absence of corpora lutea. Significant ovarian asymmetry or abnormal texture detected by palpation may indicate neoplasia. Early in the season, if it is not known if the mare has become cyclic, it can be difficult to determine if the asymmetry is due to suppressive effects of elevated inhibin from a GCT or if one ovary is still relatively inactive and the larger ovary has an ovarian hematoma. The ultrasonographic appearance of granulosa cell tumors is so variable, depending on their structure and composition, that their definitive identification via ultrasound can be problematic. However, demonstration of high inhibin, testosterone or antimullerian hormone (AMH) concentrations in hormonal assays from a mare with an enlarged, firm ovary and a small contralateral ovary will usually confirm the diagnosis of granulosa-thecal cell tumor. VAGINAL SPECULUM EXAMINATION After thoroughly cleansing the vulva and surrounding areas to avoid contamination, a sterile vaginal speculum can be inserted into the vaginal cavity to allow examination of this area. Abnormalities detected via vaginal speculum examination include persistent hymen, vaginitis/cervicitis, vaginal varicosities, adhesions (scarring of the cervical opening or vaginal vault), lacerations or tears of the posterior cervix or vaginal walls, and accumulation or purulent material or urine in the vaginal cavity. Most abnormalities of the cervix affect its lumen and cannot be readily identified by palpation per rectum. For this reason, the cervix is more thoroughly evaluated by visual inspection and digital palpation per vaginum. For digital palpation, using a sterile glove, the index finger is inserted into the cervical lumen, the thumb is apposed on the outside of the protruding cervix, and the entire circumference of the cervix is palpated between the thumb and forefinger to determine if muscle separations or lacerations are evident. Luminal adhesions can also be detected by advancing the index finger along the entire length of the cervical lumen. In some cases, particularly older maiden mares, the cervix may be difficult to dilate. Such mares tend to accumulate fluid within the uterus due to insufficient ability of the cervix to properly dilate when in estrus.
ENDOMETRIAL CYTOLOGY Cells can be retrieved from the endometrial surface to examine for the presence of an active inflammatory process using a swab in a similar manner as when obtaining the culture. Both endometrial cultures and cytologies can also be obtained via a low volume lavage method. Stained cytology preparations are examined under a microscope for the presence of neutrophils, microorganisms, and healthy or unhealthy luminal epithelial cells. Since the cytology can be examined the same day, the presence or absence of acute endometritis can be determined immediately, whereas the culture results can take several days. ENDOMETRIAL CYTOLOGY Providing the gross physical condition of the mare and reproductive tract are within normal limits, evaluation of an endometrial biopsy is probably the single most important means of assessing the mare's potential as a broodmare. Aseptic procedure is the same as that for procuring an endometrial swabbing for culture, except that it is important to pass the closed biopsy punch far enough into the uterus to ensure a representative specimen of endometrium is obtained. Biopsy specimens should be obtained at the base of one of the uterine horns where, after cessation of the mobility phase, early development of the embryo occurs. Endometrial specimens obtained too near the cervix have reduced glandular density and shallow gland penetration into the lamina propria, which prevents accurate assessment of glandular normalcy or pathology. After acquisition, the endometrial specimen is placed in a suitable fixative, such as Bouin’s solution, Davidson’s solution or 10% buffered formalin, and transported to a reference laboratory for interpretation.
Written Summary for Client/Owner As with any type of soundness examination, a written report should be given to the client/owner that summarizes findings, including any definitive diagnosis, recommended treatment, and prognosis for future fertility. This document is also useful for review in determining response to treatments and in assessing breeding outcome
ENDOMETRIAL (UTERINE) CULTURE The objective of an endometrial culture is to determine if any microorganisms (i.e., bacteria or fungi) are present within the cavity of the uterus and are causing endometritis. It must be remembered that it is easy to contaminate the swab smple with microorganisms originating from the outside environment, perineum, vulva, vagina, or cervix. Therefore, a positive culture alone, in the absence of signs of inflammation does not indicate that the mare is infected. Contamination often leads to the false impression that a mare has an endometrial infection particularly when an endometrial cytology or biopsy is not performed in conjunction with the endometrial culture. As a result, the mare may be treated unnecessarily and/or miss an opportunity to be bred. Hence, it is imperative to thoroughly cleanse and dry the mare's hindquarters, and to use a guarded swab and sterile equipment when swabbing the endometrium for bacteriologic culture. Ideally, an endometrial cytology should be obtained with every culture to confirm the presence or absence of acute inflammation. 16 The Practitioner
Steven P. Brinsko DVM, MS, PhD, Dipl ACT ++
Received his DVM Degree from the University of Florida in 1985. ++ Completed a combined Residency and Master’s Degree program in Theriogenology at Texas A&M University in 1990. ++ ++
PhD from Cornell University, Cornell, NY, in 1995.
Four years on faculty at Colorado State University College of Veterinary Medicine and Biomedical Sciences ++
Professor and Section Chief of Theriogenology at Texas A&M University responsible for Teaching, Evaluation and Treatment of Mares and Stallions Performs Research in Multiple Facets of Equine ReproductionAuthor and Co-Author of more than 100 manuscripts related to Reproduction Current President of the American College of Theriogenologists Issue 1 • 2013