Genetic Evaluation of Sport Horses in Britain Charlotte Burgess PhD by Research The University of Edinburgh 2008 Table of Contents 1 Introduction ............................. 1 2 Literature Review .....................................................................................................................4 2.1 Introduction ...................................................................................................................... 4 2.2 Sources of data ................................................................................................................ 4 2.3 Evaluation of data ........................................................................................................... 7 2.4 Discussion and Conclusion ...................................................................................... 14 2.5 Summary ....................................................................................................................... 15 3 Industry perspectives on breeding objectives .........................................................16 3.1 Introduction .................................................................................................................. 16 3.2 Materials and Methods ..............................................................................................17 3.3 Results ............................................................................................................................17 3.4 Discussion .....................................................................................................................22 3.5 Conclusion .....................................................................................................................26 3.6 Summary ....................................................................................................................... 27 4 Analysis of Young Horse Evaluation data for use in the genetic evaluation of British sport horses....................................................................................................................... 28 4.1 Introduction .................................................................................................................. 28 4.2 Materials and methods ............................................................................................... 28 4.3 Results ............................................................................................................................31 4.4 Discussion .....................................................................................................................36 4.5 Conclusions .................................................................................................................. 38 4.6 Summary ....................................................................................................................... 39 5 Use of competition data for genetic evaluations of eventing horses in Britain: Analysis of the dressage, showjumping and cross country phases of eventing competition ......................................................................................................................................40 5.1 Introduction .................................................................................................................. 40 5.2 Materials and Methods ..............................................................................................41 5.3 Results ............................................................................................................................45 5.4 Discussion .....................................................................................................................56 5.5 Conclusion .....................................................................................................................60 5.6 Summary ....................................................................................................................... 61 6 Selection of sires, individual horses and riders in the dressage, showjumping and cross country phases of eventing competition ............................................................... 62 6.1 Introduction ....................................................................................................................62 6.2 Materials and methods .................................................................................................63 6.3 Results ............................................................................................................................. 66 6.4 Discussion ...................................................................................................................... 73 6.5 Conclusion ...................................................................................................................... 75 6.6 Summary .........................................................................................................................75 7 Reconciling estimated breeding values and penalty points ............................................. 76 7.1 Introduction ....................................................................................................................76 7.2 Materials and Methods ............................................................................................... 78 7.3 Results ............................................................................................................................. 79 7.4 Discussion ......................................................................................................................91 7.5 Conclusion ......................................................................................................................92 7.6 Summary .........................................................................................................................92 8 General Discussion ...............................................................................................................93 8.1 Introduction ....................................................................................................................93 8.2 Breeding values ............................................................................................................ 94 8.3 Future of genetic research in horses ....................................................................... 96 8.4 Recommendations for the industry ..........................................................................98 8.5 Summary ...................................................................................................................... 103 9 R eferences ............................................................................................................................ 105 10 Appendix A Glossary of equine terms ....................................................................115 11 Appendix B Survey questions ...................................................................................116 12 Appendix C Summary of edits made to British Eventing database in preparation for use in analyses .................................................................................................118 13 Appendix D Calculations for the presentation of EBYs ................................... 120 Declaration I declare that: (1) this thesis was composed by myself (2) the work contained in this thesis is my own (3) this work has not been submitted for any other degree or professional qualification Charlotte Kearsley Acknowledgements I would firstly like to thank my supervisors John Woolliams, Sue Brotherstone and Mike Coffey for all of their help and support, without them I would not have been able to produce this work! Another important thank you must go to the BBSRC and BEF for funding this study. I would also like to thank Jan Rodgers and Graham Suggett for acquainting me with the finer points of sport horse breeding in Britain and providing me with data from British Breeding. Thanks also to British Eventing for providing me with their competition database. There are also many people involved in British Breeding and the BEF who took the time to talk to me and give me their views, thanks to all of you too! Thanks to Ian White for his help with ASReml and R and to Sarah Blott for providing me with information on new technologies in equine genetics. Thanks to Liz Brown for always keeping me right on conference and travel arrangements! And now to the personal ones....thanks to my gorgeous Dave (soon to be my husband!), my parents and Chris for all of their love and support for the last three years, it’s helped to keep me pretty much sane!!! Thanks to my ponies Woody and Max (and the dearly departed Sam) for being my inspiration in all things horsey!!! Thanks to all the girls for providing me with wine and huge amounts of fun which has been another factor in keeping me sane!!! And finally I would like to dedicate this piece of work to Nick, who never got to see me start it but would have been damn proud!!! Abstract The genetic evaluation of sport horses is common practice on the Continent and in Ireland but, until now, has not been carried out in Great Britain. The aim of this project was to derive models for predicting breeding values for British bred sport horses and hence develop procedures for their evaluation. The research consisted predominantly of the estimation of genetic and phenotypic parameters from two datasets; results from the Young Horse Evaluation Series (YHE),