Abstract
A database containing production measurements was created by abstracting data files of 124 farms in Japan which participated in the PigCHAMP data-share program. Summary statistics for breeding-herd performance data in 2002 were presented. A model was built to assess the association between herd-management factors and nonproductive days by breeding-female pigs (NPD). The NPD was defined as days when mated gilts and sows were neither gestating nor lactating. The mean of NPD was 53.9 days (SD = 16.1). In regression analysis using backward elimination, higher percentage of multiple matings, higher percentage of sows mated by 7 days after weaning, higher parity of culled sows, lower percentage of reserviced females, lower female death rate and larger herd size were the herd-management factors identified as having important associations with shorter NPD (P<0.05). Lactation length, gilt pool size, parity of farrowed sows, replacement rate and culling rate were not significant (P>0.10) in the analysis. It is recommended that producers change their management systems to increase the percentage of multiple matings, the percentages of sows mated by 7 days after weaning, and the parity of culled sows, and to decrease the percentage of reserviced females and the female death rate in order to improve the NPD and breeding herd productivity.
