Having said and read: I do not believe that the teaching of science requires the sacrifice of any living organism simply to teach acedemic points.
In this sense, a frog a cat or a dog should not be killed simply to teach anotomy. But, on the other hand, if the animal was killed by other means, say an accident, or for other legitimate reasons, then I would agree with and support the use of the corpse to be used for teaching. In this sense it would be a worthwhile endeavor.