Gestation
Normal gestation length in the mare is 335 - 342 days.
The birth of foal before 320 days of gestation is considered premature
and may require extensive veterinary care for survival. Going longer than
342 is generally not a problem and it is not uncommon to go a full 12
months. In general, the fetus will be born when ready. It has been hypothesized
that long gestation lengths of 12 months or longer involve a pause in
embryo development between the 3 - 6th week. The embryo may pause in development
at this time for up to 5 weeks with no problem.
