Space allowance, or stocking density, is expressed in terms of pigs per floor area. Space allowance requirements are based on the bodyweight of the pig, which is proportional to surface area of the pig.

The optimal space allowance is the minimum area per pig for maximal individual weight gain.

Many experiments have arrived at the same conclusion: “a decrease in space allowance per pig reduces growth performance” because reduced floor-space allowance increases competition for water and feed, reducing feed intake and consequently body weight gain.

However, from an economic perspective, it is clear that fewer pigs per pen means fewer kilograms of pork will be produced per pen, despite the improvement in individual weight gain.

Under conventional management in the grower-finisher period, pigs remain in the same pen for several weeks until they reach market weight.

The maximum space requirement has to be calculated based on the day that the first pig is sent to market.

Considering a target market weight of 125kg, the first pigs would be typically sent to market when the average weight of pigs in the pen is around 105 to 110kg.

According to the Canadian Code of Practice for the Care and Handling of Pigs (2014) the minimum space allowance per pig under these circumstances will be 0.75 to 0.77 square metres or 8.04 to 8.29 square feet.

According to the same publication, a decrease of up to 15 per cent is allowed in the grower-finisher period if the higher density does not compromise the welfare of the animals as determined by average daily gain, mortality, morbidity and treatment records, as well as the absence of or no increase in vices such as tail-biting.

June 2015