February 3, 2010

Danish scientists develop tool to identify weak sows

Danish scientists from Aarhus University's Faculty of Agricultural Sciences have developed a tool that eases the task of identifying weak sows, making the process safer and more systematic.

The scientific project is about the development of an index that can identify weak sows, i.e. sows that are not expected to stay the course.

Researcher Jan Tind Sørensen said, "We provide farmers with a tool that helps him observe his animals in a systematic manner and to treat the observations to an index. Firstly, the assessments take place at certain times; secondly, they follow a protocol for short, systematic, clinical examinations of the individual sows in the farrowing or gestation pens, and, thirdly, they are converted into an index."

Sørensen has been the leader of the project that has collaborated closely with KU-Life and an advisory group with representatives from the Swine Information Centre.

When the scientists started the project, their hypothesis was that a weak sow is a sow with several clinical signs that when combined means she is at risk of being slaughtered early, dying or being euthanised.

After extensive assessments of 36 herds of sows, the hypothesis turns out to hold true. Weak sows have an increased risk of being slaughtered early due to disease or being sent for destruction.

Through the clinical examinations in the farrowing and gestation stalls in the 36 herds, the scientists have found a number of characteristics that are both easy to observe and that are determinants for whether the sow can be defined as weak.

"We structured our data into 16 causes, ten of which could be related to three factors directly linked to culling or disease," Sørensen said.

"The analyses show that the main factors are lameness and willingness to stand, as well as bites on the vulva for pregnant sows, and lesions, body condition and vulva colour for lactating sows. The factors are weighted and included in an index that can be used directly on the farm," he said.

The project is now in its final stage that includes an analysis of risk factors that code for a high prevalence of weak sows in individual herds so the scientists can define preventative measures. They are also calculating the effect on production of a high weak-sow index.

The project is supported by the Danish Pig Levy Foundation.