The mare is probably in labor! If the breech position has been maintained for a long period of time, this can lead to dehydration and heat exhaustion. The mare may also be uncomfortable from the pressure on the pelvic region as well as from not being able to use her muscles effectively due to pain or discomfort. She will most likely strain and become anxious with increased straining efforts.
How do I know if my horse is overdue? How do you tell when your horse is actually pregnant or just going into early pregnancy? Is it possible for a horse that isn’t supposed to conceive (for instance an older mare)to get pregnant anyway? Good question…I think it’s more like “when” they are late rather than “if”. It could be several days before you notice any changes; sometimes those changes come quickly, other times they don’t show up until after she goes into labor..so keep checking back every now and then!! This depends on how far along she got before starting birth control, whether she was ever bred at all, how old/healthy/strong she was etc. You might have noticed some of these things by now but there could still always be surprises around the corner! And yes – it IS possible especially if everything else checked out fine during breeding season etc..but usually only very rarely so I wouldn’t worry too much about it unless you felt real certain about things happening later than usual 🙂