Consegna del latte con un carretto per cani, Belgio, (1880) [1573 × 1223]

That seems like the must annoying way to tie five dogs to a cart!

My grandfather did that, in Brugse Poort in Gent.

My dad was born just before WW2 and he often talks about dogs who actually loved to pull carts. So I always assumed this happened until somewhere around the 50’s.
There were different taxes for regular dogs and pulling dogs. Pulling dogs were cheaper, so in those days, if you had a Jack Russell, it was often registered as a pulling dog, even though the dog had never been in front of a cart.