BRENDON CANT brendon at iinet.net.au
Wed Jan 23 02:22:35 CET 2008

Pork CRC Media Release -- 23.1.08



During the seasonal infertility period (summer and early autumn), sow
farrowing rate typically drops by 5-10 per cent.


And about half of the pregnancy loss occurs after the usual five week
pregnancy check, making it difficult for producers to predict or maintain
production volume and income.


Recently published Pork CRC supported research at the University of Sydney
indicated that parity (number of pregnancies), wean to service interval
(WSI), lactation length and litter size weaned were risk factors for late
pregnancy loss (LPL) in sows.


Researcher Michael Bertoldo said the aim of his research was to identify
gilts and sows "at-risk" of LPL.


"We looked at mating records for 10,122 sows and 3900 gilts from three
farming groups in different parts of Australia, identified sows with LPL and
compared their immediate past farrowing performance with those that
farrowed," he said.


"For gilts, the effect of age at first service on LPL was a risk factor on
only one farm. On two farms we found that as sow parity, or the number of
pregnancies a sow has had, increased, so too did the incidence of LPL."


Mr Bertoldo noted that longer lactations appeared to protect against LPL by
allowing more complete repair of the reproductive tract and hormones to
return to normal levels.


"Perhaps related to this, we found that as WSI increased, the chance of LPL
also rose. This is consistent with previous research suggesting longer
lactations reduce WSI and increase subsequent litter size and farrowing


"Our data is new in that we are the first group to specifically relate this
to LPL during seasonal infertility. Our analysis also indicated a different
effect of WSI across parities, with no effect for first parity sows," he


"Interestingly, we found that sows weaning seven piglets had the highest
risk of LPL and sows weaning more than 13 piglets had the lowest, suggesting
lactation pressure had no impact on LPL in the subsequent mating."


In the next stage of the Pork CRC project, the University of Sydney team,
which also includes Chris Grupen, Peter Thomson, Gareth Evans and Trish
Holyoake, will conduct more detailed on-farm studies to identify
environmental and management risk factors for seasonal infertility.


Mr Bertoldo suggested producers should consider the project's results in
conjunction with analysis of available data from their own farms.


"Decisions regarding early culling of older sows, increasing lactation
length, gilt management and fostering should only be made after advice from
your consultant.


"Good reproductive records and accurate pregnancy diagnosis are essential to
assist decision making on gilt and sow management during the seasonal
infertility period, the severity of which varies from farm to farm," Mr
Bertoldo said.



HYPERLINK "http://www.porkcrc.com.au/"www.porkcrc.com.au


Authorised by Pork CRC and issued on its behalf by

Brendon Cant & Associates, Tel 08 9384 1122


MEDIA CONTACTS: Dr Roger Campbell, Mobile 0407 774 714

                                  Michael Bertoldo, Mobile 0409 698 801







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