We developed a nonlinear programming model that selects the optimal cropping plan and diet ration to maximize farm income over feed cost (IOFC) or minimize greenhouse gas emission (GHG) in a representative 200-lactating cow, 100-ha south-central Wisconsin farm. Nutrition requirements for 6 cow-groups were formulated according to the 2001 Dairy NRC equations. In each of 25 weather scenarios, farm-produced feed, forage quality, and feed production costs were simulated with the Integrated Farm System Model using 25-year daily weather data (1986 to 2010). Feed prices, collected as the monthly market prices from the Understanding Dairy Market website during 2015 and 2016, were randomly assigned to each scenario. The model contained 3 sections: (1) Maximizing IOFC under a fixed or flexible cropping plan; (2) Minimizing farm GHG emissions under the fixed cropping plan; (3) Maximizing IOFC by constraining the GHG emissions. Farm IOFC included milk and surplus feed sale, feed production cost, and feed purchasing costs. Hedging decisions were included in the first section to compare the difference from contracting feed or milk prices with different cropping plans. The optimal solution maximized the total IOFC across 25 scenarios through the expected utility theory. Aggregated IOFC across 25 scenarios was $8.31/cow per d with the original cropping plan of 54.6 ha of corn and 45.4 ha of alfalfa while the GHG emission was 1.33 kg CO₂eq. per kg of FPCM. The model chose to produce at the greatest production for all scenarios with the original cropping plan. Diet formulation and purchasing strategies changed for each weather scenario to maximize IOFC according to farm-grown feed condition. Flexible optimal cropping plans for each scenario improved IOFC slightly (0.2–0.4% depending on risk attitude and elasticity); however, incorporating both flexible cropping plans and commodity hedging improved farm IOFC by 16%. The minimum GHG emission was 1.20 kg CO₂eq. per kg of FPCM with IOFC at $7.04/cow per d. The farm reduced milk production and changed the rations in some groups and scenarios to minimize GHG emission. By increasing the upper limit of GHG emission from the minimum emission in the third section, farm IOFC increased with a declining rate.