Economic order quantity for growing items

- A general EOQ/EPQ model is proposed for growing inventory.
- A particular EOQ/EPQ model is formulated and solved for a type of poultry.
- The EOQ/EPQ of growing items in the beginning of a growing cycle is calculated.
- The optimal length of the growing cycle is calculated.
- A sensitivity analysis reveals production costs is the most crucial parameter.

Economic order/production quantity (EOQ/EPQ) models have generally been presented for manufacturing products. Incorporating some important features of a specific category of products, different EOQ/EPQ models have been proposed in literature. This study proposes a new class of inventory models, i.e. a model for a specific type of inventory items: growing items. Poultry and livestock are good examples of growing inventory items. We begin by proposing a general mathematical model, which can be used for different types of growing items, followed by a particular mathematical model for a specific type of poultry. We calculate the optimal order quantity of the growing items at the start of a growing cycle, the optimal length of the growing cycle and the optimal total profit. Numerical examples are provided, for a type of poultry, to illustrate the model. A sensitivity analysis is presented to study the effect of the main parameters of the model in terms of its decision variables and objective function. The results of the sensitivity analysis suggest that production costs are the most crucial parameter.