Economical Sensitivity of Four Main Parameters Defining the Room for Investment of Automatic Milking Systems on Dairy Farms

摘要

The introduction of an automatic milking system (AMS) on a farm has a large influence on farm management. In many cases it may increase milk yields, and it may reduce labour requirements. The farmer may also choose to change his farm management on several other points depending on specific circumstances, e.g. summer feeding instead of grazing. All of these changes have more or less significant economical and social consequences. In order to evaluate the economical consequences the “room for investment” was introduced. The room for investment (RFI) equals the total amount that can be invested in an AMS on a farm, to yield the same net return compared with an alternative (conventional) milking system (in other words to break even). It is calculated by adding (annual) returns from increase in milk yield (Rmy), (annual) savings in labour costs (CL), savings in annual costs by not investing in a alternative milking system (ACAlt) other (annual) savings (Smis), and substracting (annual) miscellaneous costs (Cmis) due to robotic milking and then by dividing this total by the annual costs of the AMS (ACAms). In formula: RFI = (Rmy + CL + ACAlt + Smis - Cmis) / (ACAms) Depending on the circumstances and the type of farmer these parameters vary, thus influencing the RFI on the farm. Using a deterministic simulation model Dairy Farm Budget Program (BBPR) various calculations were made to examine the sensitivity of the RFI for the main four parameters. BBPR consists of three major parts that are integrated at farm level. The standards for fodder supply play a central role and incorporate a set of more fundamental models for simulating feed intake and production of dairy cows, young stock, grass growth and grassland utilisation. Technical results are translated to economic results with economic modules. Mineral surpluses and energy used are calculated with environmental modules. First a basic farm was defined with a traditional milking parlour. Using BBPR the economic results of this farm were calculated. The basic RFI for this farm was calculated for this farm making realistic assumptions for Rmy, CL, ACAlt, Smis, Cmis, and ACAms. No other changes than the introduction of an AMS were made in the farm set-up or in the farm management. Then Rmy, CL, ACAlt and ACAms were varied, to determine the sensitivity of the RFI for changes in each of these parameters separately. Finally more than one of the four parameters were varied to show their relative effects on the RFI. Using RFI and sensitivity, calculations can be made for every individual situation to see if robotic milking is an economically interesting alternative for that farm(er).