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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.

2024

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Sammendrag

Income comparisons between farm and non-farm households play a crucial role in many aspects of farm policy. Using household income data from tax returns of all Norwegian taxpayers in the period 2006–2015 we study these income differences. We find that the unconditional mean income is higher for farm households, but with important differences depending on the comparison group considered. We also find that the income difference is reduced when we control for differences in the personal characteristics of the different non-farm comparison sub-groups. This finding implies that income comparison using unconditional means, as frequently done in agricultural policy making, is potentially misleading. We also show that the income effect of personal characteristics is not the same for different comparison sub-groups, as has been assumed in previous studies of income disparities. Differences in personal characteristics, and the income effect of those characteristics, therefore need to be accounted for if income comparisons between farmers and non-farmers are to inform farm support policies.

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Sammendrag

Housing and indoor feeding of sheep is required throughout the cold season, which can last more than half a year, in Nordic highlands and Alpine regions. This study aimed to examine and evaluate the housing costs, including labour requirements, according to type of sheep housing system and degree of mechanized feeding by investigating systems commonly used in Nordic and Alpine regions. Detailed cost data were obtained from 61 surveyed sheep farmers in Norway with sheep houses built between the years 2008 and 2015. Costs were calculated for a baseline scenario (2021-prices) as well as for five scenarios at low and high discount rates and opportunity cost of labour, and high energy prices. The median (interquartile range) flock size was 150 (100) winter-fed sheep. Houses with slatted floors were more expensive than deep-litter systems. Costs of bedding material and feed waste were however higher, and the net value of the manure were lower in houses with deeplitter systems. At the baseline assumptions, overall net housing costs per sheep was not statistically different among the main housing types studied. Multiple regression analyses showed that net housing costs per sheep were lower in larger flocks and for centrally located farms (control variables). Undertaking daily chores, such as feeding of roughages twice a day rather than once, resulted in significantly higher net housing costs. Mechanized feeding of roughages, and even more so for concentrates, were not economically justified since labour savings were not sufficient to pay for the additional capital costs. A round bale chopper lowered net housing costs, significantly at a high labour cost. None of the scenarios found slatted floors to be significantly more expensive than deep-litter systems. High costs of labour and capital favoured deep-litter systems, while slatted floor systems were more advantageous at rising prices of energy that resulted in increased values of organic manures and costs of feed wastes and bedding materials. The study was based on a decade old data from common Norwegian sheep house variants. Farmers that consider constructing a new sheep house today, still must compare these variants as their main alternatives. We encourage other researchers to include effects of housing systems and mechanized feeding on animal performance, health, and welfare. Moreover, future studies should preferably also be undertaken in other environmental or socio-economic settings to produce more general results.

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Sammendrag

Regeneration of polyploidy from young thallus segments of Kappaphycus alvarezii was optimized for genetic improvement. Kappaphycus thallus segment cultured on sterile sea water supplemented with various combinations of Indole acetic acid, Kinetin and Acardian Marine Plant Extract Powder revealed differential response on callus proliferation and development of new thallus. Presence of Acardian Marine Plant Extract Powder (3 mg/l) in combination with Indole acetic acid and Kinetin (0.01 mg/l each) had induced the longest emerging thallus. Exposure of thallus to colchicine at 0.01% with above combination was optimal to induce high frequency regeneration of polyploidy mostly from the meristematic cells. Anatomical study of colchicine induced polyploidy revealed larger cortical cells with irregular thickening of epidermal layer. Phase contrast and Scanning Electron Microscopic study revealed increase in cell size in cortical region with significantly larger number of spherical shaped carrageenan globules in colchicine induced polyploidy than normal thallus. Single cells isolated using enzymatic treatments from colchicine induced polyploidy, shown chromosome number with a ploidy status of 4n ≈ 40. Whereas in normal thallus, only half the number of chromosomes (2n ≈ 20) were observed. Polyploidy were successfully acclimatized gradually using raft method for further evaluation. This is the first report reveals the induction and regeneration of polyploidy in Kappaphycus. The possible application of this finding in genetic improvement of Kappaphycus is discussed.