Natasha Galpin, a member of Iain Jardine's racing team stables in Dumfries, has died following a fall on the gallops.
The 22-year-old sustained fatal injuries when the horse she was riding suffered a ruptured artery during a workout on Tuesday.
An accomplished event rider, she was a full-time member of Jardine's staff and ran her own livery yard.
The trainer issued the following statement: "It is with great sadness that the team at Iain Jardine Racing wish to report that we suffered a tragic accident on our grass gallops on Tuesday morning which has resulted in the untimely death of a member of our team, Natasha Galpin (22), as well as the loss of a horse.
"Sadly, our horse suffered gutteral pouch mycosis (a ruptured artery) during work, resulting in the unavoidable and unpredictable accident. He was given all the necessary care and treatment required, and the owners were immediately informed.
"Our main priority throughout has been Natasha and the rest of our staff, who are distraught at the loss of a colleague and friend but have been extremely supportive of each other. As a team here, we are doing our best to get through and cope with this devastating situation.
"Natasha was an experienced and valued, full-time member of Team IJR. She was an accomplished event rider and ran her own livery yard. She worked alongside her boyfriend, Olyn.
"Our thoughts and prayers are with Natasha's parents and sisters at this very sad time, and we hope you will join us in respecting their privacy.
"We are grateful for the help we are receiving from racing's support network, including Racing Welfare and the National Trainers Federation."