Gastric dilatation and volvulus (GDV), also known as bloat, is an acute and life-threatening condition in large and giant breed dogs when their stomach flips over on itself and begins to fill up with gas. This rotation (volvulus) can sometimes be greater than 180 degrees and trap gas in the stomach, causing the stomach to become greatly distended (dilatation). GDV requires immediate medical and surgical intervention, usually within six hours from the onset of clinical signs.
It is not wholly understood why volvulus occurs, but veterinarians do know that there are certain predispositions for GDV. Deep-chested breeds and older dogs are more likely to develop bloat. Dog breeds at a higher risk for developing GDV include Great Danes, German Shepherds, Weimaraners, Standard Poodles, and Saint Bernards. Other predisposing factors include fearful or aggressive behavior, once-daily feedings, eating large amounts of food very quickly, and having an immediate relative with a history of GDV. For some dogs, the onset of bloat can be a sign or symptom of a bigger underlying problem, such as splenic disease or cancer.