Publikasjoner
NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.
2008
Sammendrag
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Forfattere
Trond Rafoss Arild Sletten Leif SundheimSammendrag
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Forfattere
Merete Wiken Dees Carl Jonas Jorge Spetz dag-ragnar blystadSammendrag
A virus (isolate 10306) was isolated from bait plants (Nicotiana sp.) grown in a soil sample collected from cultivated soil in the eastern part of Norway. Preliminary results from electron microscopy identified isolate 10306 as a putative member of the genus Potexvirus based on particle morphology. Molecular and biological methods were further used to determine the coat protein (CP) sequence and the host range of isolate 10306, respectively. Potexvirus-specific degenerate primers were designed and used to amplify a ~300 nucleotide fragment belonging to the RNA-dependent RNA-polymerase region of the viral genome by reverse-transcription PCR (RT-PCR). Based on the results from the sequencing analysis, new specific primers were designed to amplify a fragment encompassing the CP gene. Furthermore, isolate 10306 was mechanically inoculated to different test plants and was found to infect systemically eight plant species belonging to five families. CP sequence comparisons, on amino acid and nucleotide level, as well as phylogenetic analysis identified isolate 10306 as Tulip virus X (TVX). However, results from the host range studies differed from the ones previously published for this virus, suggesting that isolate 10306 could be considered a different strain of TVX. This is the first report of TVX in Norway.
Sammendrag
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2007
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
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2006
Sammendrag
White clover (WC, Trifolium repens L.) or red clover (RC, Trifolium pratense L.) was grown in mixture with grasses. Samples of the mixtures and pure clovers were taken during three cuts, and the fatty acids (FA) compositions were determined. The clover species had no significant effect on the individual FA contents of the leys (g kg-1 dry matter (DM)), nor on the total FA content. Pure clovers had lower content of all individual FA (8.2 vs. 12.4 g kg-1 DM) than mixtures; the contents of all FA decreased with increasing percentage of clover in the mixture, but the decrease was weaker for C18:3n-3 than for the other FA. Although pure WC and RC had similar FA contents, the relative proportions (percentage of total FA content) of C16:0 and C18:3n-3 differed; RC had a higher proportion of C18:3n-3 and a lower proportion of C16:0. These results are partly in contradiction with previously reported.
Forfattere
Steffen Adler Åshild T. RandbySammendrag
Feed fatty acid (FA) composition influences the FA composition of cow milk. In a continuous production experiment with 32 Norwegian red dairy cows fishmeal (FM) was compared to peameal (PM) as protein supplement to home-grown cereals and grass silage in organic farming. The protein supplements were together with cereals formulated to be isonitrogeneous and isoenergetic (NEL) and were compared at high (HC) and low concentrate (LC) level. The concentrate rations did not affect the intake of silage. Fishmeal resulted in significantly higher milk yield (kg) with a lower fat concentration (HC) compared to PM. Lower concentrations of urea and FFA were found in milk produced with FM compared to PM. Milk flavour and odour was equal or better when FM rather than PM was fed. Fishmeal diets increased significantly the proportions of several long-chain FAs: oleic acid (C18:1c9), vaccenic acid (C18:1c11), CLA (C18:2c9,t11, not significant at HC), C20:0, C18:1t10, and DHA (C22:6 n-3) in milk fat compared to PM. DHA, which is found in high concentrations in FM (14 g/100g FAME), had the most significant increase. The proportion of C18:3 n-3 (ALA) was significantly lower when FM was fed compared to PM. The percentage of saturated FA was significantly lower and the percentage of monounsaturated FA was higher when FM rather than PM was fed. For cows on HC the n-6/n-3 ratio was lower in the FM group than in the PM group, and the ratio was lower at LC than at HC (p = 0.006, interaction p = 0.02). Fishmeal diets included higher proportions of oats than PM diets. Oats have high content of oleic acid and may therefore have influenced the composition of FAs in milk fat as well as the protein supplements. Fishmeal increased the proportion of beneficial FAs without reducing the sensoric quality of milk. It remains unclear whether this is an effect of protein source or an effect of the higher oat proportions in FM diets.
Forfattere
Steffen Adler Åshild T. RandbySammendrag
Three continuous production experiments and three short term cross over experiments were carried out in Northern Norway to investigate different feeding strategies for dairy cows in organic farming. This paper focuses on the effects on sensoric milk quality. Half of the 32 Norwegian red dairy cows in the production experiments were fed 40% (HC) concentrates (on energy basis per year) and the other half 10% (LC). Twelve cows (HC) participated in the short term cross over experiments. The experimental factors in the continuous production experiments were barley preservation method (P1), grass silage maturity (P2) and type of protein supplement (P3), and in the short term cross over experiments barley preservation method (C1), type of protein supplement (C2) and time for fishmeal feeding (C3). In all experiments the cows were offered grass silage ad libitum, restricted amounts of cereals and protein feeds, and mineral and vitamin supplements. The sensoric quality of milk was in general high. In the production experiments, milk from cows in HC had slightly higher quality than from cows in LC (significant in P2, p = 0.04). Neither the preservation method of barley (dried or ensiled with molasses), maturity of grass silage or type of protein supplement (fishmeal or peameal) influenced the sensoric milk quality significantly. Also in the cross over experiments no effect of the studied factors was found in milk flavour and odour. Early harvested grass silage gave significantly lower FFA contents than grass silage cut at normal time (P2) and FM gave significantly lower FFA concentrations than peameal (P3). These results indicate that organic farmers with different feeding regimes can produce milk of first class sensoric quality. Also the content of FFA has been low in all experiments (except C1). However, feeding regimes containing low levels of concentrates may reduce milk taste slightly.
Sammendrag
Early stage of grass maturity increased the total concentration of fatty acids (FA) and the concentration of alpha-linolenic acid in organic ley compared to normal stage. Organic ley with red clover resulted in higher concentration of alpha-linolenic acid than white clover. Unexpectedly, increased portions of clover in the ley resulted in lower total concentration of FA. Early harvested ley with red clover may result in forage with high concentrations of alpha-linolenic acid and thus provide a good basis for milk production with a healthy composition of milk fat with a low omega-6/omega-3 FA ratio.