There are many many exams you can do at colleges with horses.
Here are some-
BTEC First Diploma in horse care (I have this),
City and Guilds National Certificate in horse management,
BTEC National Diploma in horse management,
Higher national certificate in horse management,
Higher national diploma in horse management
Some colleges do equine science or horse breeding.
NVQ's are city and guilds. I have level 1 and am working towards level 2.
There are also BHS and ABRS exams.
Hope that helps!