In a paper published recently in Journal of Swine Health and Production, Yosuke Sasaki and Yuzo Koketsu of Meiji University in Kanagawa, Japan, compared lifetime efficiency and by-parity reproductive performance of female pigs categorised by culling reason or herd productivity group.

Lifetime records were analysed for 62,775 females in 101 Japanese commercial herds. Culling reasons were categorised into four groups. Three herd groups were based on the upper and lower 25th percentiles of pigs weaned per mated female per year: high-, intermediate- and low-performing herds. Annualised lifetime pigs born alive (PBA) was calculated as:
the sum of PBA in the sow's lifetime ÷ female life-days × 365 days.

Multilevel linear mixed-effects models were performed to compare measurements by sub-groups.

The researchers found that females culled for 'reproductive failure' had 7.5 pigs fewer annualised lifetime PBA and 43.0 more lifetime non-productive days than those culled for 'high parity' (P<0.01).

Females culled for reproductive failure in high-performing herds had 34.7 fewer lifetime non-productive days than those in low-performing herds (P<0.01) but lifetime PBA was similar to those in the other herd groups.

Females culled for reproductive failure had a longer weaning-to-first-mating interval and lower farrowing percentage from parity 1 to 4 than those culled for 'high parity' (P<0.01) but PBA values were similar to those in other parity groups.

Females culled for 'locomotor problems' had 0.3 pigs more annualised lifetime PBA than those culled for reproductive failure (P<0.01).

Sasaki and Koketsu concluded that it is critical to decrease non-productive days in each parity of females with reproductive problems in order to increase sow lifetime efficiency. They found that fertility traits are more important than litter-size traits to define sows with low lifetime efficiency, and that better sow lifetime performance is associated with improved farrowing percentage and shorter weaning-to-first-mating and culling intervals. Finally, reducing the risk of culling due to locomotor problems in low-performing herds alleviates concerns about sow welfare, which would otherwise require such females to be euthanised, according to the Meiji researchers.

Reference

Sasaki Y. and Koketsu Y. 2011. Reproductive profile and lifetime efficiency of female pigs by culling reason in high-performing commercial breeding herds. J. Swine Health Prod. 19(5):284–291.

Further Reading

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You can view the full report by clicking here.