This article highlights some old and new approaches that may be useful in assisting livestock-dependent people to meet their production objectives through the planning of diets and/or feeding strategies for their animals. It first describes the initial application of mathematical techniques based on linear programming (LP) using the simplex method or its derivatives. It explains that, although these simple applications have proved to be very effective in situations where one objective (generally profit maximization) is regarded as being overarching, they are of little use to livestock owners who keep their animals for multiple uses. Moreover, LP applications cannot identify near-feasible solutions that in many instances may be adequate for the user and more cost-effective. Although these drawbacks have been addressed by using a number of different approaches, each with its own merits, no single approach has been extensively adopted. Recent increases in desktop computing power and user-friendly software interfaces may, however, call for a re-evaluation of some of them.
The article also points out that the computer-based applications of mathematical programming techniques that are currently available require an availability of data and a degree of sophistication on the part of the user that are unlikely to qualify them for field use in developing countries. The final section of the article, however, describes two recent innovations for the delivery of animal nutrition biology in a format that is both user-friendly and effective. The first of the methods described is the Dairy Rationing System for the Tropics (DRASTIC), which was developed with the objective of producing a genuinely usable, decision support tool for planning dairy feeding under tropical conditions. DRASTIC has a user-friendly design, it requires no expert knowledge of nutrition and the nutritional variables in the underlying model are assessed from simple indicators of feed quality, allowing the system to cope with variable feed compositions in the absence of quantitative data. Use of DRASTIC in an interactive mode with farmers in the field has shown that it can be very effective in predicting outcomes and designing modified feeding strategies for more cost-effective production or increased yield. Nevertheless, DRASTIC still relies heavily on frequent contacts between extension systems, which are often functioning inadequately, and farmers. Deficiencies in this process may mean that the outputs produced by such tools as DRASTIC will not always be sufficiently responsive to changing conditions. The article then explains how the need to generate information that reduces the complexity of the interaction between extension services and farmers and allows farmers to take a more active part in the evaluation of alternative strategies has led to the development of Talking Pictures. This is a dynamic pictorial system that represents the nutritional management of dairy cows in smallholder farming systems. The tool builds on the principles used in the development of DRASTIC, using this software to generate hard-copy guides in an easily understood pictorial format consisting of several pictorial input layers that incorporate genotype, condition, stage of lactation and physiological status, calf rearing system, and quantity and quality of feed inputs (basal and supplements) that are dynamically linked and that provide pictorial answers for the expected production outputs. Although still under development, the initial evaluation of the Talking Pictures methodology in the field has shown encouraging results.
The article concludes with some remarks that underline the continuing rapid development and spread of computer technology in the world, which is likely to generate considerable practical benefits in the further development of simple decision support for feed planning.
Thorne, P. J.; Dijkman, J. Simple decision support for feed planning. In: FAO FEEDback review. FAO, Food and Agriculture Organisation of the United Nations, Rome, Italy (2003)