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Birth of a Foal
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Introduction
We often think of pregnancy as a delicate and fragile condition. When it comes to horses, this perception is perhaps due to the mare's relatively poor reproductive performance in comparison to other domestic animals. However, in a natural setting, the mare does comparatively well reproductively. Therefore, this seemingly poor performance is due as much to improper management as to any reproductive deficiency. Fortunately, management is something we can control.
Is my mare pregnant?
Your veterinarian will play an important role in helping your mare to get with foal, whether she goes to stay at the breeding farm, is only shipped in for breeding and then brought home, and especially if she is artificially inseminated. Your vet will determine if she is in season, whether or not ovulation is imminent, and any additional assistance that might be required after breeding.
The vet can rectally palpate the mare two days after breeding to see if she has ovulated. If she hasn’t, you will need to return her to the breeding farm. If she has ovulated, the vet might recommend suturing her. Five days after breeding, the vet can check her blood progesterone levels. After eighteen days, tease her if you can to determine if she is in season. If not, the vet can palpate her again.
50 days old fetus
Pregnancy can be checked by ultrasound. If she is carrying twins, the vet might attempt to abort one fetus at this early stage to reduce the risk of miscarriage and complications. The heartbeat should be visible on the twenty-sixth day after breeding, and the vet will sometimes ultrasound again to check.
Also, blood tests at eighteen days can determine if the mare is pregnant. This is especially important for maiden mares without any pregnancy history to refer to. If the test indicates a need, the mare can begin taking supplemental progesterone at this time. However, oral synthetic progesterone supplements are expensive. One brand, Regumate, could cost between six and seven hundred dollars over the course of the mare’s pregnancy. If it is needed, vets generally recommend a one hundred fifty day course. Some breeders continue the supplementation all the way to term, but there is no evidence that the additional supplementation is helpful.
Birth of a Friesian foal
Signs of foaling
It is prudent to observe mares for signs of foaling so that assistance may be provided if needed. The average gestation length of the mare is 335 days but the range is quite broad. In fact, gestation lengths from 305 to 400 days have resulted in normal, healthy, foals. Remember to have the vulva opened as the expected foaling date approaches if the mare has had Caslick's surgery.
The mare prefers quiet and solitude at foaling and can apparently delay the onset of parturition. We suspect this to be one of the primary reasons why the majority of foals are born at night. The signs of impending parturition include a gradual relaxation of the ligaments around the tailhead which may be difficult to detect, especially in well muscled or over-conditioned mares.
The udder will begin to enlarge 3 to 6 weeks before foaling with a major increase seen in the last 2 weeks. Some mare may leak colostrum for days before foaling and, in these cases, you must insure an adequate supply of good quality colostrum for the newborn foal. Waxing (the presence of a few drops of sticky colostrum on the teat ends) can occur from 1 to 72 hours, but is usually seen from 6 to 48 hours, before foaling.
Some mares leak colostrum days before foaling
To avoid many nights of foal watch, a helpful method of predicting foaling is to monitor the changes in electrolytes in the mammary secretions. Kits are available which make use of the rise in calcium occurring shortly before parturition to predict foaling (1). When the concentration of calcium in the secretions is greater than 200 ppm, there is an 88% chance that the mare will foal within 24 hours. In a recent study, 94% of the mares reached this value before foaling and only 6% foaled without reaching it. To perform the test, mammary secretions are diluted (one part secretion to six parts distilled water). It is important that the udder be clean and dry and to keep debris out of the sample. In addition, the collector's hands should be clean and dry, and they should avoid touching the test materials since skin secretions may result in a color change.
Foaling
Foaling is typically divided into three stages.
• The first stage is the preparatory phase. Although this stage can last from ten minutes to five and a half hours, it typically lasts a little over an hour. This phase is characterized by sweating, especially in the flank regions and behind the elbows, an increase in pulse and respiration, and restless behavior. The mare may act slightly colicky, look at her flanks, switch her tail, stretch as if to urinate, and roll. These movements help to position the foal for delivery. The foal takes an active role in this positioning, and it is for this reason that weak foals may cause dystocia.
Stage I ends with the rupture of the chorio-allantois, commonly referred to as breaking the water bag. If Stage I is prolonged over 4 hours, a careful examination is warranted. Whenever an examination or intervention is to be performed in the birthing process, cleanliness and lubrication must be stressed. Both the mare and the examiner must be scrubbed adequately with a disinfectant soap. Adequate restraint of the mare is essential to ensure the safety of the examiner and other handlers.
Lubrication is very important when examining a foaling mare. Petroleum jelly (e.g. Vaseline) is a good lubricant for obstetrical procedures. Liquid soaps or detergents are not recommended for use as lubricants due to their de-fatting properties. If the forefeet are present in the canal along with the muzzle of the foal, let the mare progress with foaling. If there is any doubt about the normalcy of the delivery or the course of foaling, it is best to contact your veterinarian. Foaling is a rapid process and if dystocia (difficult birthing) occurs, a veterinarian may be needed quickly.
• Stage II is defined as the actual birth of the foal. This is a very rapid phase, typically lasting 15 to 20 minutes on the average. Mares will typically lie on their side and may turn to their hindquarters and whinny or nicker, as well as lick allantoic fluid on the bedding or herself. Most mares will return to standing at least once before final delivery but repeatedly rising and lying down may signal a problem. Normally, several strong efforts of straining are followed by 2 to 3 minutes of rest. If 10 minutes of strenuous labor occurs without results, examination is needed. If the forefeet and muzzle are in the canal, let the mare proceed. If they are not present, contact your veterinarian for assistance.
After a period of intense contractions, a bluish-white membrane, the amnion, should appear at the vulva. The forelimbs should be enveloped within this membrane and one foreleg should be approximately 6" behind the other. The appearance of a red, velvety membrane, the chorio-allantois, indicates premature separation of the placenta and can result in a dead or weak foal. When this occurs, the chorion should be cut and the foal delivered promptly. Foals are normally delivered in the intact amnion, which usually ruptures by the time delivery is complete. If it does not rupture, it should be torn and pulled back away from the muzzle to permit the foal to begin breathing on its own.
Delivery of the foal usually leaves the mare in a tranquil state. It is not necessary to break the umbilical cord in most cases, as it will break when wither the mare or foal rises soon after birth.
After foaling, the navel should be dipped with a 3.4% iodine solution; 7% solution may scald the skin of the foal. Good quality colostrum should be available. Methods are available to check the quality of the mare's colostrum. Colostrum which has an adequate amount of immunoglobulin has a specific gravity of 1.060 or greater. Your veterinarian can also check the foal, using a blood sample, to determine if an adequate amount of good quality colostrum has been ingested.
• The last stage of foaling consists of the passage of the placenta. This usually occurs within 3 hours of foaling, and often sooner. If the placenta has not passed within 6 hours, contact your veterinarian. Serious consequences, including toxemia and laminitis, can result from retained placenta in the mare.
Fortunately, problems with foaling such as dystocia and retained placenta occur infrequently in the mare. Being prepared for foaling and recognizing problems when they occur are key steps in preventing serious problems.
Breeding
After the long awaited birth of a foal, the decision must be made as to the appropriate time to breed the mare again. Many facts, figures, emotions and tales exist as to the wisdom of breeding a mare on foal heat. We usually define foal heat, or nine day heat, as the first ovulation that a mare displays within the 20 day period after foaling. The first thing that must be positively accomplished is accurate estrus (heat) detection. Only diligent and judicious teasing of each individual mare with a stallion will optimize the observation of estrus. Many mares, particularly those with newborn foals, are very nervous and may resist the stallion's flirtations. These mares must be adequately restrained for teasing. Their foals must also be safely restrained, within sight of the mare, but out of potential danger. Teasing is best done every day to ensure that the first day estrus is positively observed. Obvious decisions not to breed on foal heat are based on factors such as perineal laceration (tear), metritis (uterine infection), early foals and late foals. If the decision is made not to breed on foal heat, teasing is still important so that the mare's estrous cycle can be documented and predicted for future management. Any problems noted while deciding whether to breed on foal heat should be corrected as soon as possible to avoid subsequent delays in breeding.
The decision to breed on foal heat should be based on scientific fact, not folk-lore or dogma. Remember that foal heat is the first ovulation within 20 days of foaling. Fertility at foal heat is primarily influenced by how soon a mare has foal heat and is bred after foaling. Simply stated, the earlier the foal heat breeding, the lower the conception rate. In summary, if a mare is bred sooner than 9 days after foaling, don't expect high fertility, but fertility can be quite acceptable is she is bred after 9 days.
Some strategies can be used to manage foal heat to improve conception rates. The first strategy, although time is lost, is to skip foal heat breeding and induce an earlier second cycle by injecting the mare with prostaglandin 5-6 days after the first ovulation. The prostaglandin acts upon the corpus luteum of the mare and causes her to come into heat earlier than normal. Good fertility has resulted from this approach to foal heat breeding.
A second alternative is to delay the normal foal heat by using hormones. It has been shown that the uterus repairs very quickly after foaling, but it takes about 10-15 days for the endometrial glands to proliferate to a near normal stage. Injecting progesterone or giving an oral progesterone analogue (Regumate R) for about 8 days after foaling delays foal heat. This apparently allows for greater uterine repair and results in significantly higher pregnancy rates than in mares bred on earlier foal heats.
Prostalene, a prostaglandin analogue, has been successfully used to hasten the repair period of the uterus. Mares given prostalene twice a day for ten days after foaling, had greater pregnancy rates from both the foal heat breeding and from breeding on the second heat than mares not treated with the drug.
Ultrasonography
Ultrasonography can aid in maximizing the pregnancy rates of foal heat breeding. If mares had signs of fluid in the uterus when bred at foal heat, their pregnancy rates were much lower than mares that did not have fluid in the uterus. The appearance of fluid in the uterus did not really correlate with the size of the uterus. Therefore, it may be better to ultrasound than to palpate a mare's uterus to detect fluid at foal heat breeding, and then delay foal heat breeding if fluid is present. This simple management tool can help preserve the stallion for the most opportune breedings.
Three questions always arise about foal heat breeding:
1. Will it increase the chance of uterine infection?
2. Will the subsequent heat cycles have lower fertility?
3. Will there be a higher risk of early embryonic death after foal heat breeding?
The answer to all these questions is NO. There is no information available to support the notion that any detrimental effects result from breeding at foal heat.
If foal heats occur early, breed on the next heat or delay foal heat with drugs if you expect to obtain normal pregnancy rates. Examinations by ultrasound can accurately determine whether or not fluid is present at foal heat breeding. If fluid is present, expect decreased conception rates. Foal heat breeding is a sound management practice that can maximize a mare's reproductive performance when used correctly.
Summary
In summary, the careful management of the pregnant mare, astute observation and timely intervention at foaling and well calculated strategies for foal heat breeding can help maximize a mare's reproductive potential. Mares are fairly self-sufficient during pregnancy, but they do need some special care. A little extra effort can ensure a smooth pregnancy for both the mare and the foal. If you have any questions about your pregnant mare, please contact your local equine veterinarian.
Raising a newborn foal
