I'd look for some dog carting/drafting groups on Facebook or a weight pull/carting/drafting forum to join for specific training information. I know you'll want a specialized harness (they can be fairly pricey) that won't squeeze the dog when they pull a weight forward. You'll probably also want to start in small increments, starting with the dog pulling a light length of chain and working up to a cart (then working up weight on the cart, if you want to load it). Just like humans, a dog can get easily hurt if you ask them to do something physically demanding without having built up the muscle for it. There is a thread here that was originally written by someone knowledgeable about weight pull: Everything You Wanted to Know About Weight Pulling
I know it's not specifically about carting, but the basic gear, physical conditioning, and training for pulling a cart vs. pulling weights for competition are going to be very similar. Aside from the cart itself, of course!
I'd be very picky about the German Shepherd I got to do this. I don't know how it is where you are, but in the US and Western Europe, where I've lived, there are lines of GSD (German Shepherd Dog) that have serious physical problems, roached backs (and I mean really roached, not just slanted down when the dog is stacked), weak pasterns (the 'ankle' of the back leg), and/or really exaggerated angulation overall. This can impact what they can and should do, physically, as they'll be more prone to injury. There are some really excellent, sound GSD lines too! But if you want an athletic, active dog, definitely look for breeders who are producing physically sound dogs.
You will also need the dog to be somewhat mature before starting pulling. It's not as high impact as some activities, but you don't want a growing puppy putting too much strain on their bones and joints. I'd personally want to wait until a dog is at least one year old - waiting for the dog to grow has the added bonus of only needing to buy a pulling harness for their adult size, instead of multiple as they grow bigger. A community that specializes more in weight pull or carting can help you more with the specifics about what exercises are appropriate for what ages.
I know it's not specifically about carting, but the basic gear, physical conditioning, and training for pulling a cart vs. pulling weights for competition are going to be very similar. Aside from the cart itself, of course!
I'd be very picky about the German Shepherd I got to do this. I don't know how it is where you are, but in the US and Western Europe, where I've lived, there are lines of GSD (German Shepherd Dog) that have serious physical problems, roached backs (and I mean really roached, not just slanted down when the dog is stacked), weak pasterns (the 'ankle' of the back leg), and/or really exaggerated angulation overall. This can impact what they can and should do, physically, as they'll be more prone to injury. There are some really excellent, sound GSD lines too! But if you want an athletic, active dog, definitely look for breeders who are producing physically sound dogs.
You will also need the dog to be somewhat mature before starting pulling. It's not as high impact as some activities, but you don't want a growing puppy putting too much strain on their bones and joints. I'd personally want to wait until a dog is at least one year old - waiting for the dog to grow has the added bonus of only needing to buy a pulling harness for their adult size, instead of multiple as they grow bigger. A community that specializes more in weight pull or carting can help you more with the specifics about what exercises are appropriate for what ages.
