If farm animals are on the same intellectual level as dogs why do we need dogs to herd them, could just train the sheep to herd themselves
Pigs are a farm animal that are considered as intelligent, and possibly more so, than dogs. People do train them.
Not that the ability to be trained is an accurate gauge of intelligence because a lot of intelligent animals aren't as subservient as dogs. Cats, for example.
But that's neither here nor there because AFAIK cats and dogs aren't tasty when cut into strips, cooked, lashed with brown sauce, and place between two pieces of bread.