why do horses bloat when they die

Why Your Horse’s Corpse May Look Pregnant – Bloating After Death

I’ll never forget the first time I saw a horse bloat after it passed away.

It was my childhood pony Princess and she had gotten severe sand colic during a hot summer day.

We waited with her all night as the vet tried everything to save her, but by dawn it was clear she wasn’t going to make it.

When I went out to say goodbye the next morning, I gasped so loud the barn cats scattered – Princess’s once slender belly was hugely distended and tight as a drum, like she was carrying 10 foals.

It was downright bizarre!

What is Bloating and Why Does it Happen?

When a horse dies, their digestive tract essentially “shuts down” since the muscles that push food and gases through the gastrointestinal (GI) tract are no longer working due to the lack of oxygen and blood flowing to those muscles after death.

why do horses bloat when they die

Without circulation and digestion continuing, gases from the cecum, large intestine and stomach begin to accumulate inside the intact GI tract.

The strong abdominal muscles of a horse normally keep everything squeezed in and moving through digestion, but once death occurs those muscles remain contracted, essentially trapping all the built up gases inside and causing the classic “pregnant” look that can be shockingly dramatic.

So in simple terms, bloating occurs because the gas produced naturally in a horse’s digestive system, like methane, carbon dioxide and hydrogen, gets trapped inside their corpse with nowhere to escape once the digestive processes cease.

The main gases that cause bloating are methane produced by bacteria that normally live within the large intestine called methano bacteria, carbon dioxide produced by all living cells, and hydrogen produced during microbial fermentation in the large intestine.

In living horses, these gases are constantly being removed from the GI tract as food moves through the digestive process, about 5-10 times the speed of a car on the interstate.

But in a dead horse, that built up gas in the GI tract has nowhere to exit once the muscles relax – so it expands the abdomen like a water balloon being overfilled with air.

Autopsies of bloated horse corpses often find the stomach and intestines distended to 2-3 times their normal size from all that trapped gas pressure.

It’s important to remember bloating can occur after any type of equine death whether from colic, injuries, disease like equine influenza or strangles, or old age.

The natural bacterial fermentation processes that produce gases like methane continue within the sealed digestive tract of a deceased horse.

So these post-mortem bloat mechanisms have absolutely nothing to do with the initial cause of death – it will happen to essentially any dead equine or other hindgut fermenter corpse as their normal gas expulsion processes cease functioning.

The rate bloating progresses depends on factors like the ambient temperature and how long the horse has been deceased.

On hot sunny days bloating can be noticeable just a few hours after death. But even in winter, give it a day or two and Ol’ Paint’s gut will start looking like he swallowed a medicine ball.

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This whole biological process can be downright unsettling to discover, making that first bloated corpse a real mind bender as a kid like it was with my Princess.

While some species like cattle and llamas are less likely to bloat due to anatomical differences, horses almost always visibly bloat to some degree post-mortem unless they are promptly frozen or the carcass is left outside to fully decompose.

Autopsy studies have shown the average horse gut increases 40-85% in volume from gas within 24 hours of the heart stopping. So in summary – bloating is a predictable, unavoidable side effect of the complex digestive decay cycle in dead equine bodies.

Why You Shouldn’t Automatically Blame Colic

why do horses bloat when they die

Many small horse owners tend to assume that if a family member horse’s stomach is hugely ballooned out after being found dead in the pasture, colic must have certainly been the cause of its demise.

But veterinary pathology shows this isn’t necessarily true at all. While severe colic from a gut impaction or twist can certainly lead to mortality, bloating itself provides no clues about what directly killed an expired horse.

During a post-mortem exam on bloated corpses, veterinarians often find no evidence that colic was even involved. Autopsies reveal things like pneumonia, colitis, laminitis, injuries or senior citizen issues as the primary causes instead.

The gas accumulation mechanisms behind bloat have no connection to whether colic signs were present while the horse was still alive. It’s an after death occurrence that doesn’t depend on the proximate cause of death.

One study of over 150 deceased farm horses found only about 30% showed intestinal lesions likely to have directly caused their demise. The rest exhibited various other conditions unrelated to colic like organ failures.

And disturbingly, 10 horses had visible fractures indicating they may have been killed intentionally rather than dying of natural causes. So while colic is a frequent killer of domestic equids, it’s dangerous to link bloating alone as proof colic must have been involved without further investigation.

Veterinary forensics have proven bloating happens after any mortality in horses – whether it be acute colic, chronic pneumonia over days/weeks, or sudden traumatic injuries during turnout.

The post-mortem gaseous changes in the digestive tract depend purely on normal bacterial fermentation processes continuing as cells die, not the initial cause of clinical signs before death.

So in summary, don’t assume bloat = colic was the culprit – it needs to be confirmed with a full exam and necropsy by an equine vet.

What to Expect When Burying or Rendering a Bloated Carcass

why do horses bloat when they die

If you’re faced with having to dispose of a freshly deceased horse yourself on your farm or ranch, dealing with a hugely bloated corpse adds a considerable challenge compared to a normal-sized cadaver.

Those seemingly endless gut bubbles are deceiving in just how much sheer heft all that extra gas volume adds. A 1,000 pound mare may feel closer to 1,500 pounds once her middle’s reached hot air balloon status. And forget dragging – you’ll need a tractor with adequate horse power (no pun intended) to shift those swollen sides an inch.

When it came time to retire old rowdy Marley to the horse graveyard after he finally crested the rainbow bridge at age 32, I was not prepared for his post-death inflation.

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My friends and I spent hours digging a grave over 6 feet deep in the hard, clay soil – and even then we practically had to wrestle his rotund remains in like some sort of sumo match. By the time we had him tucked in and the hole refilled, the sun was setting and we were drenched in sweat. I tell you what, I was feeling that workout for a week!

If using a rendering service, be ready for them to charge you extra due to the extra effort involved with loading and transporting such a portly patient. One local pickup said they add a 20% surcharge for bloated animals weighing over 1500 pounds due to mechanical and safety issues.

And forget trying to drag it into a trailer yourself without a small crane or front end loader style machine. I’ve seen some doozies of distended dearly departed where you’d swear they swallowed a pony whole before croaking.

Unless you’ve got heavy farm equipment on hand, calling in extra muscle from the neighbors is really your best bet.

Trying to take on several hundred pounds of gaseous gigantism solo will likely land you on the disabled list faster than that poor horse wound up on the dead list! ¡Ay, caramba! What a mission – make sure to have your shovel, a six-pack and some cigars to share with the helping hands once the beast is laid to rest.

In summary, remember that the day you have to send a horse to that big pasture in the sky could require a lot more heavy lifting, both literally and figuratively, if bloating has had its way by the time they are buried or picked up. Plan accordingly to save yourself some serious grief down the line when disposal time comes knocking, partner.

An Interesting Fact About Bloat

Did you know equine bloating in some rare instances can become so severe, the extreme internal gas pressure can actually cause the torso’s outer skin and muscles to catastrophically explode apart? Veterinary pathologists have coined such a gruesome phenomenon “cutaneous gastric rupture”.

It happens when digestion-related gases, mainly carbon dioxide and methane, continue accumulating under intense pressure within the deceased animal’s bloated abdomen faster than they can diffuses through the abdominal wall tissues.

Autopsy findings show the stretched digestive tract may reach upwards of 5 to 10 times its normal volume and tension in these extreme bloat blowouts.

The first signs something’s seriously wrong are often more

How Long Does It Take For Bloating To Occur?

The average time for noticeable equine bloating to start post-mortem is between 3 to 8 hours.

However, temperatures and environmental conditions can speed up or slow down the process.

On hot, sunny summer days bloating may be visible just 1-2 hours after death as bacteria activity increases more rapidly.

Autopsies have found measurable gut distention begins within 30 minutes as gas production commences internally.

Whereas on cooler, cloudy winter days it may take up to 12-24 hours for noticeable abdominal enlargement to occur.

Once started, the bloating will steadily continue for 3-5 days until levels plateau as gases perfuse through tissues.

After a week, decomposition usually advances to a point the swollen belly deflates some as tissues break down.

Does Bloating Happen In All Species?

While most ungulate species like horses, cattle, deer will bloat, some are less likely to due to anatomical differences.

Ruminants like dairy cows, goats and sheep have more muscular stomach compartments that segment gases better to limit bloat.

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pigs do not commonly bloat due to shorter intestines and straighter gut pathways moving contents along rapidly.

Llama and alpaca foreguts are simpler which circulates gases more efficiently to alleviate most post-mortem bloat.

rabbits, birds and monogastric pets almost never exhibit the expanded abdomen look of a bloated carcass.

horses are among the most susceptible due their extensive, distensible large intestine perfect for gas fermentation and entrapment.

Can Bloating Occur In Live Horses?

While bloating is primarily a post-mortem occurrence, living horses can on rare occasions experience abdominal distention.

Gas colic where intestinal gas backs up into stomach can cause visible bloating seen in some severe colic cases.

Arch obstructions or infarctions cutting off gas release from GI tracts may lead to life-threatening primary gastric bloat.

Feeds high in soluble fiber like legumes that ferment excessively can induce pasture bloat if ingested rapidly.

Stresses like transportation may cause some horses to consume air and stall or “traveled” bloat to a mild degree short-term.

Vets will often pass stomach tubes and give anti-gas epidural injections to relieve clinical bloat in living patients.

But generally post-mortem bloat is a totally different scenario involving suspended digestion rather than active colic.

Other Interesting Bloating Facts

Once distended, animal corpses can become buoyant enough to float if immersed in water due to trapped gases.

This is why drowned livestock carcasses washing ashore are often bloated beyond recognition.

Bloat gases give off distinctive odors as they break down – some describe it as smells like rotten eggs or spoiled cheese.

Early farmers thought bloating spirits invaded the corpse, while some cultures viewed it as the soul bloating the body.

Forensic study of bloat timing and extent helps estimate time of death in legal cases involving animal remains.

In horror films, bloating props are sometimes used to gross out viewers with simulated zombified or decaying bodies.

Can Bloating Be Prevented After Death?

There are a few measures that can slow down or temporarily delay post-mortem bloating in horses:

Prompt refrigeration of the entire carcass to below 40°F can halt bacterial activity responsible for gas production.

Removing and freezing just the abdominal viscera is also effective at limiting gut bloating for a period.

Quickly rendering the fat and bones within 24 hours of death minimizes gases accumulating within the digestive tract.

Use of chemical preservatives or formaldehyde injected into body cavities may inhibit bacteria without freezing.

Allowing the entire remains to fully decompose naturally will eventually resolve any abdominal distention.

But no method entirely prevents bloating long-term – it’s an unavoidable part of the decomposition process for hindgut fermenters.

Consumer Warnings About Eating Bloated Meat

Some homeowners and butchers have tried processing bloated livestock for meat with usually poor results.

Internally, rotting bacteria infiltrate distended intestines leaving the meat highly contaminated and hazardous.

Gas exposure taints tissues with foul odors even if surface flesh seems normal.

Digestive tract rupturing during processing risks release of pathogens into the workspace.

Most food safety agencies advise against consuming any meats from obviously bloated carcasses for risk of food poisoning.

It’s best to render or dispose of bloated remains properly rather than risk serious illness from spoilage.

With humans, extreme bacteria-filled bloating is also a sign of imminent body cavity distress or demise.


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