USEF,is the governing body for horse sports in the United States. They
enforce the rules for each sport. Each sport can decide to join USEF or not.
USDF is the national level organization for dressage. The USDF's job is to educate
it's members about dressage. They do this through training judges, sponsoring
clinics, etc.RMDS,
Rocky Mountain Dressage, is the regional GMO, General Membership Organization
for our area under USDF. RMDS
send delegates to vote on the rule changes at the yearly USDF convention. RMDS
is our regional educational organization. They run clinics, sanction shows, put
on training sessions for judges, keep track of horse show results,etc.
It
is _not_ required that you also join USEF and USDF. If you would like to
attend USDF/USEF shows then you would avoid paying an extra fee at each
show if you were a member. USDF collects all horse show results from each
sanctioned show and has awards each year. If you are interested in the various
awards programs, then you should join.