A family farm model was used in order to study the economic importance of pasture utilization in sheep breeding and cattle fattening during the summer period. The model was based on real technological, organizational and economic conditions of a farm in the hill and mountain regions of eastern Serbia. The economic competitiveness of different ways of pasture utilization was studied based on the processing price of green feed obtained from pastures. Under the given economic conditions, a higher processing price of feed may be expected in cattle fattening. Thus, from the economic standpoint farms involved in cattle fattening would have a justifiable production. However, due to the changing market conditions it was necessary to determine the processing prices at different price levels of fattened cattle, animals for fattening and the production value per breeding ewe. A special diagram was constructed enabling a rapid and easy determination of the processing price of feed in practice taking into account different market conditions of sheep breeding and cattle fattening. In addition using the same diagram it was possible to determine the relationship between the production value per breeding ewe and the price of fattened cattle at different price levels of animals for fattening inducing the same processing price of pasture feed.