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.
2016
Authors
D. Kristic S. Vujic B. Cupina P. Eric R. Cabilovski M. Manojlovic Peder LombnæsAbstract
In Serbia permanent grasslands represent a significant source of animal feed. However, in most regions the animal production and grazing, and thus the productivity and investment in grasslands, are on a very low level. This research aims to analyse impact of nitrogen fertilization and harrowing on lowland permanent grassland (Vojvodina province, Serbia) in order to improve floristic composition and thus yield and quality. Research was carried out during 2012-2015 in Vojvodina province, Serbia, on permanent grassland which was mainly used for sheep grazing. Trial included two nitrogen rates, namely 40 kg ha-1 and 80 kg ha-1, divided on plots with and without harrowing, as well as control treatments. Floristic composition was mostly composed of species from families Poaceace and Asteraceae with a small number and presence of legume species. The number of species changed in the third and fourth years of the trial. Cynodon dactylon L., Lolium perenne L., Festuca sp., were significantly higher on plots with the higher nitrogen rate, while on the control the most frequent spp. were Trifolium campestre Schreb. and Medicago lupulina L. Harrowing, on the other hand, had smaller impact on improvement of permanent grassland.
Abstract
There are differences in grass-clover proportions and chemical composition between herbage from primary growth (PG) and regrowth (RG) in grass-clover leys. Mixing silages made from PG and RG may provide a more optimal diet to dairy cows than when fed separately. We tested the hypotheses that increasing dietary proportions of grass-clover silage made from RG compared with PG would increase digestion rate of potentially degradable NDF (pdNDF), and increase ruminal accumulation of indigestible NDF (iNDF). Eight rumen cannulated Norwegian Red cows were used in two replicated 4 × 4 Latin squares with 21-day periods. Silages were prepared from PG and RG of an organically cultivated ley, where PG and RG silages were fed ad libitum in treatments with RG replacing PG in ratios of 0, 0.33, 0.67 and 1 on dry matter basis in addition to 8 kg concentrate. We evaluated the effect of the four diets with emphasis on rumen- and total tract fiber digestibility. Increasing RG proportions decreased silage intake by 7%. Omasal flow of pdNDF decreased, whereas iNDF flow increased with increasing RG proportions. Increasing RG proportions decreased rumen pool sizes of NDF and pdNDF, whereas pool sizes of iNDF and CP increased. Increasing RG proportions increased digestion rate of NDF, which resulted in greater total tract digestion of NDF. Pure PG diet had the highest calculated energy intake, but the improved rumen digestion of NDF by cows offered 0.33 and 0.67 of RG leveled out milk fat and protein yields among the three PG containing diets.
Authors
Mai Van Trinh Mehreteab Tesfai Andrew Borrell Sekhar Udaya Nagothu Thi Phuong Loan Bui Vu Duong Quynh Le Quoc ThanhAbstract
No abstract has been registered
Abstract
Under Norwegian conditions, diets based on primary growth (PG) silage typically increase milk yield compared to silage prepared from the regrowth (RG). Organic PG, dominated by immature grasses, is often high in energy and low in crude protein (CP), whereas the opposite is the case for organic RG harvests, dominated by clover. Here, we tested the hypotheses that increasing proportions of RG will reduce the total supply of metabolizable energy, but increase the CP intake, and that there is a dietary optimal mix of PG and RG to meet requirements for optimal milk production. Sixteen Norwegian Red cows were used in an experiment designed with four balanced 4 × 4 Latin squares with 21-day periods to evaluate the effect of incremental replacement of PG with RG on feed intake, nutrient digestion, and milk production. Silages were prepared from PG and RG of an organically managed grassland. Treatments comprised silages fed ad libitum with RG replacing PG in ratios of 0, 0.33, 0.67, and 1 on dry matter (DM) basis. Additionally, concentrate was offered with 8 kg for pluriparous and 7 kg for primiparous cows. The PG had higher content metabolizable energy (ME), potentially degradable neutral detergent fiber (NDF), and water-soluble carbohydrates, while RG contained more CP and indigestible NDF. The already mentioned characteristics led to higher intakes of DM, organic matter, NDF, and ME and lower intakes of CP and indigestible NDF with increasing proportions of PG in the diet. Milk yield tended to be higher when PG and RG were offered as a mixture than when fed alone. The milk fat concentration decreased linearly with increasing proportions of RG proportion, while protein concentration was unaffected by diet. This led to a similar production of energy-corrected milk among cows fed diets containing PG while cows fed pure RG diet produced 0.9 kg less daily. Silage energy concentration and energy intake influenced milk production more than CP supply.
Abstract
Clover proportions, and thereby chemical composition of herbage, differ between primary growth (PG) and regrowth (RG) in organic managed grass-clover fields. The characteristics of PG and RG silages suggest different supplementary feeding strategies to sustain an efficient milk production in dairy cows. Silage made of the RG generally offers more crude protein (CP) in the diet than silage made of the PG because of an increasing proportion of clover later in the season. Additionally, grass and clover have different amino acid (AA) profiles. His has been suggested to be the first limiting AA in grass silage, while Met has been suggested to be the primarily limiting AA in red clover silage. Eight rumen cannulated Norwegian Red cows were used in two replicated 4 × 4 Latin squares with 21-days periods. Organic PG and RG silages were fed ad libitum in four diets with RG replacing PG silage in ratios of 0, 0.33, 0.67 and 1 on dry matter (DM) basis. Changing RG silage proportions from 0 to 1 increased daily CP intake from 2.90 to 3.08 kg and rumen NH3-concentrations from 4.9 to 8.4 mmol/L, but did not promote a better protein supply. Neither total ruminal outflow of AA nor the AA profile in the small intestine differed between dietary treatments. Met and His were probably the most limiting AA for a higher milk production. Limitations by His may be more related to diets based on PG, while production by cows fed diets based on more RG herbage were more likely limited by Met.
Abstract
No abstract has been registered
Abstract
No abstract has been registered
Abstract
Ventilation management and the tuber maturity at harvest are essential factors in maintaining potato quality during long-term storage. The aim of this study was to examine the effect of ventilation strategy on storage quality of potato tubers with three different maturity levels at harvest. Two potato cultivars, Saturna and Asterix, were stored in small-scale experimental stores and large-scale commercial stores. Both storage categories were ventilated by both low continuous air rates (natural ventilation) and intermittent high air rates (forced ventilation). The different maturity levels were obtained by a combination of pre-sprouting strategy, planting date and level of nitrogen fertilization of the seed tubers, where pre-sprouting, early planting date and low amount of nitrogen resulted in the most mature tubers. Storage quality parameters investigated during and after long-term storage (6 months in small-scale and 4 months in large-scale stores) included weight loss, respiration, dry matter, sucrose, glucose/fructose content and fry colour. In average over three years natural ventilation resulted in higher weight losses in small- and large-scale stores (1.36 and 3.93%), lower content of reducing sugars (glucose + fructose) in large-scale stores (2.35 mg g 1) and lighter fry colour than did forced ventilation. Immature potatoes had higher weight losses (4.16%), higher respiration rates (1.68 mg CO2 kg 1 h 1) and lower dry matter content (22.3–22.5%) than more mature potatoes. This study show that both maturity and ventilation strategy affects storage quality of potatoes as measured by weight loss, sugar content and fry colour.
Authors
Hugh Cross Ed Biffin Kor-Jent Van Dijk Andrew Lowe Michelle WaycottAbstract
No abstract has been registered
Authors
Frode VeggelandAbstract
No abstract has been registered