Describe the fight and the final outcome of the showdown between Buck and Spitz?

When Buck decides that he can no longer take the abuse Spitz gives to the members of the pack, he fights for all he is worth and ultimately defeats Spitz.  The rest of the pack set upon Spitz once he is defeated and quickly dispatch what little is left of him.

One night the dogs spot a rabbit, and they chase after it, joined by a nearby pack of fifty police dogs. Buck, leading the pack, rejoices in the hunt, all of his instincts overwhelming him. Spitz, cold and calculating, takes a different route to head off Buck before he can reach the rabbit. Spitz jumps upon the rabbit, and without thinking Buck leaps upon him. He knows that their time has come. This is a fight to the death. At first Spitz clearly betters Buck. After a few moments Buck is covered in blood, while Spitz is untouched. Spitz is an experienced fighter, but Buck possesses imagination. He tricks his rival, and is able to break both forelegs. Spitz is beaten. Buck knows that this is no place for mercy. He knocks Spitz onto his back and the sixty dogs rush in to finish him off.