**4. Diagnosis**

Uterine biopsy is a standard test to evaluate the endometrium, to grade it and most importantly to give the clinician a prognosis of likelihood of the mare to carry a pregnancy to term. This is an indispensable test for evaluating fertility in our mares. Endometrial Biopsy are used to evaluate endometrial health, presence and degree of uterine disease and as a prognostic indicator to future fertility of our equine patients. Evaluation of the degree of endometrial fibrosis is essential as, in contrast to the inflammatory changes, fibrosis is of a permanent nature, and, if it is intense, it becomes the main factor that reduces the reproductive performance of the mare [117].

A detailed description and step by step guide to obtaining a biopsy from a mare's uterus is provided in the book Equine Reproductive Procedures [118], however a brief overview is provided here. It is recommended that a transrectal ultrasound is performed prior to obtaining a biopsy, especially in unknown mares, to rule out concurrent pregnancy. It is also recommended to obtain the sample in either diestrus or early estrus (confirmed by transrectal ultrasonography) and this information should be supplied to the pathologists, to allow for normal alterations of the endometrium due to stage of the estrous cycle to be considered.

The perineum should be thoroughly washed with a non-residual soap and rinsed clean with clean water, and dried with disposable tissue. A sterile obstetrical sleeve with sterile lubricant is worn by the veterinarian, and with the biopsy instrument in a closed position is advanced through the vagina, and carefully through the cervix, with the examiners hand acting as both a guide and protector to the delicate tissues of the reproductive tract. The veterinarian removes his arm from the vagina and inserts it rectally; this is to guide the instrument to the correct location for sampling typically at the base of either of the uterine horns. The biopsy instrument is carefully opened, and with a ventral pressure from the rectum, the endometrial tissue is forced into the cutting basket of the instrument. The examiner then closes the instrument and retracts it from the vagina. The small sample of uterine tissue is then placed into a fixative solution such as 10% formalin or Bouin's solution. The container should be labeled appropriately and sent to the pathologists for interpretation. A single biopsy from this area has been shown to be representative of the entire endometrium [118]. A slight hemorrhagic discharge from the vulva may be seen up to 24 hours post biopsy, and owners should be informed of such.

## **5. Treatment**

There is no satisfactory treatment for equine endometriosis and this is frustrating for all clinicians working within equine theriogenology. The changes to the endometrium are considered by most authorities to be irreversible. However, there is some anecdotal evidence for treatments that revolve around mechanical curettage or use of chemical agents such as kerosene, DMSO and isotonic salts which may be beneficial [119]. Analysis of physical curettage applied to mares will typically cause hyperemia within the endometrium and lead to establishment of endometritis, which can be treated utilizing appropriate antibiotic therapy based on culture and sensitivity. After treatment mares treated with kerosene intrauterine showed an

improved biopsy score; 44% increase, 51% no change, and 5% showed a deterioration of grade [120]. Kerosene is widely used in broodmare practice to potentially revert uterine fibrosis, via endometrial necrosis.

A detailed description and step by step guide to lavaging a mare's uterus is provided in the book Equine Reproductive Procedures [121], however a brief overview is provided here. The mare is retained in adequate stocks, and can be sedated if required. Her tail should be wrapped and held to the side to allow visualization and access to the vulva, without the possibility of contamination from her tail. The vulva and surrounding perineum is washed with a non-residue soap and rinsed. It is then dried with disposal paper. The clinician should put on a sterile, disposal glove and a small amount of sterile lubricant applied to the back of the gloved hand. The assistant should open the sterile y-tubing, avoiding contamination and allow the veterinarian to put the tubing end into his/her hand. The other end of the tubing should be connected to a fluid bag containing approximately 500 mL kerosene. The clinician should open the clasp to allow some kerosene to run through the tubing before it is entered into the uterus to prevent instilling air into the uterus. The clinician should alert the horse of their presence by gently patting the mare of her side with his/her ungloved hand. The sterile glove containing the lubricant should be slowly introduced through the vulva, avoiding any contamination. Clasp the hand around the end of the tubing as you advance through the cervix; this will protect the delicate mucosa from any potential damage. Once the cervix has been located, slowly advance the tubing into the uterus. Utilizing the hand that is inside the mare gently clasp the cervix closed around the tubing and begin instilling the kerosene. Approximately 500 mL should be infused into the uterus. Once delivered, slowly remove your arm from the mare's reproductive tract. Leave the kerosene in the mare for approximately 24 hours.

The following day the mare is returned to the stocks, and her perineum is cleaned as above. The mare is then subjected to a uterine lavage, utilizing Lactated Ringer's solution (LRS). Initially the fluid that is returned from the uterus is cloudy often with particular matter - these are sloughed off parts of the endometrium. Continue to lavage the uterus until the returned fluid runs clear. This may be several liters. Often it is recommended to repeat the uterine lavage the next day. The clinician may utilize the aid of ecbolic agents such as oxytocin given I.V. or I.M. (one unit) to aid in the evacuation of uterine contents.

## **6. Concluding remarks**

Endometriosis is often linked to endometritis in our mare patients. This frustrating disease complex is irreversible and debilitating for the mare and owner alike. This condition once diagnosed leaves the clinician with little options when it comes to treatment choices. Although strides have been made in utilizing enzymatic and protein detection in biopsy sampling for grading of the uterus, this, unfortunately offers the clinician little in terms of possible treatments. Any mare suspected to be suffering from endometriosis should have a uterine biopsy performed. This allows for classification, grading and prognosis, which will help the practitioner to have educated discussions with the mare's owner. If the clinician at hand is working on sport horses, such as show jumpers or quarter horses, options include embryo transfer or intracytoplasmic sperm injection (ICSI). However, should the clinician be working on thoroughbreds for racing, all worldwide jurisdictions ban such measures, and the mare must carry and deliver her own offspring. In these situations, faced with a mare with endometriosis, leaves the veterinarian with little option but to try chemical lavages as

*Endometriosis in Mare; What the Mare Can Teach Us When Dealing with Endometriosis... DOI: http://dx.doi.org/10.5772/intechopen.100515*

described above, such as kerosene uterine lavage. However, prior to this a biopsy should be obtained to confirm endometriosis, and to allow the clinician to clearly and precisely explain to the owner of the mare, the mare's likelihood of carrying a foal to term.
