Low Lifetime Efficiency Sows in Low Parity were Culled Due to Reproductive Failure in Commercial Herds

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The objective of the present study was to characterize culling patterns of low lifetime efficiency sows (LE sows), by comparing between high-performing and ordinary herds for relative frequencies of parity at culling and culling reasons, and by-parity reproductive performance. The present study analyzed 30,914 sows entered to the herds from 2001 to 2003 in 101 commercial herds. Sows were categorized into two groups on the basis of the lower percentile of the annualized lifetime pigs born alive, namely LE or ordinary lifetime efficiency sows. Additionally, two herd groups were formed on the basis of the upper 25th percentiles of pigs weaned per mated female per year, averaged over six years : high-performing herds and ordinary herds. A Chi-squared test was performed to compare relative frequencies (%) of parity at culling and culling reasons between the herd groups. Mixed-effects models were performed for comparisons in statistical analyses. More LE sows in the high-performing herds were culled due to "reproductive failure" in parity 1 (54.0 vs. 41.5%) and parity 2 (61.2 vs. 42.2%) than those in ordinary herds (P< 0.05). No difference between the herd groups was found for pigs born alive in LE sows culled due to "reproductive failure" in any parity group. In summary, high-performing herds were more active in culling potential LE sows due to "reproductive failure" in low-parity than ordinary herds.