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.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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The effect of allocation frequency in rotational grazing systems on the fatty acid profile in milk fat of dairy cows
Vlaeminck, B. ; Abrahamse, P.A. ; Fievez, V. ; Lourenco, M. ; Dijkstra, J. ; Tamminga, S. - \ 2010
In: 23th General Meeting of the European Grassland Federation, Kiel, Germany, 29 August - 02 September, 2010. - Duderstadt : Mecke Druck und Verlag - p. 102 - 102.
Four Holstein cows were used to evaluate the effect of allocating cows every 4 day (d) to a new 0.5-ha plot of Lolium perenne L. on the profile of fatty acids (FA) in milk. The experiment was run during 2 rotations with 2 measuring periods of 4 d each. During the 4 d period, the proportion (g per 100 g FA) of 18:3n-3 and total FA content (mg per g DM) of grass decreased linearly. Similarly, milk FA composition was largely affected by day within the 4 d period. Proportions of t11-18:1 in milk fat increased on d 2 (4.52 g per 100 g FA) and decreased thereafter (3.77 g per 100 g FA on d 4). Proportions of c9t11-18:2 (2.36 and 1.83 g per 100 g FA), t11c15-18:2 (0.81 and 0.63 g per 100 g FA) and 18:3n-3 (0.92 and 0.88 g per 100 g FA) in milk followed the same pattern. Results from this study suggest short term variation in pasture quality during the 4 d affected milk FA composition, with a greater effect on biohydrogenation intermediates in milk fat compared with its major precursor, 18:3n-3.
Producing milk from grazing to reconcile economic and environmental performances
Peyraud, J.L. ; Pol, A. van den; Dillon, P. ; Delaby, L. - \ 2010
In: 23th General Meeting of the European Grassland Federation, Kiel, Germany, 29 august - 02 September, 2010. - Zürich, Switzerland : European Grassland Federation EGF - ISBN 9783869440200 - p. 163 - 164.
Several reports, directives, regulations and initiatives challenge high-input dairy systems at the environmental level. At the same time the dairy sector has to adapt to a greater volatility of prices and to the projected increase in energy and fertiliser prices. In this new context, it should be considered whether the model of development based on intensification, often in connection with the reduction in the use of grazing, is always well adapted. Dairy systems that maximise grass utilisation appear to be highly competitive and the various roles of grassland in providing regulating and supporting services are now widely recognized. Thus grassland should form the basis of more sustainable dairy systems in the future, provided technical innovations are produced to improve the efficiency of grassland-based dairy systems. Innovations in forage production, innovations in characteristics of the cows and management of lactations, as well as innovations in the management of the system have potential for increasing economic and environmental performances of grassland-based systems. The more systematic use of legume forages in multi-species swards makes it possible to reduce the consumption of mineral N, to reduce the carbon footprint of the dairy system, to regularize the forage production over the year and to increase the nutritional quality of the forages. It clearly appears that intensive selection for milk based on high concentrate diets has generally resulted in genotypes that are not well suited for systems maximising forage utilisation. In these systems there needs to be a special focus to address fertility, survival and other functional traits such as mastitis resistance, although high genetic merit for milk should be maintained to produce efficient responses to concentrate supply. Finally, extending the grazing season with early turnout or late grazing, and tactical use of grazing in association with conserved forages in large herds, offers many opportunities to reduce the requirement of expensive conserved forage and to reduce the utilisation of purchased feeds. All these potential sources of progress are discussed.
Simulation of the effect of grass intake on the farmer's income
Pol, A. van den; Haan, M.H.A. de; Evers, A.G. ; Philipsen, A.P. - \ 2010
In: Grassland in a changing world. Proceedings of the 23rd General Meeting of the European Grassland Federation, Kiel, Germany, 29th August - 2nd September 2010.. - Zürich, Switzerland : European Grassland Federation EGF - ISBN 9783869440200 - p. 100 - 102.
Grazing affects people, planet and profit. In general, the farmer's income will be higher when grazing of dairy cows is applied. We studied the economic effects of grazing for situations where we expect that grazing is difficult to apply. These situations could result in lower incomes for grazing. Farms with automatic milking systems, a small grazing surface, a large herd and/or a high milk yield per cow were studied. For the situations with automatic milking systems, large herds and high milk yields per cow, the farmer's income remained the highest for grazing. The difference between grazing and zero-grazing, however, was smaller than for farm situations without restrictions. In situations with more than 10 dairy cows ha" grazing surface, zero-grazing was more profitable than grazing. There was a strong relationship between intake of grass in pasture, on a typical farm, and the difference in income between grazing and zero-grazing. The more grass the cows eat in the pasture, the larger the income profit from grazing compared to zero-grazing.
Better grazing opportunities with a mobile milking robot
Haan, M.H.A. de; Philipsen, A.P. ; Pol, A. van den; Holshof, G. ; Lenssinck, F.A.J. ; Koning, C.J.A.M. de - \ 2010
In: 23th General Meeting of the European Grassland Federation, Kiel, Germany, 29 August - 02 September, 2010. - Zürich, Switzerland : European Grassland Federation EGF - ISBN 9783869440217 - p. 178 - 180.
Although grazing of dairy cows is very common in the Netherlands, the number of grazing cows is decreasing. Mobile milking robots might support grazing, in particular in situations of large herds, in remote grassland areas and in extensive natural grasslands. In the Netherlands, a stand-alone mobile milking robot has been developed using caterpillar tracks. Every day, this milking robot moves to a new part of the pasture and every two days concentrates, fuel, water and milk are separately transported from and to the mobile milking robot. The system was tested in the 2008 grazing season using a herd of 35 dairy cows. During the 2009 grazing season the project was scaled up to a herd of 60 cows on an area of 20 ha peat soil. In 2009 a strip grazing system with controlled as well as free cow traffic was used in order to increase the visit and milking frequency. The mobile milking robot was capable of managing a 60-cow herd grazing 24 hours while producing a rolling milk average of 7500 kg cow-1 yr-1. The challenge is to improve the milk yield per cow and year by increasing the milking frequency.
Overview over the WG 3 common protocol - influence of contrasting environments on forage quality of grass and legumes
Gierus, M. ; Dorland, H.A. van; Elgersma, A. ; Kreuzer, M. ; Loges, R. ; Smit, H.J. ; Steinshamn, H. ; Taube, F. ; Wachendorf, M. - \ 2007
In: Quality legume-based forage systems for contrasting environments. - Gumpenstein : - p. 157 - 160.
Influence of contrasting environments on forage quality of ryegrass and four legumes growing in binary swards
Gierus, M. ; Dorland, H.A. van; Elgersma, A. ; Kreuzer, M. ; Loges, R. ; Poetsch, E.M. ; Smit, H.J. ; Steinshamn, H. ; Taube, F. ; Wachendorf, M. - \ 2007
In: Permanent and temporary grassland: Plant, environment and economy / De Vliegher, A., Carlier, L., Ghent : European Grassland Federation EGF - p. 162 - 165.
Physico-chemical characteristics and degradation rate of soluble protein obtained from the washout fraction of feeds
Gierus, M. ; Jonge, L.H. de; Meijer, G.A.L. - \ 2005
Livestock Production Science 97 (2005)2-3. - ISSN 0301-6226 - p. 219 - 229.
ruminal degradation - dairy-cows - in-situ - grass-silage - rumen - degradability - hay - digestibility - supplements - system
The (water)-soluble fraction of feeds is often assumed to be completely and immediately degraded in the rumen. The objective of this study was to separate the washout fraction (fraction A) obtained usually by difference after submitting the nylon bags to the machine-washing program, to investigate the nature and the degradation of the soluble crude protein in the washout fraction. The washout fraction obtained in vitro (filtrate) of 10 feeds was collected in water using nylon mesh as a filter. The feeds used in the study were: two grass silages, soybean meal, three corn gluten feeds, lupine meal, rapeseed meal, wet brewers grain silage and corn gluten feed silage. Average N losses during filtration and from machine-washed nylon bags ranged from 15% (rape seed meal) to 74% (grass silage) and were not different between procedures. N recovered in the filtrate ranged from 12% (soybean meal) to 60% (corn gluten feed silage) of sample N. The three fractions obtained from the filtrate were: soluble protein (TP), non-protein N (NPN) and fine particles (NS). The NS fraction was obtained after centrifugation of the filtrate and comprised 0% to 87% of N in the filtrate. Soluble protein (TP) in the supernatant was obtained after precipitation with trichloroacetic acid and N in the remaining supernatant was defined as non-protein N (NPN). Significant amounts of TP were found in soybean meal (58%), lupine meal (30%) and rapeseed meal (27%) as percent of total N in the filtrate. NPN ranged from 13% to 100% of N in the filtrate. The in vitro incubation of the protein N (NS + TP) showed that all fractions were not completely degraded, suggesting a potential participation as escape protein. Fine particles in the filtrate have similar degradation rates as the residue left in the filter. It is concluded that the washout fraction consisted of different crude protein fractions that were not always completely and immediately degraded in the rumen.
Utilisation of forage legumes: plant and animal science linked in the common protocol of COST Action 852 - Working Group 3.
Wachendorf, M. ; Kreuzer, M. ; Collins, R.P. ; Vaccia Carvalho, P.C. de; Dewhurst, R.J. ; Elgersma, A. ; Gierus, M. ; Höglind, M. ; Huyghe, C. - \ 2004
In: Land Use Systems in Grassland Dominated Regions. Book of Abstracts, Luzern, Switzerland, 21-24 June 2004. - Zurich : Vdf Hochschulverlag AG, ETH - ISBN 9783728129413 - p. 93 - 94.
Selenium supplementation and selenium status of dairy cows fed diets based on grass, grass silage or maize silage
Gierus, M. ; Schwarz, F.J. ; Kirchgessner, M. - \ 2002
Journal of Animal Physiology and Animal Nutrition 86 (2002). - ISSN 0931-2439 - p. 74 - 82.
Chemical characteristics and degradation of crude protein in the S-fraction of feed stuffs
Melin, M. ; Gierus, M. ; Vuuren, A.M. van; Meijer, G.A.L. - \ 2001
Lelystad : ID-Lelystad
Degradation of soluble crude protein in the rumen
Melin, M. ; Gierus, M. ; Vuuren, A.M. van; Meijer, G.A.L. - \ 2001
Journal of Dairy Science 84 (2001)suppl. 1. - ISSN 0022-0302 - p. 161 - 162.
Although CP in the soluble fraction lost during washing of nylon bags is often assumed to be fully and rapidly degraded in the rumen, its actual fate in the rumen is questioned. We developed a filtration procedure that mimics machine washing of nylon bags and enables a further characterization of this soluble fraction. The filtrate of 1-3 g of DM of ten feeds was collected in 100 ml of rinsing water. Feeds were two grass silages (GS1, 25% of DM, and GS2, 53% of DM), wet brewers grain silage (WBGS) and corn gluten feed silage (CGFS), 3 types of corn gluten feed (CGF1 to 3), soybean meal (SBM), lupine meal (LPM) and rape seed meal (RSM). DM and N losses of the filtration procedure and machine washing were compared in quadruplet samples. DM losses during filtration and from nylon bags ranged from 16% in WBGS to 46%in GS1 and were not different between procedures. N recovered in the filtrate ranged from 11.5% for SBM to 56.1% for GS1. The filtrate was centrifuged at 1500 g for 20 min. The pellet was analyzed for N in non soluble particles (NS). Soluble true proteins (TP) in the supernatant were precipitated with TCA (10% in the final volume), and the N in the remaining supernatant was defined as non-protein N (NPN). The NS fraction comprised 0% (GS1 and 2) to 87% (WBGS) of N in the filtrate. Significant amounts of TP were found in SBM (53%), LPM (30%) and RSM (27%). NPN ranged from 13% (WBGS) to 100% (GS1 and 2) of N in the filtrate. The degradation of the protein N (NS +TP) in the filtrate of 6 feeds was measured in rumen fluid using a modified Broderick method. After 4h of incubation the percentages of degraded protein were: 0% (WBGS and CGFS), 24% (CGF 2), 55% (RSM), 79% (LPM)and 80% (SBM). These results show that CP in the soluble fraction, as determined in the nylon bag technique, consists of different protein and non-protein fractions, that are not always rapidly and fully degraded in the rumen. The potential underestimation of the protein value of these feeds, calculated as ((NS + TP)/ N feed) x %undegraded4h,is2- 7 % for the concentrates, and 13 % and 26 % for CGFS and WBGS, respectively
Appearence of aminogenic nutrients in the portal vein as a tool for feed protein evaluation in the DVE/OEB system [Zur Anflutung von aminogenen Naehrstoffen in der Pfortader als Mittel zur Bewertung von Futterproteinen im DVE/OEB System]
Gierus, M. ; Meijer, G.A.L. ; Vuuren, A.M. van - \ 2001
In: Proceedings of the Society of Nutrition Physiology 10, 82 (abstract)
Selenium supplementation for dry dairy cows [Untersuchungen zur Selenzulage in der Fuetterung von trockenstehenden Milchkuehen]
Gierus, M. ; Schwartz, F.J. ; Kirchgessner, M. - \ 2001
In: Proceedings of the Society of Nutrition Physiology 10, 82 (abstract)
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