A cat yowling after eating is fairly unusual. I think that there are two initial aspects of the question which need examining. Firstly, what kind of cat sound is a yowl and under what circumstances do cats normally make this sound? The second is whether the yowling is linked to the eating.
A feline yowl is a very particular sound. It is the plaintive sound (sowmehat melancholy) of a cat calling. It indicates that the cat might be distressed, confused or makng a forceful attempt at attention. Sometimes cats with dementia yowl at night because their owner is asleep, they are left alone and they want company and the reassurance of their human caregiver. A cat does not normally yowl before, during or after eating. If a cat wants to be fed they will normally meow. The feline meow is the normal sound to request something from their owner.
Discomfort after eating due to medical condition
So the yowl is normally more of a distress signal and not a request or demand. So why would a cat make a distress sound after eating? Is it linked to the eating? It might be if in eating something the cat suffers distress or discomfort. I am not a veterinarian so I am loathe to write on the subject of medical conditions and illnesses concerning a cat’s digestive system. However, acute gastritis might cause the cat to vomit shortly after eating and before vomiting the cat might yowl indicating pain. This is just one example. Another possibility is that the cat is suffering from a gastrointestinal foreign body. A third possibility is poor oral health which makes eating painful. This is a real possibility. You can confirm this by checking the mouth for gum disease and tooth decay. I’ll stop there. The point I’m making is that a cat might yowl after eating if eating causes discomfort.
Calling for owner
Alternatively, the yowling may be linked to calling for their owner. The call might not be linked to eating. Or the feeding may have distracted the cat and she suddenly realises that her owner is not around and calls out.
In heat and calling
Another possibility for yowling after eating and which is not linked to eating is that the cat is in oestrus. Perhaps she’s not spayed or neutered and yowls to alert males to attract attention.
Confused and eating at night
As mentioned earlier in the article, the cat may be confused and yowl anyway, perhaps at night when she eats. Cats eat throughout the night very often because they are active during the night.
My cat I think is getting a touch of dementia, she does this a lot now in the night when she leaves the bed to take care of urgent business – April DeShields on Facebook.
Siamese cat demand for attention
This is a distinct possibility as Siamese cats have special way of communicating. It can be quite harsh and yowly. The yowling in this instance is not necessarily linked to eating.
Not a demand for food
I don’t think that the yowling is a demand for more food unless it is a modified yowl and the cat is particularly vocal and has an individual way to make demands. However, this would be unlikely in my opinion. It could happen because each cat is an individual and each individual cat makes their own sounds within the general framework and limitations of the sort of sounds that domestic cats can make. So this possibility cannot be completely discounted.
Satisfaction with the food
It may be that it’s a sign of satisfaction at the food provided. Once again I would argue that this is unlikely because, as mentioned earlier, the yowl is a call to attract attention and rarely a thank you for food or anything else provided.
High blood pressure
High blood pressure can cause neurological issues leading to yowling. There is no necessity for it to be linked to eating.
These are my best thoughts on this topic. Of them all, the most likely is that the yowling is unassociated with the eating unless it causes pain and I would check the cat for health issues first. This box need to be ticked before you can move onto behavioural issues which rarely may be linked to dementia if the cat is elderly.