Pneumovagina in mares is primarily caused by poor perineal conformation

Outline:

• Hook: pneumovagina in mares is more about anatomy than infections or age

• What pneumovagina is and why it matters

• The primary cause: poor perineal conformation (how it happens)

• Why this matters for health and performance

• Other factors to know (infection, genetics, age) and what they do

• How vets evaluate and how owners can help

• Prevention and management options (non-surgical and surgical, with Caslick as an example)

• Realistic takeaways and a gentle, practical mindset

Pneumovagina in horses: the real driver is how the mare’s perineal region sits

If you care for mares, you’ve probably heard the term pneumovagina—the condition where air sneaks into the vagina through the vulva. It’s not about a bad breath problem; it’s about how the anatomy sits and works. The quick version: the primary cause is poor perineal conformation. That phrase is a mouthful, but it simply means the way the vulvar lips and surrounding tissues are shaped and sit together isn’t doing a perfect job of sealing the opening. When the opening isn’t well closed, air can move in during normal breathing, and that air can irritate or upset the vagina and even lead to respiratory or reproductive issues down the line.

Let me explain what this looks and feels like in real life. A mare with less than ideal perineal conformation often has vulvar lips that don’t come together snugly. There might be laxity in the surrounding muscles, or the vulva might sit higher or lower than optimal, creating a gap. Think of it like a door that doesn’t latch properly—air (and yes, a little dirt or moisture) can slip through. In horses, that “slip” means the vagina can be exposed to air more than it should be, which can set up irritation, inflammation, or infections over time. The core issue isn’t an active infection to begin with; it’s the door that doesn’t close all the way.

Why is this the main cause, and not something else? Because anatomy is the starting point. Infection can certainly develop as a consequence if air, moisture, and bacteria find pathways inside, but without the structural predisposition, the passageway isn’t there to begin with. Genetics and age-related changes can influence how severe the problem becomes or how quickly it progresses, but they aren’t the spark that starts it all. The best way to think about it is this: the physical setup sets the stage; other factors can influence the script, but the primary cause is how the perineal area is built and sits.

The consequences aren’t just about the vagina. Pneumovagina can ripple outward. Air exposure can contribute to vaginitis or cervicitis, and some horses show respiratory signs if the condition goes hand-in-hand with other airway sensitivities. And yes, there can be secondary infections if moisture and bacteria linger around the opening. For stall-side caretakers, that means a mare with this issue might show subtle signs first—unexplained vaginitis, unusual discharge, or recurrent respiratory or general signs of irritation. None of these are dramatic, but they’re worth paying attention to because they point back to what the mare’s anatomy is doing.

Beyond the main cause: other factors to consider

While poor perineal conformation is the star, other players can influence the picture:

• Infection can be a downstream consequence. If air exposure facilitates moisture and bacteria near the vaginal opening, infections can occur.

• Genetic influences can shape tissue quality or connective tissue characteristics, affecting how well the area can seal.

• Age-related factors can change tissue elasticity and muscle tone, potentially worsening existing laxity over time.

• Overall health, body condition, and reproductive history can modulate risk. A mare with strong overall health and good conditioning may cope better, while one with chronic inflammatory issues or obesity-related changes might show more pronounced signs.

Reading the signs in context helps you decide when to call the vet. A lot of this is about pattern recognition: repeated vaginitis in cycles, unusual discharge that doesn’t clearly fit a straightforward infection, or a mare that seems predisposed to issues around the vulvar area.

How veterinarians assess and what you can do about it

If you’re observing signs that raise a question mark, a good route is a veterinary perineal assessment. This is where the clinician checks the vulvar lips, the external anatomy, and how the perineal region sits in relation to the mare’s pelvis. A simple, but important, part of this is noting how well the vulva closes at rest and during movement or straining. In some cases, a scoring system for perineal conformation might be used to quantify risk and guide treatment decisions.

There are practical steps you can take with your vet in mind:

• Keep the area clean and dry. Excess moisture can worsen irritation, especially in warmer weather.

• Maintain good overall health and body condition. Gentle exercise routines and a balanced diet help keep tissues supportive.

• Monitor for recurrent signs. If a mare seems prone to vaginitis or respiratory irritants around the time of foaling or cycling, this is a red flag to revisit the anatomy and management plan with a vet.

Prevention and management: what to do before a door doesn’t latch

Prevention isn’t about magical fixes; it’s about thoughtful care and appropriate medical decisions when needed. Here’s a practical way to approach it, with a few concrete options:

Non-surgical measures

• Regular perineal evaluation: At least once a year, have a vet assess the conformation. If any laxity is noted, plan ahead.

• Keep her environment clean and dry: Minimizing moisture and irritants helps the skin stay healthy and resilient.

• Gentle conditioning and pelvic floor support: While you’re not rebuilding anatomy in a gym, keeping the mare fit can help tissues remain supple and responsive.

Surgical and semi-surgical options

• Vulvar reconstruction or repair: In mares with significant laxity and a higher risk, surgical approaches to improve seal can be discussed with a veterinary surgeon. These procedures aim to tighten the vulvar opening and improve closure.

• Caslick-type procedures: In certain cases, a vet may perform a procedure that sutures the vulvar lips together temporarily or permanently to reduce air exposure. This can be a very effective fix for mares with persistent opening gaps, especially around foaling time or when other measures aren’t enough. It’s a precise, veterinary procedure that requires careful consideration of timing and mare health.

Important note: any intervention should be guided by a veterinarian who can assess the mare's overall health, reproductive plans, and risk factors. These decisions aren’t casual DIY projects—opening or stitching tissue changes the mare’s anatomy and requires professional judgment, anesthesia considerations, and careful postoperative care.

A few extra thoughts that help keep the topic human and practical

• The conversation around perineal conformation often circles back to one idea: prevention through awareness. If you know what you’re looking at, you’re already a step ahead. It’s a bit like maintaining a fence line around a yard—you can’t always see every inch from the outside, but you can spot loose boards, sagging posts, or gaps that invite trouble.

• You don’t have to be a specialist to start good habits. Simple check-ins, accurate observations, and timely veterinary referrals go a long way. When in doubt, it’s better to ask than to guess.

• Every mare is different. Some have perfectly functional perineal anatomy with no fuss; others may have a mild predisposition that responds well to routine care. Others still require surgical consideration. The pattern you notice—how often signs appear, how severe they are, and what else is going on in her life—will guide your next steps.

• It’s okay to admit uncertainty. This topic touches on anatomy, physiology, and sometimes evolving management strategies. A thoughtful conversation with a vet can bring clarity and a practical plan you can act on.

A practical takeaway

The bottom line is straightforward: pneumovagina primarily arises from poor perineal conformation. In plain terms, the way the vulvar region sits and closes isn’t sealing off the vaginal opening effectively, allowing air to slip in. Infections and other factors can complicate the picture, but the structure is the main stage setter.

If you’re stewarding a mare, keep an eye on that opening’s health and function, stay connected with a trusted veterinarian, and consider low-key preventive steps as part of regular care. With the right attention, you can reduce risk, support her comfort, and keep her riding and breeding life smoother—less worry, more confidence.

In the end, understanding the anatomy behind pneumovagina isn’t just a veterinary trivia moment. It’s a practical, compassionate approach to mare care. When you know where the door should close and you see it’s not, you’ve already taken the first step toward a stronger, healthier horse. And that’s something worth aiming for, whether you’re training, riding, or simply enjoying time at the barn.