Cat suddenly hates other cat?

  I have two adult cats. Both are four years old. Both are siblings and were raised together. Both are spayed/neutered. Last week I noticed one cat seemed hurt so I took him to the vet only to find out that he had a bad fall from some place high. I brought him home and his sister started freaking out and hissing around him. This has happened before when he comes home from the vet (i think it's because he has the vet smell) so I didn't worry. Approximately one week later she is still doing it and now I'm starting to worry. Before the freak outs last 1-2 days and everything is fine. Now that it is lasting a week it is starting to get on my nerves and more importantly I'm worried that something is wrong with one of them. Any suggestions from cat owners as to how I can resolve the situation and get my cat to stop freaking out would be most helpful.
This is why it's important to keep cats isolated for a few hours when they come home from the vet. I would separate them for tonight and rub down the boy with something that smells like him - maybe a favorite blanket or bed. Then tomorrow you can try reintroducing them, preferably after they are both fed and calm. Getting a Feliway plug-in wouldn't be a bad idea either.
It's no big deal. Kitty came back from the vet with weird smells, which is why the other cat is hissing at him. Obviously kitty # 2 is really freaking out. pets question and answers,www.5d2d.com

You could a) get some Feliway spray, b) rub a towel on the freaking out kitty to get her scent on it, then rub it all over the other kitty, thus changing the way he smells (to her).

Good luck!
They may just not recognize the scent. My cats were siblings and after one had surgery her sister did the same thing. They may also sense something is wrong with the injured cat and instinctively dislikes them. My cats just seem to get over it but it took longer than a week.
cats will be cats .... I had cats who were siblings that got into fights all the time. They did ended up getting along afterwards later
He is fighting to be the leader of the pack
I'm not really sure, like you said this happening is common but usually stops after a day or so ...



My suggestion would be to first, wash all their beds, blankets, toys, etc to change the smells. Then procede to wipe down surfaces, including couches, arm chairs, desks, window sills, etc to get rid of those smells too. Before putting the bedding and toys back (so the cats don't smell them up), give each cat a bath and dry them with the same towel. pets question and answers,www.5d2d.com



This might work because the vet smell is still going to be on your cat, and thus will leave the vet smell all over your house. Maybe there was something particulary scary to cats at the vet that left a strange or frightening smell. By washing items they use and then washing them, everything is neutral again.



I don't think there is anything wrong with either of them, so you shouldn't feel worried about that!



However, I would just monitor your cat that came home from the vet: are they sick? Cats generally don't like other sick cats. Also, if they're taking any new medication that could cause something too.



And finally, wash/empty the litter box as well.
Ohh boy do I relate to this. I have this issue currently. I have one older cat that is dying due to renal failure and those she is doing well, the others sense she is sick. I have had to give her a room to herself to isolate the her from the beatings they will give her. It means I have to give her extra attention since she is isolated but it's safer for her. Anytime two cats that were friends begin to fight, there are several things to look for,

pets question and answers,www.5d2d.com



first, is one sick or hurt in anyway?

second, is there a feral or female/strange cat new in the neighborhood that is frequentling your area? (this is a major problem for me. I keep my cats inside but they know if here is an intruder in our yard and will spray the walls by the doors/windows inspite of being neutered and also beat on each other) Do NOT feed strays or they will keep coming back. Your cats will know this.

Next, Have you made any changes to their livng space. (IE your home) Cats are creatures of habit and don't like change. Each should be able to have space to all his own. MY cats all have certain areas of the house they consider their own territory and while fights will still break out, it minimizes things.



Some squabbling is to be expected. It just goes with the territory but if mine are suddenly beating on each other or on one in particular the first thing I do is look for illness and that can mean a trip to the visit. My oldest kitty is in renal failure now. (she's doing fine with help) While it took me longer than it should have to know this, my other cats knew long before me and I now know the minute they began to pick on her, there was a problem. pets question and answers,www.5d2d.com

Finally, could they be jealous of each other and competing for your attention? I have two that do this Both wish to be the favorite. I try to give each lots of attention, but what has helped the most is to be sure each has his own territory where he feels safe. Cats are extremely intuitive/sensitive. They will also react to any stress YOU are having in your life and that can set off fights.