The objective of the commercial pig breeder is, normally, profit per sow place per annum. Pigs reared per sow place per annum must be optimised to cover the fixed and variable costs of the business and leave an acceptable financial surplus. “Optimising output” is emphasised because in the late 1970s and early 1980s conmercial pig breeders were often encouraged to maximise sow output at any cost. The efficiency parameter “pigs reared per sow place per annum” takes into account the fact that many units run below capacity increasing the costs both fixed and variable carried by the sows actually in the herd. In a herd producing 20 pigs per sow per annum each 5% shortfall in herd size is equivalent to a reduction of one pig per sow per annum.

Every producer should assess the resources at his disposal namely capital, labour, buildings, stock, etc. and then optimise sow output within the limitations imposed by those resources. Output from the breeding herd is dependent on pigs born alive per litter, piglet survival rate, the interval from weaning to successful service, lactation length and the ability to maintain herd size.