Production planning of supply chains in the pig industry.

• First model multi farm, multi stage and multi period to optimize a Pig Supply Chain. • Fattening planning under all-in-all-out management in a multi farm environment. • Collaborative research supported by a Spanish pig company. This paper presents a production planning model for managing the pig herd production system operating as a Pig Supply Chain (PSC). The model is formulated as a multiperiod mixed-integer linear programming (MILP). The production system may represent a large farmer, a private company or a cooperative managing several farms operating according to the so-called three site system (sow, rearing and fattening farms; the latter under all-in-all-out management). The model is intended for practical use and illustrated with a case study based on a real instance in Catalonia (Spain). The model helps PSC managers when making decisions by providing an overall view for planning production over time. The objective is to maximize the total revenue calculated by the total amount of sales to the abattoir minus production costs. The latter depend on the feeding system, veterinary and medical care, labor and transportation. Practical results include a schedule of animal transfers between farms, batch management and deliveries to the abattoir from fattening farms, number of trips and the occupancy rate of all facilities. Bottlenecks in the production process regarding flow of animals, throughput and capacities along the PSC were detected beforehand allowing the company to react accordingly. Then, as three fattening farms were found to be redundant, farm occupation rate could be improved by 22% purchasing additional piglets. We estimated a maximum purchase price of 70.15 Euros per piglet beneficial for the company. [ABSTRACT FROM AUTHOR]