July 22, 2018
Treatment Technique Can Lead To Improved Equine Breeding by K.C. Jaehnig, Southern Illinois University Treatment with a plant-based sugar called mannose not only can cure but can prevent endometritis, a common uterine infection that makes mares infertile, a Southern Illinois University Carbondale scientist has found. This treatment should relieve a major headache for owners of mares that seldom conceive. "We use it with all the problem mares that we breed, and they've gotten pregnant every time," says Sheryl S. King, who heads SIUC's horse program. Endometritis, an inflammation of the uterine lining most often caused by bacteria, costs horse owners big bucks. It's hard to get rid of and pricey to treat -- 10 days of antibiotics can come to as much as $2,000 -- not to mention the downtime expense when a breeder mare fails to breed. King's sugar treatment works on three different bacterial strains, including the nasty, $2,000-to-treat-it variety. Breeders can administer it in two ways: They can mix a dab of mannose in a salt solution and flush the whole shebang through the uterus, or they can add mannose to the semen extender they use in artificial insemination. Used in the salt solution, mannose can keep inflammation-causing bacteria from clamping on to uterine tissue; if the bugs have already attached, the sugar-salt mix can make them let go. It's a sure-fire winner, King says. Used with semen, the results are a little more iffy. While a mannose-laced semen extender prevents infection from occurring in healthy mares and does it without a drop in pregnancy rates, infected mares inseminated with that semen often fail to conceive. "What we found when we looked at it under a microscope was that both the sperm and the bacteria attached to the mannose, and all the sperm were trying to impregnate the bacteria," King says. Solving that problem is simple. First, use the mannose-salt mix to flush out the uterus, then inseminate the mare with the mannose extender. That's how King treats her problem mares. "It works every time," she says. While that extra step might involve a little extra work, it's worth it, King says. By using mannose in semen, breeders can avoid extenders that traditionally contain antibiotics. This in turn may slow the evolution of superbugs -- bacteria that have become resistant to antibiotics through overexposure. King's sugar treatment isn't commercially available, and she doesn't expect that it ever will be. "Even though this works marvelously, it's not a technology -- it's a sugar, and sugars are everywhere," King says. "Drug companies will not be interested in this because its use as a drug can never be patented." For horse owners who would like to make their own, mannose can be obtained from Metro Medical (1-800/444-4818) or Becton-Dickinson Microbiology Systems, 250 Schilling Circle, Box 243, Cockeysville, MD 21030. Their prices run about $1 per gram. King suggests an Internet search may turn up mannose suppliers with cheaper rates. Once you find a mannose source, the treatment itself is a snap to mix up. Here are two recipes for Dr. Sherry's Super Sugar, one for the flushing solution and one for the semen extender. Mannose Flushing Solution Purchase presterilized physiological saline solution or make your own by mixing 500 milliliters of distilled water with 4.5 grams of salt and sterilizing it. Add 25 grams of mannose to the saline solution. Infuse into the mare's uterus and drain back out. Mannose Semen Extender Mix 100 milliliters of sterile, distilled water with 2.4 grams of dry, skim milk (Sanalac), 1.2 grams of glucose and 3.7 grams of mannose. Add to semen. You can find more technical reports on this research in volume 61 of the American Journal of Veterinary Research, and volumes 13 and 18 of the Journal of Equine Veterinary Science.
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