Weight loss is terrific if we have an overweight pet that is on a specific diet in order to reach our ideal weight. Other than this it is of course a potentially serious problem, and an indicator of many potential diseases.
The list includes, depending on age:
Hence again our list is extensive. The take home message is that if we have weight loss, it is almost always a sign of some sort of significant ongoing problems and should be investigated and worked up.
Often pet owners make the mistake of allowing weight loss to go on too long before being worked up, as the pet may otherwise be quite well and have a good appetite. Cancer for instance may often cause weight loss before it actually causes inappetance or lethargy. If unsure as to whether your pet has weight loss, weighing them regularly is important. Make sure you always use the same scales as different scales may have slightly different inaccuracies to each other. Of course if weight loss is obvious without the need for weighing, then see your vet and work the problem up.
Old pets: Pet owners often put weight loss down to the fact that a pet is ageing. This is in fact rarely the case. Even for ageing pets, weight loss is usually a sign of further problems and really should be worked up. If initial clinical examination and tests reveal no problem, then it may be a result of just ageing, but this is in fact far less likely than being an indication of an actual disease process.