30 - Equine Female Infertility

Behavioral

What type of anestrus is also called silent heat, and refers to the mare appearing to have normal cyclic ovarian activity, with ovulation and typical changes in the uterus, cervix, and vagina? However, the mare will not show the stallion.

Seasonal

What type of anestrus is when a mare that foals early in the year reverts to anestrus after the foal heat? It can be prevented by placing pregnant mares under artificial photoperiods.

Anovulatory

What type of follicles can cause one type of anestrus, and normally occur in the spring or autumn transition periods? It mainly is a problem if this occurs during the breeding season. It is when the dominant follicle fails to ovulate and becomes filled with blood (hemorrhagic). The exact cause is unclear, possibly due to lack of GnRH/LH support, and it can become very large, up to 10 cm in diameter and can recur in subsequent cycles.

Ovulate

Anovulatory follicles form when the dominant follicle fails to what and becomes hemorrhagic?

PGF2a

What drug is given to treat anovulatory follicles after the hemorrhagic follicle has luteinized?

Granulosa

What cell tumor is the most common type of ovarian tumor? It is usually unilateral, slow-growing, and benign, and destroys normal ovarian architecture. It is usually secretory and can secretey estrogen, AMH, testosterone, and inhibin, causing atrophy of the controlateral ovary. Clinical signs include aggression, stallion-like behavior, masculine neck muscle development, irregular estrous cycles, and anestrus.

Benign

Are granulosa cell tumors usually benign or malignant?

Inhibin

While granulosa cell tumors secrete a number of hormones, which one will cause atrophy of the controlateral ovary?

Honeycomb

What appearance of the ovary on ultrasound will indicate a GCT? Palpation will usually show one small ovary and one very large one. Cystadenomas will also produce this appearance.

AMH

GCT diagnosis with hormone assays usually reveal increased inhibin (80% of patients), increased testosterone (48% of patients), decreased progesterone, and high what hormone (abbreviated) even in the early stages of the tumor? This will be increased in 98% of mares with this tumor and is a hallmark.

Good

What is the prognosis for GCT recovery after surgical removal of the affected ovary? Return to cyclicity is usually in 3 months-2 years, and normal fertility will return, with minimal risk of metastasis.

Teratoma

What tumor of the ovary originates from germinal cells, is not hormonally active, has no effect on ovarian function, and will allow the contralateral ovary to remain active? There will be no metastasis, it is very rare, and removal is not necessary.

No

Must a teratoma be surgically removed from the ovary?

Cystadenoma

What tumor of the ovary forms from the superficial epithelium, and will cause the ovary to become enlarged, with loss of the ovulation fossa? On ultrasound there will be a large number of small cysts, producing a honeycomb appearance, and the contralateral ovary will be normal and active. It is slow-growing, does not metastasize, and does require surgery but it is not urgent.

Dysgermimoma

Which tumor of the ovary forms from germ cells, produces an enlarged ovary with no ovulation fossa, and is diagnosed on ultrasound by an atypical image with a massive echogenic structure in the ovary? The contralateral ovary will be active, the tumor is hormonally inactive and slow-growing. Surgery will be required, and metastasis is possible.

Pyometra

What condition is the equivalent of a chronic, closed abscess in the uterus? Etiology is usually inability of the cervix to open and drain. The endometrium will usually be damaged, preventing PGF release and damaging future fertility, so a biopsy of this tissue is required after treatment. A history of anestrus with an enlarged uterus on ultrasound is usually diagnostic. There will not be systemic illness, and manual dilation with PGE cream locally on the cervix may resolve the condition. Uterine lavage with large amounts of saline or hysterectomy/cervical wedge resection can also be done in recurrent cases. Recurrence rates are high.

PGE

Topical application of what cream to the cervix can be used to treat a pyometra?

Fibrosis

Periglandular what condition often occurs in older mares with a history of repeated pregnancy loss between day 35 and 80? Diagnosis is with endometrial biopsy, revealing degenerative endometrial changes. No treatment can be given for this condition.

Incompetence

Cervical what condition is diagnosed with a history of dystocia/forcible extraction of the foal at the last foaling, as well as with careful palpation of the cervix during diestrus and visual inspection with a speculum? Clinical signs include failure to conceive after repeat breedings, endometritis, and pregnancy loss, and treatment is corrective surgery.

Luteal

What insufficiency (broad phase of estrous) is of questionable significance in causing infertility in mares, but can be treated with regumate?

Endometritis

What condition refers to inflammation and the presence of inflammatory cells in the uterine wall and lumen? Various types include acute post-breeding, chronic infectious, and chronic degenerative. Diagnosis is with ultrasound (free fluid in uterus, excessive uterine edema in diestrus), or by vulvar discharge and cloudy mucus in the vagina. Cytology with a guarded swab or low volume flush, and a biopsy to determine histopathologic changes can also be used.

Acute

What type of post-breeding endometritis will occur in all mares after breeding and is a normal physiological immunoreaction? It will resolve in 12-48 hours in most mares, but inflammation can persist in 10-15% of mares resulting in low pregnancy rates. Treatment for persistent cases is with minimal contamination, single breeding, uterine lavage with saline or LRS, oxytocin every 4 hours until fluid resolves, or intrauterine antibiotics if necessary.

Clearance

Uterine what refers to the process by which the cervix opens, and there is increased: cilial action, endometrial gland secretion, neutrophils/WBCs, uterine contractions, and lymph drainage? This will be impaired in mares susceptible to persistent breeding-induced endometritis. Typically susceptible mares will be middle-old aged, pluriparous, and will have a pendulous uterus and perineal defects.

Chronic

What type of endometritis can be cause by opportunistic organisms (S. equi zooepidemicus, E. coli, S. aureus) or by specific pathogens (P. aeruginosa, K. pneumonia, T. equigenitalis)? It is treated with uterine lavage (saline/LRS), intrauterine antibiotic infusion, mucolytics, and oxytocin administration if required.

Mucolytics

What drugs are often used in combination with antibiotics to treat chronic endometritis, as they combat biofilm-forming bacteria? DMSO, N-acetylcysteine, and Tris-EDTA are three possible options.

Fungal

What type of endometritis is usually secondary to prolonged antibiotic treatment for chronic bacterial endometritis? It is important to treat the reservoir of the organism (clitoral fossa) in order to prevent recurrence.

Metritis

Contagious equine what condition (CEM) is caused by T. equigenitalis, is a notifiable disease, and is transmitted venereally from a carrier stallion, as well as by fomites? Clinical signs include copious mucopurulent discharge. The mare will usually clear herself and 25% may become chronic carriers. Diagnosis is with swabs from the clitoral fossa and clitoral sinus, and is cultured in charcoal Amies medium (must be taken to lab in 24 hours).

T. equigenitalis

What bacteria is the causative agent of CEM?

Nitrofurazone

CEM is treated by washing the clitoral area with chlorhexidine, followed by topical application of what antibiotic? A clitoridectomy may be required in areas where this disease is more prevalent.

63

While chromosomal abnormalities are uncommon in horses, deformity of which chromosome is the most common, causing an XO gonadal dysgenesis condition similar to Turner’s syndrome? Clinical signs include extremely small ovaries and infantile reproductive organs, and is diagnosed by karyotyping.