Managing variation to produce quality in farm products

Abstract

The fundamental influence of variation on the production of quality products is reviewed. The partitioning of this variation into that which is controllable on the farm and that which is uncontrollable on the farm is discussed. The effectiveness of an on-farm quality assurance programme depends on the level of variation in a trait than can be controlled by farm management practices. A simple graphical tool that can be used on farm and is suitable for monitoring performance through time is the cusum control chart. This chart plots the cumulative sum of deviations from target performance. It is designed to identify the occurrence of problems in production on farm for which effective management action may be taken. The operation of a cusum chart for monitoring a quality assurance programme on farm is illustrated, using as an example the control of ultimate muscle pH in cattle. The cusum chart in this example is designed and operated using measurements supplied by a meat processor which were made on the muscle following slaughter. Keywords: controllable variation, cusum chart, farm monitoring, quality assurance, uncontrollable variation