A dog has been banned from competing at Crufts after having her tail amputated due to ‘happy tail syndrome.’br br Dalmatian-Vizsla cross Gwen, three, had the procedure after repeated injuries, but her owner, Sophie Scott-Thomas, was later informed of a Defra rule prohibiting docked dogs from fee-paying events.br br Sophie, from Merthyr Tydfil, Wales, has launched a petition to allow medically docked dogs to compete.br br Defra and The Kennel Club say the rule aims to prevent cosmetic tail docking, with exemptions only for certified working dogs.