Bovine Vaginal Prolapse Study Guide

Overview and Clinical Importance

Vaginal prolapse (eversion) is one of the most common prepartum reproductive emergencies in cattle, occurring predominantly during the last trimester of pregnancy. This condition involves the protrusion of vaginal tissue through the vulva, which can progress to include the cervix (cervicovaginal prolapse) and occasionally entrap the urinary bladder. Early recognition and appropriate management are essential to prevent complications including tissue necrosis, urethral obstruction, peritonitis, and reproductive failure.

Understanding vaginal prolapse is critical for the NAVLE examination because it tests knowledge of reproductive anatomy, surgical techniques, anesthetic protocols, breed predispositions, and the important distinction between vaginal and uterine prolapses. This condition is frequently encountered in bovine practice and represents a significant category of reproductive emergencies.

Etiology and Pathophysiology

Mechanism of Prolapse

The prolapse begins as an intussusception-like folding of the vaginal floor just cranial to the vestibulovaginal junction. The discomfort caused by this initial eversion, combined with irritation and swelling of the exposed mucosa, triggers straining (tenesmus), which leads to more extensive prolapse. Eventually, the entire vagina may prolapse with the cervix visible at the most caudal portion of the protruding tissue.

Predisposing Factors

Clinical Presentation and Grading

Grading System

Vaginal prolapses are classified into four grades based on severity, extent of tissue involvement, and degree of tissue damage. This classification guides treatment decisions and prognosis.

Clinical Signs

• Pink to red mass protruding from vulva - size varies from grapefruit to soccer ball
• Tenesmus - continuous or intermittent straining
• Dysuria or anuria - if bladder is entrapped or urethra occluded
• Anorexia and decreased rumination
• Mucosal drying, contamination with bedding/manure, trauma
• Progressive edema and induration if untreated

Differential Diagnosis

Treatment Protocol

Treatment follows the "Three Rs" principle: Replace, Retain, and prevent Recurrence. In pregnant animals, the additional goal is to allow normal parturition and delivery of a live calf.

Step 1: Epidural Anesthesia

Caudal epidural anesthesia is essential to eliminate straining and provide analgesia for manipulation and suture placement. The injection is administered at the sacrococcygeal (S5-Co1) or first intercoccygeal (Co1-Co2) space.

Epidural Drug Dosages

Step 2: Tissue Preparation and Replacement

• Restrain the cow in standing position in a chute; sedation usually not required with adequate epidural
• Empty the bladder by elevating the prolapsed mass to straighten the urethra; if unsuccessful, needle puncture through vaginal wall may be necessary
• Clean the prolapsed tissue with warm water and mild disinfectant (dilute chlorhexidine or povidone-iodine)
• Reduce edema using osmotic agents (hypertonic saline, 50% dextrose solution) or gentle compression; wrapping with elastic bandage may help
• Lubricate thoroughly with sterile lubricant or non-irritating gel
• Replace the tissue using fist or cupped hands with gentle, steady pressure; ensure complete reduction without invagination
• Hold in position until tissue feels warm again, indicating restored blood flow

Step 3: Retention Techniques

Several retention methods are available, each with specific indications based on pregnancy status, proximity to parturition, and management capabilities.

Buhner Suture (Purse-String Technique)

The Buhner suture is a deeply buried, circumferential suture placed around the vestibulum using a specialized Buhner needle and umbilical tape. It provides support at the point where the initial eversion occurs.

• Technique: Stab incisions made at 12 o'clock (perineum) and 6 o'clock (ventral commissure); needle passes in semicircles on each side
• Tightening: Leave 2-3 finger widths (3-4 cm) opening for urination
• Critical: MUST be removed before parturition or severe lacerations will occur
• Best for: Dairy cattle with monitored calving; NOT suitable for beef cattle calving unsupervised on pasture

Minchev Pexy (Vaginopexy)

The Minchev procedure creates an adhesion between the vaginal wall and the sacrosciatic ligament, providing permanent fixation without closing the vulva.

• Advantage: Does NOT need to be removed for parturition - cow can deliver normally
• Technique: Sutures placed through vaginal wall into sacrosciatic ligament; buttons/stents used to prevent tissue cut-through
• Caution: Place both sutures on same side to avoid compressing the rectum; avoid large vessels
• Best for: Beef cattle with unsupervised calving; recurrent prolapses

Comparison of Retention Techniques

Step 4: Supportive Care and Medications

Complications and Prognosis

Potential Complications

• Recurrence: Most significant issue; cows that prolapse once have high probability of recurrence in subsequent pregnancies
• Tissue necrosis: From prolonged exposure, trauma, or compromised blood supply
• Vaginal wall rupture: Can lead to evisceration and requires euthanasia
• Peritonitis: From contamination and tissue compromise
• Bladder rupture: If urethral obstruction is prolonged
• Dystocia: If retention sutures not removed before parturition
• Secondary rectal prolapse: From continued straining

Prognosis

Prognosis is generally favorable if treatment is prompt and correct. Key prognostic factors include the grade of prolapse, duration of exposure, degree of tissue damage, and appropriate retention technique selection.

Prevention and Herd Management

• Genetic selection: Cull affected animals and their offspring from the breeding herd
• Body condition: Prevent overcondition in late gestation (target BCS 5-6 at calving)
• Nutrition: Avoid estrogenic plants (subterranean clover); maintain adequate calcium and magnesium
• Housing: Provide exercise; avoid prolonged confinement; ensure adequate bedding
• Breeding: Use low birth weight sires to reduce dystocia risk
• Monitoring: Close observation of high-risk animals in late gestation

"VAGINAL vs UTERINE" Memory Aid:

Vaginal = Very smooth (no caruncles)

Uterine = Uneven (caruncles present = "bread loaf")

PREgnant = PREpartum = Vaginal | POSTpartum = Uterine

"THREE Rs" for Treatment:

Replace, Retain, prevent Recurrence

"BUHNER BEFORE BIRTH" Reminder:

Buhner suture MUST be removed BEFORE parturition - or severe lacerations result!