If even a 2 minute drive down the road to the local vet results in your cat pooing in his travel box and limiting his food intake prior to car rides and trying to keep him calm and comfortable in the car makes no difference, your cat is clearly very anxious about car journeys. He’s frightened of confinement, the box, leaving the house, and the car with it’s movement and smell.
And how do cats know they’re going to the vet? I’ve lost count of the times people arrive late for appointments because the cat has got wind of it and bolted or hidden.
Let him use the box not just for scary travel but as a bed and safe place in the home. Sit in the car with him without going anywhere (the neighbours will think you’re weird, but they probably do anyway). If he’s OK with that, start the engine for a bit, but don’t go anywhere. Try feeding him in the car to give it some positive associations. Don’t hurry things.
We use Zylkene (a modified form of casein, one of the milk proteins), Feliway (the happy cat pheromone – you can get small spray bottles for travel), SereneUm (contains B vitamins and tryptophan) and Bach Rescue Remedy or Homeopet Anxiety Remedy.
And once again, why is it that most of my life seems to involve discussions of pee and poop?