NAVLE（北美执业兽医考题）Day 685

An obese 7-year-old Labrador Retriever is presented for annual vaccinations. The owners claim that they have restricted his diet and try to exercise him but he still keeps the weight on. There is alopecia on the dorsum of his tail and he has an unusual worried facial expression. Which one of the following choices is the most likely diagnosis？
这是一只肥胖的7岁拉布拉多犬，他每年都有接种疫苗。畜主表示他们有控制他的饮食并试图多让他跑步锻炼，但他的体重仍然没有变化。他的尾巴背侧有掉毛的表现，脸部有一种不同寻常的担忧的面部表情。以下哪个选项是最有可能的诊断？