Canine Bloat

From The ARK - 4th Quarter 1995 ..Reprinted from "Animal News", Volume 111, 1994, a publication of Morris Animal Foundation, Englewood Colorado

Yogi, one of Colorado's most famous Bloodhounds, has been in the spotlight again. Only this time it isn't because of his ability to aid police in cases by scenting and tracking victims and suspects. Yogi has received accolades for his sensitivities in the case of five-year-old Aleszandra Berrelez, who was abducted. Yogi led police on a nine-mile trail and they eventually found her body. He then led police to the place of her abduction.

Yogi has been receiving public attention and well wishes this time because of gastric dilatation volvulus, commonly called bloat. Thanks to the quick actions of his trainer, Officer Nichols, and the assistance of several area veterinarians, Yogi is recovering from his near fatal condition and will soon be nosing around the police department.

Yogi is one of 60,000 dogs that will have a bloat episode this year. Nearly 20,000 will die from it. Scientists, veterinarians and pet owners alike want to know why dogs get this fatal condition. Bloat is a rapid accumulation of gas in the stomach causing compression of the surrounding organs called gastric dilatation. Often, the stomach twists at the same time compression of the organs occurs. This condition is called gastric dilatation with volvulus. Shock is the result and can lead to death if immediate medical care isn’t administered.

When a dog bloats, quickly stabilizing its condition with treatment for shock may keep it alive. In cases like Yogi's, gastropexy surgery, a procedure that involves attaching the stomach to the abdominal wall, is usually successful in preventing a recurrence of the volvulus, but not necessarily the dilatation.

Bloat is a top priority for Morris Animal Foundation. In November, 1990, the Foundation held a panel discussion of scientists who recommended priorities for the direction of bloat study. In the past four years, the Foundation has committed $115,850 to bloat studies at Purdue University and Ohio State University. These funds are possible because of generous contributions from individuals and breed clubs who designated their gifts for bloat, and two matching fund campaigns including the most recent program being spear headed by chairman of the board, Fred Meyer, Jr.

Promising information comes from principle investigator Dr. Lawrence Glickman and coinvestigator Dr. Garry Lantz at Purdue University who have completed Phase I of an epidemiology study and are beginning Phase II.

Bloat Study Phase I

Veterinarians know how to diagnose and treat bloat, but don't know what events trigger it. This study focuses on identifying the predisposing and precipitating factors, so that veterinarians and owners can determine if their dogs are likely to bloat and then provide preventative care. The scientists collected and evaluated risk factors using three methods: analyzing the Veterinary Medical Data Base (VNMB), studying dogs admitted to veterinary practices, and surveying owners of dogs that survived bloat episodes.

Scientists believe that bloat is probably caused by many factors. These risk factors include lifestyle or behavior, environmental exposure, or inherited characteristics. They want to know more about these risk factors and how they interact. Because dogs are likely to bloat again once they get the condition, scientists are studying long-term following to evaluate the effectiveness of treatments.

Dr. Glickman's team analyzed information from twelve veterinary teaching hospitals from 1980 to 1989. They evaluated information that had been collected on the VNMB comparing 1,934 dogs with naturally occurring bloat and 3,868 dogs without bloat. The dogs’ weight, breed and certain other characteristics were evaluated.

SIX MAIN FINDINGS

Frequency of bloat among all dogs admitted to the different hospitals ranged from 2.9 to 6.8 per 1,000 dogs.

A total of 28.6 percent of the dogs with gastric dilatation alone and 33.3 percent of those with dilatation with volvulus died in the hospital.

Bloat risk increased with age. Dogs seven years and older were at least twice as likely to have bloat as dogs two to four years old.

Purebred dogs were three times as likely to have bloat as mixed breed dogs.

The six more common breeds with the highest risk of bloat are Great Dane, Weimaraner, Saint Bernard, Gordon Setter, Irish Setter, and the Standard Poodle. Less common breeds with greatly increased risk included Irish Wolfhound, Borzoi, Bloodhound, Mastiff, Akita and Bullmastiff.

Increasing expected adult weight of the breed, based on breed standards, was a significant risk factor. However, there were great differences in the risk of bloat among breeds with similar expected weight. for example among the more common breeds, the Basset Hound has the seventh highest risk overall, although it was in the lowest weight group.

Actual body weight is less important than expected breed weight as a risk factor for bloat. Overnutrition and undernutrition are not important risk factors; changing caloric intake may not be effective in preventing bloat. The overall pattern of risk suggests that body conformation, particularly a narrow and deep thoracic cavity, influences the risk of bloat for specific breeds.

Veterinary practitioners and owners in the Midwest participated in Purdue's bloat study by identifying in their practices 59 pairs of dogs. The pairs consisted of two dogs of the same age and breed -- one with bloat and one without bloat. through interviews with owners, detailed information such as breed, age, sex, neuter status, health history, body weight, body conformation and body condition (i.e., thin, lean, optimum, overweight or obese), diet, and exercise patterns was collected.

The findings suggest that body weight, body condition and obesity index (actual weight/ ideal weight) are not important risk factors when dogs of the same breed are compared.

The last part of the study involved follow-up interviews with the owners who participated in the survey and had their dogs treated for bloat. While 29 percent of the dogs died after the bloat episode, survival of dogs after treatment demonstrates the success of gastropexy in preventing recurrence. In the future, scientists will compare surgical techniques and other aspects of treatment for up to three years.

In the VMDB study, the investigators ranked 24 breeds according to their risk and developed a hypothesis regarding the role of chest conformation, which is currently being tested in Phase II.

Bloat Study Phase II Under Way

The scientists at Purdue are examining several anatomic, genetic and environmental factors that were significant in Phase 1. They are comparing bloat risk for dog breeds by measuring chest depth, width and length and dog height. They are studying pedigrees and measurement of dogs in relation to family history of bloat. The risk factors relating to eating and feeding habits are being analyzed. Long-term follow-up is continuing in relation to recurrence and postoperative mortality.