[header] How to diagnose bloat in great danes [title] Look for swelling. [step] Your dog's stomach may be swollen if it makes a tympanic, drum-like sound when you flick it. This means the stomach is full of gas. 
While swelling is the most obvious symptom of bloat, it can be difficult to spot in great danes because of their large size. If you're unsure whether your great dane has a swollen stomach, discuss your concerns with a veterinarian rather than wait for symptoms to improve.