Equine Reproduction On-line Information source.

Here is a website that I visit quite often if I have questions and my vet isn't available.

Some of the articles are a little outdated, but overall the information they have is a good source for over all basic care for horses (stallions and mares) for before, during, and after breeding.

They also offer an excellent seminar several times a year. I have a friend who took the 3 day one last year and she LOVED it. I hope to take one myself next year.

http://www.equine-reproduction.com/index.shtml

Me too Chelle,
I have that Bookmarked.... that is the website i went to when my mare did not foal on her due date! there saying that mares can go up to 445 day's or longer..so i am not worrying yet...


Is my mare overdue?



By Jos Mottershead


One of the most commonly asked questions of the foaling season is "Is
my mare overdue?". This is often precipitated by the misbelief that 340
or 341 days of pregnancy duration represent a "due date". Not so!

The average duration of gestation is anywhere between 320 and 370 days
- so that mare which is at 345 days is not "overdue", but well within
the normal range! The foaling date is picked by the foal who dictates
that he or she is sufficiently developed and ready to be born, not by
the mare who is watching the calendar on the wall!

Note too that the terms "premature", "dysmature" and "postmature" refer to the condition of the foal at birth and not to the gestational duration.

Here are some important facts to consider about gestational lengths:

• 
  Foals born prior to 300 days are unlikely to be viable.
  
  
  
  • 
    Their lungs are not fully developed and they will not be able to breath.
    
    
    
    • 
      Unlike similar premature situations with humans, the use of a
      surfactant in the foal to assist with development and breathing has not
      proven succesful.
      
    • Note that this is referencing a
      normal, healthy pregnancy. Mares that manage to support a pregnancy
      threatened by something such as placentitis to term may have
      shorter-than-"normal" pregnancy duration, and yet still present a
      viable foal. It is unusual that the gestational period will be lower
      than 300 days in this case, but it can happen. This is thought to be as
      a result of elevated cortisol levels - due to fetal stress - causing
      accelerated fetal development.
      
    
    </li>
    
  • 
    It should be noted that considerably shorter Miniature Horse pregnancies (~280 days) have resulted in healthy foals.
    
  
  </li>
  
• 
  Foals born after 300 days but prior to 320 days are at risk of being born in a premature condition.
  
  
  
  • 
    Premature foals will require neonatal intensive care;
    
  • 
    The closer to 300 days the foaling, the more intensive the needed care will be;
    
  • 
    Foals born from mares that suffered from infectious placentitis during
    pregnancy may be born between days 300 and 320 and yet not show
    prematurity as there is an accelerated developmental rate in utero with
    many of these foals;
    
  
  </li>
  
• 
  The average range of gestation is between 320 and 370 days.
  
  
  
  • 
    340 or 341 days are accepted as the most common foaling days, but they
    are not a "due date", merely an average of the average.
    
  
  </li>
  
• 
  Foaling days after 370 days of gestation are not uncommon and usually do not represent a problem.
  
  
  
  • 
    The longest live foal delivery on record is 445 days!
    
  • 
    Foals born after a prolonged gestation are often small in size as a
    result of a delayed uterine development period, and rarely present
    foaling problems as a result of "having grown too big".
    
  
  </li>
  

Some other important points for consideration:


It should be noted that if the mare is displaying severe signs of
discomfort, she should be evaluated by a veterinarian. "Severe signs of
discomfort" are not represented by a mare looking miserable, but rather
by colic-like symptoms or extreme depression (no interest in feed,
turnout, other animals etc.).

Induction of foaling simply because it is convenient for the mare
owner, manager or veterinarian and not because of the presence of a
medical problem with the foal or mare should be a crime
that carries a mandatory life sentence!
Induction of foaling results in a higher-than-normal number of
dystocias (presentation problems), premature foals, and premature
placental separations ("red bag" deliveries) than are seen with regular
presentations. Do not induce foaling except in the face of a very clearly defined medical need, and only under strict veterinary
supervision.

It is also important to note that while mammary gland development may
be indicative of impending foaling (note that "waxing" is not a
reliable indicator across the board, and other methods of prediction
such as the one described in the article available by clicking here
should be used), an absence of mammary development when in concert with
prolonged gestation may be indicative of a problem with
endophyte-infected fescue toxicity, and immediate veterinary
involvement should be sought, as drug therapy (Domperidone) and other
protocols (removal of the animal from the endophyte source) can be used
to reverse the symptoms. Just to confuse the issue however, some mares
do not show mammary development prior to foaling, and yet have not been
exposed to endophyte-infected fescue!

Horses are not humans! They have different needs, and while the
gestational period for humans is quite closely defined, there is a wide
range of "normal" for the equine! Consequently, if you are reading this
as a result of being concerned about your mares pregnancy duration,
while we certainly encourage you to consult with your veterinarian to
be on the safe side, you are, in all probability, merely losing sleep
and worrying for no reason!

Yep, I go to that website too!