What does it mean when a horses scratches from race?

Answer 1

Horses can be scratched (removed) from a race for a number of reasons.

These are some general reasons for a horse to be scratched as well the the indivdual (usually) responsible for each type

Scratched by the veterinarian for illness, lameness etc.

Scratched by the stewards for procedural issues or violations. They can also

scratch horses before they enter the starting gate for perceived lameness.

Scratched by the trainer for issues like the race was moved from the turf to

the dirt. Trainers will also sometimes enter horses in multiple races to optimize their chance of getting into a race...if the horse gets into both races the trainer usually scratches the horse from one or the other.