Preventing Shipping Fever

Science, Early Signs, and Best Practices for Protecting Your Horse on the Road

Shipping fever is one of the most significant health risks associated with equine transport, particularly during long-distance travel. Despite advances in trailer ventilation, climate regulation, and handling practices, shipping fever remains a condition every owner, trainer, and transport professional must understand fully. Not only is it potentially serious—it is also, in many cases, preventable.

At Crown & Rein, protecting respiratory health is woven into every aspect of how we prepare, handle, and monitor horses on the road. This elevated guide explores the science behind shipping fever, how to identify early signs, and the thoughtful steps that dramatically reduce risk.

What Exactly Is Shipping Fever? The Science Behind the Term

“Shipping fever” is an umbrella term for a group of transport-associated respiratory conditions, most commonly pleuropneumonia—a bacterial infection that affects both the lungs and the pleural cavity surrounding them.

To understand why it occurs, you must first understand how a healthy equine respiratory system functions.

Horses rely on:

• A long, delicate airway

• Constant mucociliary clearance

• Efficient removal of inhaled dust and debris

• The ability to lower the head to clear secretions

Transport interrupts several of these protective mechanisms simultaneously.

Head Position Matters More Than Most Owners Realize

The mucociliary escalator—the system of tiny cilia that moves mucus up and out—requires horses to lower their heads periodically. In the trailer, especially when balance is required, horses often keep their heads elevated for hours at a time. This limits drainage and allows bacteria-laden mucus to accumulate.

When bacteria migrate deeper into the airway, infection can follow.

Why Transport Increases Respiratory Risk

Travel introduces a perfect storm of factors that challenge airway health:

1. Reduced Head-Lowering

Movement of the trailer requires bracing, which encourages an upright head carriage. This prevents the natural clearing of mucus.

2. Dust, Hay Particles & Environmental Irritants

Shaking hay nets, bedding dust, or road debris can enter the airways.

3. Humidity & Heat Buildup Inside Trailers

Warm, moist air slows mucus clearance and supports bacterial overgrowth.

4. Stress-Induced Immune Suppression

Even low-level stress elevates cortisol, weakening the immune system’s defenses.

5. Dehydration

Thicker mucus, reduced moisture in the airway, and lower systemic hydration all increase susceptibility.

6. Cross-Contamination in Shared Trailers

When horses travel together—especially unfamiliar horses—bacterial exposure increases.

Understanding these factors is essential for prevention.

Early Signs of Shipping Fever: What Owners Should Watch For

Shipping fever often begins subtly, which is why attentive monitoring during and after travel is so vital.

Common early symptoms include:

• A low-grade fever, often the first measurable sign

• Slight nasal discharge (clear or cloudy)

• Lethargy or an unusual quietness

• Decreased appetite

• An elevated heart or respiratory rate

• A cough that begins within hours or days of arrival

If the infection progresses, horses may develop:

• High fever

• Depression or reluctance to move

• Pain upon touching the rib cage

• Rapid, shallow breathing

• Standing with elbows turned outward (to ease breathing)

• Thick nasal discharge

• Signs of endotoxemia

Immediate veterinary care is essential if any of these symptoms appear.

How Long-Distance Travel Influences Risk

Distance matters, but not in isolation.

Most cases occur after journeys exceeding 4–6 hours, but horses have developed shipping fever after shorter trips when ventilation was poor or the horse was already stressed.

Trips of 8 hours or more significantly increase the likelihood of respiratory compromise, especially without adequate rest periods.

At Crown & Rein, we plan rest stops meticulously, allowing horses to lower their heads, hydrate, and breathe easier—one of the simplest yet most profound preventatives.

The Most Effective Prevention Strategies: What Truly Works

Preventing shipping fever requires a combination of preparation, equipment, and skilled handling. Below are the practices that consistently protect equine respiratory health.

1. Begin With a Healthy Horse

No horse showing:

• fever

• nasal discharge

• cough

• increased respiratory rate

• or dullness

should travel unless it is a medical referral approved by a veterinarian.

A pre-trip temperature check is one of the easiest, most powerful tools owners have.

2. Hydration Is Non-Negotiable

Dehydration thickens mucus and reduces airway clearance. Ensuring your horse is well-hydrated before the journey—and offers of water are given during appropriate stops—supports respiratory health.

Horses who refuse unfamiliar water may benefit from:

• flavored additives

• water from home

• electrolyte supplementation when appropriate

3. High-Quality Ventilation Is Critical

Trailers must maintain continuous airflow that removes:

• dust

• heat

• moisture

• ammonia

Airflow reduces bacterial concentration and keeps the airway moist and functional. Rigs with advanced ventilation, such as those used by Crown & Rein, dramatically reduce respiratory risk.

4. Allow Horses to Lower Their Heads

This is one of the most important preventative measures.

Box stalls—or any configuration allowing natural head movement—support the mucociliary escalator and allow mucus and debris to drain.

Horses confined with restricted head movement are at higher risk.

5. Minimize Dust Exposure

Transport hay should be:

• dampened lightly (if appropriate)

• high quality

• free of mold and debris

Bedding should be dust-controlled, and the trailer must be cleaned thoroughly between horses.

Crown & Rein disinfects and resets the trailer prior to every trip, reducing airborne irritants and bacterial load.

6. Reduce Stress Wherever Possible

Stress is physiologic.

Even a calm horse experiences hormonal changes during transport that reduce immune efficiency. Quiet, patient handling; experienced loading; familiar hay; and gentle voice cues all support a calmer, healthier horse.

7. Avoid Unnecessary Mixing of Horses

Cross-contamination is a real concern, particularly with upper respiratory bacteria like Streptococcus equi zooepidemicus.

Private or semi-private transport, increased spacing, and strict sanitation all help limit exposure.

8. Monitor Temperature After Arrival

Shipping fever often shows itself 24–72 hours after transport.

Taking your horse’s temperature twice daily for the three days following arrival is an invaluable early-detection method.

A fever caught early can prevent a far more serious infection from developing.

What Crown & Rein Does Differently

Protecting horses from shipping fever is not an afterthought—it is a design principle.

At Crown & Rein, we implement:

• Disinfected, deeply sanitized trailers before each trip

• Excellent ventilation and temperature regulation

• Box stalls for longer journeys

• Air-ride suspension to reduce balance stress

• Continuous monitoring via cameras

• Frequent rest stops

• Hydration support

• High-quality, low-dust hay

• Calm, professional handling

• Clear communication and post-arrival guidance

Because respiratory health is foundational to equine wellbeing, every detail is built around supporting it.

The Bottom Line: Shipping Fever Is Preventable

When owners, veterinarians, and professional transporters work together, the risk of shipping fever can be dramatically reduced. Prevention is centered on:

• Healthy horses

• Clean trailers

• Excellent airflow

• Adequate hydration

• Freedom to lower the head

• Skilled handling

• Attentive monitoring

Horses deserve journeys that protect their lungs as carefully as their legs and bodies. With intentional preparation and thoughtful stewardship, transport can be both safe and restorative—not stressful.