The objective was to evaluate the economic viability of using different lipid sources in the diet of lactating cows. The experiment was done in an area of 42ha, divided into eight paddocks with an average size of approximately 5.3ha each, consisting of Brachiaria brizantha. Twelve Holstein x Zebu crossbred cows were distributed in three 4 x 4 Latin Squares. The four treatments consisted of different lipid sources, as follows: no extra source of dietary lipids, diet with cottonseed, diet with soybean oil, and diet with soybean frying oil. The diets were formulated to meet the requirements for maintenance and production of 15 kg/day, with 3.5% fat. To study the effect of economic analysis, two economic indicators were used: net present value and internal return rate. A one year simulation was produced to study economic characteristics, computing the depreciation of facilities and machinery in this period. The total cost per animal and per liter of milk produced increased with the use of lipid sources in the diet. All treatments had positive values for profit per animal, with observed values of R$ 2.82, R$ 2.68, R$ 2.39 and R$ 2.09, for treatments without lipid source; soybean frying oil as lipid source; cottonseed as lipid source and soybean oil as lipid source, respectively. The internal return rate was more advantageous when no fat source was used in the diet, demonstrating that this treatment is economically better for an investor, generating 0.73% per month. The net present value calculation shows that this investment is viable for all treatments with a 6% discount rate. Treatment without lipid source had a lower production cost and therefore is more cost-effective. Milk production is not viable for any treatment with return rates of the net present value of 10 and 12%.
economic return; fat; performance; production cost
