Necrotic Vaginitis in Horses and Donkeys After Foaling: Signs, Treatment, and Recovery

By Dr Duncan Houston

A mare can deliver a healthy foal and still suffer significant internal birth trauma.

That is one of the reasons postpartum complications are sometimes missed. The foaling is over, the foal is standing, and attention shifts away from the mare. But inside the birth canal, bruised and damaged tissue may already be progressing toward necrosis.

Necrotic vaginitis is one of the more serious post-foaling injuries seen in mares, especially in maiden mares, miniature horses, donkeys, and difficult deliveries. It is painful, easy to underestimate early, and capable of causing long-term reproductive damage if it is not identified and managed properly.

The key is not just treating infection. It is recognising tissue injury early, limiting further damage, preventing adhesions, and protecting future fertility.

Quick Answer

Necrotic vaginitis is tissue death in the vaginal lining after foaling trauma. It is most likely after difficult births, assisted deliveries, first foalings, and in miniature horses or donkeys. Early vaginal examination, prompt treatment, and close follow-up are critical because delayed care can lead to infection, painful healing, adhesions, scarring, and long-term reproductive problems.

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What Is Necrotic Vaginitis?

Necrotic vaginitis is severe injury to the vaginal lining after foaling, where damaged tissue loses blood supply and begins to die.

This usually starts with:

• bruising

• compression

• tearing

• swelling

• tissue devitalisation after trauma

In mild cases, the tissue is inflamed but recoverable. In more severe cases, the blood supply is compromised, the tissue breaks down, and necrosis develops.

That is the point where this moves beyond normal postpartum soreness and becomes a true clinical problem.

Why this matters

Once tissue becomes necrotic, the risks increase quickly:

• bacterial contamination

• pain and straining

• delayed healing

• adhesion formation

• permanent narrowing or scarring

• future breeding and foaling complications

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Why It Happens After Foaling

The vaginal tissues are stretched and compressed during normal delivery. That alone can cause minor trauma.

The risk rises sharply when there is:

• dystocia

• prolonged second-stage labour

• a large foal

• forced traction

• internal obstetrical manipulation

• first-time foaling

• small maternal size relative to the foal

Higher-risk patients include:

• maiden mares

• miniature mares

• donkeys

• mares after difficult or assisted foaling

Clinical insight

Some of the worst cases are not always the most dramatic at the time of delivery. A mare can appear only mildly uncomfortable at first, while tissue injury is already evolving.

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Why Miniature Horses and Donkeys Need Extra Attention

Miniature horses and donkeys are at particular risk because the margin for error is smaller.

They may have:

• less pelvic space

• more soft tissue compression during delivery

• greater swelling relative to tissue size

• higher risk of opposing vaginal surfaces sticking together as they heal

That means a postpartum injury that might heal reasonably in a larger mare can become a major reproductive problem in a miniature or donkey if follow-up is poor.

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What Are the Early Signs?

Early signs are often vague, which is why cases are missed.

A mare with necrotic vaginitis may show:

• lethargy

• depression

• reduced appetite

• discomfort around the vulva or hindquarters

• tail swishing

• reluctance to move

• frequent urination

• straining to urinate

• urine dribbling

• sensitivity when the hindquarters are touched

Urinary signs are common because trauma often occurs close to the urethral opening and surrounding vaginal tissue.

Decision checkpoint

If a mare is more painful, dull, or irritated than expected after foaling, especially after a difficult birth, do not assume it is normal postpartum soreness.

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When Should You Suspect Significant Post-Foaling Trauma?

Suspicion should be high if:

• the foaling was difficult

• traction was used

• internal manipulation was required

• the mare is a maiden

• the mare is a miniature or donkey

• there is urinary dribbling

• the mare stays depressed after delivery

• there is visible vulvar swelling, bruising, or discharge

The key point is simple:

A successful foaling does not guarantee an undamaged mare.

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How Is Necrotic Vaginitis Diagnosed?

Diagnosis depends on examination, not guesswork.

Vaginal Examination

A speculum exam is the most useful way to assess the vaginal lining after suspected trauma.

This allows the veterinarian to check for:

• bruising

• swelling

• tearing

• tissue discolouration

• devitalised areas

• sloughing tissue

• involvement near the urethral opening

Tissue colour matters

• red or bruised tissue suggests trauma and inflammation

• dark purple, blue, grey, or black tissue raises concern for necrosis

That distinction matters because bruised tissue may recover, while devitalised tissue requires closer management and carries a higher risk of complications.

Additional assessment

Depending on the case, the veterinarian may also perform:

• rectal examination

• transrectal ultrasound

• transabdominal assessment

• evaluation for deeper tears or internal trauma

Clinical insight

The real value of early examination is not just identifying damage. It is identifying tissue before it progresses from bruised to necrotic.

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The 12 to 24 Hour Rule

This is one of the most important time points in postpartum reproductive care.

A mare examined early may only have:

• bruising

• swelling

• localised trauma

A mare examined late may already have:

• necrotic tissue

• secondary infection

• painful sloughing

• adhesion formation

Practical rule

Any mare with a difficult foaling should be assessed within 12 to 24 hours. In miniature mares and donkeys, that recommendation becomes even more important.

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Severity Framework: How Worried Should You Be?

Mild

Signs:

• mild bruising

• little or no appetite change

• no urinary difficulty

• minimal discomfort

What it usually means:
Superficial postpartum trauma

What to do:
Monitor closely and follow veterinary guidance. Recheck if signs worsen.

Moderate

Signs:

• obvious bruising or swelling

• reduced appetite

• urinary irritation

• mild depression

• discomfort on examination

What it usually means:
Significant tissue injury with risk of progression

What to do:
Veterinary treatment and follow-up are warranted. This should not be managed as simple watch-and-wait soreness.

Severe

Signs:

• dark or devitalised tissue

• foul discharge

• marked pain

• worsening demeanour

• persistent urinary signs

What it usually means:
Established necrotic vaginitis with increased risk of infection and scarring

What to do:
Prompt treatment and structured rechecks are required.

High Risk for Long-Term Reproductive Damage

Seen in:

• miniature mares

• donkeys

• delayed diagnosis

• extensive tissue injury

• adhesion formation

What it usually means:
The mare may recover, but not necessarily without functional damage unless managed carefully.

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When Is This an Emergency?

A postpartum mare needs urgent veterinary attention if she has:

• marked depression

• fever

• refusal to eat

• severe straining

• foul-smelling discharge

• major vulvar pain

• progressive swelling

• difficulty passing urine

• signs of systemic illness

These signs raise concern not just for necrotic vaginitis, but also for deeper tears, infection, or more severe postpartum complications.

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Treatment of Necrotic Vaginitis

Treatment is aimed at preserving tissue, controlling contamination, reducing inflammation, and preventing long-term complications.

The goals are to:

• control bacterial spread

• support healing

• minimise pain and inflammation

• prevent vaginal adhesions

• preserve future reproductive function

1. Control Contamination and Infection

Systemic antibiotics are often used when there is significant trauma, contamination, or evidence of developing infection.

Choice of antibiotic depends on:

• severity of injury

• contamination risk

• tissue appearance

• the mare’s overall condition

• veterinary judgement

This is not an area for random treatment. Antibiotics should be selected based on the clinical picture.

2. Use Local Therapy Where Appropriate

Topical treatment may be used to protect damaged tissue and reduce inflammation.

In suitable cases, a veterinarian may apply a topical antibiotic and anti-inflammatory preparation to the vaginal lining. The aim is to:

• reduce local irritation

• lower contamination risk

• support healing

• reduce the chance that damaged surfaces will adhere together

Application must be gentle and controlled. Aggressive handling can worsen tissue damage.

3. Prevent Adhesions

This is one of the most important parts of treatment, especially in miniature horses.

When raw, inflamed surfaces heal against each other, fibrous adhesions can form. These adhesions may:

• narrow the vaginal canal

• interfere with future breeding

• complicate later foalings

• lead to chronic reproductive problems

This is why follow-up matters so much. Starting treatment is not enough. Healing has to be monitored.

4. Reassess Until Healing Is Clearly Progressing

These mares often require repeat examinations to check:

• tissue viability

• reduction in swelling

• progression of healing

• pain levels

• discharge

• signs of adhesion formation

Clinical insight

One of the most common mistakes is assuming that because the mare looks brighter externally, the vaginal tissue must be healing well internally. That is not always true.

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What Should You Do Right Now?

If a mare has foaled recently and you are concerned about trauma:

1. Assess her attitude, appetite, and urination.

2. Look for vulvar swelling, pain, discharge, or urine dribbling.

3. Do not dismiss persistent soreness after a difficult birth.

4. Arrange a veterinary reproductive exam promptly.

5. Do not attempt internal treatment yourself unless specifically instructed by your veterinarian.

Time-based guidance

If the mare is dull, off feed, painful, or showing urinary signs in the first 12 to 24 hours after foaling, do not wait several days to see if it improves.

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Common Mistakes Owners Make

Assuming the mare is fine because the foal is fine

A healthy foal does not rule out serious maternal trauma.

Dismissing pain as normal postpartum recovery

Some soreness is expected. Persistent pain, depression, or urinary signs are not.

Skipping an exam after a difficult foaling

This is how bruised tissue progresses unnoticed into necrosis and adhesion risk.

Focusing only on infection

The issue is not just bacteria. It is tissue viability, healing quality, and long-term function.

Underestimating the risk in miniatures and donkeys

These patients are more vulnerable to serious healing complications.

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Can It Affect Future Fertility?

Yes.

If the injury is severe or healing is poor, mares may develop:

• scar tissue

• vaginal adhesions

• narrowing of the canal

• breeding difficulty

• increased risk in future foalings

That is why early treatment matters. It is not just about getting the mare through the next few days. It is about protecting her reproductive future.

Practical takeaway

The earlier significant birth canal trauma is identified, the better the chance of healing without permanent damage.

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Prevention: How Do You Reduce the Risk?

Not every case is preventable, but risk can be reduced by:

• close foaling supervision

• early recognition of dystocia

• timely veterinary assistance

• careful obstetrical technique

• postpartum examination after assisted delivery

• a low threshold for internal examination in miniatures and donkeys

Prevention in these cases is really about early detection and good foaling management.

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Frequently Asked Questions

Is necrotic vaginitis the same as a vaginal tear?

No. A vaginal tear can occur with or without necrosis. Necrotic vaginitis specifically refers to tissue death after trauma.

Can a mare seem normal at first and still have serious injury?

Yes. Some mares show only subtle signs early on, which is why post-foaling examination matters.

Why does urine dribbling happen?

Trauma near the urethral opening can cause pain, swelling, irritation, and altered urination.

Are miniature mares at higher risk?

Yes. They are at increased risk of trauma and adhesion-related complications.

Will this always affect future breeding?

No. Many mares recover well if the injury is recognised and managed early.

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Final Thoughts

Necrotic vaginitis is one of the postpartum complications that can be easy to miss early and difficult to fix once delayed.

The key message is simple:

A normal-looking foaling does not always mean a normal postpartum recovery.

If there has been trauma, the job is not finished once the foal is born. The next priority is making sure the mare heals properly, without infection, adhesions, or lasting reproductive damage.

That is why early examination matters so much.

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If there is any doubt about how a mare is recovering after foaling, especially after a difficult delivery or in a miniature or donkey, ASK A VET™ can help clarify the next steps and when urgent examination is needed.