My 12 week old lab x collie has just had his vacs and I would like to start taking him for walks but have been told to keep them short at first. However once he's on his lead theres no stopping him and he just wants to keep going. Will this do him any harm.

Don't forget, you're the boss! You decide how far you go. Two or three 15 minute walks will be fine for now. He doesn't need walks for exercise - he needs them for socialisation and mental experiences. Take him to as many different places as you can - around the town, the High Street, the pub, the railway station, the bus station - everywhere you can think of!
:)

In a word, yes! You are in charge. You would not expect a 12 week old human baby to decide what to do, neither should a puppy.

Hi guys,

Ruby, just a thought. If you're worried that your pup is a bit bored with only going for a couple of really short walks, you could always so what I did with mine.  If you've got a car, drive to the nearest large supermarket when its busy, park the car and open the back and let him watch for a short time.  This gets him used to the noise and excitement, while keeping him under control.  I found it a great help to get mine used to people as my breed (labrador) does have a problem with jumping up and generally being over-excitable with people.
I'm lucky enough to have a tailgate thingy in my car, so, I'd get a drink and a paper and sit on the bumper with the back door up while Kester watched with great interest.  People used to come up and say hello, which was also great.The people who worked at Tesco thought I was nuts, but after a few weeks of doing it a couple of times a week, the security guards and the trolley collectors all used to come and admire him.

Have fun - they're not that small for very long.
Cheers Ali :)

general rule is 5 mins exercise per month of age, so a 3 month old should be having walks of around 15 mins - too much now could cause bone problems later in life - its hard cos as you say, they seem to be able to go on forever!!!!