Dairy farming has the objective of the "new agricultural policy" is efficient land utilization. But, as the pace of herd size expansion considerably exceeded that of forage area expansion, various problems including manure treatment have accumulated. In this paper, the writer analyzes past trends and circumstances in dairy farming, and seeks to clarify how scale expansion for the purpose of cost reduction has led Hokkaido dairy farming to import concentrate.
　Management circumstances leading up to the 1980s was characterized by high milk and heifer prices, and a low price for concetrate. Under these conditions, technological developments in cattle breeding and feeding, which made it possible to supply concentrate in large quantity, as well as cowsheds for feeding large herds were introduced. As a result, herd size expansion per household and increases in yield per cow were simultaneously possibie. Meanwhile, technological development in forage production enabled a limited improvement in yield per area. As a result, forage area per household did not increase much compared to increase in herd size, thus furthering dependence on concentrate purchased. The feed sufficiency rate droppd and self-supplied yieid per cow stagnated. Although debts increased as a result of investment in scale expansion, the profitability of dairy farming improved. Profitability, correlated on the surface to such farm scale features as cow herd size, was determined essentially by expenditures. This cost structure, increasingly dependent on outside factors represented by the purchase of concentrate, became latent due to high milk prices and the low cost of concetrate.
　After entering the 1990s, profitability became untenable in the face of certain outside elements, namely cheaper milk prices and the high price of concentrate. Farms could not repay their liabilities, thus making the profitability of dairy farming unstable. At the same time, long labor hours due to herd size expansion reached a peak and a manure treatment issue emerged.