I watched this with my kids the other day just to share some of my childhood memories with them.
I sure was surprised to learn the plot of the movie was that some bad guys had developed a new type of bullet and needed to test it out on the thick skulls of live animals. They try to kidnap Beethoven so that they can shoot him in the head. In order to accomplish this, they abuse the dog until it attacks one of them and then cover themselves in fake blood so the family is forced to agree to have the dog put down.
Somehow childhood me had blocked all of this out and just remembered “haha funny big dog”.