Domestic animals can be brought to the settlement by capturing their equivalent wild counterpart, or by purchasing them from traders.
They can be slaughtered for meat or kept alive to collect the resources they produce. During winter they have to be kept in stables and be given water and food: straw or frain.
Before you can domesticate or purchase the you have to research the appropicate taming tech.
2 Raw Skin, 4 Raw Meat, 1 Bone