Goat
The goat is a formerly domesticated animal originally from the Middle East. After collapse, goats went feral.
#Human usage
People of the Fifth World hunt goats for meat and make clothing from their skins. More rarely, when specializing in relationship with goats (see below), they may milk goats.
#Specialization
A community that specializes in relationship with goats will likely tend towards horticulture, and therefore live in settled villages. Alternatively, they may follow the semi-feral herds of goats as they travel, possibly going so far as to burn out fields for them to graze in.
They may have a tradition wherein certain people manage to so closely befriend individual female goats that the goats allow them to milk them. One such tradition may limit only children to this task (maybe young girls, in vague memory of milkmaids), as milk of any kind is generally meant only for babies. Regardless, the consumption of milk or milk products by adults is very rare in the Fifth World. Milking animals, and making butter or cheese from that milk, would make this community fairly unique. Such a community clearly wishes to live deliciously.