Canine Bloat Science

Canine Gastric Dilatation Volvulus or bloat is a devastating, life-threatening condition that happens acutely, sometimes without warning. The pathogenesis of the disease is poorly understood but new research has shed light on possible causes and risk factors.

Bloat is caused by the stomach twisting on itself, effectively blocking the ability of gastric contents from leaving. As the stomach becomes dangerously distended with air, major blood vessels are compressed, cutting off blood supply to vital organs.

Left untreated, GDV or canine bloat is almost always fatal. Even with treatment the disease has about a 30% fatality rate [1, 2, 3]. This article will explore scientific based ways to treat and prevent this devastating disease.

Recent studies have identified risk factors for canine bloat. Recognizing these risks is paramount to adequately prevent or lessen the likelihood of bloat.

The number one risk factor for GVD or canine bloat is being a purebred large or giant breed dog. Great Danes, Weimeraners, Doberman Pinschers, and German Shepherd Dogs, for example, are all over represented in cases of canine bloat [4].

Great Danes, for example, have a 36% lifetime chance of developing bloat at some point in their lifetime. This means that 1 in 3 Great Danes are likely to suffer from this disease [5].

Deep-chested dogs, that is, dogs with narrow and tall chests are at an increased risk for bloat as well. Many veterinarians will advocate that these high risk breeds, or dogs with deep chests be prophylactically gastropexied as puppies [5, 6].

Gastropexy, or stomach tacking, is a surgical procedure that secures the stomach in place, negating the ability for it to twist. This is the most effective way to prevent bloat [6].

While long term risks are minimal to non-existant, it is an invasive procedure and requires abdominal surgery. This is often done at the same time the dog is spayed or neutered.

Much research is aimed at finding other non-surgical ways to help decrease the likelihood of canine bloat. Recent grants from the American Kennel Club Canine Health Foundation have funded studies looking into both the genetics behind bloat, and the potential for gut flora to play a role [7].

Research published in the American Journal of Veterinary Research looking into the genetics of Great Danes has found that dogs that carry certain ‘risk’ alleles have a two thirds chance of suffering from bloat at some point in their lives [8]

This is significant because if this gene can be recognized in Great Danes, it may also be present in other at risk breeds. Owners can have there dogs tested for the gene and then alter their breeding plans, or opt to have the stomach tacked at an early age.

VetGen currently offers a commercial DNA test for Great Danes based on this research. The hope is to have additional genetic testing for other breeds in the near future.

Another emerging topic in the study of canine bloat is the role of the gut flora. There are some theories that the gut microbes maybe play a part in increasing certain breed’s risk [8].

Research published in the Journal PLOS ONE shows that the Great Danes in the study that suffered bloat and survived had alterations in their gut flora that may have contributed to their likelihood of bloating [8, 9].

Additionally, a study published in the Journal of Veterinary Internal Medicine showed that the air in the stomachs of dogs having emergency surgery to correct bloat had a higher concentration of carbon dioxide than room air. This implies that this air had not been swallowed, but rather was more likely the result of gas producing bacteria [10].

If microbes in the gut play a role in the disease process, it could be postulated that probiotics or diet changes aimed at creating a more favorable gut environment may help aid in the prevention of canine bloat. More research needs to be done before this can be relied on.

One preventative measure that is often touted is to prevent stress or excessive exercise after eating meals. While this isn’t a fool-proof preventative measure, it can decrease the likelihood of bloating. Always ensure you have your dog rest for at least 30 minute after eating [11, 12].

Another easy preventative measure you can take at home is to feed more frequent smaller meals.  Additionally, there is some support for forgoing dry kibble in favor of a moistened food. There has been shown to be an increased risk of bloating in dogs who are fed infrequent large meals of small dry kibble [11, 12].

Rapid eating seems to also be a risk factor. Attempting to slow your dog’s eating time can help prevent bloating as well. There are many products aimed at slowing rapid eating, such as special bowls or feeding ‘toys’ [12].

There has been controversy surrounding the recommendation to use elevated dishes during feedings to help decrease likelihood of bloat. One study actually found an association between elevated feedings and an increased likelihood of bloat [1].

It must be reminded though, that association doesn’t necessarily equal causation. That is, owners of more at risk dogs are more likely to feed elevated (because this is what they have been told to do), and because their dogs represent a higher risk breed there are more incidents of bloat among this group than the general population.

At this time it is not recommended to feed at risk giant and large breed dogs elevated [1].

Interestingly, a calm and happy temperament correlates to a decreased risk of bloat. Dogs who are aggressive or anxious have been reported to be more likely to develop the disease [11, 12].

Dogs that have been splenectomized, or had their spleen removed for some reason, also seem to be at an increased risk [13, 14]. One study published in the Journal of the American Veterinary Medical Association suggests dogs without a spleen are more than 5 times more likely [13].

Experts in emergency and critical veterinary care are in agreement that dogs who need to have their spleen remove should have a prophylactic gastropexy performed at the time of the their surgery to prevent future bloat.

Shifting from prevention to canine bloat treatment, there are much fewer options. Treatment for canine bloat almost always involves emergency surgery to derotate the stomach and tack it in place to prevent recurrence.

The faster the treatment is instituted, the more likelihood of survival. A study published in the Journal of the American Veterinary Medical Association reported a 10% fatality risk for dogs who had emergency treatment within 5 hours of clinical signs of bloat. This fatality number jumps to almost 50% for dogs who didn’t receive treatment for five hours or more [15, 16].

Some patients can be managed medically if the stomach can be derotated and decompressed with a stomach tube placed by a veterinary professional, however it is estimated that about 75% of these patients will relapse and bloat again. Therefore surgery to tack the stomach in place is recommended [17].

Antioxidant treatment following the diagnosis of canine bloat has been historically of interest. The idea is to help ameliorate the tissue injury from lack of oxygen to vital organs. In theory, this might help lessen the morbidity and mortality associated with bloat.

While there is ample research suggesting the benefits of antioxidants for overall health and wellness, its use as an adjunct to surgical treatment of canine bloat has given mixed results [18, 19]. At this time we can conclude the use of antioxidants in dogs with bloat is unlikely to hurt, but may not be helpful.

Take Home Message

In conclusion, it is important for owners to recognized their at risk dogs based on their breed and chest conformation. Dogs that fall into a high risk should discuss prophylactic gastropexy, or stomach tacking with their veterinarian.

Feeding small meals frequently, without elevating food and encouraging slow eating can be helpful. Allowing the dog to rest for at least 30 minutes after meals has also shown to help lessen the likelihood of developing bloat.

Genetic testing is available for Great Danes to identify genes that correlate to an increased risk of bloat. Researchers are hopeful to have additional genetic testing available for other breeds in the future.

At the first signs of bloat, seek emergency veterinary medical care, as expedited treatment is correlated with a higher survival rate.

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