MILK PER ACRE SPREADSHEET FOR COMBINING YIELD AND QUALITY INTO A SINGLE TERM

Improvements in forage quality have historically been difficult to qua ntify or determine cost/benefits. A spreadsheet (Milk90) was developed that combines yield and quality into a single term using the concept of milk produced per acre of forage. Forage yield and quality, animal production, and inputs costs can be varied. The spreadsheet assumes ma ximum forage use and approximates a balanced ration given the forage q uality, with corn (Zea mays L.) and soybean (Glycine max L.) meal used as the energy and protein sources, respectively. Milk from forage is determined as the percentage of total ration energy coming from forage times total milk production less animal maintenance requirement. Milk per acre is calculated as milk per ton of forage times forage yield. The spreadsheet allows comparison of changes in yield, forage quality, and production costs. Milk90 is intended for extension and teaching p urposes to allow ranking of benefits resulting from changes in managem ent practices. The spreadsheet operates in Lotus 123(1) version 2.0 or higher and is available on request.