| Records |
| Author |
Bannink, A.; van Lingen, H.J.; Ellis, J.L.; France, J.; Dijkstra, J. |
| Title |
The contribution of mathematical modeling to understanding dynamic aspects of rumen metabolism |
Type |
Journal Article |
| Year |
2016 |
Publication |
Frontiers in Microbiology |
Abbreviated Journal  |
Frontiers in Microbiology |
| Volume |
7 |
Issue |
|
Pages |
1820 |
| Keywords |
lactating dairy-cows; milk urea concentration; fatty-acid production; ruminal fermentation; mechanistic model; holstein cows; beef-cattle; stoichiometric parameters; methane production; feeding frequency |
| Abstract |
All mechanistic rumen models cover the main drivers of variation in rumen function, which are feed intake, the differences between feedstuffs and feeds in their intrinsic rumen degradation characteristics, and fractional outflow rate of fluid and particulate matter. Dynamic modeling approaches are best suited to the prediction of more nuanced responses in rumen metabolism, and represent the dynamics of the interactions between substrates and micro-organisms and inter-microbial interactions. The concepts of dynamics are discussed for the case of rumen starch digestion as influenced by starch intake rate and frequency of feed intake, and for the case of fermentation of fiber in the large intestine. Adding representations of new functional classes of micro-organisms (i.e., with new characteristics from the perspective of whole rumen function) in rumen models only delivers new insights if complemented by the dynamics of their interactions with other functional classes. Rumen fermentation conditions have to be represented due to their profound impact on the dynamics of substrate degradation and microbial metabolism. Although the importance of rumen pH is generally acknowledged, more emphasis is needed on predicting its variation as well as variation in the processes that underlie rumen fluid dynamics. The rumen wall has an important role in adapting to rapid changes in the rumen environment, clearing of volatile fatty acids (VFA), and maintaining rumen pH within limits. Dynamics of rumen wall epithelia and their role in VFA absorption needs to be better represented in models that aim to predict rumen responses across nutritional or physiological states. For a detailed prediction of rumen N balance there is merit in a dynamic modeling approach compared to the static approaches adopted in current protein evaluation systems. Improvement is needed on previous attempts to predict rumen VFA profiles, and this should be pursued by introducing factors that relate more to microbial metabolism. For rumen model construction, data on rumen microbiomes are preferably coupled with knowledge consolidated in rumen models instead of relying on correlations with rather general aspects of treatment or animal. This helps to prevent the disregard of basic principles and underlying mechanisms of whole rumen function. |
| Address |
2017-01-06 |
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| Language |
English |
Summary Language |
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| Series Volume |
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Series Issue |
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Edition |
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| ISSN |
1664-302x |
ISBN |
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Medium |
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Conference |
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| Notes |
LiveM, ft_MACSUR |
Approved |
no |
| Call Number |
MA @ admin @ |
Serial |
4932 |
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| Author |
Barber, H.M.; Lukac, M.; Simmonds, J.; Semenov, M.A.; Gooding, M.J. |
| Title |
Temporally and Genetically Discrete Periods of Wheat Sensitivity to High Temperature |
Type |
Journal Article |
| Year |
2017 |
Publication |
Frontiers in Plant Science |
Abbreviated Journal |
Front. Plant Sci |
| Volume |
8 |
Issue |
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Pages |
51 |
| Keywords |
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| Abstract |
Successive single day transfers of pot-grown wheat to high temperature (35/30°C day/night) replicated controlled environments, from the second node detectable to the milky-ripe growth stages, provides the strongest available evidence that the fertility of wheat can be highly vulnerable to heat stress during two discrete peak periods of susceptibility: early booting [decimal growth stage (GS) 41-45] and early anthesis (GS 61-65). A double Gaussian fitted simultaneously to grain number and weight data from two contrasting elite lines (Renesansa, listed in Serbia, Ppd-D1a, Rht8; Savannah, listed in UK, Ppd-D1b, Rht-D1b) identified peak periods of main stem susceptibility centered on 3 (s.e. = 0.82) and 18 (s.e. = 0.55) days (mean daily temperature = 14.3°C) pre-GS 65 for both cultivars. Severity of effect depended on genotype, growth stage and their interaction: grain set relative to that achieved at 20/15°C dropped below 80% for Savannah at booting and Renesansa at anthesis. Savannah was relatively tolerant to heat stress at anthesis. A further experiment including 62 lines of the mapping, doubled-haploid progeny of Renesansa × Savannah found tolerance at anthesis to be associated with Ppd-D1b, Rht-D1b, and a QTL from Renesansa on chromosome 2A. None of the relevant markers were associated with tolerance during booting. Rht8 was never associated with heat stress tolerance, a lack of effect confirmed in a further experiment where Rht8 was included in a comparison of near isogenic lines in a cv. Paragon background. Some compensatory increases in mean grain weight were observed, but only when stress was applied during booting and only where Ppd-D1a was absent. |
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Edition |
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| ISSN |
1664-462x |
ISBN |
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Medium |
article |
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| Notes |
CropM, ftnotmacsur |
Approved |
no |
| Call Number |
MA @ admin @ |
Serial |
4974 |
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| Author |
Semenov, M.A.; Stratonovitch, P. |
| Title |
Designing high-yielding wheat ideotypes for a changing climate |
Type |
Journal Article |
| Year |
2013 |
Publication |
Food and Energy Security |
Abbreviated Journal |
Food Energy Secur. |
| Volume |
2 |
Issue |
3 |
Pages |
185-196 |
| Keywords |
Climate change impacts; crop modeling; LARS-WG; Sirius; wheat |
| Abstract |
Global warming is characterized by shifts in weather patterns and increases in climatic variability and extreme events. New wheat cultivars will be required for a rapidly changing environment, putting severe pressure on breeders who must select for climate conditions which can only be predicted with a great degree of uncertainty. To assist breeders to identify key wheat traits for improvements under climate change, wheat ideotypes can be designed and tested in silico using a wheat simulation model for a wide range of future climate scenarios predicted by global climate models. A wheat ideotype is represented by a set of cultivar parameters in a model, which could be optimized for best wheat performance under projected climate change. As an example, high-yielding wheat ideotypes were designed at two contrasting European sites for the 2050 (A1B) climate scenario. Simulations showed that wheat yield potential can be substantially increased for new ideotypes compared with current wheat varieties under climate change. The main factors contributing to yield increase were improvement in light conversion efficiency, extended duration of grain filling resulting in a higher harvest index, and optimal phenology. |
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English |
Summary Language |
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Series Issue |
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Edition |
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| ISSN |
2048-3694 |
ISBN |
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Medium |
Article |
| Area |
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Expedition |
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Conference |
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| Notes |
CropM, ft_macsur |
Approved |
no |
| Call Number |
MA @ admin @ |
Serial |
4505 |
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| Author |
Irz, X.; Kuosmanen, N. |
| Title |
Explaining growth in demand for dairy products in Finland: an econometric analysis |
Type |
Journal Article |
| Year |
2013 |
Publication |
Food Economics |
Abbreviated Journal |
Food Economics |
| Volume |
9 |
Issue |
sup5 |
Pages |
47-56 |
| Keywords |
Consumption; food; almost ideal demand system; decomposition; elasticities; milk; demand analysis; farm |
| Abstract |
The dairy sector represents the cornerstone of Finnish agriculture but faces new challenges linked to the decoupling of farm subsidies and abolition of milk production quotas. Because of its increasing exposure to market forces, the sector must anticipate future changes in demand and deliver precisely what Finnish consumers want. This paper contributes to that goal by analyzing retroactively the drivers of demand for dairy products over the period 1975–2010 using National Accounts Data. After presenting the evolution of consumption for dairy products, we estimate a complete system of demand for food and dairy products and use it to decompose demand growth into a substitution effect, income effect, and trend effect. The analysis points to the severity of the challenges that the sector is facing. Stagnant consumption is at least partially the result of continuous but adverse taste changes, and as Finnish consumers grow more prosperous, they allocate an increasingly smaller share of their food budget to the dairy group. The low own-price elasticity of demand for dairy products also limits the benefits to the sector of growth in milk production. Hence, business-as-usual will result in the dwindling importance of the dairy sector in the Finnish food chain. Innovation and product differentiation, perhaps emphasizing the attributes of livestock production processes, are clearly required to counter this evolution. |
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English |
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Edition |
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| ISSN |
2164-828x |
ISBN |
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Article |
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Conference |
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| Notes |
TradeM, ftnotmacsur |
Approved |
no |
| Call Number |
MA @ admin @ |
Serial |
4491 |
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| Author |
Olesen, J.E.; Børgesen, C.D.; Elsgaard, L.; Palosuo, T.; Rötter, R.P.; Skjelvåg, A.O.; Peltonen-Sainio, P.; Börjesson, T.; Trnka, M.; Ewert, F.; Siebert, S.; Brisson, N.; Eitzinger, J.; van Asselt, E.D.; Oberforster, M.; van der Fels-Klerx, H.J. |
| Title |
Changes in time of sowing, flowering and maturity of cereals in Europe under climate change |
Type |
Journal Article |
| Year |
2012 |
Publication |
Food Additives & Contaminants: Part A |
Abbreviated Journal |
Food Addit. Contam. Part A |
| Volume |
29 |
Issue |
10 |
Pages |
1527-1542 |
| Keywords |
Agriculture/*methods/trends; Avena/growth & development; *Climate Change; Crops, Agricultural/*growth & development; Edible Grain/*growth & development; Europe; Flowering Tops/growth & development; Forecasting/methods; Germination; Humans; Models, Biological; Models, Statistical; Seasons; Seeds/growth & development; Spatio-Temporal Analysis; Triticum/growth & development; Zea mays/growth & development |
| Abstract |
The phenological development of cereal crops from emergence through flowering to maturity is largely controlled by temperature, but also affected by day length and potential physiological stresses. Responses may vary between species and varieties. Climate change will affect the timing of cereal crop development, but exact changes will also depend on changes in varieties as affected by plant breeding and variety choices. This study aimed to assess changes in timing of major phenological stages of cereal crops in Northern and Central Europe under climate change. Records on dates of sowing, flowering, and maturity of wheat, oats and maize were collected from field experiments conducted during the period 1985-2009. Data for spring wheat and spring oats covered latitudes from 46 to 64°N, winter wheat from 46 to 61°N, and maize from 47 to 58°N. The number of observations (site-year-variety combinations) varied with phenological phase, but exceeded 2190, 227, 2076 and 1506 for winter wheat, spring wheat, spring oats and maize, respectively. The data were used to fit simple crop development models, assuming that the duration of the period until flowering depends on temperature and day length for wheat and oats, and on temperature for maize, and that the duration of the period from flowering to maturity in all species depends on temperature only. Species-specific base temperatures were used. Sowing date of spring cereals was estimated using a threshold temperature for the mean air temperature during 10 days prior to sowing. The mean estimated temperature thresholds for sowing were 6.1, 7.1 and 10.1°C for oats, wheat and maize, respectively. For spring oats and wheat the temperature threshold increased with latitude. The effective temperature sums required for both flowering and maturity increased with increasing mean annual temperature of the location, indicating that varieties are well adapted to given conditions. The responses of wheat and oats were largest for the period from flowering to maturity. Changes in timing of cereal phenology by 2040 were assessed for two climate model projections according to the observed dependencies on temperature and day length. The results showed advancements of sowing date of spring cereals by 1-3 weeks depending on climate model and region within Europe. The changes were largest in Northern Europe. Timing of flowering and maturity were projected to advance by 1-3 weeks. The changes were largest for grain maize and smallest for winter wheat, and they were generally largest in the western and northern part of the domain. There were considerable differences in predicted timing of sowing, flowering and maturity between the two climate model projections applied. |
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English |
Summary Language |
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Edition |
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1944-0049 1944-0057 |
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Article |
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| Notes |
CropM |
Approved |
no |
| Call Number |
MA @ admin @ |
Serial |
4590 |
| Permanent link to this record |
