The cat scene sure looked real to me when I saw it; I believe it was. I rather thought it was a good movie regardless.
As anyone might, I get really sensitive about it, not to mention, as my cat was killed by bastard kids and a dog they had set loose on it years ago, so I wonder how I'd take it. I wouldn't be surprised if it was real, in a recent interview I read, the director shied away from talking about the cat scene, as he's no doubt seen enough controversy over it, but I imagine he didn't want to delve into it anymore because it may have been real and people would have obviously reacted worse.