The development of the Colombian agricultural sector, predominantly rural country, has combined two models: one led by rural entrepreneurs and one that has been promoted by the rural economy. The two have survived to the debate on agricultural policy that sought the legalization and use of land, access to credit and productive development in general. This historical reflection with support regional sources, a policy associate for the legalization of public lands in relation to business development in rural sector: Livestock in Middle Magdalena in the department of Antioquia in the first half of the twentieth century. The farm and rural production unit is understood as rural company and the landowner as an entrepreneur. In the end, it is presented the magnitude of farms in the region and period studied. This product of the doctoral thesis “Rural enterprises in Antioquia: the case of livestock in the Eastern and Middle Magdalena in the department of Antioquia, 1920-1960.