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.
2023
Abstract
Ethiopia has the highest livestock numbers in Africa, and a large part of the population depends fully or partly on cattle for their livelihoods. The country experiences high rates of soil erosion due to degradation of cropland and rangelands, and overgrazing is a serious problem. In this paper, we report results from the first two harvests of two field experiments established in June 2021 at two different highland locations in Ethiopia: Hawassa in the south, and Bahir Dar in the north. Four species; two legumes (Desmodium intortum and Stylosanthes guianensis) and two grasses (Brachiaria hybrid ‘Cayman’ and Panicum maximum ‘Mombasa’) were sown in monocultures and various mixtures in a simplex design. Dry matter yields and botanical composition from each cut were recorded. The first harvest was taken around 100 days after establishment, while the second harvest was taken during the drought period, i.e. in January 2022 at Hawassa and in March 2022 at Bahir Dar. The difference between monoculture and mixture community performances varied in magnitude from site to site and across harvests; we found evidence of positive interactions between grasses and legumes at Hawassa. These preliminary results show that grass-legume mixtures using tropical species have some potential under Ethiopian conditions.
Authors
Marit JørgensenAbstract
No abstract has been registered
Abstract
No abstract has been registered
Authors
Caroline Chylinski Kristin Fløgstad Degnes Inga Marie Aasen Sokratis Ptochos Berit Marie Blomstrand Karl-Christian Mahnert Heidi L Enemark Stig Milan Thamsborg Håvard Steinshamn Spiridoula AthanasiadouAbstract
The antiparasitic potential of plants could offer a vital solution to alleviating the costs of gastrointestinal nematode (GIN) infections in ruminant production globally. Leveraging known bioactive molecules, however, is complex, where plant species, extraction processes and seasonality impact bioavailability and efficacy. This study assessed the impact of a comprehensive set of factors on the antiparasitic activity of Norwegian conifers to identify bark compounds specific against GIN. Antiparasitic activity was determined using in vitro assays targeting morphologically distinct life stages of ovine GIN: the egg hatch assay and larval motility assay. In depth characterisation of the chemical composition of the bark extracts was carried out using chromatographic separation, UV-absorbance, and molecular mass profiles to identify compounds implicated in the activity. Three key findings emerged: (1) the activity of bark extracts varied markedly from 0 to 100% antiparasitic efficacy, owing to tree species, extraction solvent and seasonality; (2) the GIN exhibited species-and stage-specific susceptibility to the bark extracts; (3) the presence of condensed tannins, amongst other compounds, was associated with anthelmintic activity. These findings add new insights into urgently needed alternative parasite control strategies in livestock.
Authors
Kim Viggo Paulsen Weiby Sophie Julie Krizsan Ingjerd Dønnem Liv Østrem Margrete Eknæs Håvard SteinshamnAbstract
Mitigating enteric methane (CH4) emissions is crucial as ruminants account for 5% of global greenhouse gas emissions. We hypothesised that less frequent harvesting, use of crops with lower WSC concentration, ensiling at low crop dry matter (DM) and extensive lactic acid fermentation would reduce in vitro CH4 production. Timothy (T), timothy + red clover mixture (T + RC) or perennial ryegrass (RG), cut either two or three times per season, was wilted to 22.5% or 37.5% DM and ensiled with or without formic acid-based additive. Silages were analysed for chemical composition and fermentation products. In vitro CH4 production was measured using an automated gas in vitro system. Methane production was, on average, 2.8 mL/g OM lower in the two-cut system than in the three-cut system (P < 0.001), and 1.9 mL/g OM lower in T than in RG (P < 0.001). Silage DM did not affect CH4 production (P = 0.235), but formic acid increased CH4 production by 1.2 mL/g OM compared to the untreated silage (P = 0.003). In conclusion, less frequent harvesting and extensive silage fermentation reduce in vitro CH4 production, while RG in comparison to T resulted in higher production of CH4.
Authors
Martha Grøseth Linda Karlsson Håvard Steinshamn Marianne Johansen Alemayehu Kidane Egil PrestløkkenAbstract
Increasing the protein value in grass silages for dairy cows is of interest to increase use of homegrown protein sources and reduce nitrogen (N) losses to the environment. Studies have shown that wilting of grass silage can improve the metabolizable protein (MP) value by increasing the rumen microbial protein yield (MCP) and rumen escaped feed protein. We hypothesised that feeding wilted grass silage can improve milk and milk protein production in dairy cows and reduce the need for MP, estimated as amino acids absorbed in the small intestine (AAT), in concentrate. To test this, a continuous feeding experiment with 48 early to mid-lactation Norwegian Red dairy cows, kept in a loose housing system was conducted. Treatments were first cut grass silages from round bales, harvested at early booting from a sward of timothy (Phleum pratense), perennial rye grass (Lolium perenne) and meadow fescue (Festuca pratensis), wilted to 260 and 417 g dry matter (DM)/kg fresh matter. The grass silage was fed ad libitum and supplied with 8.3 kg/d of concentrate, either low (108 g AAT/kg DM) or high (125 g AAT/kg DM) in MP concentration, in a 2×2 factorial arrangement. The experiment lasted for 11 weeks, with the 2 first weeks, where cows received same feeding, used as covariate, and the last 4 weeks were used as data collection period. Wilting reduced fermentation products, ammonia and soluble N in the grass silage, while increased residual water-soluble carbohydrates, like expected. However, there was no difference between treatments in daily silage DM intake (13.1 kg) and milk yield (30.2 kg) or milk content, but feeding high MP concentrate increased urea and uric acid in urine. No major differences were found for rumen pH, amino acids in blood plasma or purine derivatives over creatinine index, as indirect estimate for MCP. In conclusion, high silage DM and high MP in concentrate did not increase the milk production in this study.
Authors
Martha Irene Grøseth Linda Karlsson Håvard Steinshamn Marianne Johansen Alemayehu Kidane Egil PrestløkkenAbstract
A continuous production experiment was conducted in Norway with 48 Norwegian Red dairy cows in early- to mid-lactation, to investigate the effect of grass silage with lactic acid bacteria (LAB) or formic acid (FA) additives, on milk yield (MY) and milk protein yield (MPY). Grass wilted to 250 g dry matter (DM)/kg was inoculated with homofermentative LAB to obtain LAB silage, whilst FA silage was produced adding a FA-based additive. The two silages were fed ad libitum and supplemented with an average 10.3 kg of either high (H) or low (L) metabolizable protein (MP) concentrates, in a 2 ✗ 2 factorial arrangement of treatments. The treatments were LAB silage and L concentrate, LAB silage and H concentrate, FA silage and L concentrate and FA silage and H concentrate. The use of FA resulted in lower levels of residual water-soluble carbohydrates (WSC), and higher levels of ammonia nitrogen (NH3single bondN), compared to LAB. In situ results for FA silage showed lower rumen degradability of crude protein (CP), while gas in vitro results showed lower utilizable CP (uCP), compared to LAB silage (782 vs. 750 g/kg DM and 128 vs. 119 g/kg DM, respectively). The purine over creatinine (PDC) index did not indicate any effects on the microbial protein synthesis (MPS) from any of the treatments. The higher daily intake of FA silage (12.5 vs.13.7 kg DM for LAB and FA, respectively, P < 0.001), did not result in significant differences in daily MY (31.0 vs. 30.2 kg, P = 0.208), nor MPY (1.08 vs.1.07 kg/day, P = 0.878) for LAB and FA, respectively. Feeding H concentrate gave higher MPY (P = 0.036), higher urea in milk (P < 0.001), plasma (P < 0.001) and urine (P = 0.008) and tended to give higher MY (P = 0.063) for both silages. For amino acids (AA) in plasma, alanine was higher for FA silage than for LAB silage (P = 0.030), while histidine (P = 0.001), leucine (P = 0.015) and glutamine (P = 0.007) were higher for both silages when cows were fed H concentrate. In conclusion, the FA and LAB additives did not affect MY or MPY any differently. Feeding H concentrate resulted in higher MPY for both silages, but reduced nitrogen (N) efficiency.
Abstract
Vitamin E is essential and supplementation to the diet is often needed to meet the requirements of farm animals. This is particularly relevant during long indoor periods where conserved forages must be fed, as conservation can degrade Vitamin E. However, synthetic vitamins are regarded as contentious inputs in organic agriculture. Therefore, the aim of this work was to evaluate if the standard recommendations for supplementation can be revised and adapted for organically managed dairy cows, on the basis of that the diets differ from those in conventional systems. A systematic literature review was conducted to assess the response to Vitamin E supplementation considering lactation and gestation stage and the composition of the basal diet. Most of the experiments that focused on animal health-related issues were conducted during late gestation and early lactation. In more recent studies reporting positive effects of Vitamin E supplementation on animal health and fertility, cows were fed conserved forages such as hay, haylage or maize silage, which all have low natural content of Vitamin E. In the studies reporting no or only minor positive effects of Vitamin E supplementation, cows were often fed diets based on grass or grass-clover silages, which reflects the structure of organic cattle diets. In conclusion, it was proposed that Vitamin E supplementation is not needed for mid and late lactating cows on pasture or fed a basal diet of grass-clover-silages. For dry and peripartum cows as well as for cows fed maize silage, hay or haylage, supplementation was strongly recommended
Authors
S. Thamsborg Håvard Steinshamn Heidi Larsen Enemark Spiridoula Athanasiadou Berit Marie BlomstrandAbstract
No abstract has been registered
Authors
Håvard SteinshamnAbstract
No abstract has been registered