I’m pretty sure what Nelson meant is that you could keep animals for domestic use, while what OP is suggesting is that animals could be bred for specific purposes. (Not 100% sure about how I’m interpreting either of them though)
First of all, domesticating animals is confirmed a loooong while ago.
Second, domesticating animals wont just be by them following you around because that would be a useless mechanic.
Third, based off the Shooting range beta gameplay we got, we have the option to interact with 1 thing in multiple ways, so there is no doubt that there will be an option to tell a dog to sit/roam or follow you. The dog would be better at alerting the player, but attacking could be better set on a specific species of dogs. Either Nelson has to have aggressive dogs which attack all unknown players (which makes it hard to tame), or they just bark at you. And based on THAT, you’ll know what the dog will do when it sees someone else near your house. Other than that, he will have to do some magic and apply 2 lists if different interactions on the same object.