Fundamentals Of Foaling

To understand some of the unusual aspects of birth in horses, it is helpful to consider how the species survived before domestication. The horse's 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 newborn?

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. All of which explains the behavior of mares under the controlled conditions we tend to impose upon them.

Management systems that give mares freedom of choice about foaling are fairly common in milder climates and with breeds where the individuals are moderate in value. Groups of mares running on large pastures, with some cover, do a pretty good job of foaling, with few complications. The problem is that the complications, which often occur at night, are difficult to correct in time to save the foal, and occasionally the mare. Thus ,the standard of care for foaling mares has moved toward intensive observation and immediate assistance. This situation, driven by the value of the breeding stock, is unfortunate in that it not only is very expensive and time consuming, but also is less than ideal for both dam and offspring.

So, in accepting the responsibility for overseeing the foaling process, we should be well prepared to help. At the same time, we also should be prepared to let Nature take its course whenever possible. This article will first describe the important events in the foaling process, then point out when and how to assist in the processes. The target of this discussion is the novice and less experienced horse breeder.

Basic Elements Of Foaling

After the long gestation period, characterized by tremendous growth of the fetus, some critical maturation processes occur in the last days of pregnancy. Most important of these is the ability of the foal's lungs to exchange oxygen. Compounds called surfactants develop to readiness only when the final steps of development are complete. Also, there is a concentration of antibody in the udder during the final weeks of pregnancy, which is important to the formation of colostrum. Thus, there is a stage of pregnancy where the foal is ready to be born. That condition usually can be identified by the rapid changes in the mare's udder in the 24-48 hours before foaling.

The udder, which slowly has been enlarging, develops more swelling (edema) and the secretions in the udder change in a very specific manner. Also, certain physical changes in the mare become more evident, such as relaxation of the pelvic ligaments and the vulva and "waxing" on the ends of the teats.

Unfortunately, gestation length is not necessarily tied to these changes, and mares can produce normal, healthy foals, with access to good-quality colostrum, from 305 days to 365 days, or even a bit longer. The point is that length of gestation is not a good gauge of imminent foaling.

In the final stages before delivery, the mare's placenta begins to separate slightly. This change is linked to the production of milk in the udder, which might leak from the teats before labor begins. At that point, the mare maintains a degree of control over the event. In fact, the first stage of labor, which is marked by the beginning of contractions of the uterus, can be interrupted by the mare, occasionally for several days.

During the 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 labor.

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 labor. 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. 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. 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. The amnion usually is 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 correction of that situation obviously is the simple tearing of the membrane away from the nose.

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. There long has been a notion that significant amounts of blood pass to the foal in the first few minutes after delivery. That notion currently is somewhat in doubt.

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 labor process, delivery of the placenta. 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. 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.

Overseeing And Managing Foaling

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 multiple mares in all sorts of weather dictate a different approach. The usual compromise involves box stalls or small sheltered lots, close together for ease of observation, and with lighting that can be reduced to low levels. Essential amenities include available clean warm water and access to a telephone or other reliable communication. Mares in the last month or two of pregnancy should be housed in a central area where daily observation is accomplished easily, then be moved to the foaling area when overnight observation is needed.

Personnel And Observation
Whether one mare or a hundred are to foal in the facility, the observer should be a reliable individual, hopefully with some experience, and with the good judgement to call for help when indicated. Small operations with one or two mares usually dictate that the owner(s) watch the mares. Their stake in a successful foaling makes this situation ideal.

Observation should be arranged so that mares are seen at least three times an hour until labor 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.

The observer should check the mares without disturbing them, under minimal lighting conditions. Any other approach will disrupt mares and cause interruption of the process. When observation is by the owner, great discretion is indicated when allowing guests to witness the foaling. Excitement and celebration are not what foaling mares need.

There are several approaches to the problem of observation that make sense for small operations, where 24-hour days get to be a problem. Closed circuit television allows the observer to watch from a remote location, but still requires staying awake. Several variations of techniques that give warning when labor has commenced are available. As with any technological approach, errors, either false alarms or no alarms, are possible. Yet there are many examples of satisfactory utilization of these methods. The reader is urged to investigate carefully and get personal references to these methods.

Attendant's Approach To Foaling
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. The following guidelines might help:

  • By 10 minutes after second stage labor has started (water breaks), the mare should be progressing to delivery with both of the foal's forefeet and a head visible. The experienced attendant should evaluate the situation by that time, determine if intervention is needed, and summon help. (The inexperienced attendant should have summoned help as soon as labor started.)

  • If the mare appears to tire after the feet and head are clear of the birth canal, and vigorous abdominal contractions have stopped, some traction on the legs is indicated. Grasp the legs above the fetlocks and pull slowly. That pressure often will restart productive contractions.

  • If the foal is delivered to the point where the shoulders are clearing and progress stops, more serious traction should be applied, preferably by two people. Don't use ropes or chains unless you are very experienced. If results are not evident very quickly, call your veterinarian.

If any if the following situations are evident, help from your veterinarian is clearly indicated:

  • No progress observed when serious contraction is applied by the mare.

  • Labor stops after it is well under way.

  • Exhaustion of the mare, including obvious weakness or unsteadiness, is observed.

  • The foal appears weak, not attempting to get up after 20 minutes, not breathing well.

After Delivery Is Completed

Routine post-delivery treatment of the mare is not indicated, assuming her tetanus prophylaxis is up to date and her behavior is normal. Delivery of the placenta is important. Find out when your veterinarian would like to intervene if delivery is not accomplished.

Routine post delivery treatment of the foal will vary with the area and the operation. The importance of the antibodies in colostrum must be recognized. Make a plan with your veterinarian for routine care of foals, beginning with early navel disinfection and including evaluation of antibody transfer by 24 hours.

Get the mare and foal out for exercise as soon as possible if the foal is healthy and the weather is good.

About the Author

A.C. Asbury, DVM

A. C. (Woody) Asbury received his DVM from Michigan State University in 1956, then spent 21 years in California in breeding farm practice and at UC Davis. He joined the faculty at the University of Florida in 1977 and was involved in teaching, research, and administration until 1996. An Emeritus Professor at Florida, he lives in Kentucky, where he and his wife are developing a small farm.

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