Multi-step beef ration optimisation: application of linear and weighted goal programming with a penalty function

Abstract

The aim of this paper is to present the method and tool for optimisation of beef-fattening diets. Changes in policy environment and changes in costs of feed pose challenges for farm efficiency. We construct a spreadsheet from two modules based on mathematical deterministic programming techniques. In order to obtain an estimate of the magnitude of costs that may be incurred, the first module utilizes a linear program for least-cost ration formulation. The resulting value is then targeted as a cost goal in the second module. This is supported by weighted goal programming with a penalty function system. The approach presented here is an example of how a combination of mathematical programming techniques might be applied to prepare a user-friendly tool for 'optimal' ration formulations. We report results that confirm this approach as useful, since one is able to formulate a least-cost ration without risking a decrease in the ration's nutritive value or affecting the balance between nutrients.

Time series livestock diet optimization: cost-effective broiler feed substitution using the commodity price spread approach

“…These parameters are used in the LP model to minimize the feed cost, considering nutritional limitations (Peric andBabic 2009, Saxena 2011;Žgajnar et al 2010). The biggest challenges in LP modeling in the 1980s were the absence of information about the biological restrictions of animals and the varying quality of feed ingredients (Saxena and Chandra 2011;Beckman et al 2011).…”

Spremembe sestave krmnih obrokov za goveje pitance: primer uporabe normativnih in pozitivnih matematičnih metod

“…Analizo vpliva cen krme na sestavljanje krmnih obrokov smo z vidika ekonomske teorije izvedli s pomočjo normativnih in pozitivnih metod. Za potrebe normativne analize smo uporabili že razvito orodje (DSS) za sestavljanje krmnih obrokov bikov pitancev, ki je podrobneje opisano v prispevku Žgajnar in Kavčič (2008). Orodje je zasnovano na t.i.…”

Resilience of dairy farms measured through production plan adjustments

“…In the past, researchers have developed many models with different purposes to address challenges in agriculture. Breen et al (2019) Examples of modeling in agriculture in Slovenia include fertilizer planning (Žgajnar and Kavčič, 2011), feed ration optimization (Žgajnar et al, 2007), emergy analysis (Kocjančič et al, 2018), and economic analysis of the equestrian center (Žgajnar, 2015). To analyze the impact of agricultural policies, the European Commission uses the IMF CAP model, which is also based on a mathematical programming approach (Langrell et al, 2013).…”