An investigation of culling guidelines for gilts and sows in Japanese commercial herds and comparison of the differences between culling guidelines and actual culling practices in different herd productivity groups were reported by Yosuke Sasaki and Yuzo Koketsu of Japan’s Meiji University in Journal of Animal Science recently.

A questionnaire survey was undertaken to obtain information on culling guidelines in 115 commercial swine herds that participated in the PigCHAMP data-share programme. The questionnaire included questions on guideline values for culling intervals and the number of conception failure occurrences that would trigger a culling decision to be made.

Ninety-two of the 115 herds (80.0 per cent) returned appropriate data for the study and were included in the present study. In addition to questionnaire data, culling data regarding the actual culling intervals and number of re–services for gilts and sows culled during 2007 to 2008 were also obtained for the same herds from a PigCHAMP database.

Culled gilts and sows were divided into four female groups on the basis of the stages of their reproductive life when they were culled: unmated gilts, mated gilts, unmated sows, and mated sows. Culling intervals in unmated gilts and sows were defined as the number of days from birth or weaning to culling, respectively, whereas in mated gilts and sows culling intervals were the number of days from last service to culling. Three herd productivity groups were formed on the basis of the upper and lower 25th percentiles of pigs weaned per mated female per year: high–,intermediate– or low–performing herds.

For unmated gilts and sows, actual culling intervals were 15 days shorter than the guideline culling intervals in the surveyed data submitted by producers (P<0.05). This shorter actual culling period for unmated gilts and sows did not vary significantly between herd productivity groups in any parity.

However, for mated gilts and sows the actual culling intervals were at least 30 days longer than the guideline culling intervals (P<0.05).

Guideline and actual culling intervals for mated gilts and sows were at least 10 days shorter in high–performing herds than in low–performing herds (P<0.05). High–performing herds had a lower proportion of sows culled after the second re–service than intermediate– or low–performing herds in parity groups 0 to 5 (P<0.05).

The Meiji researchers concluded that culling guidelines for mated sows differed between herd productivity groups, and culling guidelines for mated gilts and sows were not strictly followed in any herd group in the commercial herds.

Reference

Sasaki Y. and Y. Koketsu. 2012. A herd management survey on culling guidelines and actual culling practices in three herd groups based on reproductive productivity in Japanese commercial swine herds. J. Anim. Sci., 90(6):1995-2002. doi: 10.2527/jas.2011-4313

Further Reading You can view the full report (fee payable) by clicking here.