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What to do with the 'leftovers'
Finding reasons for last year's non-breeding mares a priority this time of year


DVM360 MAGAZINE


The retrieved fluid is centrifuged (1,000 to 1,500 rpm for five minutes) and the pellet is resuspended in 0.5 ml of fetal calf serum and cell smears are then made. This technique is likely to produce more accurate cell counts and to give a better representation of the entire uterine environment.

Oviduct evaluationIf everything is still normal at this point, you may need to evaluate the mare's oviducts.

It has long been thought that the horse had few oviductal problems because of its particular anatomy. Oviductal problems, in contrast, can be quite significant in women.

Drs. Dascanio, Parker, Ley and others, writing in The Compendium for Continuing Education for the Practicing Veterinarian, state that, "Oviductal dysfunction is a poorly understood facet of equine reproduction." This particular problem cannot be diagnosed by any of the methods currently available to practitioners. Yet, according to the veterinarians in this article, "Oviductal dysfunction should be considered in mares that cycle and ovulate normally; fail to conceive despite good breeding practice; and possess normal or acceptable uterine, cervical, and vulvovaginal health.

Some studies have given veterinarians more reason to be cautious about the status of the oviducts in problem mares. Drs. Saltiel, Paramo and Murcia looked at 325 mares and found that 87.7 percent had at least one macroscopic lesion in their oviducts and 93.5 percent of 124 mares had at least one microscopic oviductal lesion.

The most common macroscopic lesions were adhesions while cysts were the most common microscopic lesion. Either type of problem, if large enough, could occlude the oviduct lumen and be a cause of failed conception.

Tubal patency assessmentWhile there are no diagnostic tests available for evaluation of oviductal transport, Drs. Dascanio, Parker, Ley et al do provide instructions for a simple means of clinical assessment of tubal patency.

A solution of starch granules is deposited onto the ovarian surface. This is done transabdominally using a long needle and an ultrasound guided approach. Twenty-four hours later, the uterus and cervical area are lavaged with saline and the fluid is collected. The fluid is stained with 2 percent Lugol's iodine solution and examined microscopically for the presence of starch granules carried to the uterus via the oviducts. Each side must be evaluated on separate occasions. The presence of starch indicates successful transport.

"We have used this technique clinically with good results," write Dascanio, Parker, Ley and others, "however it is time-consuming and stressful to the mare."

Care must be taken with any transabdominal injection. Bacterial contamination and trauma are possible complications.

Complete pictureThis extensive evaluation should provide the practitioner with a complete picture of each problem mare.

Hopefully, by now, the source of particular "problems" may be identified and steps can be taken toward a solution. Hormonal therapy, antibacterial therapy, lavage and oxytocin, or some other techniques may be needed for specific mares, but at least there is now a plan in place.

It has been written that only an idiot will do the same thing over and over and yet expect different results. By aggressively evaluating your problem mares now and outlining a treatment approach for the upcoming breeding season you can hopefully avoid another year like the one before. With some changes in management for these problem mares you may have everyone pregnant this coming fall and the only leftovers you'll have will be of the turkey variety in the refrigerator.

Dr. Marcella, a 1983 graduate of Cornell University's veterinary college, was a professor of comparative medicine at the University of Virginia. His interests include muscle problems in sport horses, rehabilitation and other performance issues.


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