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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.

2006

Abstract

When using chitosan as an antifungal agent in wood it is important to understand which factors contribute to a higher fixation ratio to optimize the utilization of chitosan, the active component. Small pine samples were impregnated with chitosan solutions varying in molecular weight, concentration, pH, polymerization agent, acid and degree of deacetylation. Different post-treatments such as time, temperature, moisture content and the effect of present air were applied to the samples to evaluate the effect on the relative retention. After impregnation, the samples, with a volume of 1.5 cm3, were leached in separate test-tubes according to EN-84. The samples were prepared in a paired design where both samples were impregnated, but only one was leached. Both leached and unleached samples were analysed for their chitosan content, and the relative ratio was used as a measure for the relative retention of chitosan during leaching. The results from these trials show that pH in the range of 5.1-5.9 is favourable. The molecular weight should be as high as possible yet able to penetrate the wood structure, and the use of acetic acid gives far better fixation than the use of hydrochloric acid.

Abstract

The effect of concentrate supplementation on nitrogen (N) intake and excretion in grazing lactating dairy cows was determined in three herds in Norway. Grazing trials were conducted with each herd in June and August for two consecutive years. The average supplementation was 1.8 (S.D. 2.1) kg DM/day, and the concentrate was based on grain with a N content ranging from 18.7 to 24 g/kg DM. Herbage DM and N intake were reduced with increasing supplementation, but total DM and N intake increased. Milk yield and protein content increased by 1.1 kg milk and 0.28 g protein per kg milk for each kg extra concentrate. Milk N excretion increased with increasing supplementation (6.5 g N/kg DM), and N utilisation improved by 11.7 g N per kg N intake per kg extra concentrate. Excretion of urine N and its share of total excreta N decreased by 4.0 and 9.2 g/kg concentrate, respectively. The reducing effect on urine N excretion of supplementation was, however, numerically low compared with other studies, most likely due to a high crude protein content of the concentrate used. (c) 2006 Elsevier B.V. All rights reserved.

Abstract

Use of high energy feed supplementation can improve the protein retention by the cattle, and it has been suggested as a way to increase the nitrogen (N) effi-ciency of dairy production. However, in praxis feed supplementation is also used to increase the intensity of animal production above the level that can be supported by the farm's local plant production. A collection of published surveys showed that dairy farms that buy feed are considerably lees N efficient than farms that supply the entire animal ration from their own plant production. The total N emission to the environment per litre milk doubled when 30% of the total feed ration was produced outside the dairy farm. This was so for organic as well as conventional farms. Similar results can be expected for phosphorous and other nutrients. In order to ensure a sustainable and environmentally friendly organic production, imports of feed produced far away from the dairy farm should be strictly limited. We suggest a ceiling of 5 - 10% of total feed ration.

Abstract

Use of high energy feed supplementation can improve the protein retention by the cattle, and it has been suggested as a way to increase the nitrogen (N) effi-ciency of dairy production. However, in praxis feed supplementation is also used to increase the intensity of animal production above the level that can be supported by the farm's local plant production. A collection of published surveys showed that dairy farms that buy feed are considerably lees N efficient than farms that supply the entire animal ration from their own plant production. The total N emission to the environment per litre milk doubled when 30% of the total feed ration was produced outside the dairy farm. This was so for organic as well as conventional farms. Similar results can be expected for phosphorous and other nutrients. In order to ensure a sustainable and environmentally friendly organic production, imports of feed produced far away from the dairy farm should be strictly limited. We suggest a ceiling of 5 - 10% of total feed ration.