Sidney qualified as a veterinary surgeon at the University of Bristol in 1971 after intercalating an honours degree in biochemistry at the same university. He interned in equine medicine and surgery at the University of Pennsylvania, as a Thouron Fellow, before joining Rossdale & Partners, an internationally renowned large specialist equine practice in Newmarket, in 1972. He became a partner in the practice in 1975, retired his partnership in March 2012 and is now a consultant.
His particular clinical interest is equine stud medicine. He was awarded a Fellowship of the Royal College of Veterinary Surgeons for his thesis on equine endometrial histology and histopathology in 1978, was awarded a foundation Diploma in Equine Stud Medicine by the RCVS in 1986 and RCVS specialist status in Equine Stud Medicine in 1991. Until his retirement, he was senior veterinary advisor to The Royal Studs and remains a veterinary advisor to Juddmonte Farms. The Queen awarded him the honour Lieutenant of the Royal Victorian Order (LVO) in 1998, for services to the Royal Studs.
He is also particularly interested in equine clinical pathology and was responsible for developing Beaufort Cottage Laboratories, an internationally acclaimed specialist equine clinical pathology laboratory, now servicing referrals from Rossdales clinicians and referrals from many other veterinary practices from all over the United Kingdom and other European Union countries. He was awarded a Diploma by the European College of Equine Internal Medicine in 2002 as a defacto specialist and a Fellowship of the Royal College of Pathologists in 2004 by submission of published works. He was a member of Defra’s Science Audit team for their Veterinary Laboratories Agency in 2007.
He was a member of the RCVS’s Equine Board for continuing professional development until 1998 and has acted as an advisor and examiner for stud medicine Certificate and Diploma candidates. He was awarded Honorary Membership of the British Equine Veterinary Association in 1997 and has sat on the editorial boards of Equine Veterinary Journal and Equine Veterinary Education. He organised BEVA’s continual professional development courses on equine stud medicine from 1980 to 2007. He has represented BEVA on medicines, clinical pathology laboratory and equine disease surveillance issues. He has been a member of the Horserace Betting Levy Board’s advisory committee for their Code of Practice on Equine Venereal Diseases since 1977 and is a member of the Thoroughbred Breeders’ Association Veterinary Committee, the British Horseracing Authority’s Veterinary Committee and is joint Veterinary Advisor to the TBA. He is joint author, with Dr Peter Rossdale, of the text book Equine Studfarm Medicine (two editions), has contributed to a number of multi-author text books, has published widely in international peer-reviewed veterinary journals and has lectured on equine stud medicine and equine clinical pathology at the UK University veterinary schools and at many other veterinary schools, institutions and veterinary conferences internationally.
He has lectured to veterinary students on equine stud medicine at the University of Bristol for more than twenty years and was appointed Visiting Professor in the Department of Clinical Veterinary Science in 2001. In 2007 he was appointed Visiting Professor of Equine Pathology at the Royal Veterinary College, University of London. In 2012, the University of Bristol awarded him Honorary Doctorate of Science (honoris causa).