> with my gelding and his first 50 miler.
>         I have a question though about riding pregnant mares in
> competition.....is it allowed?  Does AERC allow it?  I didn't think it was
> allowed in SEDRA(which of course includes CTR).
Can't speak to CTR, but...in endurance.
Most rides, at least in these parts, will include as one of their rules:
"No mares in foal."  Some people are of the mistaken impression that this
is an AERC rule, which it is not (just like the "shoes are required" rule
which is not a rule). 
I suppose there is some reason to contend that, in fact, disallowing 
mares in foal is contrary to AERC rules 3 "The ride must be open to any 
breed or type of equine" and 4 "Entry to a ride may not be refused 
exccept for cause."  And it lists some causes, pregnancy is not among 
them, other causes must be determined by AERC Board or Committee 
members.  However, I have never heard of anybody challenging rides that 
have the rule about no pregnant mares.
I ride my pregnant mares up until about their 9th or 10th month of 
pregnancy (not in sanctioned rides, but I will take them out for long 
treks in the hills).  One ride manager told me that mares in foal were 
not allowed because the mare might start hemoraging out on the trail (she 
also told me it was against AERC rules too, so you can take that 
information at what ever value you would like).
I have been to rides where there have been pregnant mares in the LD ride, 
but this was fairly early in the stages of the pregnancy.
Incidentally, Thoroughbred breeders in England are just beginning the 
practice of breeding their maiden mares in the Spring and then taking 
them back to the race track to compete for the early months of their 
pregnancies, and there are certainly many stories of the competing people 
have done on their pregnant mares...because they didn't know they were 
pregnant until shortly before they foaled (as little as one or two weeks).
Does this answer your question?
kat
Orange County, Calif.