Mixing sows at weaning or after mating had minimal long-term impacts on welfare and reproduction in a study by the Co-operative Research Centre for High Integrity Australian Pork (Pork CRC).
The large, collaborative study investigated how floor spaces between 1.45 and 2.9 square meters affected the welfare and performance of sows grouped within four days of mating. Cortisol levels and aggression were measured immediately after mixing through day 26.
The researchers found that although floor space had no long-term effects on sow welfare or reproduction, aggression and cortisol levels were markedly higher in the smaller floor spaces immediately after mixing. However, they observed, sows change their behavior rapidly and these effects disappeared by day 26. In fact, the effect had stabilized by day 9.
According to Roger Campbell, CEO of Pork CRC, the study’s outcome “supports the mixing pen concept where sows are given more space in the week after grouping and then their space allowance can be reduced.”
He added that while it is impossible to eliminate aggression at and immediately after mixing, CRC participant feedback indicates that floor space of 1.8 to 2 square meters supports good performance.