Canine Gastric Dilatation-Volvulus (Bloat)

School of Veterinary Medicine

Purdue University, West Lafayette, IN 47907-1243

BLOAT NOTEs

News from the Canine Gastric Dilatation-Volvulus Research Program

Phone: (765) 494-6301 FAX: (765) 494-9830

December, 1994

EPIDEMIOLOGY PROGRAM RESEARCH TEAM

Department of Veterinary Pathobiology

Larry Glickman, VMD, DrPH

Diana Schellenberg, MS

Tana Lee

Department of Veterinary Clinical Sciences

Gary C. Lantz, DVM

William R. Widmer, DVM, MS

Center for the Human-Animal Bond

Nita Glickman, MS, MPH

Measurements and Bloat History: Data Obtained at the Irish Setter National Specialty 22-23 June 1994

Preliminary data on the risk of bloat in different breeds have raised the possibility that a dog's conformation influences the likelihood that it will develop bloat. The Irish Setter was selected for an epidemiologic study of bloat inheritance patterns and morphometry because it ranked 5th highest among 24 breeds in a recent study of records from veterinary hospitals.( LT Glickman et al: Journal of the American Veterinary Medical Association, 104:1465-1471, May 1, 1994.)

At the invitation of the Health Committee of the Irish Setter Club of America, chaired by Mrs. Connie Vanacore, a team from Purdue collected data at the 1994 National Specialty in Canton, Ohio. Owners were asked for information about each dog, including whether the dog or any of its close relatives had ever had an episode of bloat. The dog was measured, using a tape measure and (for depth and width), a measuring device called a Canine Caliper.

In 1 1/2 days, 155 dogs were enrolled in the study. Owners were very cooperative in providing all the information requested and in agreeing to provide pedigrees and follow-up information. Of the 155 dogs, 84 (55%) were females and 69 (45%) were males. The mean age was 3.6 years, with a standard deviation (a measure of variability) of 2.6 years. Table 1 summarizes the data on bloat history. Table 1. Summary of Bloat History Data

The 11 dogs that had bloated were not significantly more likely to have parents, grandparents, or siblings who had bloated.

Table 2 summarizes average measurements for the 11 dogs which had bloat and the 144 which did not. Table 2. Mean and Standard Deviation (SD) of Body Measurements (Inches)

Figure 1 below shows the distribution of chest depth:width ratios. The mean ratio for all 155 dogs was 1.55 (0.13), with a range of 1.23 to 1.85. Figure 1. Distribution of Chest Depth:Width Ratios in 155 Irish Setters

Evidence to date suggests that the chest depth:width ratio and possibly abdominal depth:width ratio are related to a breed's risk of bloat, i.e., the deeper the chest in relation to width, the greater the risk of bloat in that breed (see "Bones and Bloat," p. 7). But what about individual members of a breed?

Preliminary analysis of the relationship between chest and abdominal depth:width ratios and risk of bloat in the Irish Setters suggested that the greater the ratio, the greater the risk. However, with so few dogs with bloat, these relationships were not statistically significant. The relationships will be better defined when more dogs have been studied.

How should a dog owner interpret these data, e.g., for an individual Irish Setter? Ratios at the left side of the distribution curve in Figure 1 imply a shallower, wider chest. Based on what we know now, there is no cut-off point on this curve below which a dog could be considered "safe" from bloat in the future.

Ratios at the right side of the curve imply a deeper, narrower chest. Our hypothesis predicts, and preliminary evidence supports the prediction, that Irish Setters whose ratios are on this side will be more likely to bloat. However, again there is no cut-off point above which a dog is certain to bloat -- or below which it is entirely safe from bloat.

The relationship between chest depth:width ratio and bloat risk is a continuum. It is analogous to the relationship between blood cholesterol levels and risk of heart disease in humans.

By following these Irish Setters over the next year and beyond to find out whether they bloat in the future, we hope to determine whether body measurements can be used to predict the likelihood that a dog will bloat. Gathering Data at the

ISCA National Specialty, June 1994 Diana Schellenberg, Tim Emerick, Nita Glickman (behind the camera: Larry Glickman)

Extraordinary People

The Practitioner/Owner Case-Control Study of Risk Factors for canine gastric dilatation-volvulus (CGDV; bloat) relies on the willingness of dog owners to provide information about their dogs. Once a veterinarian has supplied medical information about a dog, we ask the owner's permission for a telephone interview to provide information about the dog's diet, exercise patterns, medical history, characteristics related to temperament, etc. If the dog has had an episode of bloat, i.e., is a case, we also ask about events during the 8 hours before the symptoms began. All information about specific dogs is confidential unless owners grant permission to use it, e.g., in BLOAT NOTEs.

"Hiro" Kolavo and friend. Hiro is a control dog, i.e., a dog who has never had bloat, in the case-control study of risk factors for bloat. According to his owner, he "talks" a lot -- like other Akitas.

Owners receive no compensation for their time except, we hope, the satisfaction of knowing that they have provided data critical for a study that can eventually lead to effective strategies to prevent bloat. Many whose dogs have had bloat have commented that they will do anything they can to help fight this disease.

Controls are as important as cases in this study, because each case is compared with a control dog, i.e., without bloat, of the same age (+2 years) and breed (or weight for mixed-breed dogs). Some owners of controls mention that they are willing to participate because they have heard that their dog is from a high-risk breed. Whatever their motivation, they have our gratitude!

Usually we don't get to meet the study dogs, but "Hiro" Kolavo and "Aragorn" Schumann allowed us to get acquainted when they visited Purdue.

In Memoriam

We are now receiving donations from veterinarians on behalf of clients in their practice in memory of dogs who died from bloat. We are grateful to Dr. Daniel G. Forman, Spring Creek Animal Hospital, Jackson, WY, for the donation honoring "Kato" Macintosh and "Louie" Adler. Those wishing to donate can send contributions to Dr. Larry Glickman, Veterinary Pathobiology VPTH-101, Purdue University, West Lafayette IN 47907-1243.

Honor Roll of Veterinary Clinics

An hour in the waiting room of a busy veterinary clinic, watching the traffic pattern removes any mystery about why busy veterinary practitioners and their staff members may find it difficult to participate in research projects. This makes us especially grateful to those who have been participating in our Practitioner/Owner Case-Control Study of Risk Factors for CGDV. Their help is critical, because all the dogs, those who have had bloat (cases) and those who have not (controls), are enrolled through veterinary clinics.

After the first year, we began recruiting emergency clinics because they usually see more bloat cases in a year than other clinics. So far a total of 20 clinics in 10 states have contributed data for dogs in this study.

Clinics which have contributed at least 10 dogs are on our Honor Roll! The current Honor Roll includes:

Emergency Animal Clinic, Ltd., Phoenix AZ

Emergency Veterinary Services, Lisle IL

Animal Emergency Service/Pima Pet Clinic, Tucson, AZ

This clinic had a "mini-epidemic" of bloat cases soon after agreeing to help with the study. We're gland for the dogs' sake that things have calmed down -- but are grateful for all the cases and controls enrolled in the study.

Purdue University School of Veterinary Medicine, West Lafayette IN

Two Veterinary Technicians at Purdue University School of Veterinary Medicine pose with their patients. They have identified many of the controls now enrolled in the case-control study.
 

Patty Bonney (Oncology)       Beth Sprecher (Community Practice)

Capitol Illini Veterinary Services, Ltd., Springfield IL Dr. Jane Schumann, Capitol Illini Veterinary Services, is a great Dane fancier as well as a veterinarian. "Aragorn" Schumann is a control dog in the case-control study. In his spare time he visits schools, obedience clubs, etc. Dr. Larry Glickman is the Principal Investigator for the bloat research project.

All in the Family??

Some breeders are convinced that there are families or lines at high risk of bloat, that bloat is an inherited disease. Many others are convinced that environmental factors such as diet or stress are the most important risk factors. Both ideas may be right and wrong -- nothing is simple about bloat!

We are working to untangle and define the relative importance of genetic factors in bloat. We are analyzing pedigrees supplied by Irish Setter breeders and also evaluating in detail the patterns in high-risk families of several breeds. These data and the other information available so far suggest that most cases are sporadic in nature, i.e., there is no obvious genetic predisposition other than that the dogs belong to a high-risk breed. However, there are clusters of cases within families in a number of breeds, which suggests a familial form in which the genetic influence is strong.

The same situation exists for many human diseases which occur in both sporadic and familial forms, e.g., cancer, lupus, and heart disease.

With assistance of a geneticist, Dr. Robert H. Schaible, Indianapolis, Indiana, we hope to be able to define the modes of inheritance in the familial type of bloat.

Bones and Bloat Risk: The Rest of the Story

The previous issue of BLOAT NOTEs included preliminary results from a radiographic study showing that chest depth:width ratio is highly correlated with bloat risk for 7 breeds. Chest radiographs from 437 dogs of 17 different breeds were used for the final analysis. The depth, width and length of the chest were measured.

Relationships between chest measurements and bloat risk for each breed, based on a previous study, (LT Glickman et al: Journal of the American Veterinary Medical Association, 104:1465-1471, May 1, 1994) were analyzed.

The mean chest depth/width ratio alone explained 37% of the variability in bloat risk among these breeds. This relationship is illustrated in the figure below.

When bloat risk was evaluated as a function of both chest depth/width and the ideal adult breed weight, 76% of the variability in bloat risk was explained.

This study provides the strongest evidence to date that chest depth:width ratio is an important risk factor for bloat. Relationship Between Bloat Risk and the Mean Chest Depth/Width Ratio for 17 Breeds

The number of dogs for which radiographic measurements were made is in () following the breed name: 1. Miniature Poodle (48); 2. Cocker Spaniel (25); 3. Basset Hound (23); 4. Labrador Retriever (25); 5. Newfoundland (11); 6. St. Bernard (21); 7. Dachshund (24); 8. Golden Retriever (25); 9. Alaskan Malamute (19); 10. Airedale Terrier (26); 11. German Shepherd (38); 12. Weimaraner (22); 13. Doberman Pinscher (30); 14. Standard Poodle (25); 15. Great Dane (25); 16. Collie (22); 17. Irish Setter (28).

Thanks! -- Epidemiologic studies of bloat and other areas of companion animal health at Purdue University School of Veterinary Medicine are made possible by contributions from the Morris Animal Foundation, animal health companies, and private foundations, and individuals whose dogs have experienced bloat. We welcome your comments, suggestions, and support. For additional information, contact Diana Schellenberg at (317) 494-1226.

Editor's Corner -- Material in BLOAT NOTEs is not copyrighted and may be freely reproduced, with acknowledgment of the source. -- Diana Schellenberg