The killing of Candy's dog was related to when George killed Lennie in several ways. First of all, both the dog and Lennie were weak, and killed as soon as they became useless to the society. Also, the dog was Candy's friend, and Lennie was George's friend. In both cases, Slim viewed the deaths as mercy killings. The last similarity was that both Candy and George felt lonely after the death of their companions. The difference was that Carlson killed the dog for selfish reasons, while George killed Lennie out of mercy. This was how the killing of the dog relates to the killing of Lennie.
The society wished both Lennie and the dog dead as soon as they were no longer useful to it. The dog was smelly and old, therefore it became unwanted by the society. Carlson said "God awmighty, that dog stinks. Get him outta here, Candy! I don't know nothing that stinks as bad as an old dog.
You gotta get him out." (Pg. 45). This showed that even though he was probably aware of the fact that the dog was Candy's good friend, he did not care. He only cared about his own interests, which were to get rid of an old animal that was useless to him. This showed his self-centeredness, and since Carlson represented the society, it also showed how unwilling the society was to understand its own vice. Slim said "He's all stiff with rheumatism. He ain't no good to you, Candy. An' he ain't no good to himself. Why'n't you shoot him, Candy?" (Pg. 45). This displayed that Slim views this as a