What happened to Cujo?

In the novel "Cujo" by Stephan King, Cujo, the rabid St. Bernard, is ultimately killed by Donna Trenton. After Cujo had chased and attacked Donna and her son Tad in their car, Donna managed to escape and barricade herself and her son in their car. Cujo continually circled the car and tried to break in.

Donna used a baseball bat to try and fend off Cujo, and eventually, hit him in the vulnerable area of his skull with the bat. Although Cujo was weakened, he still attempted to attack Donna and Tad. Donna saw a piece of wood and managed to stab it into his neck, severing his spinal cord and finally killing him.