Publications
NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.
2021
Authors
F. Shepherd C. chylinski M. Hutchings R. Kelly A. MacRae J.-P. Salminen V. Maurer Håvard Steinshamn S. Fittje A. Morell Perez S. AthanasiadouAbstract
No abstract has been registered
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Authors
Håvard SteinshamnAbstract
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Abstract
Inclusion of clover in grasslands increases functional diversity, N yield and forage quality and has been advocated for mitigating nitrous oxide (N2O) emissions. However, boreal grass-clover leys often show poor winter survival with considerable aboveground losses of nitrogen (N) and carbon (C). Little is known about how these losses affect off-season N2O emissions. Here we report field experiments over two winters, conducted at two coastal locations in Western and Northern Norway. N2O emissions were measured in plots with 0, 30 and 100% red (T. pretense) and white clover (T. repens) in a timothy - meadow fescue mixture. Overwinter N loss from the sward was quantified by comparing N contents in roots, stubble and herbage in autumn and spring. Additional treatments were removal of above-ground biomass in autumn and soil compaction. Off-season N2O emissions correlated positively with estimated overwinter N loss from herbage, which in turn depended on the fraction of clover in the ley. Pure grass leys emitted less N2O than leys that contained clover. Corrected for background emissions from pure grass, up to 13% of the above-ground N loss was emitted as N2O–N when clover was grown in pure stand. This fraction was much smaller, however, when clover was grown in mixture with grass (1.9 ± 0.9%), suggesting reassimilation of inorganic N. Indeed, we found significant increases in root and stubble N in mixtures throughout winter. Removal of above-ground biomass in autumn appeared to reduce the sward's ability to retain N throughout winter, and hence had no or a stimulating effect on N2O emissions. Soil compaction increased off-season N2O emissions 1.3–1.6-fold. Our results show that boreal grass-clover leys can be a significant source of N2O during winter, intricately controlled by loss and reassimilation of N. This underscores the importance of off-season plant-soil management for reducing the greenhouse gas (GHG) footprint of animal production in high latitude ecosystems.
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Authors
Marit JørgensenAbstract
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Abstract
Self-sufficiency with feed (SSF) is a basic principle in organic animal production. The current regulations do not impose strict requirements for SSF at farm level, but further restrictions are expected in future. The aim of the present work was to quantify SSF on a range of organic dairy farms in Norway and study farmers’ strategies to produce milk with a high degree of SSF. Nine farms were selected for interview and data collection. On farm level, the proportion of SSF varied between 66 and 99 %. SSF increased to 88-100 % when expressed on national level. Land area is among the limiting factors for famers to reach higher SSF while maintaining the milk production level. A lower proportion of concentrates in the diet seems to have as strong impact on SSF as using own cereals and protein crops as feed, but milk production per total feed production area was highest for the latter. The farmers’ goals and actions are important driving forces to develop more SSF in dairy production systems.
Authors
Caroline Chylinski Sokratis Ptochos Berit Marie Blomstrand Håvard Steinshamn Inga Marie Aasen Karl-christian Mahnert Stig Milan Thamsborg Spiridoula AthanasiadouAbstract
Subclinical parasite infections in livestock production have huge economic impact on the farming industry, leading to decreased animal welfare and reduction in meat, milk and wool production. The global spread of anthelmintic resistance has exacerbated the threat of gastrointestinal nematode (GIN) infections to small ruminant health and production. Phytochemicals, such as condensed tannins (CT), have shown promising anthelmintic potential, and could complement other management practices to reduce anthelmintic use for parasite control. Conifer bark is a rich source of CT. Studies have shown that the content of CTs in Norway spruce and Scots pine varies, but on average they contain around 4% CTs. This study explored the anthelmintic activity of bark from Norwegian conifers over two seasons, extracted with three different solvents (water, acetone, methanol), against two sheep GIN, Teladorsagia circumcincta and Trichostrongylus colbriformis. Bark extracts were analysed to determine their total CT content and tested in vitro, with the aim to quantify their impact on egg hatching and L3 larval motility. Results show significant variation in efficacy of the extracts on egg hatching in a dose dependent manner. The CT content of the bark extracts were not always associated with LD50 values, indicating that other plant compounds may have additional anthelmintic effects. Preliminary results of the L3 larval motility test showed that incubation in the bark extracts had a smaller impact on this parasite stage at the concentrations tested. This research brings new insights into the potential anthelmintic activity of different phytochemicals and discusses the potential of bark extracts as a tool in the sustainable control of GIN in small ruminants.