This would be the next step I would take if you're unable to get her to eat. Here are my concerns: When cats begin not eating their liver suffers the effects. This can result in a condition known as Fatty Liver Disease (aka Hepatic lipidosis) which can result in liver failure if not addressed. More info here: http://www.peteducation.com/article.cfm?c=1+2135&aid=217 We may never know the original cause leading up to this, only that the symptom of not eating is extremely risky for cats and simply monitoring at home following the third day is typically even more risky. I would schedule some diagnostics at this time. Bloodwork to look at the liver values would be wise, but also to determine on the blood work if there are any additional concerns which might have originally been the cause of not eating. We can see medical concerns like liver disease, kidney disease, bladder infections, periodontal disease, etc. all contribute to not eating in any age of cat.
If she's willing to drink cat milk, encourage her to do so as this will keep up her caloric intake. I would also try pureed baby food in chicken, turkey and similar flavors. Avoid those that contain onion or garlic in the ingredient panel. You might also want to try a gravy lovers variety of cat food to see if she will ingest this. Quite often when cats will eat liquid foods but not canned or kibble they're suffering from pain in the mouth. That said, there's no way to be absolutely certain an underlying condition, such as those mentioned above, is not the cause or has not developed with her avoidance of food and, thus, examination and diagnostics are indicated.
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