Development of a Curvilinear Economic Function for Carcass Leanness
Purdue University 1997 Swine Research Report. The amount of selection pressure placed on a performance trait relative to other traits is determined by its economic value relative to the other traits. The economic value of carcass leanness should be based upon current and anticipated future carcass merit programs. In the mid 1980s, pork processors were merchandising partially trimmed lean cuts. During the late 1980s and early 1990s, consumer demand for increasingly lean products was communicated via retailers back to the pork processors. Subsequently, pork processors focused on the production of a higher percentage of highly trimmed lean products. In the early to mid 1980s, the economic value for backfat based on carcass cut-out and the weights of partially trimmed pork products was estimated at approximately 1% per .1 inch change in backfat thickness. Based on the production of highly trimmed lean cuts, the economic value for backfat increased to a range of $14.00 to $18.00 per inch. Recently, a value of $15.00 was estimated by the National Swine Improvement Federation (1996). A linear economic value for a measure of carcass leanness such as percent lean, backfat thickness or loin eye area assumes that the value of each unit of improvement is constant over the entire range of pigs currently being produced. Implementation of carcass merit programs has resulted in intense selection for leanness by domestic seedstock producers and importation of extremely lean pigs from Canada and Europe. Currently, pork processors, industry leaders and seedstock producers are reconsidering the use of linear economic values for measurements of carcass leanness. Based on these concerns, an alternative curvilinear economic value for carcass leanness was developed.