Anyone know what the ruling is for this?

Whilst we were walking down the fairway to play our second shot of 2 balls nicely in the middle of the fairway a dog ran out from a path nearby and picked up one of the balls. despite it's owners endevers the dog ran about proudly with the ball in its jaws. As the owner managed to grab the dog it had dropped the ball somewhere. The owner apologised and said the dog had never done that before despite walking down the side of golf course many times. As my ball was the one that had gone I guessed roughly where the ball was in relation to my partners ball and replaced it playing on.

If this had been a competition would I have treated this as a lost ball and replayed the shot? or was replacing the ball the right action?

Rule 18-1 Ball Moved by an Outside Agency

The ball must be replaced without penalty.

Hmmm, I remember seeing a famous incident at sawgrass on the island green where a shot was played which landed on the green and the ball vame to rest just as a seagull flew down and picked the ball up in its beak before depositing it in the water as it flew away. The player then went and played his shot from the Dropzone under penalty of 1 stroke which is why I questioned this when my playing partner said it was about here drop a ball and play on. I love the game to bits but I find some of the rules a little confusing some times. The pros call on an independant official because they are not sure sometimes, what hope have I got so long as the people I play with think the decision we make is correct.

this one

http://www.youtube.com/watch?v=zr8JwKaXONA

The player in question was Steve Lowery. He was allowed to replace his ball without penalty under rule 18-1.

thanks for your help Richard, I feel less guilty now.