Dogmeat almost never made it into the Fallout series because of the tech involved, according to an interview posted over on The Escapist.
The developers also never realized how popular he would turn out to be or the lengths players went through to keep him alive.
"We never expected that Dogmeat would become such a popular character," said lead designer Chris Taylor. "I always intended that the various NPCs that joined up with the player would come to a violent end.
"I was shocked when I heard of all the work people went through to keep Dogmeat alive to the end - especially the hell that they went through with the force fields in the Military Base."
The developers also state that the inspiration for Dogmeat came from A Boy and His Dog and, obviously, The Road Warrior.
More about the pup is through the link.