Gestation or the period of pregancy in each mare is different, there is no definitive gestation length. Normal gestation in a mare is anywhere from 320 to 350 days. However, normal healthy foals have been delivered anywhere from 305 to 360 days. Foals born before day 300 usually are considered non-viable. Foals born between day 300 and 320 usually are weak and have a low birth weight and although usually considered premature, have a reasonable chance of survival with intensive care. Though obviously there are variations, but as a rule, colts tend to be carried longer than a filly. The term for colts is approximately 334 days and for fillies 332½ days though there is a possible variant of 9½ days either way.
The natural instinct, in order to protect their foals from predators, is that mares like to foal when it is quiet and they are undisturbed. Therefore, having a mare foal when it is convenient for you is unlikely. Most mares foal either late at night or in the early hours of the morning. Therefore, close monitoring of the late-term mare for sometimes weeks at a time has been the only way to ensure that the birth was attended.
Eleven months is a long time to anticipate the birth of a foal. A lot of hope, excitement, dreams, and financial investment can accompany the arrival of a newborn. Because of the long wait, most owners want to monitor the birth of the foal, to make sure nothing goes wrong, and 90% of the time, the birth goes as Nature intended. However, there are times when human intervention is necessary, and being there makes the difference between a healthy newborn foal and one which does not survive.
There are several obvious signs a mare will have as she nears foaling. These signs will let you know she is getting ready, so you should prepare, too. A mare will physically prepare to give birth as her foal matures inside of the uterus. As a mare nears the date of parturition (giving birth), not only will her abdomen continue to increase in size, but she will begin to develop an udder (bagging up). This might start as early as six weeks prior to the date of birth. Bagging up depends on whether the mare is a maiden (first time foaling) or not. Many maidens bag up several weeks in advance and then stay at about three quarters bagged for a few weeks. Others will only bag days before giving birth. Maidens too can carry their foals higher and often do not look so obviously pregnant as the more mature mares, so don't be caught out.
|The udder gradually will fill with milk, then as parturition nears, the mare may begin to drip milk. At first, the "milk" will be more of a clear fluid, then it will turn the more familiar white. The milk will, within a few days to hours before the birth of the foal, turn from white to a sticky yellow, which is the colostrum, or first milk. The udder will appear to be very large and full with a clear grey wax-like coating all over it. Tiny white dots may surround the teats which will also be very full and droplets of milk may form a wax like substance on the ends of the teats. (waxing up) When this occurs foaling is usually imminent .|
Other changes that you can monitor are that the mare usually 'lets down'- she will develop a sinking on either side of the tailhead as the ligaments of her pelvis relax in order to accommodate the foal through the birth canal, akin to 'looking poor', also there is a relaxation of the perineal area, the mare's vulva will begin to get longer as she prepares to give birth. All of these signs are telling you that the mare is getting ready; however, they are not very accurate and staying up every night for a week gets tiring.
MONITORING THE LATE-TERM MARE
Using a closed-circuit television is a very convenient method to monitor the mare, as you do not have to travel to the stable to watch what is going on. You can watch the mare from your house or from a separate room in the stables so that she will remain undisturbed. The disadvantage of this monitoring system is that the mare might place herself in a position that is out of sight of the television camera, and also someone still has to watch the television screen during the night, and you might not notice her until she already is in labour, or even given birth!. Most stud farms use a closed-circuit television to monitor late-term mares since the mares can be monitored without disturbing them, however, those facilities would be staffed 24 hours.
Another method of monitoring the mare for foaling is a system to alert you that your mare is in labour. Several different systems are available. One is composed of a transmitter that is attached to the vulva of the mare. When the vulvar lips are separated as occurs during labour, the transmitter is activated. A receiver alerts the attendant or yourself by sounding an alarm. This is a good system, but you must be close by since it alerts you when the mare is already in labour. So, if you are 30 minutes away, it could be too late by the time you arrive. Another works on temperature changes in the mare as she prepares to give birth, again alerting the attendant via an alarm.
PREPARING FOR BIRTH
Prior to actually giving birth, usually between a day to a few hours before, the mare will show several signs of discomfort.
She may stand around, at first sight looking relaxed and resting, but on closer observation signs of stress can be seen. The head held
high and rigid, the eyes worried, the ears back. Often she will stretch her body, yawning and the same time, or stamp her legs and swish her tail.
She may also appear slightly colicky, lying down, getting up, stamping her legs or kicking her stomach. She is turning the foal into the 'birth' position. Sometimes you may see legs sticking out to the sides.
When the foal has reached the correct position, the mare will look unusually 'narrower' on the belly......It is now time to look forward to the event itself..