Multi-goal Optimization Process for Formulation of Daily Dairy Cow Rations on Organic Farms: A Slovenian Case Study

A model for the optimization of daily feed rations for dairy cows on organic farms was developed and tested on a real case study (organic farm) from Slovenia. The methodological approach was based on a combination of linear programming (LP) and weighted goal programming (WGP) techniques. For the formulation of balanced rations, penalty function intervals were introduced. The model took into account five different nutritional and mineral requirements and it precisely calculated the daily rations for dairy cows. This model was used to calculate winter and summer rations using two different scenarios (WGP_SC1 and WGP_SC2), where the net energy for lactation and the total cost of the rations each had a significantly different importance in the optimization process. The results show the WGP_sc2 feed rations are more expensive (summer for 1.19 • and winter for 1.10 •) and more balanced compare to WGP_sc1 and LP feed rations. WGP_sc1 feed rations have the same costs and also more balanced compare to LP feed rations. The balance of the feed rations confirms the fact that deviations from the daily nutrient requirements (never exceeded more than 1%) in the WGP are much lower in comparison to the LP rations.