Pneumovagina / Wind-Sucking

Pneumovagina, commonly referred to as wind-sucking, is a reproductive condition affecting mares in which air is aspirated into the vaginal cavity through the vulvar opening. This abnormal aspiration of air occurs due to poor perineal conformation, where the vulvar lips fail to form an adequate seal against the external environment. The condition allows contamination of the reproductive tract with air, bacteria, debris, and sometimes feces, leading to chronic inflammation and infection that severely compromises a mare's fertility and reproductive health.

This condition is particularly prevalent among older broodmares who have experienced multiple foalings, as the repeated stretching and trauma to the perineal tissues during parturition leads to progressive weakening and poor apposition of the vulvar lips. Thoroughbred mares are especially predisposed due to their typically slender body conformation and high tail set, which creates an anatomical predisposition to poor vulvar seal. Additionally, mares that have lost significant body condition or experienced rapid weight loss may develop pneumovagina as the loss of perineal fat pad support allows the vulvar opening to gape.

The impact of pneumovagina on a mare's reproductive capability can be devastating. Chronic aspiration of air and contaminants leads to persistent vaginitis, cervicitis, and endometritis, creating a hostile uterine environment that prevents successful conception and pregnancy maintenance. Affected mares may experience repeated breeding failures, early embryonic death, and chronic vaginal discharge that indicates ongoing reproductive tract inflammation. The economic consequences for breeding operations can be substantial, as valuable mares may remain open season after season despite intensive breeding management.

Fortunately, pneumovagina is a highly treatable condition when properly diagnosed and addressed through appropriate surgical intervention. The Caslick's procedure, which involves suturing the dorsal vulvar lips together to create a physical barrier against air aspiration, has been the gold standard treatment for over eight decades and remains highly effective. Early recognition of conformational predisposition and proactive management can prevent the development of secondary uterine infections, preserving a mare's fertility and allowing successful breeding outcomes with appropriate intervention.

The primary cause of pneumovagina is poor perineal conformation that prevents the vulvar lips from forming an adequate seal against the external environment. Normal vulvar conformation positions approximately eighty percent of the vulvar opening below the level of the pelvic floor, with the vulvar lips meeting in a vertical orientation that naturally closes against air entry. When conformational abnormalities cause the vulva to tilt cranially or position a significant portion above the pelvic brim, the anatomical seal is compromised, and air can be drawn into the vaginal vault during movement, respiration, or changes in abdominal pressure.

Genetic and breed predisposition plays a significant role in the development of pneumovagina. Thoroughbreds and other breeds with refined, athletic body types often possess naturally high tail sets and slender perineal regions that predispose them to poor vulvar seal. This conformational tendency can be inherited, and breeding managers should evaluate perineal conformation when selecting breeding stock to minimize the propagation of this trait. Certain bloodlines within breeds may demonstrate higher incidences of poor perineal conformation, warranting careful attention during mare selection for breeding programs.

Environmental and management factors significantly contribute to the development and progression of pneumovagina. Multiple pregnancies and foalings cause cumulative trauma and stretching to the perineal tissues, progressively weakening the vulvar seal with each parturition. Mares that have experienced dystocia, foaling injuries, or perineal lacerations during delivery are at heightened risk for developing chronic pneumovagina. Additionally, mares maintained in poor body condition lack adequate perineal fat pad support, allowing the vulvar lips to retract and gape, facilitating air aspiration.

Age and reproductive history represent critical risk factors for pneumovagina development. Older mares with extensive breeding histories show the highest incidence of this condition, as years of reproductive activity take a cumulative toll on perineal tissue integrity. Mares that have experienced difficult deliveries, retained fetal membranes, or post-partum complications may develop scar tissue and adhesions that alter normal vulvar conformation. Nutritional status also impacts risk, as rapid weight loss associated with lactation demands, inadequate nutrition, or systemic illness can precipitate the loss of perineal support structures.

The pathophysiology of pneumovagina involves a cascade of events triggered by air aspiration into the reproductive tract. When air enters the vaginal vault, it carries environmental bacteria, fungal organisms, debris, and potentially fecal material directly into the reproductive tract. This contamination triggers an inflammatory response in the vaginal and cervical tissues, leading to vaginitis and cervicitis that may progress to endometritis if organisms ascend through the cervix into the uterus. The chronic inflammatory state creates an environment hostile to sperm survival, fertilization, and embryo development, while also predisposing the mare to persistent uterine infections that further compromise fertility.

Early warning signs of pneumovagina may be subtle and easily overlooked, particularly in mares that are not actively being bred. Observant handlers may notice a slight vulvar gaping when the mare moves, defecates, or strains, with the vulvar lips failing to maintain tight apposition. Some mares produce a characteristic sucking or aspirating sound when walking, trotting, or during exercise, as air is drawn into and expelled from the vaginal vault with changes in abdominal pressure. This audible sign, when present, is highly diagnostic and warrants immediate veterinary evaluation to assess perineal conformation and reproductive tract health.

Vaginal discharge represents one of the most common and obvious symptoms of pneumovagina and its secondary complications. Affected mares may exhibit chronic, often malodorous discharge that ranges from clear and mucoid to cloudy, purulent, or even containing visible debris or fecal material. The discharge may be intermittent or constant, often becoming more pronounced during estrus when the relaxed cervix allows uterine contents to drain. Mare owners may notice discharge accumulation on the inner thighs, tail, and vulvar region, or observe the mare frequently rubbing her tail head due to irritation from chronic contamination.

Behavioral changes in mares with pneumovagina often reflect reproductive tract discomfort and hormonal irregularities caused by chronic inflammation. Affected mares may demonstrate irregular estrous cycles, prolonged or shortened heat periods, or failure to demonstrate normal behavioral estrus despite ovarian activity. Some mares become irritable during handling of the hindquarters or show increased sensitivity when the tail is raised for examination. Mares actively being bred may display resistance to natural cover or artificial insemination, potentially indicating vaginal or cervical discomfort associated with inflammation.

Physical examination findings in mares with pneumovagina reveal characteristic conformational abnormalities. Visual assessment of the perineal region typically shows a vulvar opening that tilts cranially rather than maintaining a vertical orientation, with a significant portion of the vulvar lips positioned above the level of the ischial tuberosities. The vulvar lips may appear sunken or retracted, lacking the plump, well-apposed appearance of normal conformation. Digital examination may reveal poor vulvar seal, with easy entry of fingers between the vulvar lips, and speculum examination often shows air-filled vaginal vault with visible inflammation of vaginal tissues.

Symptom progression in untreated pneumovagina follows a predictable pattern of worsening reproductive tract contamination and inflammation. Initial mild vaginitis progresses to cervicitis as inflammation extends cranially, and eventually ascending infection establishes chronic endometritis that severely compromises fertility. Mares may develop fluid accumulation within the uterus visible on ultrasound examination, and repeated attempts at breeding result in failure to conceive or early embryonic death. Over time, the chronic inflammatory process may cause permanent changes to the endometrium, potentially affecting long-term fertility even after corrective treatment.

Emergency symptoms requiring immediate veterinary attention include severe vaginal discharge with blood or pus, signs of systemic illness such as fever or depression, or evidence of severe perineal trauma or laceration. Any mare showing signs of reproductive tract infection, including elevated temperature, decreased appetite, or lethargy in conjunction with vaginal discharge, should receive prompt veterinary evaluation. Additionally, pregnant mares with known pneumovagina that develop discharge or show signs of impending abortion require urgent assessment to protect both mare and fetal health.

Physical examination forms the foundation of pneumovagina diagnosis and typically provides sufficient information for definitive identification of the condition. The examining veterinarian begins with visual assessment of the perineal region, evaluating vulvar angle, position relative to the pelvic brim, and apposition of the vulvar lips. A commonly used assessment tool is the Caslick index, calculated by multiplying the vulvar length above the pelvic floor by the angle of declination from vertical, with scores above 150 indicating significant risk for pneumovagina. The veterinarian observes the vulvar region during movement and when the mare strains to assess dynamic seal integrity and may note audible air aspiration during examination.

Diagnostic tests for pneumovagina focus on evaluating both the conformational defect and the secondary complications affecting reproductive tract health. Digital examination allows assessment of vulvar seal tightness and vaginal tissue condition, while speculum examination provides visualization of the vaginal vault, cervix, and any accumulated fluid or discharge. Vaginoscopy may reveal air-filled vaginal space, hyperemic or edematous vaginal walls, and purulent or debris-laden material coating the vaginal tissues. Culture and sensitivity testing of vaginal or uterine swabs identifies specific bacterial or fungal organisms present and guides appropriate antimicrobial therapy selection.

Advanced diagnostics become necessary when evaluating the extent of reproductive tract involvement and planning comprehensive treatment approaches. Transrectal ultrasonography allows detailed assessment of the uterus, revealing any fluid accumulation, endometrial abnormalities, or pregnancy status that must be considered before surgical intervention. Endometrial biopsy provides histopathological evaluation of uterine tissue, grading the severity of endometritis and providing prognostic information regarding the mare's future fertility potential. Uterine cytology examination identifies inflammatory cells and organisms present within the uterine environment, helping to characterize the nature and severity of uterine contamination.

Differential diagnosis for mares presenting with vaginal discharge and poor perineal conformation must consider other conditions that may contribute to or mimic pneumovagina symptoms. Urovagina, where urine pools in the vaginal vault due to conformational abnormalities, often coexists with pneumovagina and requires specific surgical correction. Cervical incompetence, perineal lacerations from previous foaling injuries, and recto-vestibular fistulas must be ruled out through careful examination. Additionally, the veterinarian must distinguish between primary pneumovagina and secondary vulvar relaxation caused by systemic illness, severe weight loss, or hormonal abnormalities that may require different management approaches.

Immediate treatment for mares diagnosed with pneumovagina focuses on addressing any acute infection present in the reproductive tract while preparing for definitive surgical correction. Mares with active vaginitis, cervicitis, or endometritis require uterine lavage with appropriate solutions to remove inflammatory debris and reduce bacterial load within the reproductive tract. Systemic or local antimicrobial therapy, selected based on culture and sensitivity results, addresses specific pathogens identified during diagnostic workup. Anti-inflammatory medications may be administered to reduce tissue inflammation and improve the mare's comfort while awaiting surgical intervention.

Medical management of pneumovagina serves as a temporizing measure and adjunct to surgical correction but cannot provide definitive resolution of the underlying conformational defect. Temporary vulvar suturing using a breeding stitch or roll pattern can provide short-term protection of the reproductive tract during specific breeding cycles or while scheduling surgical repair. Regular reproductive tract lavage and monitoring help control infection in mares awaiting surgery or those with concurrent health conditions that delay immediate surgical intervention. Hormonal therapies may be employed to manipulate the estrous cycle and optimize timing for breeding after surgical correction.

Surgical correction through the Caslick's procedure, also known as vulvoplasty or episioplasty, represents the definitive treatment for pneumovagina and has been successfully employed for over eighty years. This procedure involves excising a thin strip of mucosa from the opposing vulvar lip margins and suturing the freshened edges together to create a physical barrier against air aspiration. The procedure is performed under standing sedation with local anesthesia and typically requires approximately twenty to thirty minutes to complete. The surgeon leaves the ventral-most portion of the vulva unsutured to allow normal urination, with the extent of closure determined by the severity of the conformational defect.

Supportive care following Caslick's surgery emphasizes wound protection and prevention of suture line disruption during healing. Mares are typically placed on stall rest with limited exercise for seven to fourteen days while initial healing occurs. Sutures are generally removed after two weeks, or absorbable sutures are used that do not require removal. The surgical site should be monitored daily for signs of infection, dehiscence, or excessive swelling, and any concerns warrant immediate veterinary evaluation. Sexual rest is recommended for at least one estrous cycle following surgery to allow complete healing before breeding attempts resume.

Rehabilitation and return to breeding work follows successful surgical correction and resolution of any secondary reproductive tract infections. Mares should undergo repeat reproductive examination including uterine culture and cytology to confirm resolution of infection before breeding. Timing of breeding can typically resume within one to two estrous cycles following surgery, depending on the severity of pre-existing infection and speed of healing. Mares that have undergone Caslick's repair require opening of the vulvar closure before foaling to prevent perineal laceration during parturition, followed by re-suturing after foaling and completion of the involution period.

Treatment decision factors for pneumovagina management include the mare's intended use, value, age, and severity of secondary reproductive tract changes. Valuable broodmares warrant aggressive surgical correction and comprehensive treatment of any uterine infection to maximize fertility preservation. Mares with severe endometrial changes documented on biopsy may have guarded breeding prognosis regardless of surgical success, influencing treatment intensity decisions. Some mare owners may elect for concurrent vestibuloplasty or perineal body reconstruction in cases of severe conformational defects that simple Caslick's repair may inadequately address.

Recovery timeline following Caslick's surgery for pneumovagina correction is generally straightforward, with most mares healing uneventfully within two to three weeks. The immediate post-operative period requires careful wound monitoring and restricted activity to prevent suture line tension and dehiscence. Most mares demonstrate significant improvement in vaginal environment within days of surgery, as elimination of air aspiration allows the reproductive tract to begin clearing contamination and inflammation. Complete resolution of secondary endometritis may require additional weeks to months depending on severity and chronicity of infection prior to surgical correction.

Post-treatment care and monitoring emphasize protecting the surgical site while supporting reproductive tract recovery. Daily examination of the vulvar suture line should assess for swelling, discharge, suture loosening, or signs of infection that warrant veterinary attention. Mares should be maintained in clean, dry environments to minimize contamination of the healing surgical site. Stall rest with hand-walking exercise is typically recommended for the first week, with gradual return to normal turnout and activity as healing progresses. Fly control becomes particularly important during warmer months to prevent irritation and contamination of the surgical area.

Prognosis factors for mares treated for pneumovagina depend primarily on the severity and duration of secondary reproductive tract changes that developed prior to surgical correction. Mares treated promptly before development of chronic endometritis typically return to normal fertility following successful Caslick's repair. Those with established endometritis may require additional treatments including uterine lavage, antimicrobial infusions, and ecbolic agents to fully resolve uterine infection before successful breeding can be achieved. Endometrial biopsy findings provide the most reliable prognostic information, with higher-grade endometrial changes indicating reduced likelihood of successful pregnancy establishment and maintenance.

Long-term soundness outlook for reproductive function in mares following pneumovagina treatment is generally favorable with appropriate management. Most mares successfully conceive and carry pregnancies to term following surgical correction and resolution of secondary infections. However, owners must understand that Caslick's repair is a permanent management requirement, with the vulvar seal needing to be opened before each foaling and resutured afterward to maintain reproductive tract protection. Mares with severe conformational defects may require increasingly aggressive surgical approaches over time as repeated opening and resuturing affects tissue integrity, potentially necessitating vestibuloplasty or other reconstructive procedures to maintain adequate vulvar seal.

Management practices focusing on early identification and proactive intervention represent the cornerstone of pneumovagina prevention in breeding operations. All mares intended for breeding should undergo thorough reproductive conformation assessment as part of pre-breeding evaluation, including Caslick index calculation and vulvar seal evaluation. Mares identified as having borderline or poor perineal conformation benefit from prophylactic Caslick's procedure before breeding commences, preventing contamination during the breeding process and early pregnancy. Regular reassessment of vulvar conformation should occur annually or following any significant body condition changes that might affect perineal support structures.

Nutritional prevention of pneumovagina centers on maintaining appropriate body condition that supports adequate perineal fat pad development and vulvar seal integrity. Broodmares should be maintained in moderate body condition, generally scoring between five and seven on the nine-point scale, throughout their reproductive careers. Lactating mares require carefully managed nutrition to meet milk production demands without experiencing excessive weight loss that compromises perineal condition. Gradual weight management adjustments are preferable to rapid changes that may precipitate sudden loss of perineal support and development of vulvar gaping.

Exercise and conditioning programs for broodmares should balance fitness maintenance with reproductive health considerations. Regular exercise supports overall health and appropriate body condition but should be managed to prevent excessive conditioning that reduces body fat stores needed for perineal support. Mares in athletic careers that transition to breeding may require dietary adjustments to achieve breeding body condition that supports reproductive conformation. Conversely, mares that become overly conditioned during pregnancy or lactation may benefit from dietary modifications to maintain appropriate weight distribution.

Environmental factors in pneumovagina prevention include maintaining clean, dry housing that minimizes perineal contamination risk for mares with marginal vulvar conformation. Deep bedding in stalls reduces fecal contamination of the perineal region, while regular manure removal maintains sanitary conditions. Mares with known conformational predisposition benefit from tail wrapping during estrus, breeding, and foaling to minimize contamination risk. Pasture management should provide clean, well-drained areas that reduce environmental bacterial load and contamination potential.

Breeding management protocols provide critical prevention opportunities for pneumovagina complications. Prophylactic Caslick's repair before the breeding season protects mares during the vulnerable period of breeding and early pregnancy when cervical relaxation allows ascending contamination. Veterinary oversight of all breeding activities ensures proper hygiene and technique that minimizes introduction of contaminants. Post-breeding uterine lavage and examination protocols identify early signs of infection that can be addressed before chronic changes develop. Careful foaling management including planned opening of Caslick's repairs and post-foaling resuturing maintains the protective barrier throughout the mare's reproductive career.

Daily management adjustments for mares with corrected pneumovagina focus on maintaining the integrity of surgical repairs while supporting overall reproductive health. Handlers should incorporate visual assessment of the vulvar region into daily care routines, noting any discharge, swelling, or changes in suture line appearance that warrant veterinary attention. Tail maintenance becomes particularly important, with regular cleaning and wrapping during periods of discharge or when mares are turned out in muddy conditions. Mares should be housed in clean environments with adequate bedding depth to minimize perineal contamination, and stall cleaning should prioritize the areas where mares typically urinate and defecate.

Housing and turnout considerations for affected mares balance the need for exercise and social interaction with protection of surgical repairs and reproductive tract health. Mares with fresh Caslick's repairs require initial stall rest followed by gradual reintroduction to turnout as healing progresses. Pasture selection should prioritize well-drained, clean areas that minimize mud and manure contamination of the perineal region. Group turnout decisions should consider the risk of injury from other horses that might damage surgical repairs, with gradual integration into established groups preferred over sudden introductions that might precipitate conflict.

Exercise modifications for mares with pneumovagina history are generally minimal once surgical correction has healed, though certain considerations apply. Mares can typically return to normal exercise programs within three to four weeks following Caslick's surgery, though more intensive athletic work may be delayed until complete healing is confirmed. During the immediate post-operative period, exercise should be limited to hand-walking to prevent suture line disruption. Mares that are simultaneously being treated for secondary endometritis may benefit from light exercise that promotes uterine drainage, though this should be balanced against surgical site protection needs.

Monitoring and ongoing care for mares with pneumovagina requires understanding that surgical correction represents long-term management rather than permanent cure. Regular veterinary reproductive examinations should assess vulvar seal integrity and identify any recurrence of conformational deterioration over time. Body condition monitoring helps ensure maintenance of adequate perineal support, with nutritional adjustments implemented promptly if weight loss threatens vulvar seal. Owners should maintain records of Caslick's repair dates, opening for foaling, and subsequent resuturing to ensure appropriate timing of these interventions throughout the mare's breeding career.

Quality of life and use considerations for mares with corrected pneumovagina are generally excellent, with most mares able to continue productive breeding careers with appropriate management. The condition itself causes no pain or performance limitations beyond reproductive implications, allowing affected mares to participate in other activities while managed as broodmares. Mares transitioning from athletic careers to breeding may actually benefit from the slight reduction in fitness level that accompanies breeding management, as moderate body condition supports reproductive conformation. Owners should recognize that while pneumovagina requires ongoing management attention, properly treated mares can enjoy full, productive lives with normal reproductive function when appropriate protocols are maintained.

Thoroughbreds represent the breed most commonly affected by pneumovagina due to their characteristic conformational traits that predispose to poor vulvar seal. The refined body type, relatively narrow pelvis, high tail set, and lean body composition typical of Thoroughbreds combine to create anatomical vulnerability to air aspiration. Thoroughbred broodmares with extensive racing histories may show particularly high incidence, as the lean condition maintained for racing performance lacks the perineal fat support beneficial for reproductive conformation. Breeding operations focusing on Thoroughbreds should implement routine perineal conformation assessment and prophylactic Caslick's procedures as standard management protocols.

Other breeds with refined body types and athletic builds also demonstrate increased pneumovagina susceptibility compared to heavier breeds with more substantial perineal conformation. Standardbreds, Arabians, and various Warmblood breeds may show increased incidence, particularly among individuals with finer bone structure and lean body composition. Sport horse mares transitioning from competitive careers to breeding may be at heightened risk due to the combination of naturally predisposed conformation and lean body condition maintained during athletic pursuits. Draft breeds and stock horse breeds with heavier body types generally show lower incidence, though individual variation means any mare may be affected.

Genetic testing specific to pneumovagina is not currently available, as the condition results from polygenic conformational traits rather than simple genetic inheritance. However, breeding recommendations should consider perineal conformation as a heritable trait when selecting breeding stock, avoiding propagation of severe conformational defects that would predispose offspring to reproductive difficulties. Mare owners should evaluate conformation of prospective broodmares before purchase, and stallion selection might consider whether a sire's offspring tend to demonstrate good or poor perineal conformation. Documentation of Caslick's requirements in mare records helps breeding managers make informed decisions about future breeding stock selection.

Commonly co-occurring conditions with pneumovagina include urovagina, endometritis, and cervical incompetence, as these conditions share predisposing conformational factors and pathophysiological relationships. Urovagina, where urine pools in the vaginal vault due to abnormal vestibulovaginal angle, frequently accompanies pneumovagina in mares with poor perineal conformation. The combination of air aspiration and urine pooling creates particularly hostile conditions for reproductive success, often requiring urethral extension surgery in addition to Caslick's repair. Chronic endometritis commonly develops secondary to prolonged pneumovagina, representing the accumulated result of repeated reproductive tract contamination over time.

Conditions with similar symptoms that may be confused with or coexist with pneumovagina require careful differentiation during diagnostic workup. Perineal lacerations from foaling injuries can produce similar vulvar gaping and discharge, though the traumatic etiology is usually evident from history and examination. Vestibular varicosities or masses may alter vulvar conformation and produce discharge, requiring visual examination and potentially ultrasound for identification. Primary infectious endometritis from breeding contamination may produce similar discharge without underlying conformational abnormality, emphasizing the importance of complete reproductive examination to identify all contributing factors.

Potential complications of untreated or inadequately managed pneumovagina extend beyond reproductive failure to include serious systemic health consequences in severe cases. Chronic endometritis may progress to pyometra in mares with cervical adhesions that prevent normal uterine drainage, representing a serious and potentially life-threatening condition. Repeated breeding failures and loss of reproductive function may result from permanent endometrial damage that persists despite eventual surgical correction. Additionally, mares with chronically inflamed reproductive tracts may be at increased risk for ascending urinary tract infections and other complications of persistent perineal contamination.