Beef Cattle Management Update WINTERING COW: AN EXCEL SPREADSHEET TO BALANCE WINTER Issue 44 BEEF COW RATIONS, AND EVALUATE WINTER FEEDING PROGRAMS August 1997 ON ANNUAL COW COST AND CALF BREAK-EVEN PRICE

An Excel (v 7.0) spreadsheet was created to simplify balancing winter diets (energy and protein), estimating feed needs and evaluating the impact of winter feeding programs on annual cow cost and calf break-even price by using inputs readily found on the farm (e.g., forage test results, accounting and production records). The spreadsheet operates on the substitution method and requires the following inputs: cow energy (TDN) and protein (CP) requirements, body condition score (1 = thin, 9 = fat), average effective temperature for the period in question, forage, energy and protein supplement dry matter (DM), TDN and CP concentration, feeding period length and feed delivery method, other yearly feed costs (pasture, and mineral and vitamin supplements), yearly direct and indirect costs, number of cows in the group, group weaning weight and percentage, and projected calf price. A special feature permits economic evaluation of alternative calving date scenarios (30 days earlier or later than actual). Adjustments based on BCS, effective temperature, feed quality and delivery method, weaning weight and percentage, and calving date permit economic evaluation of various scenarios the user may encounter or wish to simulate. The spreadsheet was used to simulate the impact of BCS 4 vs 5 at the beginning of the winter feeding period, feeding forage with vs without a bale feeder, or calving February 15 vs March 15 (same weaning date) on annual cow cost. One unit drop in BCS, feeding without a bale feeder or calving 30 days before March 15 represented increases in annual cow costs of 2%, 6% and 4%, respectively.