anecdotally, there's no proof that dogs that eat raw don't bloat, but I've never heard of a dog that was fed raw and bloated.

The Effect of Ingredients in Dry Dog Foods on the Risk of Gastric Dilatation-Volvulus in Dogs

Malathi Raghavan, DVM, PhD, Nita W. Glickman, MPH, PhD and Lawrence T. Glickman, VMD, DrPH

From the Department of Veterinary Pathobiology, School of Veterinary Medicine, Purdue University, West Lafayette, Indiana 47907-2027.

Using dry dog food label information, the hypothesis was tested that the risk of gastric dilatation-volvulus (GDV) increases with an increasing number of soy and cereal ingredients and a decreasing number of animal-protein ingredients among the first four ingredients. A nested case-control study was conducted with 85 GDV cases and 194 controls consuming a single brand and variety of dry food. Neither an increasing number of animal-protein ingredients (P=0.79) nor an increasing number of soy and cereal ingredients (P=0.83) among the first four ingredients significantly influenced GDV risk. An unexpected finding was that dry foods containing an oil or fat ingredient (e.g., sunflower oil, animal fat) among the first four ingredients were associated with a significant (P=0.01), 2.4-fold increased risk of GDV. These findings suggest that the feeding of dry dog foods that list oils or fats among the first four label ingredients predispose a high-risk dog to GDV.

Risk Factors

Dr. Larry Glickman, an epidemiologist at the Purdue University School of Veterinary Medicine, conducted a study on canine bloat, where he followed over 1,900 dogs to help identify risk factors. Risk factors include:

The dogs with the greatest risk of developing bloat have deep narrow chests. Breeds at highest risk for bloat include the Great Dane, Bloodhound, standard Poodle, Irish wolfhound, German Shepherd Dog, Irish setter, Akita, and Boxer. All other deep-chested breeds and deep-chested mixed-breed dogs are also at higher risk.

The risk of bloat is slightly higher in males than females.

Lean dogs were also found to be at higher risk for developing bloat than overweight dogs. It is unknown why, but some believe it is because fat takes up space in the abdomen allowing less space for the stomach to "rotate" or move around.

Older dogs are at a higher risk. Some believe that the ligaments that holds the stomach in its normal position stretches with age causing an increased risk. The risk of developing bloat goes up 20 percent each year after the age of 5 in large breed dogs and it goes up 20 percent each year after the age of 3 in giant breed dogs.

Dogs with relatives that have developed bloat are at higher risk. Dogs with parents or siblings that have experienced bloat are at 60% at higher risk for developing bloat themselves.

Fast eaters are at higher risk for developing bloat. Many believe this is due to increased swallowing of air when eating fast.

Elevated food bowls have been shown to increase the risk of bloat. This has been a previously thought "preventative".

Dogs with nervous, fearful, or aggressive personalities have a higher incidence of bloat.

Stress, such as that occurs during kenneling, is an important precipitating factor.

Dogs fed dry food only or fed one large daily meal where at a higher risk for bloat. The theory is that the stomach is weighed down and maximally stretched during the one large meal.

Dogs fed foods in which an oil or fat ingredient, such as sunflower oil or animal fat, were listed among the first four ingredients. This was associated with a 2.4-fold increased risk of GDV.

Most cases of bloat occur after 6 pm.