under general anesthesia with minimum 90 day recovery was the only option. Though it is used today to remove large tumor laden ovaries, a more modern and useful procedure is the laparoscopic ovariectomy. “This is a very safe procedure that provides
excellent intraoperative visibility and rapid return to normal exercise and activity,” says Dr. Martin Vidal, assistant professor of equine surgery, University of California Davis School of Veterinary Medicine. In this procedure the horse is standing in
stocks, sedated with tranquilizer. Her flanks are desensitized with local anesthetic. The surgeon enters with a camera and instruments through small incisions made usually in both flanks. The ovaries are detached by a laser instrument which seals the ovarian vessels so they do not bleed and the ovaries are pulled out through the incisions. Complication rate is low with this minimally invasive technique. “Mares are typically back to work within three to
four weeks when the incisions have healed,” reports Vidal. “However, behavioral changes may take a few months. The owner always has to be prepared that there may not be satisfactory modification of the mare’s behavior. Success has been reported in about 70 to 80% of horses.” “If you did less than a stellar job of clamping off the blood vessels, you couldn’t lose the horse, but you might have to do a transfusion,” says Dr. Thomas Yarbrough, equine veterinary surgeon from Northern California. When performed via a colpotomy, the surgeon
removes the ovaries from the abdomen through one intravaginal incision with an escraseur, a chain instrument similar to an emasculator used to geld a stallion, which crushes the blood vessels to prevent bleeding. The horse is standing for this procedure and the recuperation time is shorter. “It takes about 15 minutes to perform, three
days to heal and a week back to normal work,” says
Dr.Sertich. “You have to know where you are making the incision and where to palpate because you’re doing it without seeing. The risk is improper location of your instruments and risk of infection. You don’t have the potential problem of anesthesia, but you do have a greater risk of hemorrhage. You need someone who is experienced.” Dr. Sertich and Dr. Eric Parente, an equine
surgeon at the University of Pennsylvania’s New Bolton Center, are now performing a combination procedure of laparoscopicly cutting the ovaries free using a laser and removing the ovaries through a colpotomy vagina incision. “With this procedure you have less risk of hemorrhage and shorter convalescent period,” says Dr. Sertich. And finally with the horse standing and
going through the flank with a laparoscope, some surgeons are tying off the blood supply to the ovary with a zip tie rather than severing it from the ovarian pedicle (stump). A study done in1999–2000 at the University of California Davis by Dr. Yarbrough and Dr. Chris Hanson found that the tied off ovaries will degenerate and have the same effect of modulating hormone fluctuations as severing them. “I use custom made nylon zip ties, about 5
millimeters wide. We can spay in a half hour with a virtually nonexistent complication rate and effect the change you want as long as you pay attention to a few rules,” says Dr. Yarbrough.
Mixed Results The majority of owners are thrilled with the change. Steve Swanson, a farrier from Sonoma County, California, has no regrets about spaying his eight year old. “It was the thing to do for her sake,” he says about his “new and improved” mare who before kicked at every one and every thing, even at the longe whip while working. In a long career of training mares, Karen Pavicic sees split results when looking back at spaying two mares, neither whom were prospects for breeding. The first mare was uncomfortable when she was
Mare’s Reproductive System 54 July/August 2011
ridden during her heat cycle. The owner tried the hormone Regu-Mate with mixed results. “Hormone injections, however, made a big difference, but she got an infection from the shots. The client decided against further therapy and had her spayed. Then there was a clear improvement under saddle,” explains Karen. After having success with this first scenario, Karen looked forward to a positive result with the
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