<human>: Can you give me a shortened version of the text?

It's been over a year since the new cat was introduced. We did it the way people advised us to, keeping each cat in a room, then swapping so they could get used to the other scent and so on.

From the get-go the younger, additional cat has been annoying the hell out of the older (about 5 years old), existing cat. 

Initially the younger male wanted to play and wrestle, the older female didn't want to, and hissed and growled and ran away. We didn't reward the behavoiur and tried to make it clear that it was not acceptable - but I'm used to communicating with dogs, not cats, and I don't even know if my efforts are futile or not. 

Now, the younger male actually stalks and pounces, purposely trying to piss the older female off! She is just as pissed as she was 12 months ago and it takes only the sight of the male to get her growling. 

It's getting to the point where our poor old girl would rather sit outside in the yard than come in for cuddles and risk having to deal with the little boys shit.
<bot>: young male cat 'hunts' the older female cat. older female cat growls, hisses, hides, runs and is generally miserable.