TY - JOUR AB - Purpose The purpose of this paper is to discuss the animal diet problem in grey environment which is adapted to the real situations. In particular, a new approach to solve these problems is proposed.Design/methodology/approach With the objective to produce the least-cost diet, in the traditional model for optimizing the diet problem, the price of foods, the nutrients requirements and the necessity of foods requirement have been considered as grey interval numbers. Grey linear programming approach has been employed to solve the grey diet problem. Grey linear programming with flexibility in selection of the coefficients can be more effective for solving the diet problems. In this research, only the positioned method has been used. The grey diet model is solved by using GAMS software based on the positioned method.Findings The main contribution of this work is to introduce a new model in the practical case that is concerned with diet problem under a kind of uncertainty environment and furthermore, proposing a novel method to solve the formulated problem. In this way, using a grey model and applying all restrictions, the least cost for one kilogram of total mixed ration was 6,893-10,163 Rials, and at this level, cow’s nutrient requirement was met. Based on the numerical examination, which was done on the real case, the achieved results have showed that the uncertainty of foods requirement and nutrients requirements had slight effect on the animal budget diet.Originality/value This problem must be viewed from another perspective because of the uncertainty regarding the amount of nutrients per unit of foods and the diversity of animals’ daily needs to receive them. In particular, a new method to optimize the fully mixed diet of lactating cows in early lactation that are readily available in the northeast of Iran in uncertainty environment has been proposed. VL - 8 IS - 2 SN - 2043-9377 DO - 10.1108/GS-11-2017-0040 UR - https://doi.org/10.1108/GS-11-2017-0040 AU - Salookolaei Davood Darvishi AU - Liu Sifeng AU - Nasseri Sayed Hadi PY - 2018 Y1 - 2018/01/01 TI - A new approach in animal diet using grey system theory T2 - Grey Systems: Theory and Application PB - Emerald Publishing Limited SP - 167 EP - 180 Y2 - 2024/04/23 ER -