Dairy farms are constantly challenged with decisions. The evaluation of the outcome of such decisions requires the integration of technical and economic effects over time. The complexity of the multiple interactions can be resolved with the use of mathematical models that integrate biological and economical processes. The objective of the study was to develop a stochastic model to simulate technical and economic consequences of changes implemented in dairy farms. Individual cows of a dairy farm are uploaded. Data on reproduction, diseases, economics, labor, finances, management decisions, facilities and environment are introduced (default values are provided). Farm performance is modeled over a period and technical and economic performance is provided in the output. An 810 dairy cow farm (10,800 L/cow/year), 205 DIM, 15% pregnancy rate with average incidences of diseases and prices was used as a model. Three scenarios were tested: (1) CON = No change in the current conditions; (2) CULL = Increase in voluntary culling rate by 5 percentage units (31 vs. 36%); and (3) SEMEN = Change from the use of low cost semen vs. high cost semen (€10 vs. €20) assuming that the use of the more expensive semen results in an increased genetic potential of 2% in the daughters. A simulation of 10 years was repeated 40 times with stable technical and economic conditions. At the end of the 10-year simulation, CULL increased benefits by 14%. Treatment SEMEN resulted in reduced income for the first 5 years, probably due to the increased cost of semen and the time required for the expression of the genetic improvement. After the 10-year simulation, SEMEN accumulated a 20% loss, although in the year 10 of simulation SEMEN had a 16% higher benefit. It took 13 years to reach the breakeven point for SEMEN. Although genetic improvement cannot be ignored in dairy farms, the benefits are long-term. In contrast, CULL resulted in short and medium term benefits.