stuart Reid and Roger Morris, for their guidance and advice, and to colleagues from the Institute of Veterinary, Animal and Biomedical Sciences for their general support. Finally to Kim, Emily and Caroline, and my extended family, your love and support has been wonderfully sustaining throughout this process. viii ix Table of Contents Abstract: ..........................................................................................................................v Acknowledgements........................................................................................................vii List of Tables .................................................................................................................xv List of Figures.............................................................................................................xxiii Introduction.....................................................................................................................1 Literature Review............................................................................................................5 1. Introduction...............................................................................................................6 2. New Zealand racing industry ....................................................................................7 3. Review of epidemiological study design ................................................................14 3.1. Experimental studies ........................................................................................14 3.2. Observational studies .......................................................................................14 4. Sources of bias in epidemiological studies .............................................................18 4.1. Selection bias ...................................................................................................18 4.2. Information bias ...............................................................................................20 4.3. Confounding bias .............................................................................................21 5. Matching .................................................................................................................21 6. Measures of frequency and association...................................................................22 7. Chronological development of research methods to investigate racehorse health and performance..........................................................................................................24 8. Data sources and Outcomes used............................................................................29 9. Events interfering with training and racing.............................................................34 9.1. Classification by location and system affected ................................................34 9.2. Frequency estimates.........................................................................................40 10. Specific risk factors for musculoskeletal injury....................................................45 x 10.1. Age.................................................................................................................45 10.2. Gender............................................................................................................46 10.3. Quality of horse and class of race ..................................................................46 10.4. Leg: left vs right.............................................................................................47 10.5. Race type........................................................................................................48 10.6. Race number ..................................................................................................49 10.7. Barrier position ..............................................................................................49 10.8. Race distance..................................................................................................50 10.9. Jockey.............................................................................................................50 10.10. Racetrack and racing surface .......................................................................50 10.11. Surface condition .........................................................................................52 10.12. Season ..........................................................................................................54 10.13. Exercise intensity .........................................................................................54 10.14. Pre-existing conditions.................................................................................59 10.15. Shoeing ........................................................................................................61 10.16. In-race activity and interaction ....................................................................61 10.17. Trainer..........................................................................................................63 11. Conclusion ............................................................................................................63 Effect of training location and time period on racehorse performance in New Zealand. I. Descriptive analysis * ................................................................................65 Abstract .......................................................................................................................66 Introduction.................................................................................................................67 Materials and methods ................................................................................................68 Study design............................................................................................................68 Variables .................................................................................................................68 xi Statistical analysis.......................................................................................................70 Results.........................................................................................................................70
Load more

Recommended publications
  • Articles on Race Track Safety & Subjects Associated with the Welfare and Safety of the Racehorse
    Track safety has come a long way in a short period of time . Reprinted with permission of. Reprinted owner. copyright BEYOND The Blood-Horse S Copyright©2013, Copyright©2013, SCRATCHING THE SURFACE RICK SAMUEL BY FRANK ANGST s New York-area racing fans get the track,” Kozak said. awakened to pouring rain Fri- While trucks and tractors rolling around Belmont may be a familiar sight, day, June 7, plenty of break- Racing Surfaces Testing Laboratory ex- fast conversations turned to ecutive director Dr. Mick Peterson said Aspeculation of the day’s races’ being there’s more than meets the eye. In recent canceled and the dimming prospects years several tracks have added technol- ogy and information gathering to their for a fast track June 8, Belmont Stakes surface maintenance. (gr. I) day. “In New York we’re at the point now where we have this real-time tracking, But well before those conversations weather stations providing updates. started, the New York Racing Associa- Then they have very complete data that tion already had rolled out one of the most they’re entering every day,” Peterson high-tech fleets of maintenance vehicles said. “They go out and measure points on in the world. Each vehicle includes cus- the cushion every day—cushion-depth tom-made equipment designed for the measurements—that goes in the data- challenges of each NYRA track, which at base. They’re measuring moisture con- Belmont can include spring downpours KEVIN THOMPSON tent and how that affects the toe going and strong winds. GPS technology is being used in track into the material.” As the vehicles rolled over the massive maintenance vehicles in New York On Belmont day Kozak would face what Belmont dirt oval, which was scheduled Peterson calls one of the toughest deci- 1 to use both turns of its 1 ⁄2-mile main track information, along with his experience sions for track operators: when to make in the Brooklyn Handicap (gr.
    [Show full text]
  • Dissertation
    DISSERTATION EFFECT OF BONE GEOMETRY ON STRESS DISTRIBUTION PATTERNS IN THE EQUINE METACARPOPHALANGEAL JOINT Submitted by Katrina L. Easton Graduate Degree Program in Bioengineering In partial fulfillment of the requirements For the Degree of Doctor of Philosophy Colorado State University Fort Collins, Colorado Spring 2012 Doctoral Committee: Advisor: Chris Kawcak Wayne McIlwraith Christian Puttlitz Sue James Kevin Shelburne Paul Heyliger Copyright by Katrina L. Easton 2012 All Rights Reserved ABSTRACT EFFECT OF BONE GEOMETRY ON STRESS DISTRIBUTION PATTERNS IN THE EQUINE METACARPOPHALANGEAL JOINT Catastrophic injury of the equine metacarpophalangeal joint is of major concern for both the equine practitioner and the American public. It is one of the major reasons for retirement and sometimes euthanasia of Thoroughbred racehorses. The most common type of catastrophic injury is fracture of the proximal sesamoid bones and lateral condyle of the third metacarpal bone. Many times these injuries are so disastrous that there is no possibility of fixing them. Even in the injuries that are able to be fixed, complications arising from the fracture such as support limb laminitis may ultimately lead to the demise of the horse. Therefore, prevention of these types of injuries is key. In order to decrease the incidence of injury, it is important to understand the risk factors and pathogenesis of disease that leads to them. This project was established to create a finite element model of the equine metacarpophalangeal joint in order to investigate possible risk factors, namely bone geometry, and its effect on the stress distribution pattern in the joint. The first part of the study involved in vitro experiments in order to provide a comprehensive dataset of ligament, tendon, and bone strain and pressure distribution in the joint with which to validate the finite element model.
    [Show full text]
  • Drug Use in Racehorses, Difficulty Assigning Responsibility and the Need for a National Racing Commission
    Online at www.michbar.org/aglaw Transgressing Trainers and Enhanced Equines: Drug Use in Racehorses, Difficulty Assigning Responsibility and the Need for a National Racing Commission By Kjirsten Lee Introduction From Saratoga Race Track in New York State to Santa Anita Park in California, and from Canterbury Downs in Minnesota to Gulfstream Park in Florida, horse racing spans the United States and has always been a part of American culture.1 It is known as “the sport of kings,”2 and millions of dollars change hands every year chasing “1,200-pound investment vehicles running on legs more slender than the average human’s.”3 Tragically, the sport has been tainted by the use of steroids and painkilling drugs, the administration of which masks injury and creates an unfair advantage by allowing horses to race that are not physically up to the challenge.4 Genetically built for speed, over time the Thoroughbred horse has been bred to be faster, with little concern for what might be sacrificed in return. Recently, the American general public has become more aware of the sacrifices breeders make as horses in prestigious races break down on the track.5 In 2006, Americans’ hearts stopped in their chests when Barbaro shattered his leg in the Preakness Stakes, the second jewel of racing’s illustrious Triple Crown. He was euthanized in January of 2007 when veterinarians were unable to repair his leg following multiple surgeries.6 The next year was particularly dark for racing: after watching the remarkable filly Eight Belles collapse after finishing second to Big Brown in the Kentucky Derby,7 racing fans hoped Big Brown, after winning the Kentucky Derby and the Preakness Stakes, might be the first Triple Crown champion since Affirmed in 1978.8 But hopes were dashed when the Derby and 1 See, e.g., Horse racing, Wikipedia, stating that the oldest Thoroughbred track in the United States dates back to 1665 on Long Island.
    [Show full text]
  • Riding for a Fall the Genetic Time Bomb at the Heart of Racing
    Riding For a Fall The genetic time bomb at the heart of racing wwwwww.animalaid.or.animalaid.org.ukg.uk Contents Summary 5 Tel: The Breeding Stallion - Worked to Death 7 01732 364546 • [email protected] www.animalaid.org.uk The Mare’s Burden - Production Line Pregnancies 9 Mares ‘doped and raped’ Animal Aid The Violence of Embryo Transfer Malformed Foals Cloning on the Agenda Throughput and Output 13 Kent TN9 1AW. The Old Chapel, Bradford Street, Tonbridge, A Downward Spiral The Offspring - ’We Are Ruining The Breed’ 14 Hard ‘Remedies’ - The Drugs, the Whip and the Lethal Experiments 17 Lethal Experiments on Live Horses – 19 the Role of the Animal Health Trust Raced to Death – 300 Every Year 21 The Grand National 21 When Racing is Over – Thousands Disposed of Every Year 21 References 23 Written by Andrew Tyler, director, Animal Aid Key research by Kareena Grey of Discover Racing Death ([email protected]) Tel. 07814 925473 Dr Tim O’Brien, independent animal welfare researcher Dene Stansall Kathy Archibald, Animal Aid science researcher All photos by Brian Moody, except horse with broken leg Published by Animal Aid, March 2003 ISBN: 0-9508990-7-0 Riding for a Fall 3 ‘Many learned students of this sport think the creature on which it all depends may now be in decline. Their disturbing contention is that excessive inbreeding for speed, as well as breeding [from] horses whose congenital defects may have been masked by so-called ‘medications’, has turned, or is turning, the thoroughbred (which don’t forget is a human invention...) into an increasingly fragile and vulnerable creature that is having ever greater trouble meeting the demands we place on it.
    [Show full text]
  • Heritability Analyses of Musculoskeletal Conditions and Exercise-Induced Pulmonary Haemorrhage in Thoroughbred Racehorses
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Glasgow Theses Service Welsh, Claire Elizabeth (2014) Heritability analyses of musculoskeletal conditions and exercise-induced pulmonary haemorrhage in Thoroughbred racehorses. PhD thesis. http://theses.gla.ac.uk/4862/ Copyright and moral rights for this thesis are retained by the author A copy can be downloaded for personal non-commercial research or study, without prior permission or charge This thesis cannot be reproduced or quoted extensively from without first obtaining permission in writing from the Author The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the Author When referring to this work, full bibliographic details including the author, title, awarding institution and date of the thesis must be given. Glasgow Theses Service http://theses.gla.ac.uk/ [email protected] Heritability analyses of musculoskeletal conditions and exercise-induced pulmonary haemorrhage in Thoroughbred racehorses By Claire Elizabeth Welsh BVMS (Hons) MSc (VetSci) AHEA MRCVS A thesis submitted for the degree of Doctor of Philosophy School of Veterinary Medicine College of Medical, Veterinary and Life Sciences University of Glasgow January 2014 ABSTRACT Musculoskeletal conditions and exercise-induced pulmonary haemorrhage are commonly diagnosed in Thoroughbred racehorses worldwide, and have serious consequences for racehorse welfare and the racing economy. Despite increasing interest in the study of genetic susceptibility to disease from the veterinary research community as a whole over past decades, the Thoroughbred has been largely ignored as a study group. The availability of software capable of complex genetic analyses using large, unbalanced pedigrees has made the study of genetic susceptibility to disease a realistic prospect for veterinary researchers.
    [Show full text]
  • Catastrophic Injuries
    Understanding and Preventing CATASTROPHIC INJURIES BY STACEY OKE, DVM, MSC ER ST U L ILL B 26 25TH ANNIVERSARY SPONSORED BY PFIZER ANIMAL HEALTH TheHorse.com THE HORSE July 2008 DR. RoBIN PETERSON ILLUSTRATIONS ollowing the euthanasia of filly Eight Belles, who suffered cata- Six different types of catastrophic injuries: (left to right) condylar fracture of the cannon bone, strophic injuries to both front legs a quarter mile after finish- sesamoid fracture, long pastern bone fracture, ing second in the Kentucky Derby, members of every sector of third carpal slab fracture (in the knee), tibial the Thoroughbred industry have banded together to proactively fracture (in the stifle; this is actually relatively common in racing Thoroughbreds), and the Faddress safety and welfare issues. In this article, representative mem- rupture of the suspensory apparatus. bers of the equine industry together provide an in-depth exploration of catastrophic injuries in the Thoroughbred racehorse, focusing on what veterinarians know about catastrophic injuries based on the available scientific data, and looking at what work is still to be done. What are Catastrophic Injuries? According to epidemiological surveys The term “catastrophic injury” in the What happened to Eight performed in California, Kentucky, On- context of equine veterinary medicine tario, the United Kingdom, Australia, refers to a severe musculoskeletal injury Belles is tragic, but it has gal- and Hong Kong, the number of cata- sustained by athletic horses during rac- vanized the industry like I have strophic injuries incurred by racehorses ing or training that results in an acute is small. lameness. Such injuries include (either never witnessed before.
    [Show full text]
  • HEADLINE NEWS • 2/24/07 • PAGE 2 of 4
    HONEY RYDER TAKES ON THE BOYS HEADLINE AT GULFSTREAM...p2 NEWS For information about TDN, DELIVERED EACH NIGHT BY FAX AND FREE BY E-MAIL TO SUBSCRIBERS OF call 732-747-8060. www.thoroughbreddailynews.com SATURDAY, FEBRUARY 24, 2007 HKJC TEAMS WITH BREEDERS’ CUP DREAMING OF ANNA BACK ON THE GRASS The Hong Kong Jockey Club and Breeders= Cup Lim- Dreaming of Anna (Rahy), who suffered the first loss ited have entered into a marketing partnership, it was of her career when third in the Feb. 10 announced yesterday. As part GIII Old Hat S., will return to the turf of the agreement, the Apr. 29 for tomorrow=s $100,000 Gaily Gaily G1 HKJC Champions Mile at S. at Gulfstream. The chestnut was Sha Tin will become the first named champion two-year-old filly af- race outside the U.S. to be in- ter posting a 1 1/2-length score in the cluded in the Breeders= Cup GI Breeders= Cup Juvenile Fillies. She Challenge, a series of races that ran twice on the grass, taking the automatically qualify the winner Tippett S. at Colonial Downs in July for the World Thoroughbred and the GIII Summer S. against colts at Horsephotos Championships. AThe Breeders= Woodbine in September. She faces Cup World Championships at- eight rivals in the 1 1/16-mile Gaily Gaily. Breaking from post five, she will carry co-highweight of 121 pounds. about.horseracing.com tract the very best Thorough- breds from around the world,@ said Breeders= Cup Chairman Bill Farish. AExtending the STREET SENSE TO SKIP HUTCH [series] to some of the top international races is a natu- Eclipse champion Street Sense (Street Cry {Ire}), ral development of the Breeders= Cup Challenge.@ For runaway winner of the Nov.
    [Show full text]
  • Journal of Animal Natural Resource
    ISSN 2154-9656 VOL. XI 2015 JOURNAL OF ANIMAL & NATURAL RESOURCE LAW Michigan State University College of Law For optimum page navigation of this Journal, open Bookmarks in Adobe Acrobat Reader. JOURNAL OF ANIMAL & NATURAL RESOURCE LAW Michigan State University College of Law MAY 2015 VOLUME XI The Journal of Animal & Natural Resource Law is published annually by law students at Michigan State University College of Law. The Journal of Animal & Natural Resource Law received generous support from the Animal Legal Defense Fund and the Michigan State University College of Law. Without their generous support, the Journal would not have been able to publish and host its annual symposium. The Journal also is funded by subscription revenues. Subscription requests and article submissions may be sent to: Professor David Favre, Journal of Animal & Natural Resource Law, Michigan State University College of Law, 368 Law College Building, East Lansing MI 48824, or by email to [email protected]. Current yearly subscription rates are $27.00 in the U.S. and current yearly Internet subscription rates are $27.00. Subscriptions are renewed automatically unless a request for discontinuance is received. Back issues may be obtained from: William S. Hein & Co., Inc., 1285 Main Street, Buffalo, NY 14209. The Journal of Animal & Natural Resource Law welcomes the submission of articles, book reviews, and notes & comments. Each manuscript must be double spaced, in 12 point, Times New Roman; footnotes must be single spaced, 10 point, Times New Roman. Submissions should be sent to [email protected] using Microsoft Word or PDF format. Submissions should conform closely to the 19th edition of The Bluebook: A Uniform System of Citation.
    [Show full text]
  • Task Force on Racehorse Health & Safety
    New York Task Force on Racehorse Health and Safety OFFICIAL REPORT Investigation of Equine Fatalities at Aqueduct 2011-2012 Fall/Winter Meet TABLE OF CONTENTS I. Introduction ................................................................................................................................ 3 II. Scope of Investigation and Methodology ........................................................................... 7 III. Historical Perspective ........................................................................................................... 11 IV. Review of the 2011-2012 Aqueduct Fatalities .............................................................. 15 V. Factors Common to the Fatally Injured Horses ............................................................ 35 VI. Other Potential Contributing Factors .............................................................................. 37 VII. Overall Conclusions Regarding the Fatally Injured Group ....................................... 71 VIII. Additional Matters Addressed by the Task Force ....................................................... 75 IX. Recommendations of the Task Force .............................................................................. 87 X. References ................................................................................................................................ 97 XI. Exhibits ................................................................................................................................... 101 1 This Page Intentionally
    [Show full text]
  • Relationship Between Historical Lameness, Medication Usage, Surgery, and Exercise with Catastrophic Musculoskeletal Injury in Racehorses
    UC Davis UC Davis Previously Published Works Title Relationship Between Historical Lameness, Medication Usage, Surgery, and Exercise With Catastrophic Musculoskeletal Injury in Racehorses. Permalink https://escholarship.org/uc/item/02m8g1wb Journal Frontiers in veterinary science, 5(SEP) ISSN 2297-1769 Authors Hitchens, Peta L Hill, Ashley E Stover, Susan M Publication Date 2018 DOI 10.3389/fvets.2018.00217 Peer reviewed eScholarship.org Powered by the California Digital Library University of California ORIGINAL RESEARCH published: 07 September 2018 doi: 10.3389/fvets.2018.00217 Relationship Between Historical Lameness, Medication Usage, Surgery, and Exercise With Catastrophic Musculoskeletal Injury in Racehorses Peta L. Hitchens 1,2*, Ashley E. Hill 3 and Susan M. Stover 1 1 J.D. Wheat Veterinary Orthopedic Research Laboratory, School of Veterinary Medicine, University of California, Davis, Davis, CA, United States, 2 Equine Centre, Melbourne Veterinary School, Faculty of Veterinary and Agricultural Sciences, University of Melbourne, Werribee, VIC, Australia, 3 California Animal Health and Food Safety Laboratory System, University of California, Davis, Davis, CA, United States Background: The rate of catastrophic musculoskeletal injuries (CMI) in racehorses is high in the United States compared to other countries. Few modifiable risk factors related to lameness, medication, and surgery history have been identified. Objective: To detect management factors that increase risk of CMI by comparing medical histories between horses that sustained, and horses that did not sustain, a CMI. Edited by: Francisco Ruiz-Fons, Study design: Case-control. Consejo Superior de Investigaciones Científicas (CSIC), Spain Methods: Racehorse necropsy data (May 2012-June 2013) were obtained through Reviewed by: the California Horse Racing Board Postmortem Program.
    [Show full text]
  • PTHA News 2012
    PTHA NEWS Pennsylvania Thoroughbred Horsemen’s Association Newsletter We ARE Pennsylvania Racing Volume 2 2012 Royal Currier Named Parx Horse of the Year The MAT Stables of Michael Ciacci Currier at the March 14 Horsemens and Gerani Morris earned Leading Awards Dinner. Owner, and took home trophies for Sponsored by the PTHA and Parx both Three-Year-Old Colt or Gelding Racing, the annual banquet honored and Horse of the Year for their Royal the “best in our business,” according to PTHA Executive Director Michael Ballezzi, who opened the evening to a crowd of nearly 300 trainers, owners, jockeys and their families. “This night is dedicated to the talent, hard work and integrity of the men and women of Parx Racing.” PTHA President Sal DeBunda (right) After acknowledging 2011 as a year presents Royal Currier’s Horse of the Year RI´ÀUVWVµLQFOXGLQJWKHQHZ+DOORI trophy to MAT Stables’ Michael Ciacci and Fame, a Parx-based Breeders’ Cup Gerani Morris. Photo by Anna Cascio Photo right shows Royal Currier galloping ZLQQHU$ÁHHW$JDLQIXOOKHDOWKFDUH back from his win in the Southampton and pensions for trainers, Ballezzi then Stakes last year. Photo by EquiPhoto thanked PA Horse Racing Commissioner (continued on page 6) Membership Unites to Confront Governor’s Budget Cuts Executive Director Michael Ballezzi and President Salvatore DeBunda presented somber news to Parx horsemen at the March 15 General Membership meeting, held at Celebrations in Bensalem. “The things we have worked so hard for in the last 10 years are at risk because of Governor Corbett’s budget proposal which would cut $72 million from the Race Horse Development Fund,” said Ballezzi in front of the crowd of nearly 200.
    [Show full text]
  • Equine Musculoskeletal Development and Performance: Impact of the Production System and Early Training
    CSIRO PUBLISHING Special Issue: EQUINE SCIENCE Animal Production Science, 2020, 60, 2069–2079 Perspectives on Animal Biosciences https://doi.org/10.1071/AN17685 Equine musculoskeletal development and performance: impact of the production system and early training Chris W. Rogers A,C, Charlotte F. Bolwell A, Erica K. Gee A and Sarah M. Rosanowski B AEquine Research Centre, School of Veterinary Science, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand. BDepartment of Infectious Diseases and Public Health, College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong, SAR. CCorresponding author. Email: [email protected] Abstract. The welfare debate around horse racing appears to be focussed on musculoskeletal injury and the racing of 2- year-olds. Much of this debate appears contrary to the evolutionary history of the horse as a cursorial animal and the capability of the equine musculoskeletal system to respond to the demands of race training. Epidemiological studies have reported that 2-year-old racehorses have a longer time period from entering training to the first race and a greater number of lost training days than older horses. However, this is, in part, due to the time taken to learn to train and the impact of dorsal metacarpal disease, which is due to loading of naïve as opposed to immature tissue. Across several racing jurisdictions and codes, it has been demonstrated that horses that train and race as 2-year-olds have longer, more successful, careers than those that start racing later in life. This positive trend has also been observed with horses starting in equestrian sport at an early age.
    [Show full text]