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.
2025
Abstract
Introduction: The discovery of the methane-mitigating effect of the red seaweed Asparagopsis taxiformis has triggered a search for other seaweed species with similar effects. Brown seaweeds constitute the largest production volume of seaweeds in Europe. Some brown algae are known to inhibit methanogens and could potentially reduce enteric methane emissions. Use of by-products generated from industrial processing of plants are typically inedible for human consumption but well known as ruminant feeds. As fractions from Laminaria hyperborea showed significant reductions in methane emissions in vitro, a L. hyperborea by-product was chosen for an in vivo trial with sheep. The aim was to investigate the effect of L. hyperborea by-product inclusion in the diet of growing lambs on dry matter intake, methane emissions, growth rate and nitrogen digestibility. Methods: Twenty-four Norwegian White Sheep lambs (12 ewe and 12 male lambs, 4 months; 36.8 kg live weight) were fed a Control diet (grass silage and control concentrate) or an Algae diet (grass silage and algae concentrate 2% inclusion rate). Lambs were fed a basic diet (grass silage and neutral concentrate) and, in staggered order, introduced to their respective diets for five weeks before entering one of six open circuit respiration chambers. Methane production was measured for three consecutive days. All lambs entered the chambers three time (Periods 1, 2 and 3). Feed intake was measured four consecutive days a week, and live weight (kg) was measured every two weeks. Twelve male lambs were used to investigate in vivo nitrogen digestibility using metabolism crates. Results: The inclusion rate of L. hyperborea by-product was above the target and ended at 2.5% of DM. There was an increase in feed intake and live weight over the experimental period, consistent with the growth of the lambs. Methane production, yield, or intensity was not affected by diet, overall, but the Algae diet reduced methane in Period 1. Male lambs produced more methane than female lambs. Algae inclusion affected live weight negatively. Discusssion: It is concluded that use of L. hyperborea by-products as a feed additive to sheep needs further investigation due to inconclusive results in the present study.
Authors
Mekjell Meland Oddmund Frøynes Darius Kviklys Uros Gasic Uroš Gašić Tomislav Tosti Milica Fotiric AksicAbstract
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Authors
Anders Bryn Rune Halvorsen Peter Horvath Lasse Torben Keetz Ida Marielle Mienna Trond Simensen Olav Skarpaas Ingrid Vesterdal Tjessem Joachim Paul Töpper Vigdis Vandvik Liv Guri Velle Catharina Caspara VloonAbstract
No abstract has been registered
Authors
Even Unsgård Erling Meisingset Inger Maren Rivrud Gunn Randi Fossland Pål Thorvaldsen Vebjørn Veiberg Atle MysterudAbstract
No abstract has been registered
Authors
Darius KviklysAbstract
No abstract has been registered
Authors
Darius KviklysAbstract
No abstract has been registered
Authors
Kristian Hansen Håvard Steinshamn Sissel Hansen Matthias Koesling Tommy Dalgaard Bjørn Gunnar HansenAbstract
To evaluate the environmental impact across multiple dairy farms cost-effectively, the methodological frame- work for environmental assessments may be redefined. This article aims to assess the ability of various statistical tools to predict impact assessment made from a Life Cyle Assessment (LCA). The different models predicted estimates of Greenhouse Gas (GHG) emissions, Energy (E) and Nitrogen (N) intensity. The functional unit in the study was defined as 2.78 MJMM human-edible energy from milk and meat. This amount is equivalent to the edible energy in one kg of energy-corrected milk but includes energy from milk and meat. The GHG emissions (GWP100) were calculated as kg CO2-eq per number of FU delivered, E intensity as fossil and renewable energy used divided by number of FU delivered, and N intensity as kg N imported and produced divided by kg N delivered in milk or meat (kg N/kg N). These predictions were based on 24 independent variables describing farm characteristics, management, use of external inputs, and dairy herd characteristics. All models were able to moderately estimate the results from the LCA calculations. However, their precision was low. Artificial Neural Network (ANN) was best for predicting GHG emissions on the test dataset, (RMSE = 0.50, R2 = 0.86), followed by Multiple Linear Regression (MLR) (RMSE = 0.68, R2 = 0.74). For E intensity, the Supported Vector Machine (SVM) model was performing best, (RMSE = 0.68, R2 = 0.73), followed by ANN (RMSE = 0.55, R2 = 0.71,) and Gradient Boosting Machine (GBM) (RMSE = 0.55, R2 = 0.71). For N intensity predictions the Multiple Linear Regression (MLR) (RMSE = 0.36, R2 = 0.89) and Lasso regression (RMSE = 0.36, R2 = 0.88), followed by the ANN (RMSE = 0.41, R2 = 0.86,). In this study, machine learning provided some benefits in prediction of GHG emission, over simpler models like Multiple Linear Regressions with backward selection. This benefit was limited for N and E intensity. The precision of predictions improved most when including the variables “fertiliser import nitrogen” (kg N/ha) and “proportion of milking cows” (number of dairy cows/number of all cattle) for predicting GHG emission across the different models. The inclusion of “fertiliser import nitrogen” was also important across the different models and prediction of E and N intensity.
Authors
Atle Wibe Berit Marie Blomstrand Lisa Deiana Davide Bochicchio Tommy Ruud Richard Helliwell Matthias Koesling Anne Grete Kongsted Marina Štukelj Marina Spinu A Vasiu Andrew Richard Williams Amalie Camilla Pedersen Helena Meijer Stig Milan ThamsborgAbstract
No abstract has been registered
Authors
Eystein Skjerve Erik Georg Granquist Tone Kristin Bjordal Johansen Ingrid Olsen Truls Nesbakken Amin Sayyari Kristin Opdal Seljetun Morten Tryland Åsa Maria Olofsdotter Espmark Grete H. M. Jørgensen Janicke Nordgreen Ingrid Olesen Sonal Jayesh Patel Sokratis Ptochos Marco Vindas Tor Atle MoAbstract
Following the verification of bovine tuberculosis (bTB) after an outbreak in 2022, concerns were raised about the true epidemiological situation of bTB in Norway. Consequently, the Norwegian Food Safety Authority commissioned VKM to assess the risk of introducing Mycobacterium bovis to Norway, and the risk of its spread and establishment in Norwegian livestock and wild fauna. VKM was also tasked with assessing the risk of infection to humans and identifying risk-reducing measures and diagnostic options for detecting infection in Norway. Background: bTB is a bacterial disease affecting animals and humans, caused by M. bovis. The prevalence varies greatly across European countries. Norway has held an official free status since 1963, with only a few cases reported in the 1980s. The 2022 outbreak was identified through routine meat inspection, revealing several infected animals in a specific herd. The source of this outbreak remains unidentified, and no infected animals have been detected since early 2023. Contact network tracing linked many farms to the index (outbreak) herd through cattle trade. The identified contact herds are still monitored for infection, and the possibility of a spread to other farm animals or wildlife cannot be excluded. Norway maintains strict regulations on live animal imports and monitors the presence of bTB through mandatory reporting, meat inspections, and breeding station testing. M. bovis can infect a wide variety of domestic and wildlife species. Furthermore, there is a significant public health concern due to its zoonotic potential. bTB is a chronic disease, and the incubation period can span from months to years. The bacterium can survive for months in the environment. Diagnosing bTB in live animals is challenging and time-consuming, implying that detection and eradication of the infection is difficult. Key Findings: Norway has had a very low number of imported cattle during the past 10 years. However, some imports of small ruminants and camelids (llamas, alpacas, camels) have occurred. Import of cattle and camelids from countries with bTB in the animal population is assessed as a risk of introducing the bacterium to Norwegian cattle. This risk assessment concludes that introduction of bTB to Norway from imported cattle is unlikely based on the current situation with low number of imports. However, introduction by camelids is regarded as more likely. There is significant domestic trade and transport of beef and dairy cattle within Norway, sometimes without proper registration. If bTB is established in the country, cattle movements are likely to spread the infection between herds. Furthermore, direct and indirect transmission to other domestic species or free-ranging animals (semi-domesticated reindeer and wildlife) may occur, which may complicate the control of bTB in outbreak regions. Indirect transmission can occur via contaminated feeds, pastures, and salt licks that are shared with free-ranging animals. Many species of free-ranging animals are susceptible to M. bovis. Depending on population density and other ecological factors, these species may play the role as hosts and a source of infection for cattle, other livestock and humans. Based on experience from Europe, M. bovis is considered as extremely difficult to eradicate in a country if established in free-ranging species. Badgers, cervid species (i.e. red deer, reindeer, roe deer, and moose), and a growing population of wild boars are of special concern. A contingency plan that takes into account the risk of spread to wild fauna may thus be crucial for successful control of an outbreak with bTB. In periods of severe drought, import of roughage to Norway may be necessary. It is uncertain how well different feed materials and ensiling methods will enable survival of M. bovis. Therefore, restricting import of roughage to Norway to countries and regions certified as officially tuberculosis free (OTF), will reduce the risk of introduction to Norwegian cattle. In the event of introduction and establishment of M. bovis to Norwegian cattle, slurry may pose a risk of spread to domestic and wild animals due to survival of the bacterium in liquid manure. Survival in slurry is uncertain; however, a minimum of six months storage before spreading or alternatively disinfection of slurry will reduce the risk. Zoonotic transmission of bTB remains a relatively rare event, also in countries where the infection is present in animal populations. However, M. bovis can be transmitted by direct contact between animals and humans, through handling (farmers, veterinarians, and slaughterhouse workers) carcasses, and indirectly by consumption of unpasteurised milk and dairy products, but rarely through consumption of meat and meat products. Meat inspection is the key measure for surveillance of bTB in cattle and other domestic animals. Diagnosing bTB is challenging due to the nature of the disease and the lack of a gold standard test. Test-positive animals may not show visible lesions postmortem, and sensitive methods like cultivation and PCR depend on the presence of bacteria in sampled tissues. Any test-strategy aiming to increase the possibility to detect latent infected animals will result in a higher number of culled animals where the infection cannot be confirmed. Too extensive testing in low-risk herds can lead to false positives and must be balanced against the financial costs of restrictions and culling. Combining different tests (skin test, IFN-γ test, and boosted antibody tests) improve sensitivity, and this strategy is particularly advised for imported animals and during outbreak investigations. To achieve the best sensitivity, one should apply the tuberculin test at the same time as the IFN-γ test, followed by serology 10-30 days after the tuberculin test. Culling testpositive animals, and retest after at least 60 days of animals with an inconclusive test will reduce the risk of introducing M. bovis to Norway. While tuberculin tests are labor-intensive and costly, they are regarded as the methods of choice for surveillance in endemic regions. Serological assays like Enferplex show promise for general surveillance, however, the sensitivity is relatively low without prior skin-test. Ongoing studies are evaluating the test performance in bulk-milk screening. In culled animals with suspected lesions, real-time PCR, alongside culture, is recommended for quicker diagnosis. Whole-genome sequencing is the preferred tool for molecular surveillance and outbreak investigations.
Abstract
No abstract has been registered