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Herd Management Procedures, Factors Associated with Low Farrowing Rate of Female Pigs in Japan

14 November 2012

Researchers in Japan found that commercial herds that practised twice daily oestrus detection and carried out insemination soon after the animals were found to be on heat had higher farrowing rates. Multiple inseminations also improved the farrowing rate.

In their paper in the journal, Preventative Veterinary Medicine, M. Kaneko and colleagues at Meiji University in Japan explain that the objective of their latest study was to compare management procedures and production factors between low-farrowing-rate herds (LFR herds) and the remaining herds (Non-LFR herds).

Questionnaires were sent to the producers of 115 herds that use the same recording system. The questionnaire requested information about management procedures in 2008:

  • daily frequencies of oestrus detection: once or twice a day, and
  • the timing of first insemination.

Data from 93 completed questionnaires (80.9 per cent) were coordinated with the reproductive data of individual female pigs from the recording system. The data included 78,321 service records from 37,777 sows and gilts. Herds were classified into two groups on the basis of the lower 25th percentile of farrowing rate: LFR herds (76.5 per cent or lower) and Non-LFR herds (76.6 per cent or higher).

At the herd level, a two-sample t-test, was used to compare the surveyed management procedures between the two herd groups. At the individual level, two-level mixed-effects models were applied, by using a herd at the level two and an individual record at the level one to determine associations between low farrowing rate and management procedures or production factors in gilts and sows. Gilt and sow models were separately constructed.

Means (±SEM) of farrowing rate in LFR herds and Non-LFR herds were 71.3±0.92 and 85.5±0.54 per cent, respectively. The lower farrowing rates of gilts and sows in LFR herds were associated with once-daily oestrus detection, late timing of first insemination and single mating (P<0.05).

In LFR herds that detected oestrus only once a day, the farrowing rate decreased by 10.5 per cent in first-serviced gilts and by 4.2 per cent in re-serviced sows compared with twice daily oestrus detection (P<0.05). However, there was no such association in Non-LFR herds (P>0.05).

LFR herds had higher percentages of single-mated gilts and sows than Non-LFR herds (P<0.05).

Fewer LFR herds than Non-LFR herds performed first insemination immediately after first oestrus detection for gilts or by six to 12 hours for sows (P<0.05).

In order to improve the farrowing rate in LFR herds, Kaneko and colleagues recommend detecting oestrus twice a day and performing first insemination earlier after first oestrus detection; immediately for gilts and by six to 12 hours for sows. Additionally, they added, increasing the percentage of multiple inseminations can effectively improve the farrowing rate.


Kaneko M., Iida R. and Koketsu Y. 2012. Herd management procedures and factors associated with low farrowing rate of female pigs in Japanese commercial herds. Prev. Vet. Med. 2012 Oct 20. pii: S0167-5877(12)00322-4. doi: 10.1016/j.prevetmed.2012.09.014. [Epub ahead of print]

November 2012

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