Evaluation of Current Reasons for Removal of Sows from Commercial Farms

Sow longevity is a large and often overlooked component of profitability and efficiency for commercial swine operations. Culling and mortality rates average near 50 and 9%, respectively, leaving the responsibility of profitability on sows that can remain productive past parity 3. A new study was conducted using 2,000 commercial sows, with one-half of the females being gilts and the remaining half consisting of sows that produced at least 5 litters in the same breeding herd. Although culling reasons for young sows have not changed, this study revealed the primary reason that sows over parity 5 were being culled was because of old age, regardless of their production. Sows from the parity 5 and older group had a greater number of pigs born alive through 3 parities (P < 0.05) and had a reduced wean-to-first-service interval (P < 0.05) after their first parity when compared with the females that had just entered the farm at the inception of the study. Comparisons within the young group revealed that sows that were removed from production after a single litter were inferior for the number of pigs born alive (P < 0.05) and wean-to-first-service interval (P < 0.05) compared with sows that remained in the herd for 4 parities. This study revealed that sows can be selected for longevity without detrimental effects on reproductive performance, because sows that remained in production to more advanced parities also reproductively outperformed their contemporaries that were removed early from the breeding herd.