The aim of this paper is to present possibility to combine different mathematical methods for analysis of ration composition changes in actual economic environment. On the basis of mathematical programming models, based on constraint optimization, the influence of price-cost ratios on the trends of efficient beef ration formulation in the period 1998 to 2008 has been analysed. For investigation positive and normative mathematical methods have been utilized. The normative part of methods applies a common linear programming approach supported bz penalty function. To find out the "reaction"of rational farmer within given circumstances, simulation was upgraded with positive mathematical programming approach. Obtained results illustrate change in ration composition by increased maize silage quantities and significantly lower amounts of grass silage during last decade. Due to Slovene natural conditions it is obvious that such a dramatic shift is impossible, therefore more attention should be paid to reduction of grass silage production costs.