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 study was conducted to determine whether agronomic data alone provide sufficient information to evaluate the profitability of forage management practices. Responses of four annual ryegrass cultivars (Lolium multiflorum L. and L. multiflorum × L. perenne L. hybrids) to four rates of N fertilizer were determined in a field study. We measured the following agronomic data: dry matter yield (DMY), in vitro dry matter digestibility (IVDMD), crude protein (CP), neutral detergent fiber (NDF), acid 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 costs for inputs. Return calculations were made using a hypothetical steer feeding operation as a model. Returns were defined as income over forage production, feed supplement, livestock purchase, and livestock overhead 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 varied purchase and selling prices from $0.70 to $0.95/lb. Each agronomic measure clearly ranked the four cultivars. Yield and quality were negatively related, so a producer attempting to select a cultivar and N rate would be forced to estimate the relative values of yield and quality. Cost of production data also produced distinct rankings of the management treatments. Based on returns, the four varieties were ranked in six different orders depending on market conditions, so no one cultivar could be recommended as the most profitable. Return analysis does not clearly differentiate among management treatments unless livestock and economic conditions are specified within a narrow range. As a result, return analysis is not useful for routine interpretation of forage management trials. Livestock and economic factors should be used to make recommendations to individual producers, however, because agronomic data alone are not sufficient to justify the adoption of a new practice. All forage management research should include yield and quality data that will allow return estimates to be made. Research Question The economic value of forage crops is not easily determined because most forages are fed on the farm where they are produced. Forage research results are normally evaluated using various measures of yield and quality. This study was designed to determine whether agronomic data alone are adequate indicators of the economic value of a practice to a producer. Literature Summary Many research articles report on the responses of forage crops to different agronomic treatments. Producers use a new practice when they perceive that the practice will give them an economic advantage. Authors do not always report the same type of data because their articles generally focus on one aspect of a forage‐livestock production system. Articles may or may not contain information on forage yield, forage quality, livestock performance, or production economics. The objective of this paper is to compare traditional agronomic analysis of an experiment with a more detailed analysis that incorporates livestock and economic information to predict profitability. Study Description Data from an agronomic study of annual ryegrass were used for this report. The agronomic experiment was designed to evaluate the performance of four cultivars of annual ryegrass at four rates of N fertilizer. Forage yield and quality were collected from the field study for 2 yr. The results were analyzed in a traditional manner using the following measures: dry matter yield (DMY), crude protein (CP), in vitro dry matter digestibility (IVDMD), neutral detergent fiber (NDF), acid detergent fiber (ADF), and relative feed value (RFV). Forage production costs per acre and per ton were also calculated and used to evaluate the treatments. Profitability was determined by calculating returns per acre. Returns per acre were defined as returns over the following major costs: crop production, energy and protein supplements, livestock purchase, and overhead for livestock. These calculations incorporated crop yield, crop quality, crop production costs, animal performance, and market conditions. The livestock system chosen for this analysis was a hypothetical feeding operation for beef steers (600 to 800 lb). A wide range of livestock purchase and selling prices was used. A computer program was developed to simulate feeding the steers and to calculate returns. Applied Question Can agronomic data alone indicate the profitability of forage management options? Annual ryegrass varieties and N rate treatments were compared using forage yield, quality measures, and production costs (Table ). The cultivar rankings differed for DMY and quality. High ranking for DMY was generally accompanied by low ranking for quality. Production cost rankings were related to forage yield. Higher yields resulted in higher costs per acre because the main difference among treatments was the higher harvesting costs. Cost per ton decreased as yield increased because the cost per acre was divided by the yield and this largely negated the effect of harvesting costs in the ranking. These methods of comparing treatments do not make selection of a profitable alternative simple. The relative values of yield and quality must be estimated since the yield and quality rankings are generally opposite for a group of agronomic treatments. In a forage‐livestock production system the relative values of yield and quality depend on livestock nutritional requirements, supplement costs, initial livestock costs, and market prices for livestock products. The forage‐livestock system is complex because two separate biological systems (forage and livestock) interact. Forage management decisions ultimately have an effect on livestock production. Finally, market forces affect both costs and returns. We calculated returns per acre from a beef steer feeding operation for each of the agronomic treatments (Fig. ) to determine how well the agronomic rankings (Table ) predicted the economic impact of the treatments. Returns were markedly different depending on agronomic factors (cultivar, N rate), livestock production factors (daily gain), and market prices (purchase and market prices for steers). The four varieties were ranked in six different orders, depending on market prices. Each agronomic variable results in a single ranking, so the agronomic data cannot readily predict the economic value of a management practice. Recommendation Agronomic data do not directly show the value of forage management practices. Return analysis of forage management research results is desirable for recommendations to a specific producer and forage research reports should include enough yield, quality (CP, NDF, and ADF or IVDMD), and production data for return analysis. The information could then be used to calculate expected returns for a specific farm and management system that would take local market conditions into account. However, return analysis is too specific and too sensitive for routine comparisons of forage management treatments and the formulation of general recommendations over wide areas and markets. Rankings of annual ryegrass cultivars and N fertilizer rates based on agronomic and production cost factors. Quality Costs Treatment DMY CP IVDMD NDF ADF RFV $/acre $/ton Cultivar Aubade 1 3 4 4 4 4 3 1 Tetila 3 1 1 1 1 1 1 2 Polly 3 1 2 2 2 2 1 2 Dalita 2 2 3 3 3 3 2 1 N rate lb/acre 0 4 4 ‐‐ 1 1 1 1 3 50 3 3 ‐‐ 2 2<