Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

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Milk fatty acids as possible biomarkers to diagnose hyperketonemia in early lactation
Jorjong, S. ; Knegsel, A.T.M. van; Verwaeren, J. ; Bruckmaier, R.M. ; Baets, B. De; Kemp, B. ; Fievez, V. - \ 2015
Journal of Dairy Science 98 (2015)8. - ISSN 0022-0302 - p. 5211 - 5221.
detect subclinical ketosis - beta-hydroxybutyrate concentrations - dairy-cows - energy-balance - reproductive-performance - dry period - elevated concentrations - transition period - cattle - chain
The aim of this study was to assess the potential of milk fatty acids as diagnostic tool for hyperketonemia of 93 dairy cows in a 3 × 2 factorial arrangement. Cows were fed a glucogenic or lipogenic diet and originally were intended to be subjected to a 0-, 30-, or 60-d dry period. Nevertheless, some of the cows, which were intended for inclusion in the 0-d dry period group, dried off spontaneously. Milk was collected in wk 2, 3, 4, and 8 of lactation for milk fat analysis. Blood was sampled from wk 2 to 8 after parturition for ß-hydroxybutyrate (BHBA) analysis. Cases were classified into 2 groups: hyperketonemia (BHBA =1.2 mmol/L) and nonhyperketonemia (BHBA
Effect of maternal dry period length on colostrum immunoglobulin content and natural and specific antibody titers in calves
Mayasari, N. ; Vries Reilingh, G. de; Nieuwland, M.G.B. ; Remmelink, G.J. ; Parmentier, H.K. ; Kemp, B. ; Knegsel, A.T.M. van - \ 2015
Journal of Dairy Science 98 (2015)6. - ISSN 0022-0302 - p. 3969 - 3979.
dairy-cows - energy-balance - milk-production - bovine somatotropin - metabolic status - performance - responses - lactation - pathogen - antigen
The objective was to study the effect of dry period length in dairy cows on immunoglobulin content and natural antibodies (NAb) titers in colostrum, growth, and plasma natural and specific antibody titers in plasma of calves. Holstein-Friesian dairy cows (n = 167) were randomly assigned to 3 dry period lengths (0, 30, or 60 d). Colostrum production, concentration of colostrum IgG and IgM, and titers of NAb (isotypes IgG and IgM) binding keyhole limpet hemocyanin (KLH) and human serum albumin (HuSA) in colostrum were measured. Female calves were immunized with both KLH and HuSA at wk 6 and 10 of life. Titers of NAb and specific antibody (SpAb) for isotypes IgG, IgM, and total immunoglobulin (IgT) binding KLH or HuSA were determined in plasma of female calves. Primary and secondary antibody responses to KLH or HuSA from wk 6 and 10 were expressed as the increase in antibody titers to wk 10 and 11 of life after primary and secondary challenges, respectively. Pregnancy length for cows with a 0-d dry period was 3 d shorter compared with cows with a 30- or 60-d dry period. Birth weight of calves from cows with a 0-d dry period was lower compared with calves from cows with a 30-d dry period. Growth of calves until 12 wk of life was not affected by dry period length. Colostrum production and IgG and IgM concentration in colostrum were lower for cows with a 0-d dry period than a 60-d dry period. Natural IgG and IgM titers binding KLH or HuSA were lower in colostrum from cows with a 0-d dry period compared with cows with a 60-d dry period. Natural antibody titers (IgG, IgM, and IgT) binding KLH or HuSA in plasma were lower during the first 2 wk of life for calves from cows with a 0-d dry period compared with calves from cows with a 30- or 60-d dry period. After primary and secondary immunization of calves with KLH and HuSA, SpAb titers of calves were not affected by dry period length. After secondary immunization, the response of IgG and IgT binding KLH was higher in plasma of calves from cows with a 0-d dry period. The results of this study demonstrate that, although omission of the dry period of dairy cows leads to lower plasma NAb titers in calves during the first 2 wk of life, SpAb titers in calves were not affected and even the secondary antibody responses were enhanced compared with calves from cows with a 30- or 60-d dry period.
Assessment of evaporative water loss from Dutch cities
Jacobs, C.M.J. ; Elbers, J.A. ; Brolsma, R. ; Hartogensis, O.K. ; Moors, E.J. ; Rodríguez-CarreteroMárquez, M.T. ; Hove, B. van - \ 2015
Building and Environment 83 (2015). - ISSN 0360-1323 - p. 27 - 38.
klimaatverandering - temperatuur - stedelijke gebieden - evaporatie - waterbudget - rotterdam - veluwe - climatic change - temperature - urban areas - evaporation - water budget - urban heat-island - energy-balance - large-aperture - evapotranspiration - exchange - surface - scintillometers - requirements - environments - manchester
Reliable estimates of evaporative water loss are required to assess the urban water budget in support of division of water resources among various needs, including heat mitigation measures in cities relying on evaporative cooling. We report on urban evaporative water loss from Arnhem and Rotterdam in the Netherlands, using eddy covariance, scintillometer and sapflow observations. Evaporation is assessed at daily to seasonal and annual timescale. For the summer half-year (April–September), observations from Arnhem and Rotterdam are consistent regarding magnitude and variability of evaporation that typically varies between 0.5 and 1.0 mm of evaporation per day. The mean daily evaporative cooling rate was 20–25 Wm-2, 11–14% of the average incoming solar radiation. Evaporation by trees related to sapflow was found to be a small term on the water budget at the city or neighbourhood scale. However, locally the contribution may be significant, given observed maxima of daily sap flows up to 170 l per tree. In Arnhem, evaporation is strongly linked with precipitation, possibly owing to building style. During the summer season, 60% of the precipitation evaporated again. In Rotterdam, the link between evaporation and precipitation is much weaker. An analysis of meteorological observations shows that estimation of urban evaporation from routine weather data using the concept of reference evaporation would be a particularly challenging task. City-scale evaporation may not scale with reference evaporation and the urban fabric results in strong microweather variability. Observations like the ones presented here can be used to evaluate and improve methods for routine urban evaporation estimates.
Land-surface controls on afternoon precipitation diagnosed from observatorial data: uncertainties and confounding factors
Guillod, B.P. ; Orlowsky, B. ; Miralles, D. ; Teuling, A.J. ; Blanken, P.D. ; Buchmann, N. - \ 2014
Atmospheric Chemistry and Physics 14 (2014). - ISSN 1680-7316 - p. 8343 - 8367.
carbon-dioxide exchange - boundary-layer interactions - soil-moisture feedbacks - american regional reanalysis - low-level parameters - diurnal time scales - energy-balance - atmospheric controls - northern wisconsin - heat fluxes
The feedback between soil moisture and precipitation has long been a topic of interest due to its potential for improving weather and seasonal forecasts. The generally proposed mechanism assumes a control of soil moisture on precipitation via the partitioning of the surface turbulent heat fluxes, as assessed via the evaporative fraction (EF), i.e., the ratio of latent heat to the sum of latent and sensible heat, in particular under convective conditions. Our study investigates the poorly understood link between EF and precipitation by relating the before-noon EF to the frequency of afternoon precipitation over the contiguous US, through statistical analyses of multiple EF and precipitation data sets. We analyze remote-sensing data products (Global Land Evaporation: the Amsterdam Methodology (GLEAM) for EF, and radar precipitation from the NEXt generation weather RADar system (NEXRAD)), FLUXNET station data, and the North American Regional Reanalysis (NARR). Data sets agree on a region of positive relationship between EF and precipitation occurrence in the southwestern US. However, a region of strong positive relationship over the eastern US in NARR cannot be confirmed with observation-derived estimates (GLEAM, NEXRAD and FLUXNET). The GLEAM–NEXRAD data set combination indicates a region of positive EF–precipitation relationship in the central US. These disagreements emphasize large uncertainties in the EF data. Further analyses highlight that much of these EF–precipitation relationships could be explained by precipitation persistence alone, and it is unclear whether EF has an additional role in triggering afternoon precipitation. This also highlights the difficulties in isolating a land impact on precipitation. Regional analyses point to contrasting mechanisms over different regions. Over the eastern US, our analyses suggest that the EF–precipitation relationship in NARR is either atmospherically controlled (from precipitation persistence and potential evaporation) or driven by vegetation interception rather than soil moisture. Although this aligns well with the high forest cover and the wet regime of that region, the role of interception evaporation is likely overestimated because of low nighttime evaporation in NARR. Over the central and southwestern US, the EF–precipitation relationship is additionally linked to soil moisture variations, owing to the soil-moisture-limited climate regime.
Economic comparison of a sixty day dry period with no dry period on Dutch dairy farms
Heeren, J.A.H. ; Steeneveld, W. ; Berentsen, P.B.M. - \ 2014
Livestock Science 168 (2014). - ISSN 1871-1413 - p. 149 - 158.
milk-production - energy-balance - holstein herds - short 35-d - cows - lactation - performance - lengths - health - reproduction
In the Netherlands it is general practice that dairy cows have a dry period of six to eight weeks. Research, however, shows that omission of the dry period avoids the negative energy balance after calving with its potential negative effects on metabolic disorders, infectious diseases, and fertility. On the downside, no dry period (NDP) causes a loss of milk production per cow compared with a conventional dry period (CDP). The objective of this research was to make an economic comparison between CDP with a sixty day dry period and NDP. Data on milk production per cow and on replacement rate, being the possible result of improved health, were taken from five farms involved in a research project on the effects of NDP, both from the year before and the year after switching from CDP to NDP. These data show that the replacement rate was on average 37% in the CDP situation while it was 24% in the NDP situation. Milk production was on average 13% lower in the NDP situation while fat and protein content of the milk were 0.21% and 0.42% points higher. A whole farm dairy linear programming model maximizing labor income (returns to family labor and management) was used to determine the technical and economic results for the situation with CDP and NDP. Results were calculated for three scenarios (one with milk quota and two without milk quota), representing differences in possibilities for increasing the farm size. Results show that under each scenario NDP is more profitable than CDP. The increase in labor income varies from 20% to 42%. This means that the negative effect of a lower milk production per cow is outweighed by the positive effect of a lower replacement rate and higher milk components. Sensitivity analysis shows that under a milk quota scenario NDP always results in a higher labor income than CDP irrespective of the change in replacement rate and milk production loss. Under the scenarios without milk quota a replacement rate of 34–35% or a milk production loss of 19–21% with NDP would result in a comparable labor income. The conclusion of this research is that NDP gives better economic results than CDP in a dairy quota situation for a broad range of replacement rate reduction and milk production reduction. In a situation without dairy quota, the replacement rate should be at least 3% points lower and milk production should be not more than 19% lower in the NDP situation to end up with better economic results.
Milk fatty acids as possible biomarkers to early diagnose elevated concentrations of blood plasma nonesterified fatty acids in dairy cows
Jorjong, S. ; Knegsel, A. van; Verwaeren, J. ; Val Lahoz, M. ; Bruckmaier, R.M. ; Baets, B. De; Kemp, B. ; Fievez, V. - \ 2014
Journal of Dairy Science 97 (2014)11. - ISSN 0022-0302 - p. 7054 - 7064.
northeastern united-states - propylene-glycol - early-lactation - energy-balance - beta-hydroxybutyrate - metabolic predictors - displaced abomasum - culling risk - dry period - cattle
Most cows encounter a state of negative energy balance during the periparturient period, which may lead to metabolic disorders and impaired fertility. The aim of this study was to assess the potential of milk fatty acids as diagnostic tools of detrimental levels of blood plasma nonesterified fatty acids (NEFA), defined as NEFA concentrations beyond 0.6 mmol/L, in a data set of 92 early lactating cows fed a glucogenic or lipogenic diet and subjected to 0-, 30-, or 60-d dry period before parturition. Milk was collected in wk 2, 3, 4, and 8 (n = 368) and blood was sampled weekly from wk 2 to 8 after parturition. Milk was analyzed for milk fatty acids and blood plasma for NEFA. Data were classified as “at risk of detrimental blood plasma NEFA” (NEFA =0.6 mmol/L) and “not at risk of detrimental blood plasma NEFA” (NEFA
Estimation of the refractive index structure parameter from single-level daytime routine weather data
Boer, A. van de; Moene, A.F. ; Graf, A. ; Simmer, C. ; Holtslag, A.A.M. - \ 2014
Applied Optics 53 (2014)26. - ISSN 1559-128X - p. 5944 - 5960.
obukhov similarity functions - water-vapor - optical turbulence - sonic anemometer - surface fluxes - energy-balance - temperature - radiation - land - heat
Atmospheric scintillations cause difficulties for applications where an undistorted propagation of electromagnetic radiation is essential. These scintillations are related to turbulent fluctuations of temperature and humidity that are in turn related to surface heat fluxes. We developed an approach that quantifies these scintillations by estimating Cn2 from surface fluxes that are derived from single-level routine weather data. In contrast to previous methods that are biased to dry and warm air, our method is directly applicable to several land surface types, environmental conditions, wavelengths, and measurement heights (lookup tables for a limited number of site-specific parameters are provided). The approach allows for an efficient evaluation of the performance of, e.g., infrared imaging systems, laser geodetic systems, and ground-to-satellite optical communication systems.We tested our approach for two grass fields in central and southern Europe, and for a wheat field in central Europe. Although there are uncertainties in the flux estimates, the impact on Cn2 is shown to be rather small. The Cn2 daytime estimates agree well with values determined from eddy covariance measurements for the application to the three fields. However, some adjustments were needed for the approach for the grass in southern Europe because of non-negligible boundary-layer processes that occur in addition to surface-layer processes.
The endocannabinoid system and appetite: relevance for food reward
Jager, G. ; Witkamp, R.F. - \ 2014
Nutrition Research Reviews 27 (2014)1. - ISSN 0954-4224 - p. 172 - 185.
cannabinoid receptor agonists - taste reactivity test - endogenous cannabinoids - n-acylethanolamines - eating-disorders - weight-loss - metabolic-disorders - energy-balance - 2-arachidonoyl glycerol - antagonist sr141716a
Mounting evidence substantiates the central role of the endocannabinoid system (ECS) in the modulation of both homeostatic and hedonic elements of appetite and food intake. Conversely, feeding status and dietary patterns directly influence activity of the ECS. Following a general introduction on the functioning of the ECS, the present review specifically addresses its role in the modulation of hedonic eating. Humans possess strong motivational systems triggered by rewarding aspects of food. Food reward is comprised of two components: one appetitive (orienting towards food); the other consummatory (hedonic evaluation), also referred to as ‘wanting’ and ‘liking’, respectively. Endocannabinoid tone seems to influence both the motivation to feed and the hedonic value of foods, probably by modifying palatability. Human physiology underlying hedonic eating is still not fully understood. A better understanding of the role of the ECS in the rewarding value of specific foods or diets could offer new possibilities to optimise the balance between energy and nutrient intake for different target groups. These groups include the obese and overweight, and potentially individuals suffering from malnutrition. Examples for the latter group are patients with disease-related anorexia, as well as the growing population of frail elderly suffering from persistent loss of food enjoyment and appetite resulting in malnutrition and involuntary weight loss. It has become clear that the psychobiology of food hedonics is extremely complex and the clinical failure of CB1 inverse agonists including rimonabant (Accomplia®) has shown that ‘quick wins’ in this field are unlikely.
Cow characteristics and their association with production performance with different dry period lengths
Steeneveld, W. ; Knegsel, A.T.M. van; Remmelink, G.J. ; Kemp, B. ; Vernooij, J.C.M. ; Hogeveen, H. - \ 2014
Journal of Dairy Science 97 (2014). - ISSN 0022-0302 - p. 4922 - 4931.
dairy-cows - milk-production - energy-balance - bovine somatotropin - metabolic status - holstein herds - short 35-d - lactation - health - yield
Shortening or omitting the dry period (DP) has been proposed as a management strategy to improve energy balance of dairy cows in early lactation. Both shortening and complete omission of the DP reduces milk production in the subsequent lactation compared with a conventional DP length of 60 d. Some cows have less milk production loss than other cows after applying no DP or a short DP. The aim of this study is to evaluate which cow characteristics are associated with the amount of milk production losses following no DP or a short DP (30 d). Daily production information from the lactation before and after the DP was available from 161 dairy cows (54 cows with a 0-d DP, 51 cows with a 30-d DP, and 56 cows with a 60-d DP) from a research herd. Daily production (milk, fat, and protein) until 305 d in milk was estimated for all cows. Subsequently, total fat- and protein-corrected milk yield from 60 d before the expected calving date until 305 d in the following lactation (FPCMtotal) was estimated. A statistical analysis was performed to evaluate which cow characteristics were associated with limited or no production losses following no DP or a short DP, compared with a conventional DP length of 60 d. Average FPCMtotal was 9,341, 10,499, and 10,795 kg for cows with no DP, a 30-d DP, and a 60-d DP, respectively. The cow characteristics parity, daily milk production at 12 wk before the expected calving date, and reduction in daily milk production between 16 and 12 wk before the expected calving date were associated with production loss due to a short (30 d) or no DP. Compared with 60 d DP, multiparous cows had less production loss (987 kg) following no DP than primiparous cows (2,132 kg). The difference in FPCMtotal between the 3 DP groups was largest for cows with a low milk production (e.g., 10 kg/d) at 12 wk before the expected calving date. The greater the reduction in milk production between 16 and 12 wk before the expected calving date, the larger the difference in FPCMtotal between the 3 DP groups. The difference in FPCMtotal between cows with no DP and 60 d DP at a reduction in milk production between 16 and 12 wk of 10% was 665 kg, whereas this difference was 1,138 kg at a reduction of 70%. The cow characteristics found can be used to select cows for specific DP lengths in a decision-support model to support the farmer on the economic optimal DP length for each individual cow. Output of such a decision-support model can be, for instance, to advise a 30-d DP for multiparous cows with high milk production (e.g., 25 kg/d) at 12 wk before the expected calving date.
The Third GABLS Intercomparison Case for Evaluation Studies of Boundary-Layer Models. Part B: Results and Process Understanding
Bosveld, F.C. ; Baas, P. ; Steeneveld, G.J. ; Holtslag, A.A.M. ; Angevine, W.M. ; Bazile, E. ; Bruijn, E.I.F. de; Deacu, D. ; Edwards, J.M. ; Ek, M. ; Larson, V.E. ; Pleim, J.E. ; Raschendorfer, M. ; Svensson, G. - \ 2014
Boundary-Layer Meteorology 152 (2014)2. - ISSN 0006-8314 - p. 157 - 187.
stably stratified conditions - observed evening transition - nonlocal closure-model - low-level jets - land-surface - morning transition - vertical diffusion - radiative-transfer - energy-balance - ecmwf model
We describe and analyze the results of the third global energy and water cycle experiment atmospheric boundary layer Study intercomparison and evaluation study for single-column models. Each of the nineteen participating models was operated with its own physics package, including land-surface, radiation and turbulent mixing schemes, for a full diurnal cycle selected from the Cabauw observatory archive. By carefully prescribing the temporal evolution of the forcings on the vertical column, the models could be evaluated against observations. We focus on the gross features of the stable boundary layer (SBL), such as the onset of evening momentum decoupling, the 2-m minimum temperature, the evolution of the inertial oscillation and the morning transition. New process diagrams are introduced to interpret the variety of model results and the relative importance of processes in the SBL; the diagrams include the results of a number of sensitivity runs performed with one of the models. The models are characterized in terms of thermal coupling to the soil, longwave radiation and turbulent mixing. It is shown that differences in longwave radiation schemes among the models have only a small effect on the simulations; however, there are significant variations in downward radiation due to different boundary-layer profiles of temperature and humidity. The differences in modelled thermal coupling to the land surface are large and explain most of the variations in 2-m air temperature and longwave incoming radiation among models. Models with strong turbulent mixing overestimate the boundary-layer height, underestimate the wind speed at 200 m, and give a relatively large downward sensible heat flux. The result is that 2-m air temperature is relatively insensitive to turbulent mixing intensity. Evening transition times spread 1.5 h around the observed time of transition, with later transitions for models with coarse resolution. Time of onset in the morning transition spreads 2 h around the observed transition time. With this case, the morning transition appeared to be difficult to study, no relation could be found between the studied processes, and the variation in the time of the morning transition among the models
Aerosols in the convective boundary layer: Shortwave radiation effects on the coupled land-atmosphere system
Wilde Barbaro, E. ; Vilà-Guerau de Arellano, J. ; Ouwersloot, H.G. ; Schroter, J.S. ; Donovan, D.P. ; Krol, M.C. - \ 2014
Journal of Geophysical Research: Atmospheres 119 (2014)10. - ISSN 2169-897X - p. 5845 - 5863.
large-eddy-simulation - quality interactions eucaari - european integrated project - optical-properties - ammonium-nitrate - energy-balance - climate system - global scales - cloud climate - model
By combining observations and numerical simulations, we investigated the responses of the surface energy budget and the convective boundary layer (CBL) dynamics to the presence of aerosols. A detailed data set containing (thermo)dynamic observations at CESAR (Cabauw Experimental Site for Atmospheric Research) and aerosol information from the European Integrated Project on Aerosol, Cloud, Climate, and Air Quality Interactions was employed to design numerical experiments reproducing two typical clear-sky days, each characterized by contrasting thermodynamic initial profiles: (i) residual layer above a strong surface inversion and (ii) well-mixed CBL connected to the free troposphere by a capping inversion, without the residual layer in between. A large-eddy simulation (LES) model and a mixed-layer (MXL) model, coupled to a broadband radiative transfer code and a land surface model, were used to study the impacts of aerosols on shortwave radiation. Both the LES model and the MXL model results reproduced satisfactorily the observations for both days. A sensitivity analysis on a wide range of aerosol properties was conducted. Our results showed that higher loads of aerosols decreased irradiance imposing an energy restriction at the surface, delaying the morning onset of the CBL and advancing its afternoon collapse. Moderately to strongly absorbing aerosols increased the heating rate contributing positively to increase the afternoon CBL height and potential temperature and to decrease Bowen ratio. In contrast, scattering aerosols were associated with smaller heating rates and cooler and shallower CBLs. Our findings advocate the need for accounting for the aerosol influence in analyzing surface and CBL dynamics.
Genomic selection for feed efficiency in dairy cattle
Pryce, J.E. ; Wales, W.J. ; Haas, Y. de; Veerkamp, R.F. ; Hayes, B.J. - \ 2014
Animal 8 (2014)01. - ISSN 1751-7311 - p. 1 - 10.
body condition score - dry-matter intake - 1st 3 lactations - genetic-parameters - beef-cattle - methane production - production traits - energy-balance - live weight - random regression
Feed is a major component of variable costs associated with dairy systems and is therefore an important consideration for breeding objectives. As a result, measures of feed efficiency are becoming popular traits for genetic analyses. Already, several countries account for feed efficiency in their breeding objectives by approximating the amount of energy required for milk production, maintenance, etc. However, variation in actual feed intake is currently not captured in dairy selection objectives, although this could be possible by evaluating traits such as residual feed intake (RFI), defined as the difference between actual and predicted feed (or energy) intake. As feed intake is expensive to accurately measure on large numbers of cows, phenotypes derived from it are obvious candidates for genomic selection provided that: (1) the trait is heritable; (2) the reliability of genomic predictions are acceptable to those using the breeding values; and (3) if breeding values are estimated for heifers, rather than cows then the heifer and cow traits need to be correlated. The accuracy of genomic prediction of dry matter intake (DMI) and RFI has been estimated to be around 0.4 in beef and dairy cattle studies. There are opportunities to increase the accuracy of prediction, for example, pooling data from three research herds (in Australia and Europe) has been shown to increase the accuracy of genomic prediction of DMI from 0.33 within country to 0.35 using a three-country reference population. Before including RFI as a selection objective, genetic correlations with other traits need to be estimated. Weak unfavourable genetic correlations between RFI and fertility have been published. This could be because RFI is mathematically similar to the calculation of energy balance and failure to account for mobilisation of body reserves correctly may result in selection for a trait that is similar to selecting for reduced (or negative) energy balance. So, if RFI is to become a selection objective, then including it in an overall multi-trait selection index where the breeding objective is net profit is sensible, as this would allow genetic correlations with other traits to be properly accounted for. If genetic parameters are accurately estimated then RFI is a logical breeding objective. If there is uncertainty in these, then DMI may be preferable.
Seasonal dependence of the urban heat island on the street canyon aspect ratio
Theeuwes, N.E. ; Steeneveld, G.J. ; Ronda, R.J. ; Heusinkveld, B.G. ; Hove, L.W.A. van; Holtslag, A.A.M. - \ 2014
Quarterly Journal of the Royal Meteorological Society 140 (2014)684. - ISSN 0035-9009 - p. 2197 - 2210.
warmte - steden - stedelijke planning - warmtebalans - seizoenvariatie - meteorologie - nederland - heat - towns - urban planning - heat balance - seasonal variation - meteorology - netherlands - boundary-layer - energy-balance - climate zones - model - temperature - parameterization - simulation - schemes - cabauw - field
In this paper we study the relation between the urban heat island (UHI) in the urban canyon and street geometry, in particular the aspect ratio. Model results and observations show that two counteracting processes govern the relation between the nocturnal UHI and the building aspect ratio: i.e. trapping of longwave radiation and shadowing effects. In general, trapping of longwave radiation supports the UHI, whereas shadowing effects reduce the UHI. The net effect depends on the UHI definition and the amount of available shortwave radiation penetrating the canyon. In summer, autumn and spring the shadowing effects can already reduce the UHI starting at an aspect ratio between 0.5 and 1. The analysis is carried out using several methods. Firstly, the single-column model version of the Weather Research and Forecasting model (WRF) is used extensively. Two separate runs, one rural and one urban, are used to estimate the UHI. Secondly, the urban canyon temperature at the two meter level is introduced, which allows for direct comparison between modelled and observed air temperatures within the urban canyon. Finally, the model is evaluated for all four seasons. The results of this research provide important insights for urban planning on how to use the aspect ratio to mitigate the UHI in the urban canyon
Effect of supplementing coconut or krabok oil, rich in medium-chain fatty acids on ruminal fermentation, protozoa and archaeal population of bulls
Panyakaew, P. ; Boon, N. ; Goel, G. ; Yuangklang, C. ; Schonewille, J.T. ; Hendriks, W.H. ; Fievez, V. - \ 2013
Animal 7 (2013)12. - ISSN 1751-7311 - p. 1950 - 1958.
different hypervariable regions - gradient gel-electrophoresis - myristic acid - in-vitro - methane suppression - ciliate protozoa - energy-balance - lauric acid - dairy-cows - rumen
Medium-chain fatty acids (MCFA), for example, capric acid (C10:0), myristic (C14:0) and lauric (C12:0) acid, have been suggested to decrease rumen archaeal abundance and protozoal numbers. This study aimed to compare the effect of MCFA, either supplied through krabok (KO) or coconut (CO) oil, on rumen fermentation, protozoal counts and archaeal abundance, as well as their diversity and functional organization. KO contains similar amounts of C12:0 as CO (420 and 458 g/kg FA, respectively), but has a higher proportion of C14:0 (464 v. 205 g/kg FA, respectively). Treatments contained 35 g supplemental fat per kg DM: a control diet with tallow (T); a diet with supplemental CO; and a diet with supplemental KO. A 4th treatment consisted of a diet with similar amounts of MCFA (i.e. C10:0+C12:0+C14:0) from CO and KO. To ensure isolipidic diets, extra tallow was supplied in the latter treatment (KO+T). Eight fistulated bulls (two bulls per treatment), fed a total mixed ration predominantly based on cassava chips, rice straw, tomato pomace, rice bran and soybean meal (1.5% of BW), were used. Both KO and CO increased the rumen volatile fatty acids, in particular propionate and decreased acetate proportions. Protozoal numbers were reduced through the supplementation of an MCFA source (CO, KO and KO+T), with the strongest reduction by KO. Quantitative real-time polymerase chain reaction assays based on archaeal primers showed a decrease in abundance of Archaea when supplementing with KO and KO+T compared with T and CO. The denaturing gradient gel electrophoresis profiles of the rumen archaeal population did not result in a grouping of treatments. Richness indices were calculated from the number of DGGE bands, whereas community organization was assessed from the Pareto–Lorenz eveness curves on the basis of DGGE band intensities. KO supplementation (KO and KO+T treatments) increased richness and evenness within the archaeal community. Further research including methane measurements and productive animals should elucidate whether KO could be used as a dietary methane mitigation strategy.
Effect of different dry period lengths on milk production and somatic cell count in subsequent lactation on commercial Dutch dairy herds.
Steeneveld, W. ; Schukken, Y.H. ; Knegsel, A.T.M. van; Hogeveen, H. - \ 2013
Journal of Dairy Science 96 (2013)5. - ISSN 0022-0302 - p. 2988 - 3001.
energy-balance - bovine somatotropin - metabolic status - holstein herds - short 35-d - cows - performance - yield - management - ovulation
Shortening the dry period (DP) has been proposed as a management strategy to improve energy balance in early lactation. It is well known that both shortening and complete omission of the DP reduces milk production in the subsequent lactations. In most of these studies milk production data were obtained from planned animal experiments where cows were randomly assigned to DP length treatments, and cow management and diet composition did not differ among treatments. It may therefore be hypothesized that cows on commercial herds which apply a no-DP or short-DP-strategy, and support this by management adjustments, will have a less dramatic reduction in milk production. In this study, milk production and somatic cell count (SCC) following different DP lengths was investigated under commercial circumstances. Milk production of 342 cows (2,077 test-day records) was available from 5 Dutch commercial dairy herds which started a no DP-strategy for all cows. Test days of the year before applying the no-DP strategy are used as control (323 cows, 1,717 test-day records). Six other herds applied an individual cow approach and have different preplanned DP lengths within one herd. From these herds, information on 81 cows (482 test-day records) with a DP length between 0 and 20 d, 127 cows (925 test-day records) with a DP length between 21 and 35 d, and 143 cows (1,075 test-day records) with a DP length of more than 35 d was available. A generalized linear model incorporating an autoregressive covariance structure accounting for repeated test-day yields within cow was developed to estimate the daily yield (milk, fat and protein) and SCC of all cows. Applying no DP for all cows in the herd resulted in a reduction in postpartum milk production compared with within-herd control lactations (until 305 DIM) between 3.2 and 9.1 kg/d, which was a reduction of 12 and 32%, respectively. For the 6 herds that applied an individual cow approach with different preplanned DP lengths, the cow-specific DP strategy was based on milk production and SCC approximately 2 mo before calving. Cows with a preplanned DP length ranging between 0 and 20 d had a reduction in postpartum milk production between 5.7 and 13 kg/d compared with cows with a DP length of >35 d. Cows with a preplanned DP length ranging from 21 to 35 d had a numerically lower milk production (between 0.6 and 5.3 kg/d) than cows with a preplanned DP length of >35 d, but this difference was significant in only one herd. When corrected for milk yield, no difference in postpartum SCC for cows with different DP lengths was found.
Suitability of cross-bred cows for organic farms based on cross-breeding effects on production and functional traits
Haas, Y. de; Smolders, E.A.A. ; Hoorneman, J.N. ; Nauta, W.J. ; Veerkamp, R.F. - \ 2013
Animal 7 (2013)4. - ISSN 1751-7311 - p. 655 - 665.
conventional dairy herds - somatic-cell counts - milk-production - reproductive-performance - genetic-parameters - clinical mastitis - udder health - short-communication - energy-balance - cattle
Data from 113 Dutch organic farms were analysed to determine the effect of cross-breeding on production and functional traits. In total, data on 33 788 lactations between January 2003 and February 2009 from 15 015 cows were available. Holstein–Friesian pure-bred cows produced most kg of milk in 305 days, but with the lowest percentages of fat and protein of all pure-bred cows in the data set. Cross-breeding Holstein dairy cows with other breeds (Brown Swiss, Dutch Friesian, Groningen White Headed, Jersey, Meuse Rhine Yssel, Montbéliarde or Fleckvieh) decreased milk production, but improved fertility and udder health in most cross-bred animals. In most breeds, heterosis had a significant effect (P <0.05) on milk (kg in 305 days), fat and protein-corrected milk production (kg in 305 days) and calving interval (CI) in the favourable direction (i.e. more milk, shorter CI), but unfavourably for somatic cell count (higher cell count). Recombination was unfavourable for the milk production traits, but favourable for the functional traits (fertility and udder health). Farm characteristics, like soil type or housing system, affected the regression coefficients on breed components significantly. The effect of the Holstein breed on milk yield was twice as large in cubicle housing as in other housing systems. Jerseys had a negative effect on fertility only on farms on sandy soils. Hence, breed effects differ across farming systems in the organic farming and farmers can use such information to dovetail their farming system with the type of cow they use.
Predicted accuracy of and response to genomic selection for new traits in dairy cattle
Calus, M.P.L. ; Haas, Y. de; Pszczola, M.J. ; Veerkamp, R.F. - \ 2013
Animal 7 (2013)2. - ISSN 1751-7311 - p. 183 - 191.
genetic-relationship information - breeding programs - holstein cattle - energy-balance - strategies - emissions - progress - schemes - designs - impact
Genomic selection relaxes the requirement of traditional selection tools to have phenotypic measurements on close relatives of all selection candidates. This opens up possibilities to select for traits that are difficult or expensive to measure. The objectives of this paper were to predict accuracy of and response to genomic selection for a new trait, considering that only a cow reference population of moderate size was available for the new trait, and that selection simultaneously targeted an index and this new trait. Accuracy for and response to selection were deterministically evaluated for three different breeding goals. Single trait selection for the new trait based only on a limited cow reference population of up to 10 000 cows, showed that maximum genetic responses of 0.20 and 0.28 genetic standard deviation (s.d.) per year can be achieved for traits with a heritability of 0.05 and 0.30, respectively. Adding information from the index based on a reference population of 5000 bulls, and assuming a genetic correlation of 0.5, increased genetic response for both heritability levels by up to 0.14 genetic s.d. per year. The scenario with simultaneous selection for the new trait and the index, yielded a substantially lower response for the new trait, especially when the genetic correlation with the index was negative. Despite the lower response for the index, whenever the new trait had considerable economic value, including the cow reference population considerably improved the genetic response for the new trait. For scenarios with a zero or negative genetic correlation with the index and equal economic value for the index and the new trait, a reference population of 2000 cows increased genetic response for the new trait with at least 0.10 and 0.20 genetic s.d. per year, for heritability levels of 0.05 and 0.30, respectively. We conclude that for new traits with a very small or positive genetic correlation with the index, and a high positive economic value, considerable genetic response can already be achieved based on a cow reference population with only 2000 records, even when the reliability of individual genomic breeding values is much lower than currently accepted in dairy cattle breeding programs. New traits may generally have a negative genetic correlation with the index and a small positive economic value. For such new traits, cow reference populations of at least 10 000 cows may be required to achieve acceptable levels of genetic response for the new trait and for the whole breeding goal.
Taste-nutrient relationships in commonly consumed foods
Dongen, M.V. van; Berg, M.C. van den; Vink, N. ; Kok, F.J. ; Graaf, C. de - \ 2012
The British journal of nutrition 108 (2012)1. - ISSN 0007-1145 - p. 140 - 147.
body-weight - energy-balance - sweeteners - sucrose - flavor - intensity - receptors - nutrition - sweetness - behavior
Taste is expected to represent a food's nutrient content. The objective was to investigate whether taste acts as nutrient-sensor, within the context of the current diet, which is high in processed foods. Intensities of the five basic tastes of fifty commonly consumed foods were rated by nineteen subjects (aged 21.0 (SD 1.7) years, BMI 21.5 (SD 2.0) kg/m(2)). Linear regression was used to test associations between taste and nutrient contents. Food groups based on taste were identified using cluster analysis; nutrient content was compared between food groups, using ANOVA. Sweetness was associated with mono- and disaccharides (R-2 0.45, P <0.01). Saltiness and savouriness were correlated, with r 0.92 (P
Genetic and nongenetic variation in plasma and milk ß-hydroxybutyrate and milk acetone concentrations of early-lactation dairy cows
Drift, S.G.A. van der; Hulzen, K.J.E. van; Teweldemedhn, T.G. ; Jorritsma, R. ; Nielen, M. ; Heuven, H.C.M. - \ 2012
Journal of Dairy Science 95 (2012)11. - ISSN 0022-0302 - p. 6781 - 6787.
holstein cows - subclinical ketosis - metabolic predictors - health disorders - energy-balance - body-weight - feed-intake - cattle - parameters - yield
This study assessed genetic variation, heritability estimates, and genetic correlations for concentrations of plasma ß-hydroxybutyrate (BHBA), milk BHBA, and milk acetone in early lactation to investigate differences between cows in susceptibility to hyperketonemia and possibilities to use test-day milk ketone bodies for genetic improvement. Blood and test-day milk samples were collected on randomly selected dairy farms in the Netherlands from cows of various parities between 5 and 60 d in milk. Plasma samples were analyzed for BHBA (reference test for hyperketonemia) and test-day milk samples were analyzed for BHBA and acetone using Fourier-transform infrared spectroscopy. The final data set consisted of plasma BHBA concentrations of 1,615 cows from 122 herds. Milk BHBA and milk acetone concentrations were determined for 1,565 cows. Genetic variation, heritability, and proportion of phenotypic variation attributable to the herd were estimated using an animal model with fixed effects for parity and season, a covariate for days in milk, and random effects for herd, animal, and error. Genetic correlations for plasma BHBA, milk BHBA, and milk acetone were estimated using bivariate analyses. The heritability estimate for plasma BHBA concentrations in early lactation was 0.17, whereas heritability estimates for milk BHBA and milk acetone were 0.16 and 0.10, respectively. This indicates that selective breeding may contribute to a lower incidence of hyperketonemia in early lactation. For the 3 traits, the proportion of variance attributable to herd was larger than the additive genetic variance, underlining the importance of on-farm feeding and management in the etiology of hyperketonemia in fresh cows. Prevention strategies for hyperketonemia can, therefore, include both feeding and management strategies at dairy farms (short-term) and genetic improvement through breeding programs (long-term). Genetic correlations between concentrations of plasma BHBA and milk BHBA (0.52) or milk acetone (0.52) were moderate. As milk ketone bodies can be routinely analyzed at test days, this may provide a practical alternative for breeding programs aimed at reducing hyperketonemia in early lactation.
Impact of animal health and welfare planning on medicine use, herd health and production in European organic dairy farms
Ivemeyer, S. ; Smolders, E.A.A. ; Brinkmann, J. ; Gratzer, E. ; Hansen, B. ; Henriksen, B.I.F. ; Huber, J. ; Leeb, C. ; March, S. ; Mejdell, C. ; Nicholas, P. ; Roderick, S. ; Stöger, E. ; Vaarst, M. ; Whistance, L.K. ; Winckler, C. ; Walkenhorst, M. - \ 2012
Livestock Science 145 (2012)1-3. - ISSN 1871-1413 - p. 63 - 72.
somatic-cell score - energy-balance - antimicrobial-usage - mastitis control - udder health - management - lactation - milk - quantification - program
Achieving and maintaining high herd health and welfare status and low veterinary medicine inputs are important aims in organic livestock farming. Therefore, an on-farm intervention study (CORE Organic ANIPLAN) was conducted on 128 organic dairy farms in seven European countries aiming at minimising medicine use through animal health and welfare planning (AHWP). Medicine use (excluding complementary treatments such as homeopathic remedies) was assessed as the total number of treatments and as the number of treatments of various disease categories (udder, fertility, metabolism, locomotion and others) generated from farm records and national databases, respectively. Health and production data were calculated at farm level from milk recording data: Somatic cell score (SCS) was used as an indicator for udder health, incidences of low (<1.1) and high (> 1.5) fat–protein ratio as indicators of rumen acidosis and imbalanced energy supply, respectively. Calving interval was used as an indicator for fertility. Milk recording data and treatment data were retrospectively collected for a one year period before and after the first farm visit. Focus areas of animal health and welfare plans were either generated in Stable Schools (adapted Farmer Field Schools) or using face-to-face advice but following similar principles. Most frequently chosen focus areas were metabolic disorders (66% of farms), udder health (58%), lameness (47%), and fertility (39%). General linear models for repeated measures were used to analyse the development at the farm level. The total number of treatments, the number of udder treatments and the number of metabolic treatments were all significantly reduced during the one year study period, whilst the number of treatments of lame cows increased. With the exception of SCS, which improved significantly, the other health indicators remained stable. Milk yield and average lactation number also remained unchanged. Choice of different focus areas had no significant effects on the corresponding treatment and health variables except for indication of rumen acidosis; for the latter situation on farms with an AHWP focus on metabolic issues improved, but this was not the case across all farms. Overall, the implementation of AHWP reduced total treatment incidence and improved the udder health situation across all farms regardless of the focus areas in the AHWP. Hence, AHWP can be regarded as a feasible approach to minimising medicine use without the impairment of production and herd health under several organic dairy farming conditions in Europe
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