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Essential Facts about Horse Dystocia
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Essential Facts about Horse Dystocia

Normally, a successful foaling should not take more than half an hour from the time that a mare goes into labor to the delivery of the foal. Anything longer than this is called dystocia (or difficult birth) by veterinarians. If not handled quickly and properly, it can be fatal for the mare and its foal.

According to Michael Spirito, a vet based at the Hagyard Equine Medical Institute, Davidson Surgery Center, Kentucky, time is critical when dystocia occurs. A ten-minute difference can make a difference between success and a dead foal. During the American Association of Equine Practitioners convention (2016) held in Orlando from 3rd to 7th December, Spirito described the ways that a vet can deal with dystocia as follows:

There are four ways of reducing the impact of dystocia- 

1. Assisted delivery This procedure can be done at the clinic or on the farm when the mare is either standing or under sedation. Using various tools like head snares or chains, a vet can assist the mare in the delivery. When the rib cage of the foal enters the pelvis, the mare should be left to complete the delivery by herself so as to avoid rib fractures 2.

2. Controlled delivery This is done at the clinic when the mare is under general anesthesia. It entails hoisting her upside down from her rear legs in what is called the Trendelenburg position. The benefits of this procedure are that clear it allows manipulation of the foal without getting any pressure from the mare. The foal can even be pushed inwards to give extra room for manipulation. 3.

3. Cesarean section In the event that a dystocia cannot be corrected through the vagina, the veterinarian will carry out a C-section while the mare is under anesthesia. Even though there is potential for a lot of complications, one scientific study proved that the mares discharge rate is between 80 and 85 percent after a C-section. 4.

4. Fetotomy In cases where the foal has not been delivered as yet but it has been verified that it is dead, an experienced vet will cut it into pieces using a wire and then remove it from the mother. According to Spirito, complications can arise due to the uterus being lacerated by the sharp bone ends or the fetotomy wire.

Spirito then listed positions, or presentations, that commonly cause dystocia, where a fetus can get wedged in when moving into position during delivery. He pointed out that anterior positions (where the foal faces forward out of the mother’s vulva) are normally easy to resolve. Usually, the mare will go down and adjust herself. Many vets place the mares in a stall and leave them be for several minutes to see how it goes. Anterior positions include: -Partial elbow extension-which normally can be easily resolved manually by the vet -Hurdling (Dog sitting) position-Where one or both rear feet are folded up near the front legs. In such cases, vets are sometimes able to do some manipulation when the mare is standing. Most of the times however, the Trendelenburg position is used to rearrange the foal’s rear limbs manually. If this does not work, the vet has no choice but to carry out a C-section. -Carpal flexion or contraction -This is common and it happens when one or both knees are bent backward. Here, the foals are usually either very big or contracted in some way. The vet will put a chain around the pastern of the foal in order to adjust it in the standing mother. In case this is too hard to do when standing, the mare should be placed in the Trendelenburg position -Foot above the nape position -This is experienced when one or more front legs become stuck over the head of the foal and against the vaginal roof. This must be corrected immediately by the veterinarian, once again using chains and manual manipulation. If this is not done, there is a great danger of recto-vaginal fistula (puncturing of the wall between the vagina and rectum) occurring or a perineal laceration. -Neck and Head lateral flexion -This is a common but hard-to-correct type of dystocia where the head of the foal is twisted round towards the back. Occasionally, the veterinarian can rectify this using snares and chains, but usually the mare must undergo a C-section. -Neck and Head ventral flexion -This occurs when the head of the foal is bent between its front legs. It is relatively easy to rectify unless the vet cannot get to the foal’s head. If this is the case, a C-section must be done. -Shoulder flexion -this arises when one or both shoulders of the foal stretch backwards like a diver or swimmer. The uncommon position requires chains to be used or a C-section to correct. -Ventral position-Here, the foal is in a forward-facing position, but upside down. It is normally easy to reduce and can ordinarily be rectified at the farm.

Also there are the posterior positions, where the head and body of the foal are facing backward, in an opposite direction from the birth canal. Common posterior positions are often referred to the facility at once. They are exceedingly difficult to rectify under field conditions.

Posterior positions (presentations) include: •Hock flexion-Here the hocks of the foal are folded up under his rear end and this problem makes up about 25% of all posterior cases. The majority of these cases require a C-section because there is a risk of the uterus rupturing. •Bilateral flexion of the hip -This usually occurs where the foals are deformed and it is presented with their rear legs extended beneath them. This problem normally requires a C-section. •Ventral position-extended posture-Here the foal is upside down, with the rear feet stretched out in the direction of the vulva. When it occurs, there is a risk of the feet penetrating the rectum or vagina of the mare. If the foal is not too big, the veterinarian may be able turn the foal around and do a posterior delivery.

Finally, some presentations are horizontal, where the foal lies sideways inside the body of the mare and its back, or more frequently, its four legs pointing towards the rear of the mare. This is a rare occurrence and comprises of approximately 7% of all dystocias, according to Spirito. In addition, they are usually related to a congenital abnormality. In the event that the foal is still alive, an immediate C-section is required.

Spirito asserts that before dealing with these scenarios, it is important for a veterinarian to find out if the horse owner is open to the idea of a C-section being performed if it becomes necessary, and if they have any financial limitations. Bear in mind that if between forty to sixty minutes pass from the time of the mare breaking water to foaling, the chances of the newborn foal surviving are low. If it is 90 minutes or more, the foal will almost certainly die.

According to Spirito, it is important to control the time spent trying to manipulate the foal or correct the problem while in the field. In case it takes longer than twenty minutes, one should consult with a clinic. The passage of time reduces the chances of survival for the foal and also the mare, which may get exhausted and become recumbent (which means lying down and being unable to get back up).

Whereas the objective of resolving a dystocia presentation is preserving the life of the mare and the foal, sometimes the foal may die in the womb, requiring a fetotomy. Thankfully in this scenario, the survival rate of the mare, according to previous studies, is 95.8%. Further, her chances of remaining fertile in future are 79.4%. She can even return to the farm the following day. In contrast, a mare that has undergone a C-section may need to remain at the clinic from between 5 to 7 days, subject to any complications. She also needs a longer time to recover.

Image credit: aqha.com

Disclaimer: Of Horse! and sponsors do not endorse nor validate the accuracy of a blog post. Each article is the opinion of the blogger.

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