"He was like a brother to me and became a part of our family. We are so devastated by this."
Mr Gadsby had a special talent when it came to riding horses and was prepared to back it up with plenty of hard work, Ms McFadzien said.
"He was super passionate about horses and always aspired to be the best. He was showing all the potential that he would go a long way in the sport.
"He was very professional and worked for everything he achieved."
Fellow international eventing rider Kate Wood, of Whangarei, said Mr Gadsby was a well respected competitor and was known for his infectious smile.
His recent good form on the tough British eventing circuit against some of the best riders in the world was evidence he had a bright future in the sport.
"He had the mental attributes needed for eventing as well as the technical skills. Not everyone has that combination," Ms Wood said.
"Tom had all the makings of an upper level event rider."
Equestrian Sports New Zealand chief executive Jim Ellis said Mr Gadsby had high hopes of representing New Zealand.
"Tom was a talented showjumper and eventer who was in Europe to fulfil his dream of competing as a professional event rider - a dream he achieved but which has been tragically cut short," Mr Ellis said.
He said the incident would raise questions about the safety of three-day events, but over the past decade the number of injuries and deaths had reduced "significantly".
"The sport has worked very, very hard, both at an international level and in New Zealand to increase the safety - particularly in cross country courses, both to the style of the course and to the actual fences themselves."
After many years competing at grand prix level showjumping, including two successful years in Germany, he decided to make the change back to eventing in 2012 and has been competing in Britain since last year.
