17. Optimal Delivery of Pigs to the Abattoir

Pig farmers depend on the income they get from the delivering of fattened pigs to the abattoir. Pigs are fattened in batches and all-in-all-out management strategy is common in commercial farms. This chapter presents a mixed-integer linear programming model describing a fattening pig unit delivering pigs to the same abattoir. The interest of the model is mainly to maximise the revenue from deliveries of pigs to the abattoir that pays according to a carcass classification. Carcass classification is affected by the heterogeneous growth of animals determining the weight and body composition (percent of fat and/or lean) changing over time. The delivery of all pigs of a batch at a time is shown to be less profitable than two or three within a time window of around 4 weeks. Our contribution corroborates the findings of past studies and demonstrates the benefit of homogeneous weights. It is also shown how a time window of 4 weeks delivering animals to the abattoir is optimal. However, the optimal result per batch does not correspond to the optimal result per day. The latter would imply saving 1 week in the marketing time window and increments of 5 % in the daily or annual revenue.