have a delay in oviductal transport.
A tail wrap and tail rope are placed and the perineum washed in standard fashion (see Chapter 3 & Chapter 4).
The vaginal vault is rinsed with 500 ml solution of sterile saline containing 0.05% povidone‐iodine followed by a rinse with 450 ml sterile saline containing 50 ml of 2% lidocaine.
A sterilized transvaginal probe is passed into the anterior vagina.
One ovary is grasped per rectum and stabilized near the probe head.
The 18 gauge 60 cm (24 inch) single channel needle is passed along the channel of the probe and the vaginal wall is punctured. A twitch may be applied prior to this or sedation provided to the mare, since puncture of the vaginal wall may cause a response by the mare.
5 ml of sterile saline containing 2 million fluorescent microspheres (Triton Technology, Inc., San Diego, CA, USA) is deposited over the surface of the ovary. One color of fluorescent microspheres may be applied to the left ovary and a different color microsphere is applied to the right ovary.
The uterus is lavaged 24 and/or 48 hours later with 1 liter of sterile saline.
The recovered fluid is centrifuged at 1,500 rpm for 10 minutes.
The pellet is resuspended in 5 ml sterile saline.
The sample is evaluated by flow cytometry for the presence and fluorescence pattern of microspheres. Alternatively, the presence of beads may be detected by fluorescent microscopy.
Laparoscope Technique
Mares are evaluated during diestrus.
The standard preparation for standing flank laparoscopy is performed (see Chapter 24).
The ostium of the oviduct is grasped with forceps.
An 8 Fr polypropylene catheter passed through the biopsy channel is used to cannulate the proximal oviduct.
Approximately 1 ml of solution containing 2 million fluorescent microspheres in 0.5% carboxymethylcellulose is infused into the oviduct (when possible) or spread onto the mucosal surface of the infundibulum.
A second procedure is performed on the opposite ovary using a new catheter and different colored microspheres.
The uterus is lavaged 48 hours after surgery with three 1‐liter flushes of lactated Ringer's solution. The fluid is recovered into a 5‐liter graduated cylinder.
The beads are allowed to settle for 1 hour and the supernatant decanted.
100 ml of fluid is aspirated from the bottom and transferred into two 50 ml centrifuge tubes.
The tubes are centrifuged for 10 minutes at 500× g.
The supernatant is removed, and the pellets are combined and examined for the presence of beads by fluorescent microscopy.
Additional Comments
In a study using laparoscopy, fluorescent beads were recovered from the uterus of 86% of mares with oviducts without plugs (determined by flushing excised oviducts at necropsy) as compared with only 29% of mares with oviducts containing plugs. Interestingly, 92.8% of oviducts contained beads of both colors, suggesting intraperitoneal bead movement. Ultimately, the study noted a 71.4% ability of the test to correctly detect a mare with plugs (test sensitivity) and an 85.7% ability of the procedure to correctly detect a mare without plugs (test specificity). The absence of fluorescent beads in the uterine lumen is suggestive of, but not conclusive evidence for, a blocked oviduct.
As with the starch granule test, the diameter of the microspheres used in the published studies are considerably smaller, at 15 μm, than an oocyte or early developing oviductal stage embryo (150–250 μm) and may not be the ideal size for the detection of a mass that would impede embryo transport distally through the isthmus and into the uterus.
Transvaginal deposition may result in a variable amount of beads entering the infundibulum; whereas, laparoscopic cannulation results in more accurate placement of beads. Laparoscopic deposition does, however, require a certain technical skill and specialized equipment. Laparoscopic deposition of beads also allows for direct observation of the oviduct. Mares with oviductal pathology may exhibit oviductal swelling, and an increase in vascularity or adhesions.
Further Reading
1 Arnold CE, Love CC. 2013. Laparoscopic evaluation of oviductal patency in the standing mare. Theriogenology 79: 905–10.
2 Kollmann M, Rotting A, Heberling A, Sieme H. 2011. Laparoscopic techniques for investigating the equine oviduct. Eq Vet J 43: 106–11.
3 Ley WB, Bowen JM, Purswell BJ, et al. 1998. Modified technique to evaluate uterine tubal patency in the mare. Proc Annu Conv Am Assoc Eq Pract 44: 73–104.
29 Oviductal Flush Procedure for the Evaluation of Oviductal Patency
Sofie Sitters1 and Patrick M. McCue2
1 Amsterdam, The Netherlands
2 Equine Reproduction Laboratory, Colorado State University, USA
Introduction
Blockage of one or both oviducts with intraluminal gelatinous mases consisting of a mixture of collagen, fibroblast cells, and other debris, can result in reduction of fertility in the mare. Access to the oviduct for both diagnostic and therapeutic purposes is limited. As discussed in Chapters 27 and 28, both the diagnostic starch granule test and the fluorescent microspheres test have their limitations for the evaluation of oviductal patency in the mare and neither method treats a potentially blocked oviduct.
Flushing of the oviduct has been performed as both a diagnostic and a therapeutic procedure. Techniques have included retrograde flushing from the utero‐tubular junction (UTJ) proximally toward the infundibulum and normograde flushing from the infundibulum distally toward the uterus using either a standing flank laparoscopic or ventral midline laparotomy approach. In addition, retrograde flushing of the oviduct via the UTJ is possible using a standing hysteroscopic approach (see Chapter 32).
Oviductal flush techniques are reserved for mares that have a prolonged history of infertility, with good breeding management, bred to fertile stallion(s), and that have no other significant reproductive abnormalities noted during a breeding soundness evaluation.
Retrograde Oviductal Flush (Laparotomy
