ADDITION OF LIVESTOCK PERFORMANCE AND ECONOMIC-FACTORS TO YIELD AND QUALITY ANALYSIS OF FORAGE MANAGEMENT EXPERIMENTS

Producers adopt new technology to gain an economic advantage. This stu dy was conducted to determine whether agronomic data alone provide suf ficient information to evaluate the profitability of forage management practices. Responses of four annual ryegrass cultivars (Lolium multif lorum L. and L. multiflorum x L. perenne L. hybrids) to four rates of N fertilizer were determined in a field study. We measured the followi ng agronomic data: dry matter yield (DMY), in vitro dry matter digesti bility (IVDMD), crude protein (CP), neutral detergent fiber (NDF), aci d detergent fiber (ADF), and relative feed value (RFV). We calculated three measures of economic value: forage cost per ton, forage cost per acre, and returns per acre. Forage costs were computed using local co sts for inputs. Return calculations were made using a hypothetical ste er feeding operation as a model. Returns were defined as income over f orage production, feed supplement, livestock purchase, and livestock o verhead costs. Diets were formulated to feed steers from 600 to 800 lb (1.2 and 3 lb gain/d) using the forages from the fiel dstudy. We vari ed purchase and selling prices from $0.70 to $0.95/lb. Each agronomic measure clearly ranked the four cultivars. Yield and quality were nega tively related, so a producer attempting to select a cultivar and N ra te would be forced to estimate the relative values of yield and qualit y. Cost of production data also produced distinct rankings of the mana gement treatments. Based on returns, the four varieties were ranked in six different orders depending on market conditions, so no one cultiv ar could be recommended as the most profitable. Return analysis does n ot clearly differentiate among management treatments unless livestock and economic conditions are specified within a narrow range. As a resu lt, return analysis is not useful for routine interpretation of forage management trials. Livestock and economic factors should be used to m ake recommendations to individual producers, however, because agronomi c data alone are not sufficient to justify the adoption of a new pract ice. All forage management research should include yield and quality d ata that will allow return estimates to be made.