Sara V. Rodríguez

New opportunities in operations research to improve pork supply chain efficiency

The structure of the pork sector in world economy is changing. In many countries the number of pig farms is being reduced, while the herd size of the remaining ones is increasing. Pig production process is partitioned into different phases with specialized farms devoted to piglet production, rearing or fattening pigs are common instead of old farrowing-to-fattening farms. Pig farms have tended to be integrated and coordinate their operations into pork supply chains by using tighter vertical coordination linkages. This paper presents a description of the pork supply chain, stressing the role of pig farming as one of the key issues to improve pork supply chain efficiency. A survey of literature to support the decision making on the pork sector has revealed that most papers had only considered individual farm operations, while the pork supply chain management involves the coordination of sets of farm units at different stages of production. Thus, our contribution emphasizes the importance and complexity of new decision-making tasks regarding the modern organization of the pork sector. All these elements make it possible to envisage new opportunities for operations research methods to be successfully applied to the pork supply chain. Likewise, we have identified some existing gaps in the literature that we believe should be addressed in the near future.

A linear programming formulation of a semi-Markov model to design pig facilities

Housing facilities design represents the main strategic decision in pig farms. This paper introduces a linear programming formulation of a semi-Markov process to approach the facilities design. Thus, the Linear Programming formulation determines the optimum replacement policy and provides the equilibrium distribution of the herd along pig facilities. Then, the calculation of the associated needs of room for each sow facility is derived from sow herd distribution at equilibrium. Results show the flexibility of the model for designing pig facilities and computational advantages in the solving procedure compared to previous proposals. Furthermore, the robustness of the optimal solution is studied by means of sensitivity analysis.

A Stackelberg Game Model between Manufacturer and Wholesaler in a Food Supply Chain.

This paper describes an application of the Stackerlberg game model for the food supply chain. Specifically, the focus of this work is on the pork industry and considers a production game. Such game includes two players, manufacturer and wholesaler, who both aim to maximize profit. The role of leader is played by the manufacturer, and follower by the wholesaler. Decisions involved in the game are the level of production, quantity to be sold by the leader, and level of purchased products by the follower at each time period. This paper presents a case study, and results show that coordination between these players is seen in cost savings and improved service level.

A Mixed Integer Linear Program for Operational Planning in a Meat Packing Plant

This paper reports a mixed integer linear programming model to support the planning at an operational level in a meat packing plant. The deterministic formulation considers multi-products (yielded from different cutting patterns applied to the carcasses), multi-periods, a batch quality distribution on carcasses and perishability. The perishability of the product is modeled by the inclusion of disaggregated inventory decision variables that take into account a given maximum number of days for fresh product. The main contribution of the present work is to develop an optimization model in a real tactical planning problem. Also we develop a sensitivity analysis on the quality of the carcasses, subject to large variability. We present here two different scenarios, comparing them to asses their economical impact.

An Optimization Model for Planning Operations in a Meat Packing Plant

This paper presents an optimization model for supporting planning operations in a meat packing plant. The production system considers processing raw material (carcasses) by applying cutting patterns in order to meet a given demand of different products. Major decisions in the planning problem include the number of times each cutting pattern is applied on the available carcasses, the total yield per product and its corresponding levels of inventory at each time period; as a result a Mixed Integer Linear Programming Model (MILP) is proposed. The main contribution is to give an optimal decision that maximizes the economic profit and thereby reducing the shortages for products with the highest profits and the inventory for those with low level demand, taking into account the perishability of the products, labour capacities, and the fact that it may exists different types of carcasses with different yields.