A MATTER OF SURVIVAL
The horse is a flight animal. Its greatest defense against predators always has been flight. The strongest and fastest survived and passed on their genes related to speed and agility. But what about the foal?
Adaptation made the foal one of the most precocious newborns of the animal kingdom. It must be delivered quickly, in a favorable location, and be ready to travel, fast, with its mother in a matter of hours. To a large extent, all of these characteristics remain in horses of today.
Given the opportunity, mares will seek secluded and secure places to deliver their foals. They can interrupt delivery up to the last critical minutes if danger is perceived. Ideally, they will wait until darkness to gain extra cover and time. Then, when committed, they produce the foal rapidly, rise quickly to guard it, and in a few hours are ready to lead it away. We still see this behavior in mares under the controlled conditions we tend to impose upon them today.
LOCATION AND PREPARATION
Location: In the ideal situation, mares would deliver in individual grass paddocks, reserved only for that purpose. Suitable time would elapse between foalings for the ground to "clean itself up" and harmful bacteria to be killed by normal environmental conditions. Foals then would be delivered in conditions as clean as possible. The area would be small enough to allow an observer to see the entire paddock, both day and night, and appropriate lighting would be available. This scenario assumes foaling takes place when the spring has advanced to mild weather conditions. This is as close as possible to an area a mare would select, and still be under observation.
The realities of supervising the foaling of mares in all sorts
of climates dictate a different approach. The usual compromise involves
a large loose box and with lighting that can be reduced to low levels. CCTV is often used nowadays
to observe the mare without disturbing her. Observation should be arranged so that mares are seen at least three
times an hour until labour seems imminent, then it obviously should be
continuous. An old, experienced broodmare will take great delight in
fooling you when you are gone for more than 20 minutes, but the real
problem lies in the mare which gets in trouble with presentation and
position of the foal. In those rare situations, quick assessment can make
the difference between life or death. In general, the least
intervention in the process is the best approach. The general philosophy
should be that the great majority of foalings will be successful without
your help. Putting this to practice requires the attendant have knowledge
to recognize potential problems before they progress.
This is divided up into three stages.
During this first stage the fetus begins active participation in positioning itself for delivery. The typical position of the fetus during the latter part of pregnancy is reclining on its back. The head and forelimbs are closer to the pelvic area in the great majority of cases, resulting in anterior presentation for delivery. Occasionally the hind limbs are closer, resulting in posterior presentation. In the anterior situation, as the uterus begins to contract, the fetus reaches up and back, with both head and forelegs pointing toward the pelvic canal. This is a very important function in aligning for delivery, and failure to do so can result in a difficult birth, often a problem with abnormal, weak, or dead fetuses.
Also during the first stage, the pressure of the uterus contracting against the fetus and the fluids start the cervix dilating. By now, the mare might be quite restless, maybe getting down and up and sweating a bit. If she's in an environment that doesn't really suit her, she might resist lying down until the very beginning of second stage labour.
Rupture of the outer membranes (allantochorion) occurs as the pressure
from contractions forces the fluids out through the membrane. Normally
this rupture occurs right at the spot where the membranes lie over the
cervix (cervical star).
The passing of these first fluids (allantoic fluids) to the outside, or "breaking water," marks the official start of the second stage of labour. At that point, the mare cannot turn back, and begins vigorous abdominal pressing to supplement the uterine contractions. In most cases she is lying on her side during this phase. The last of the allantoic fluid (usual total volume up to five gallons) is expelled during these abdominal presses.
As the fetus is moved back into the pelvic canal, it begins to rotate so that its head, then neck, and finally back are lined up with the top of the pelvis. This position is ideal for delivery. Now the inner set of membranes (amnion) becomes visible at the vulva. These membranes are milky white to bluish white in color and look like a baloon. It is pushed to the outside by the forefeet, one slightly in front of the other.
With each successive push, the fetus is propelled farther through the birth canal. About the time the head begins to clear the mare, the intensity of abdominal pressing increases dramatically because the shoulders are passing through the birth canal. This is also the most difficult stage of the birth process. The fact that one foreleg is advanced over the other results in the shoulders coming through in a staggered fashion as well. Finally with one or two heavy presses, the hips clear the pelvis and the foal moves out of the mare, usually about to the level of its hocks.
The second stage of labor is completed when the foal is clear of the mare. From the breaking of water to the completed delivery, elapsed time is about 15 minutes or less. If the waters break and after 15 minutes nothing happens or if the foal is not presented properly, a vet must be called. Occasionally the mare will need assistance if the foal is large or you think she appears to be struggling. To assist hold the front legs above the fetlock joints and as she pushes you pull gently but firmly towards the mare’s hocks. The amnion is sometimes still intact and over the foal's head when delivery is completed. Vigorous early head movements should cause the membrane to tear. Newborn healthy foals are strong and react quickly to external stimuli. They are urgently motivated to begin breathing. It is extremely rare, therefore, for the amnion to remain intact long enough to cause a problem, but if it does occur simply tear away the membrane from the nose and clear the nostrils and mouth.
Most mares, if undisturbed, will relax and rest at this point. The exertion has been telling. During this pause, the umbilical cord usually is still attached to the foal, which lies on his side, rolling up on his sternum to make the job of breathing easier. In totally unassisted foaling, the cord breaks either when the mare gets up, or when the foal begins vigorous movement and tries to stand. Once the cord has broken treat the stump with either purple spray or iodine.
The mare and foal should then be left alone to bond, for the foal to stand, pass its meconium and finally drink (which can take up to three hours). It is important for the foal to drink as soon as possible so that it gets the mares first milk (colostrum) which contain antibodies which are vital to protect the foal against disease. A vigorous, healthy foal will struggle to his feet within an hour and will find his way to begin nursing soon thereafter. Cooperative and experienced mares are helpful during this period by moving to positions that are helpful to the foal, and maneuvering him into the correct position.
The mare then will experience the third stage of the labour process, delivery of the placenta or cleansing. This is accomplished by further uterine contractions to squeeze the placenta out through the birth canal. The time for this passage varies, with a normal upper limit at two to three hours. If the mare shows no signs of cleansing after about six hours it is advisable to call the vet. Once the mare has cleansed check the afterbirth is intact. Only one tear should be present, if another piece is torn or a bit missing call your vet the next morning. It is important no pieces are retained as this can lead to infection.In the early stages of moving the placenta, there usually will be some degree of abdominal pain from the contracting uterus. This is manifested in colic symptoms, with the most severe being repeated lying down, getting up, and rolling. Some additional sweating is normal as well.
In the typical normal case, passage of the membranes will coincide with the foal's nursing, receiving antibodies through colostrum, and gaining strength and coordination. In other words, from the perspective of non-domesticated horses, they are ready to travel or to escape predators.