Preparing for a safe and successful foal delivery

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Farm Forum

Eleven months of pregnancy is a long anticipated wait for the miracle of birth. Normal gestation is about 340 days, with an average of 320-365 days. Labor and delivery, while momentous, are generally uncomplicated. Every effort should be made to be present during foaling. In most cases, you will simply need to be a quiet observer. Mares seem to prefer to foal at night in privacy, and apparently have some control over their delivery. Hiring a foaling attendant, installing a video monitor or using a birth alarm system can save the life of the foal and mare if a problem should arise.

The countdown

Mares provide clues that they will soon give birth. However, the timetable is far from absolute. Some mares may show all the signs like clockwork, others show practically none. The following is a general guideline, but be prepared for surprises:

· The mare’s udder begins filling with milk two to four weeks prior to foaling.

· The muscles of the vulva and croup relax. The tailhead may become more prominent a few days prior to foaling.

· The teats become engorged four to six days prior to foaling.

· “Waxing” of the teats occurs (a yellowish, honey-like secretion [colostrum] appears one to four days prior to foaling).

· The mare becomes anxious and restless. She may appear to be colicky. She may kick at her belly, pace, lie down and get up, look or bite at her flanks and sweat. She may frequently raise her tail and urinate. Generally, this is the first stage of labor (however, be aware that colic remains a possibility; if such behavior is prolonged for more than an hour or two without progress towards foaling, contact your veterinarian).

Understanding labor & delivery

Labor is divided into three stages.

Stage one begins with the onset of contractions and generally lasts one to two hours. Even in a normal delivery, the mare may stand up, lie down and roll several times in an effort to properly position the foal for delivery. During this phase, contractions move the foal through the cervix and into position in the birth canal. The fetal membranes may become visible at the mare’s vulva. When the sac breaks, signaled by a rush of fluid, stage one ends.

Stage two is the actual expulsion of the foal. This phase should only take about 30 minutes. Normal presentation of the foal resembles a diving position, with front feet first, one slightly ahead of the other, hooves down, followed closely by the nose, head, neck, shoulders and hindquarters. If you notice hoof soles up, the foal may be backwards or upside down, and you should call your veterinarian immediately. The most deadly of foaling emergencies is a premature rupture of the chorioallantois, known as “Red Bag Delivery.” If at any time during stage two you see red/maroon membranes covering the foal as it emerges from the vagina, the placenta must be rapidly torn open. The foal is detached from its blood and oxygen supply. Normal membranes that cover the foal are white or yellow and translucent.

Stage three labor begins after delivery and is the phase during which the afterbirth (placenta) is expelled. Most placentas are passed within 1-3 hours after the foal is delivered. Once the placenta has been expelled, examine it to make sure it is intact, particularly at the tips of the horns. The afterbirth will be Y-shaped and should have only the hole through which the foal emerged. A retained placenta can cause serious problems, including massive infection and laminitis.

Importance of colostrum

It is essential that the foal receive an adequate supply of colostrum. Colostrum, the mare’s first milk, is extremely rich in antibodies. It provides the foal with passive immunity to help prevent disease until its own immune system kicks in.

A foal must receive colostrum within the first eight to 12 hours of life in order to absorb the antibodies. If a foal is too weak to nurse, it may be necessary to milk the mare and give the colostrum to the foal via a stomach tube.

If a mare appears to be leaking an excessive amount of milk prior to birth, consult your veterinarian. This pre-foaling milk is not typically colostrum-rich. However, depending on your veterinarian’s recommendation, the mare may be milked and frozen to give to the foal shortly after birth. For orphan foals, or mares without an adequate supply of colostrum, it is important to locate a back-up supply. Without it, the foal is at an increased risk of infections. The foal’s serum can be tested at 18 to 24 hours of age to evaluate IgG antibody levels. The majority of absorption (85 percent) takes place within the first six to eight hours. The foal can be tested when it is eight hours old and if IgG is deficient, it can be supplemented. If you wait until the foal is 24 hours old to evaluate IgG absorption and it proves to be inadequate, your only option will be a plasma transfusion. If IgG is inadequate, treatment for Failure of Passive Transfer (FPT) should be instituted by your veterinarian.

Angular limb deformity

Many foals begin life with weak legs. Don’t be overly concerned if the baby is down in the pasterns and fetlocks for the first day or two of life. They will generally straighten up. However, if you see extreme deviations of limbs or contracted tendons intervention will be needed. It is always a good idea to have your veterinarian do a post-partum examination of both the mare and foal, as well as the placenta.

Dr. Darin Peterson, DVM, was born and raised on a horse and cattle ranch in Rosholt, S.D., and received his B.S. in Animal Science from SDSU. He concentrates most of his work time with large animals. He can be reached at 701-347-5496 or dpeterson@cassvetservice.com.