Texas Equine Veterinary Association

www.texasequineva.com • 6 Retained fetal membranes is a common post-partum occurrence and there is considerable debate regarding which treatment is the best approach. Regardless of the treatment method used, the goals remain the same: removal of fetal membranes as quickly as possible without damaging the mare's uterus, removing contamination from the uterus, controlling endotoxemia, and preventing laminitis (Canisso et al., 2013). This article discusses some of the various treatment approaches for this condition. Oxytocin Oxytocin is a cornerstone of treatment for retained fetal membranes and can be used alone or in combination with other treatments. Vandeplassche et al. (1971) found that a single IM or IV injection of oxytocin frequently resulted in spasmodic uterine contractions and conclude it was of little value. Consequently, they added 30 to 60 IU of oxytocin to 1 to 2 L of normal saline and administered this IV over an hour. They found 15 of 21 fetal membranes easily detached after this treatment and had the best results when 60 IU in 1 L of normal saline was administered. This approach is favored by many practitioners as an initial treatment for retained fetal membranes. Other methods and doses of oxytocin administration have been used, such as adding 80 to 100 IU to 500 mL of saline and administering over 30 minutes or giving a bolus IM or IV with reported dose ranges from 10 to 120 IU (Threlfall, 2011). Oxytocin boluses can be repeated at intervals as close as every 2 hours. It must be noted that high doses of oxytocin could result in spasmodic uterine contractions. Campbell and England (2002) found when giving oxytocin IV that the number of uterine contractions increased from 2.5 IU to 20 IU, but was reduced at 30 IU of oxytocin IV. Although this research was performed on cyclic mares, it suggests that giving higher doses of oxytocin IV may not improve uterine contractions and facilitate expulsion of fetal membranes. Burn's Technique and Uterine Lavage In the post-partum mare, a large volume of fluid is required for a lavage. Isotonic saline or LRS can be used, however, this can become expensive. To reduce cost, isotonic saline can be made by adding 8.5 g of table salt per liter of tap water (Brinsko, 2001). A large bore tube, such an equine nasogastric tube, makes this procedure much easier and more efficient. Smaller diameter tubes, such as those for an embryo flush, by Dale E. Kelley DVM, MS, PhD Dale Kelley is currently a second year Theriogenology resident at Texas A&M University. He graduated from North Carolina State University with a BS in Animal Sciences. After working in the equine industry for a few years he obtained a MS from Clemson University and a PhD from the University of Florida. Subsequently, he earned a DVM from University of Florida and then spent one year at Rood and Riddle Equine Hospital in Kentucky as an ambulatory intern. Dale E. Kelley, DVM, MS, Phd Treatment methods for retained fetal membranes Reproduction take much longer to fill and siphon the uterus and are more prone to clogging with fetal membrane remnants when siphoning. Fluid can be delivered several ways, such a clean or sterile drench pump can be used in a clean stainless steel pail, fluids can be poured into a clean palpation sleeve with the lavage tube inserted into the sleeve and twisted to seal the end and invert to establish gravity flow. This technique is nice, since you don't need to clean or sterilize a drench pump. Additionally, if using 3 or 5 L bags of LRS/0.9% saline the injection port can be cut off and inserted directly into the tube. All of these methods aim for rapid delivery of a large volume fluid into the uterus. The Burn's technique was first described in 1977 (Burns et al., 1977) and can be used when there is an intact chorioallantois. Briefly, the chorioallantoic cavity is filled with a balanced salt solution as described above. The opening of the chorioallantois is either held closed manually or tied off allowing the fluid to remain inside the placenta. The release of oxytocin caused by the stretching should then cause expulsion of the placenta (Threlfall, 2011). In cases where the chorioallantois is not intact, a lavage of the uterus can be performed. When a lavage is used, a large volume of isotonic saline or LRS is infused into the uterus and siphoned out. This is repeated

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