The question is asking whether your cat is underweight if you can feel the vertebrae running down the spine. I think this is quite a tricky question to answer on the internet in the written word only and I’ll tell you why. My cat is approaching seven years of age. He has always been a slender cat; what you might describe as “fighting fit”. I do not consider him underweight but you can feel some of the vertebrae down his spine. It varies from time to time and on occasions you can feel less of them but in general it is not unusual me to feel some of his backbone. He is a free feeder so he is not underfed. He is very active.
With previous cats that I have lived with, I’ve not been able to feel their spine quite so obviously. I don’t think that you can say with conviction that if you feel your cat’s backbone that he or she is underweight. It is question of degree and the extent of the definition of the bones.
If you can feel the backbone quite clearly along the length it is pretty certain that he is underweight. I would check other parts of your cat’s body as well. Can you feel the ribs? There should be a layer of subcutaneous fat over the ribs which is thick enough to provide some padding and installation but it should not be too thick. You should be able to feel the ribs as individual structures but you should not be able to see them.
From above your cat you should be able to see a waist-like effect after the rib cage and before the hips. In other words, looking down on your cat, there should be a slight thinning of the body between the rib cage and the hips. This is what my cat looks like from above. I’m convinced that my cat is not underweight so in conclusion just because you can feel your cat’s backbone you can’t say with absolute certainty that your cat is underweight.
It is likely that he might be but diagnose holistically and if necessary consult with your veterinarian. You have to apply a certain amount of common sense because most of us know what a standard domestic cat looks like in terms of body conformation. Also, if your cat is underweight he will be under feeding as well and you should be able to recognise that.
Also being underweight will be a symptom of illness and there should be other symptoms which you can call upon to make an assessment. There are very many illnesses which cause loss of weight so it would be inappropriate for me to list them here as I am not a veterinarian. The bottom line is that if you’re concerned about your cat’s weight apply common sense principles and you should see your veterinarian.
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