Assuming you mean Dr. Ian Moore, I think the short answer is: he has a significant advantage in the combination of veterinary knowledge, early development, and selection of young horses.
Why he may be winning so many 2-year-old races:
He can identify and correct problems early.
As a veterinarian, Moore likely has a more sophisticated understanding of soundness, growth plates, gait abnormalities, respiratory issues, and subtle problems that can prevent a young horse from reaching its potential.
He probably knows when not to train a horse.
With 2-year-olds, timing is crucial. Some horses need more time physically; others can be pushed forward. The ability to distinguish the two is a major advantage. Research on Standardbreds has found that early training and racing milestones are associated with longer and more successful careers, although the research does not prove that early racing itself causes success.
His horses may be exceptionally well prepared before they ever race.
The best 2-year-old trainers generally don't simply “speed up” a horse. They develop the horse's body gradually—strength, balance, gait, cardiovascular fitness, and confidence. The veterinary research emphasizes the importance of early, properly managed exercise in musculoskeletal development.
He may have a better eye for selecting the right horses.
A trainer-veterinarian can evaluate a yearling not only by pedigree and conformation but also by soundness, movement, physical development, and potential problems. That can make a big difference in a 2-year-old stable.
The quality of the horses is still the biggest factor.
I would be careful not to assume that veterinary expertise alone explains his results. If he has a particularly strong group of well-bred, well-selected young horses, the results may reflect both superior stock and superior management.
My impression is that Moore's greatest advantage may be the combination of “horseman + veterinarian.” A conventional trainer may recognize that a horse is off; a veterinarian may be better positioned to understand why and what to do about it. With 2-year-olds, where small problems can mean losing weeks or months of training, that can translate directly into more horses ready to win early.
