I disagree with that definition of replacement value (while acknowledging that it may be a legally correct one). The vet bills, cat food and other routine expenses would have been incurred with either the old cat or a new one. They are not additional expenses precipitated by the loss of the old cat.
Likewise, if someone totals my car, I expect enough money to buy a new one (including inflation, etc.), but I don't expect money to pay for my gas, oil changes, tuneups, etc., because those are expenses I would have had anyway.
I was simplifying a bit - regular, commonsense maintenance that would be common to both the original property and any replacement are generally not covered, but extraordinary maintenance costs (a documented new/rebuilt engine and transmission in a car, for example) are - if you are talking about defensible amounts when calculating an award. You wouldn't want to have your 1998 Jaguar that you just put a new engine in replaced by a 1998 Jaguar with a 100,000 mile old engine, would you? No, that wouldn't be a fair replacement.
In the case of a cat, things like chipping (the microchip ID thing), spaying/neutering (and not by the amateurs at the SPCA), and declawing (something I disagree with, but which is done by many cat owners) are all "supernormal" expenses that would have to be spent to bring the "replacement cat" up to the "spec" of the old one. All of them cost a significant amount of money - the operations I just mentioned can easily run over $1500 depending on the vet and the locale. "Normal" vaccinations and food would not normally be a defensible claim item.
Also, remember that if the other party is not there to dispute your claims, it is legal to claim all your expenditures, period. It is the responsibility of the defendant to point out why a judgement is actually excessive. All the judge is supposed to do is look at your claim and determine if it is fair or not. Remember, this wasn't a jury trial, where 12 random people can choose ridiculous amounts. She had to come up with some factual basis for her claim and she did. The fact that some of it would have been stricken if the other party had been there to object does not invalidate her request.
For the record, I didn't include costs of normal maintenance in my recent court case, much to the dismay of my lawyer. However, I don't have a problem with someone else doing so if the other person is too stupid to show up. Call it a stupidity tax.