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New project: Feeding organic sows during winter

In the future, organic pig producers must be able to feed their sows more optimally during the winter period. AU researchers lead a new project with the purpose of developing new feed mixtures for organic sows fed silage during winter. The nutrition must be better adapted to the sows’ need, thus increasing the feed efficiency, reducing the loss of nitrogen and improving the farmer’s economy.

[Translate to English:] Det nye projekt skal danne grundlag for at sammensætte nye foderblandinger, som kan tildeles søerne vinteren over, hvor græsudbuddet i marken er minimalt og ikke bidrager til søernes energioptag. Foto: Colourbox.
[Translate to English:] Det nye projekt skal danne grundlag for at sammensætte nye foderblandinger, som kan tildeles søerne vinteren over, hvor græsudbuddet i marken er minimalt og ikke bidrager til søernes energioptag. Foto: Colourbox.

The organic pig production is challenged regarding the environmental impact and the economical competitiveness. Low feed efficiency combined with the dependency of concentrates based on non-local sources of protein increases the loss of energy, the carbon footprint and the need for farmland.

Factors such as cold weather during winter, a weaning age twice as high and more physical activity in some periods influence the nutrients required by organic sows and this should be taken into account when formulating the composition of the feed. However, at present, no precise recommendations/standards exist for the optimal feed formulation for organic sows. Therefore, the organic farmers must lean on the existing recommendations for conventional sows.

New feed mixtures on the way

In a new project entitled “Winter Feeding of Organic Sows (WI-FI)”, AU researchers wish to study how much energy and protein the sows digest from silage and other roughage during the winter period. The idea behind the new project is to form the basis of mixing new feed mixtures to be provided to the sows during winter when the grass supply in the field is at a minimum, whereas silage contribute to the sows’ energy intake. “It is important that we adapt the feeding strategies according to the animals’ actual nutritional needs in order to minimise the oversupply of especially protein, thus limiting the loss of nitrogen (N) in the surrounding environment”, says senior researcher Peter Kappel Theil who leads the new WI-FI project.

Results from a previous study in 2019 (project EFFORT) showed that the organic sows cover a surprisingly high part of their protein need through grass during the period from April to November. “During the project EFFORT, we became much wiser on how much the sows pick up when on pasture during summer. However, knowledge about how large amounts of roughage they digest during winter is still lacking”, says Peter Kappel Theil.


The feeding project at AU Foulum

Part of the WI-FI project is conducted on the organic platform at AU Foulum. Twenty organic sows are fed two different types of roughage and two different levels of protein: one standard and one with 10% less protein. During the experiment, data will be collected on the sows’ condition, reproduction and litter results, which will form the basis for developing new recommendations for winter feeding of organic sows.

Subsequently, the new feeding strategies will be demonstrated in several commercial herds. These activities will be led by Simme Eriksen, Center for Frilandsdyr. Furthermore, the project group also consists of two organic producers in order to ensure that the results can easily be implemented in practice.

Vestjyllands Andel is going to convert the new knowledge into feed mixtures where the energy and protein contribution from silage is taken into account. The silage quality and silage intake differ among herds and therefore, we need to “customise”/design the feed mixtures depending on how much silage is indeed ingested.

SEGES Ecology is also part of the project. They are responsible for examining the possibilities of using by-products as sources of roughage, and they will also develop and test a tool for assessing the climate impact of different feed ingredients at four herds.

With such a tool available, combined with the new feeding strategies, the researchers expect to be able to reduce the nitrogen emission from organic pig production by 51 tons N a year and to reduce the amount of greenhouse gases with what is equivalent to 2,290 tons CO2-eq a year. “The WI-FI project will then contribute to solve some of the largest challenges in the organic pig production, which will be beneficial to the entire sector”, ends Peter Kappel Theil.


Facts about the project


Grandet by the Ministry of Environment and Food, Green Development and Demonstration Programme (GUDP), under the Organic RDD 5 programme, coordinated by ICROFS. The project runs from 2020 to 2023.  

Project partners

Aarhus University, Department of Animal Science and Department of Agroecology; SEGES Ecology, Center for Frilandsdyr (CFF); Vestjyllands Andel (VA), Hestbjerg Økologi and Krarup Landbrug I/S.    


Peter Kappel Theil, Department of Animal Science, Aarhus University

  E-mail: Peter.Theil@anis.au.dk