How to handle common foaling complications and injuries - DVM
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How to handle common foaling complications and injuries


Retained placenta

Photo 5: This photo depicts a retained placenta. The placenta is tied in a knot hanging from the vulva to apply tension through gravity on the endometrial attachment.
"I think one of the most common postpartum complications that is sometimes overlooked and that can have severe consequences is retained placenta," Wolfsdorf explains. Retained placenta — still attached to the endometrium after three hours — is the most common postpartum complication (see Photo 5). The nonpregnant horn is more commonly retained than the edematous pregnant horn. It has an incidence of up to 10 percent. According to Wolfsdorf, "higher incidence has been reported in draft mares, mares of increased age and cases of prolonged gestation, hydrops, abortion, stillbirth, twinning, dystocia, placentitis and cesarean section."

Retained placenta may not be obvious, such as when the whole placenta is retained and hanging from the vulvar lips. "Occasionally, just the tip of a nonpregnant horn may be retained, and if you don't examine the placenta routinely and completely, you can easily miss a piece of placenta," Wolfsdorf says. "If you miss a piece of placenta, then you set yourself up for metritis, endotoxemia, septicemia and laminitis. Eventually, the mare may end up with serious complications. Make sure you examine each placenta completely. Turn it inside out so that the velvety or chorionic surface can be viewed since this is the surface against the endometrium and is most likely to show pathology. In addition, you will be able to identify the tips of both horns by the avillus portion where the oviductal papillae resides."

"With a normal mare that has retained her placenta, I will start uterine lavage as soon as I examine the mare," says Sheerin. "If a majority of the placenta is retained intact, we perform the Burns technique, in which the placenta is filled with fluids and the fluids are held in the placenta for a period of time. We then remove that fluid and treat the mare with a small dose of oxytocin. Most mares will pass their placenta after this treatment. These mares are also given systemic antibiotics and anti-inflammatory drugs."

For mares that have had a uterine artery bleed as well as retained placenta, the procedure is somewhat different. "I will wait probably 24 hours before I start to do anything with the mare, and then the things I do, I do in slow increments," says Sheerin. "I will examine her and perhaps do a little bit of gentle manipulation to allow the placenta to be passed." If the mare stops pushing and enough of the placenta is sitting in the uterus, there's not enough gravity to pull it out. If you can exteriorize a portion of it, then gravity will kick in and slowly break down the attachment, and the mare will pass it. But don't start just tugging on it; gentle traction will suffice.

"If I do lavage on these mares, which I generally start within 24 to 48 hours after foaling, I use small volumes of fluid so I'm not distending the uterus too much," says Sheerin. "A liter or two, flushing it in and out, is adequate. I may do that many times to try to dilute out any potential bacteria, so we avoid dealing with septicemia or endotoxemia as well."

Periparturient hemorrhage

Obviously life-threatening, most cases of periparturient hemorrhage occur in older, multiparous mares. But, recently, it is increasingly seen in primiparous mares of almost any age, 5 to 24. "Hemorrhage may occur from the middle uterine, external iliac, utero-ovarian or vaginal/vestibule-vaginal arteries in late pregnancy and after parturition, and it accounts for 40 percent of periparturient deaths in mares," states Wolfsdorf.

You can see different levels of hemorrhage in these mares. A mare may hemorrhage prior to foaling and exhibit mild, colic signs, or you may find the mare dead. More commonly, a mare hemorrhages after foaling, which may occur from a couple of hours to a couple of days postpartum. "The majority of mares hemorrhage postfoaling or within 24 hours of foaling," says Sheerin. "But we've had mares that hemorrhage prefoaling as well as mares that hemorrhage as far as a week out from foaling."

Three different types of hemorrhage can occur, according to Wolfsdorf. First, mares can rupture a uterine artery and bleed into their broad ligament. This type is usually self-limiting, contained within the ligament by hematoma formation. Affected mares may be mildly to moderately painful and will usually show signs of colic and discomfort and eventually develop mild signs of shock.

A second, more severe and more life-threatening type occurs when the hemorrhage leaks out of the broad ligament intra-abdominally, and the mares go into full-blown shock.

The third type involves intrauterine hemorrhage in which there may be an artery or a blood vessel within the uterus that leaks or is torn during parturition, and the mares bleed into their uterus. "That is usually a more subtle scenario in which you may just find blood coming out of the mare's vulva when she walks or lies down since the uterus gets full," says Wolfsdorf. "When she moves around, there may be a trickle of blood or clots that come out of her uterus."

Veterinarians have a variety of options to treat these mares. "In my experience, it is important to keep mares quiet in a dark stall and keep them sedated, if needed, as well as comfortable with anti-inflammatory agents such as banamine," says Sheerin. "Once we determine that a mare is indeed bleeding, we'll use naloxone, which is an opiate antagonist useful for treating shock, and sedation. We may start the mare on fluids and use aminocaproic acid, which is used in people with hyperfibrinolysis-induced hemorrhage, plus or minus corticosteroids as well as additional fluids. Using fluids obviously is controversial, in that are you going to possibly increase the blood pressure too much by increasing the volume or replacing the volume. Nobody has come up with an answer because it is something that is hard to do any sort of controlled study on, so the evidence is only anecdotal. Thus, the decision is made on a case-by-case basis."

Sending these mares to a referral clinic may add additional stress, increasing blood pressure and possibly causing the broad ligament to rupture. "If there is a complete rent in the broad ligament because of the bleed, and the mare is bleeding profusely into its abdomen, then there is nothing you can do to save it," Sheerin says.


Source: DVM360 MAGAZINE,
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