The gallbladder mucocele (GBM) is one of the most common, poorly understood and deadliest biliary diseases of dogs. A GBM develops when the gallbladder secretes abnormal mucus that eventually obstructs or ruptures the gallbladder. GBM formation afflicts all dogs, but especially Shetland Sheepdogs, Miniature Schnauzers and Cocker Spaniels, and in general, dogs with disorders of steroid hormone or lipid metabolism. By the time a diagnosis of GBM is made, emergency surgery to remove the gallbladder is often required. After surgery, only 22-50% of dogs survive to be discharged from the hospital. There is a critical need to determine why dogs form a GBM, so we can prevent the high cost and lost lives of these dogs. Based on the breeds and diseases that predispose to GBM, the investigator hypothesizes these dogs have a unique disturbance in cholesterol or lipid metabolism. If the cause of this disturbance can be identified then the investigators will be able to understand why GBM form, develop tests for early diagnosis and design diets or drugs to prevent GBM formation.