agressive springer spaniel
our 7 year old spaniel has recently started getting aggressive to our cats, He has been around the cats his whole life and had never been aggressive to them. recently he went after our one cat for no reason, we separated him to the kennel for time out. this has taken us by surprise, Now whenever one of the cats walks by he becomes focused at their movement and starts to curl his lip, I have had to grab his collar a couple of times as I don't want him to attack the cat. Not sure what I can do.