Cattle Ranch is an Empire resource building. It is the tier 3 building of the pastures building chain. It requires the pastures resource in order to be built in a settlement.
Background
Milk, beef, mutton, pork and goat are all valuable commodities in a hungry nation such as the Empire.
Soldiers cannot march on empty stomachs, and so large cattle farming operations are needed to prevent famine and make a hefty profit for their owners too. The more industrial-scale farms are almost always owned by the nobility, but an increasing few have come under the sway of Burgomeisters as well.