Mammary mass in an overweight dog

A client brings in a nine‐year‐old female neutered labrador to ask your advice about a mammary mass. The mass is relatively small and well defined, and you consider it of value to biopsy and/or remove it. However, the dog is 33 kg (ideal weight 15 to 16 kg), struggles to walk and pants after coming from the car park to the waiting room. Looking at previous records, you see that the owner has not visited the practice for several months. At the last visit, they had been to two weight loss clinics and the dog's weight was 27 kg. A note on the record suggests that the owner was reluctant to follow the advice given or to change the dog's food from the working dog diet it was on, and could not afford a prescription diet. When you mention the weight problem and the need for the dog to lose weight before surgery is considered, the client becomes aggressive, tells you ‘the dog is on a diet and the weight problem is under control’ and refuses to discuss attending weight clinics again or changing food. You feel that the welfare of the dog is compromised, and mention this to the client, who becomes angrier and storms out of the practice.