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Case: Organic pig farmers may benefit from breeding for lower litter size and higher birth weight

Using sows that are bred to give birth to fewer but more robust piglets can contribute significantly to reducing early piglet mortality in organic pig farming. 

Large litters and low birth weights are important risk factors related to high piglet mortality in organic pig production, according to an extensive on-farm study carried out by researchers from the Department of Animal Science at Aarhus University. There are therefore benefits to be reaped by using sows that give birth to fewer but larger piglets than by using highly prolific sows adapted to intensive indoor production systems.

Sows that give birth to more piglets than they can raise pose a major challenge in organic pig production. Large litters also result in reduced piglet birth weights, which is one of the reasons that many piglets die. If surplus piglets from fertile sows are to survive, they must be fostered by nursing sows. Otherwise, the piglets will die if not euthanised.

- The main problem for Danish organic farmers is that they use sows bred for intensive conventional production and not for organic production. In conventional production, which takes place indoors, there are management tools that can help the numerous small, weak, and surplus piglets that the sows cannot raise on their own. This is not an option to the same extent in outdoor systems where the sows farrow in huts in the field, says Professor Lene Juul Pedersen from the Department of Animal Science at Aarhus University.

She has been involved in research projects that have studied reasons for and possible solutions to the high piglet mortality seen on Danish organic pig farms. A possible solution is to use genetics that are better at fulfilling the needs of organic pig farmers for a more robust type of pig. In this connection, TN70 sows from the pig genetics company Topigs Norsvin were compared to traditional LY sows from Danbred with regard to, among other things, litter size and piglet traits. All the sows were inseminated with semen from Duroc boars from Danavl.

Both sow groups weaned the same number of pigs, but the pigs from the TN70 sows had higher birth and weaning weights. The TN70 sows gave birth to fewer piglets. However, that meant that there were teats enough for the majority of piglets. Therefore, the need for using nurse sows and/ or euthanasia of weak and surplus piglets was reduced.

- Important criteria for a continued growth in the organic pig sector is to uphold good animal health and welfare. Being able to reduce mortality and wean heavier and more robust piglets is therefore crucial for organic farmers to comply with organic principles concerning high animal health and welfare and a resource-conscious production, says Lene Juul Pedersen.