Sow replacement: A comparison of farmers' actual decisions and model recommendations

Abstract Sow culling data were analyzed from 1617 culled sows on 12 Dutch farms, using the VAMPP herd health and management information system. The annual culling rate was found to be 50%, more than half of which was due to reproductive problems and low productivity. The risk of removal increased considerably with age, except for second parity sows. The data were economically evaluated, using the PorkCHOP replacement model. The calculated losses caused by premature disposal turned out to average Dfl. 124 per culled sow, or Dfl. 9300 per year in a 150-sow operation, which equals about 16% of pig farm income. The highest economic losses were found in cases of “lameness/leg weakness”, averaging Dfl. 183 per culled sow. In comparing the model recommendations and the actual decisions to cull sows because of low productivity there was a striking resemblance. Culling the elder, poorly producing sows directly after weaning was the right decision economically. With respect to reproductive problems, however, sows showing no heat were culled too early after weaning and sows that failed to conceive too late. Moreover, the time of culling hardly differed with the sow's age and productive performances. Further research is desired to determine whether computerized decision support can help the farmers to reduce the income losses when sows fail to conceive.