When it comes to the length of time milk is fed, there are small differences between dogs and cats. Dog puppies can have their first solid food as porridge from 4 weeks of age. Nevertheless, they should still be given milk for a while, as they will only gradually be able to replace their meals with solid food.
They can eat solid food exclusively from the 6th week if this provides them with enough nutrients. Kittens should still receive puppy milk until 8 weeks.