filly race horse

Question
from Texas:

Do they sew the vagina lips prior to a race?

Answer
Hi Joe,
          A most unusual question for this type of forum, however I'll assume its serious.
I don't know about US racing rules or common practice in US racing but it certainly would not be allowed in NZ or Australia.If it is a possibility that the mare will 'slip' the foetus then she should not be racing.
The best person to ask would be a vet.
I hope this helps,
Don Boddie
New Zealand