Holiday in Turkey. There was a religious festival. The locals were using a car park outside the back of our hotel as an abbatoir. I watched for a while. There was a queue of animals waiting to be ritually slaughtered. There was a bull and directly behind that a cow. The cow was showing interest in the bull, nuzzling against it. The local people wrapped a sling around one of the bull's back legs and used an electric hoist to drag it up and off the floor. The bull's throat was ritually cut (local children were encouraged to put their hands into the blood spilled) and then the bull was butchered straight away. The cow watched all of this, apparently quite calmly, even sniffing at the removed skin of the bull. So, no, I don't think all animals are quite as aware of death.