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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    Metabolic status, lactation persistency, and udder health of dairy cows after different dry period lengths
    Hoeij, Renny van - \ 2017
    Wageningen University. Promotor(en): B. Kemp; T.J.G.M. Lam, co-promotor(en): A.T.M. Knegsel; J. Dijkstra. - Wageningen : Wageningen University - ISBN 9789463438070 - 285
    dairy cattle - animal health - animal behaviour - dry period - metabolism - energy balance - lactation - milk production - udders - cattle feeding - melkvee - diergezondheid - diergedrag - gustperiode - metabolisme - energiebalans - lactatie - melkproductie - uiers - rundveevoeding

    Cows traditionally have a 6 to 8 week non-lactating –‘dry period’- before calving and the start of the next lactation in order to maximize milk production in the subsequent lactation. An omitted, compared with a shortened, dry period reduces milk yield and improves energy availability in cows postpartum, but effects on udder health and persistency were unclear. Cows without a dry period fattened and spontaneously dried off due to the improved energy availability. Reducing the energy availability in the feed for cows without a dry period did not affect fattening or lactation persistency in late lactation. Cows with a short or without a dry period did not receive dry cow antibiotics in this study and this did not affect udder health across the dry period or in early lactation, but seemed to impair udder health in late lactation for cows without a dry period.

    Predicting methane emission of dairy cows using milk composition
    Gastelen, Sanne van - \ 2017
    Wageningen University. Promotor(en): W.H. Hendriks, co-promotor(en): J. Dijkstra; K.A. Hettinga. - Wageningen : Wageningen University - ISBN 9789463437097 - 266
    dairy cows - dairy cattle - methane production - emission - milk composition - fatty acids - cattle feeding - fermentation - nutrition physiology - animal nutrition - pollution - melkkoeien - melkvee - methaanproductie - emissie - melksamenstelling - vetzuren - rundveevoeding - fermentatie - voedingsfysiologie - diervoeding - verontreiniging

    Enteric methane (CH4) is produced as a result of microbial fermentation of feed components in the gastrointestinal tract of ruminant livestock. Methane has no nutritional value for the animal and is predominately released into the environment through eructation and breath. Therefore, CH4 not only represents a greenhouse gas contributing to global warming, but also an energy loss, making enteric CH4 production one of the main targets of greenhouse gas mitigation practices for the dairy industry. Obviously, reduction of CH4 emission could be achieved by simply reducing livestock numbers. However, the global demand for dairy products has been growing rapidly and is expected to further grow in the future. Therefore, it is critical to minimize environmental impact to produce high-quality dairy products. The overall aim of this PhD research was, therefore, to develop a proxy for CH4 emission that can be measured in milk of dairy cows.

    There are currently a number of potentially effective dietary CH4 mitigation practices available for the livestock sector. The results of Chapter 3 show that replacing fiber-rich grass silage with starch-rich corn silage in a common forage-based diet for dairy cattle offers an effective strategy to decrease enteric CH4 production without negatively affecting dairy cow performance, although a critical level of starch in the diet seems to be needed. Little is known whether host genetics may influence the CH4 emission response to changes in diet. Therefore, the interaction between host DGAT1 K232A polymorphism with dietary linseed oil supplementation was evaluated in Chapter 7. The results of Chapter 7 indicate that DGAT1 K232A polymorphism is associated with changes in milk composition, milk N efficiency, and diet metabolizability, but does not affect digestibility and enteric CH4 emission, whereas linseed oil reduces CH4 emission independent of the DGAT1 K232A polymorphism.

    Accurate and repeatable measurements of CH4 emission from individual dairy cows are required to assess the efficacy of possible mitigation strategies. There are several techniques to estimate or measure enteric CH4 production of dairy cows, including climate respiration chambers, but none of these techniques are suitable for large scale precise and accurate measurements. Therefore, the potential of various metabolites in milk, including milk fatty acids (MFA), as a proxy (i.e., indicators or animal traits that are correlated with enteric CH4 production) for CH4 emission of dairy cows gained interest. Until recently, gas chromatography was the principal method used to determine the MFA profile, but this technique is unsuitable for routine analysis. This has led to the application of Fourier-transform infrared spectroscopy (FTIR) for determination of the MFA profile. Chapter 2 provides an overview of the recent research that relates MFA with CH4 emission, and discusses the opportunities and limitations of using FTIR to estimate, indirectly via MFA or directly, CH4 emission of dairy cattle. The recent literature on the relationship between MFA and CH4 emission gives inconsistent results. Where some studies found a clear and strong relation, other studies consider MFA to be unreliable predictors for CH4 emitted by dairy cows. Even the studies that do find a clear relation between MFA and CH4 emissions do not describe similar prediction models using the same MFA. These discrepancies can be the result of many factors, including dietary composition and lactation stage. Additionally, literature showed that the major advantages of using FTIR to predict CH4 emission include its simplicity and potential practical application on a large scale. Disadvantages include the inability to predict important MFA for the prediction of CH4 emission, and the moderate power of FTIR to directly predict CH4 emission. The latter was also demonstrated in Chapter 9, in which the CH4 prediction potential of MFA was compared with that of FTIR using data from 9 experiments (n = 218 individual cow observations) covering a broad range of roughage-based diets. The results indicate that MFA have a greater potential than FTIR spectra to estimate CH4 emissions, and that both techniques have potential to predict CH4 emission of dairy cows, but also limited current applicability in practice. Much focus has been placed on the relationship between MFA and CH4 emission, but milk also contains other metabolites, such as volatile and non-volatile metabolites. Currently, milk volatile metabolites have been used for tracing animal feeding systems and milk non-volatile metabolites were shown to be related to the health status of cows. In Chapter 4, the relationship between CH4 emission and both volatile and non-volatile metabolites was investigated, using data and milk samples obtained in the study described in Chapter 3. In general, the non-volatile metabolites were more closely related to CH4 emissions than the volatile metabolites. More specifically, the results indicate that CH4 intensity (g/kg fat- and protein-corrected milk; FPCM) may be related to lactose synthesis and energy metabolism in the mammary gland, as reflected by the milk non-volatile metabolites uridine diphosphate-hexose B and citrate. Methane yield (g/kg dry matter intake) on the other hand, may be related to glucogenic nutrient supply, as reflected by the milk non-volatile acetone. Based on the metabolic interpretations of these relationships, it was hypothesized that the addition of both volatile and non-volatile metabolites in a prediction model with only MFA would enhance its predictive power and, thus, leads to a better proxy in milk for enteric CH4 production of dairy cows. This was investigated in Chapter 5, again using data and milk samples described in Chapter 3. The results indicate that MFA alone have moderate to good potential to estimate CH4 emission. Furthermore, including volatile metabolites (CH4 intensity only) and non-volatile metabolites increases the CH4 emission prediction potential.

    The work presented in Chapters 3, 4 and 5, was based upon a small range of diets (i.e., four roughage-based diets in which grass silage was replaced partly or fully by corn silage) of one experiment. Therefore, in Chapter 6, the relationship between CH4 emission and the milk metabolome in dairy cattle was further quantified. Data (n = 123 individual cow observations) were used encompassing a large of roughage-based diets, with different qualities and proportions of grass, grass silage and corn silage. The results show that changes in individual milk metabolite concentrations can be related to the ruminal CH4 production pathways. These relationships are most likely the result from changes in dietary composition that affect not only enteric CH4 production, but also the profile of volatile and non-volatile metabolites in milk. Overall, the results indicate that both volatile and non-volatile metabolites in milk might provide useful information and increase our understanding of CH4 emission of dairy cows. However, the development of CH4 prediction models revealed that both volatile and non-volatile metabolites in milk hold little potential to predict CH4 emissions despite the significant relationships found between individual non-volatile metabolites and CH4 emissions. Additionally, combining MFA with milk volatile metabolites and non-volatile metabolites does not improve the CH4 prediction potential relative to MFA alone. Hence, it is concluded that it is not worthwhile to determine the volatile and non-volatile metabolites in milk in order to estimate CH4 emission of dairy cows.

    Overall, in comparison with FTIR, volatile and non-volatile metabolites, the MFA are the most accurate and precise proxy in milk for CH4 emission of dairy cows. However, most of MFA-based models to predict CH4 emission tend to be accurate only for the production system and the environmental conditions under which they were developed. In Chapter 8 it was demonstrated that previously developed MFA-based prediction equations did not predict CH4 emission satisfactory of dairy cows with different DGAT1 genotypes or fed diets with or without linseed oil. Therefore, the greatest shortcoming today of MFA-based CH4 prediction models is their lack of robustness. Additionally, MFA have restricted practical application, meaning that most MFA retained in the current CH4 prediction models cannot be determined routinely because of the use of gas chromatography. The MFA that can be determined with the use of infrared spectroscopy are however no promising predictors for CH4 emission. Furthermore, MFA have only a moderate CH4 prediction potential. This together suggests that it might not be the best option to focus in the future on MFA alone as a proxy for CH4 emission of dairy cows.

    The FTIR technique has a low to moderate CH4 prediction potential. However, FTIR has a great potential for practical high throughput application, facilitating repeated measurements of the same cow potentially reducing random noise. Results of this thesis also demonstrated that FTIR spectra do not have the potential to detect differences in CH4 emission between diets which are, in terms of forage level and quality, commonly fed in practice. Moreover, the robustness of FTIR spectra is currently unknown. Hence, it remains to be investigated whether FTIR spectra can predict CH4 emissions from dairy cows housed under different conditions from those under which the FTIR-based prediction equations were developed. It is therefore concluded that the accuracy and precision to predict CH4 emission using FTIR needs to increase, and the capacity of FTIR to evaluate the differences in CH4 emission between dairy cows and different types of diets needs to improve, in order to actually be a valuable proxy for CH4 emission of dairy cows.

    Reductie van ammoniak- en methaanemissie via het voerspoor : onderzoek naar de wisselwerking tussen de excretie van Totaal Ammoniakaal Stikstof (TAN) en de emissie van enterisch methaan (CH4) op de Koeien&Kansen praktijkbedrijven in de periode 2010-2013
    Spek, J.W. ; Klop, A. ; Šebek, L.B. - \ 2017
    Wageningen : Wageningen UR Livestock Research (Rapport / Koeien en kansen nr. 79) - 19
    ammoniakemissie - methaan - emissiereductie - rundveevoeding - ammonia emission - methane - emission reduction - cattle feeding
    Het verlagen van de TAN-excretie als maatregel om de ammoniakemissie op het melkveebedrijf te verminderen : methodiek voor het vaststellen van de TAN-excretie: module ‘Bedrijfsspecifieke Emissie Ammoniak’ (BEA) van de Kringloopwijzer
    Šebek, L. ; Migchels, G. ; Dijk, C. van - \ 2017
    Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1020) - 33
    melkvee - melkveehouderij - ammoniakemissie - emissiereductie - rundveevoeding - rundveemest - agrarische bedrijfsvoering - dairy cattle - dairy farming - ammonia emission - emission reduction - cattle feeding - cattle manure - farm management
    De P-benutting door het vee van melkveebedrijven, de impact van minimumwaarden en een tool voor verbetering
    Oenema, J. ; Aarts, H.F.M. - \ 2015
    Plant Research International (PRI) (PRI Rapport ) - 25
    cattle - dairy cattle - cattle feeding - phosphate - excretion - use efficiency - nutrient use efficiency - efficiency - feed conversion efficiency - rundvee - melkvee - rundveevoeding - fosfaat - excretie - gebruiksefficiëntie - nutriëntengebruiksefficiëntie - efficiëntie - voederconversievermogen
    In 2013 was de P(benutting van de Nederlandse melkveestapel gemiddeld 30%. De benutting neemt de laatste twee decennia toe met ongeveer 0.25 procentpunt per jaar, met name door het beter presteren van melkkoeien en de afname van het aandeel jongvee. Om onder het plafond van 84.9 miljoen kg fosfaat(excretie te blijven zal een uitbreiding van de melkproductie met 10% gepaard moeten gaan met een verbetering van de benutting van de veestapel met 0.8 procentpunt; een uitbreiding met 20% of 30% verlangt een verbetering van respectievelijk 2.7 procentpunt en 4.5 procentpunt. Bij indeling van bedrijven in klassen, naar grondsoort en intensiteit (melk/ha), blijkt dat de 10% best scorende bedrijven een benutting realiseren die 5.4 tot 7.6 procentpunt hoger is dan die van de 10% slechts scorende. Als de 10%, 20% of 30% slechts scorende bedrijven gedwongen worden de minimum prestatie te realiseren van de resterende 90%, 80% of 70% leidt dit per stap tot een verbetering van 0.2 procentpunt; bij 30% dus tot 0.6 procentpunt. Besproken wordt de opzet van een tool waarmee de veehouder wordt geholpen de P(benutting te verbeteren.
    Forfaitaire waarden met betrekking tot de veestapel in relatie tot de KringloopWijzer
    Aarts, H.F.M. ; Sebek, L.B. - \ 2015
    Wageningen : Plant Research International (PRI-rapport 636) - 17
    melkproductie - melkveehouderij - mestbeleid - modellen - berekening - dierlijke meststoffen - rundveemest - excretie - stikstof - fosfaat - ammoniakemissie - rundveevoeding - voederconversievermogen - milk production - dairy farming - manure policy - models - calculation - animal manures - cattle manure - excretion - nitrogen - phosphate - ammonia emission - cattle feeding - feed conversion efficiency
    Het rekenmodel KringloopWijzer brengt op jaarbasis de waarden van een aantal kengetallen van het melkveebedrijf in beeld. Aan de veestapel gerelateerde kengetallen zijn 1) de excretie van stikstof (N) en fosfaat (P2O5) ‘onder de staart’, 2) de hoeveelheden N en P2O5 als voer geconsumeerd, 3) de efficiëntie waarmee de in het voer aanwezige N en P2O5 wordt omgezet in melk en groei en 4) de emissie van ammoniak (NH3) uit mest. De waarden van deze kengetallen kunnen vergeleken worden met referentie- en forfaitaire waarden. Referentiewaarden zijn waarden die door bedrijven gerealiseerd worden die in vergelijkbare omstandigheden verkeren wat betreft grondsoort en intensiteit (melkproductie per hectare). De veehouder weet daardoor hoe hij scoort in vergelijking met collega’s. Deze notitie gaat enkel in op de forfaitaire waarden voor de eerder genoemde kengetallen.
    IAG ring test animal proteins 2015
    Raamsdonk, L.W.D. van; Rhee, N.E. van de; Scholtens-Toma, I.M.J. ; Prins, T.W. ; Vliege, J.J.M. ; Pinckaers, V.G.Z. - \ 2015
    Wageningen : RIKILT Wageningen UR (RIKILT report 2015.016) - 31
    ring test - microscopy - animal proteins - cattle feeding - pig feeding - animal health - ringtest - microscopie - dierlijke eiwitten - rundveevoeding - varkensvoeding - diergezondheid
    A ring test was organized for the detection of animal proteins in animal feed by microscopy in the framework of the annual ring tests of the IAG - International Association for Feeding stuff Analysis, Section Feeding stuff Microscopy. The organizer of the ring test was RIKILT - Wageningen UR, The Netherlands. The aim of the ring study was to provide the participants information on the performance of the local implementation of the detection method for their local quality systems. A further aim was to gather information about the application of the microscopic method. The current 2015 version of the IAG ring test for animal proteins is the first one in the IAG series of ring tests applying the full new method for microscopy as published in Regulation (EC) 51/2013 amending Annex VI of Regulation (EC) 152/2009 together with accompanying SOPs.
    Voerwinst bij dynamisch voeren hoger
    Riel, J.W. van; Lokhorst, Kees - \ 2015
    V-focus 5 (2015). - ISSN 1574-1575 - p. 30 - 32.
    melkveehouderij - krachtvoeding - rundveevoeding - automatisering - agrarische economie - productie-economie - rundveehouderij - dairy farming - force feeding - cattle feeding - automation - agricultural economics - production economics - cattle husbandry
    Sinds 2009 maken ruim 600 melkveebedrijven gebruik van dynamisch voeren. Zij behalen met deze tool financieel voordeel, omdat het krachtvoeradvies berekend wordt op basis van individuele koegegevens en rekening houdt met de actuele voer- en melkprijzen. Alleen koeien die extra krachtvoer terugverdienen door melkproductieverhoging krijgen extra krachtvoer. Het principe is diergericht (het dier ‘zoekt’ het eigen optimale krachtvoerniveau) en economisch interessant voor de veehouder. Er wordt dagelijks gestreefd naar de hoogste voerwinst (exclusief ruwvoer) per koe. In een vergelijking in de Agrifirm Focus Melkvee van 2013 vertoonden bedrijven met dynamisch voeren dan ook een lager (-9,3%) krachtvoerverbruik per 100 kg melk vergeleken met vergelijkbare bedrijven. Dit ging ook nog eens gepaard met een kortere (-7 dagen) tussenkalftijd. Conclusies uit het onderzoek • Langzaam opbouwen van de krachtvoergift in de opstart van de lactatie lijkt (met name bij vaarzen) gunstig te zijn voor het verloop van productie en voerwinst (exclusief ruwvoer). • Durf te vertrouwen op het dynamische advies en het vermogen van de koeien om zelf hun balans en optimum (het dier ‘zoekt’ het eigen optimale krachtvoerniveau) te vinden. • Het overrulen van het dynamisch voermodel door bewust meer krachtvoer verstrekken ten opzichte van het krachtvoeradvies van dynamisch voeren in de eerste 100 dagen van een lactatie is economisch niet aantrekkelijk. Op basis van deze bedrijfsvergelijking kost dit naar schatting 53 cent per koe per dag bij vaarzen en 47 cent per koe per dag bij oudere koeien in deze fase van de lactatie. Het artikel ‘Voerwinst bij dynamisch voeren hoger’ van de hand van Johan van Riel en Kees Lokhorst van Wageningen UR Livestock Research is vanaf deze week te lezen in V-focus.
    Handboek melkveehouderij 2015/16
    Remmelink, G.J. ; Middelkoop, J.C. van; Ouweltjes, W. ; Wemmenhove, H. - \ 2015
    Wageningen : Wageningen UR Livestock Research (Handboek / Wageningen UR Livestock Research 30) - 386
    melkvee - melkveehouderij - bodemeigenschappen - bemesting - graslandbeheer - voedergrassen - voedergewassen - rundveevoeding - dierveredeling - diergezondheid - melkproductie - landbouwbedrijfsgebouwen - nederland - handboeken - dairy cattle - dairy farming - soil properties - fertilizer application - grassland management - fodder grasses - fodder crops - cattle feeding - animal breeding - animal health - milk production - farm buildings - netherlands - handbooks
    Steeds meer diversiteit in voederwaardering : universitair hoofddocent Jan Dijkstra: 'Laten we blij zijn dat voerfabrikanten zelf investeren in de innovatie van veevoedingsonderzoek'
    Feenstra, J. ; Dijkstra, J. - \ 2015
    Veeteelt 32 (2015)15. - ISSN 0168-7565 - p. 22 - 23.
    rundveehouderij - rundveevoeding - voederwaardering - veevoederindustrie - cattle husbandry - cattle feeding - feed evaluation - feed industry
    De tijd is voorbij dat mengvoerfabrikanten op basis van het CVB-tabellenboekje voer allemaal dezelfde waardering gaven. Elke fabriek wil met zijn eigen rekenmodel en met eigen kengetallen de beste rantsoenmaker worden. Over de meerwaarde van deze modellen is te twisten, maar het voordeel van deze wedloop is wel dat er nog steeds volop wordt geïnvesteerd in veevoedingsonderzoek.
    Low emission feed : opportunities to mitigate enteric methane production of dairy cows
    Hatew, B. - \ 2015
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra; Andre Bannink; Wilbert Pellikaan. - Wageningen : Wageningen University - ISBN 9789462574458 - 228
    melkkoeien - rundveevoeding - methaanproductie - milieueffect - pensfermentatie - voer - zetmeel - maïskuilvoer - graskuilvoer - diervoeding - dairy cows - cattle feeding - methane production - environmental impact - rumen fermentation - feeds - starch - maize silage - grass silage - animal nutrition

    As global demand for high-quality food originating from animal production is expected to rise due to an increasing human population and consumer income level, the expected role of ruminants in meeting this demand brings multiple challenges. Ruminant production needs to adapt to environmental changes and, at the same time, reduce its impact on the environment. Ruminants production systems have a major impact on the environment through the emission of greenhouse gases such as methane (CH4), nitrous oxide and carbon dioxide. Microbial fermentation of feeds in the gastrointestinal tract, known as enteric fermentation, is the main source of CH4 emissions from dairy production. Enteric CH4 emission is strongly related to the amount of feed fermented in the rumen, which depends on feed intake, feed composition and rumen fermentation conditions associated to the intrinsic characteristics of these feeds and the characteristics of the whole diet. Important gaps in knowledge remain however. The prime aim of this thesis was to investigate the effects of various feeding strategies to mitigate enteric CH4 emissions of dairy cows.

    First experiment was conducted to investigate the effects of type and level of starch in the concentrate. Inclusion of a high level (53%) of starch in the concentrate that accounted for 40% of the total mixed ration dry matter (DM) produced lower CH4 per unit of estimated rumen fermentable organic matter (eRFOM) than a low level (27% of DM) of starch (43.1 vs. 46.9 g/kg of eRFOM). Methane production per kg of eRFOM also was lower for diets based on rapidly fermentable starch (gelatinized maize grain) compared to diets based on slowly fermentable starch (native maize grain) (42.6 vs. 47.4 g/kg of eRFOM). However, inclusion of 53% of starch in the concentrate from both types of starch did not affect CH4 emission intensity (CH4 Ei) (CH4 emission per kg of fat- and protein-corrected milk; FPCM). In a subsequent experiment, maize silage was prepared from whole-plant maize harvested at a very early (25% DM), early (28% DM), medium (32% DM) and late (40% DM) stage of maturity and fed to dairy cows as an alternative to concentrate as starch source. Diet consisted of (on DM basis) 75% maize silage, 20% concentrate and 5% wheat straw. Increasing harvest maturity of maize silage linearly decreased CH4 yield (21.7, 23.0, 21.0 and 20.1 g/kg of DM intake) and CH4 emission as a fraction of gross energy intake (6.3, 6.7, 6.3 and 6.0%). Methane Ei tended to decrease linearly with maturity (13.0, 13.4, 13.2 and 12.1 g/kg FPCM). In another experiment grass silage as roughage source was tested. This experiment was designed to investigate the effects of N fertilisation of grassland and maturity of grass at cutting on CH4 emission in dairy cows. Two N fertilisation rates (65 vs. 150 kg of N/ha) were examined in combination with three stages of grass maturity (early, 28 days of regrowth; mid, 41 days of regrowth; and late, 62 days of regrowth). Diet contained 80:20 ratio (on DM basis) of grass silage (mainly ryegrass) and concentrate. Dry matter intake decreased with N fertilisation and maturity, and FPCM decreased with maturity but was unaffected by N fertilisation. Methane Ei (mean 15.0 g/kg of FPCM) increased by 31% and CH4 per unit digestible OM intake (mean 33.1 g/kg of DOMI) increased by 15% with increasing maturity. Methane yield (mean 23.5 g/kg of DM intake) and CH4 as a fraction of gross energy intake (mean 7%) increased by 7 and 9% with maturity, respectively, which implies an increased loss of dietary energy with progressing grass maturity. Rate of N fertilisation had no effect on CH4 Ei and CH4 yield.

    Despite the importance of in vitro gas production technique for evaluating feeds, in vitro study as a stand-alone approach was considered inadequate to fully evaluate the potential effect of feeds and rumen fermentation modifiers on CH4 production, because in vitro studies are frequently performed separately rather than in parallel with in vivo studies. To test this hypothesis, both in vitro and in vivo CH4 measurements were measured simultaneously using cows in the first experiment that were fed (and adapted to) the same dietary material used as a substrate for in vitro incubation, as donor for microbial inoculum. It was found that 24-h in vitro CH4 (mL/g of incubated organic matter) correlated well with in vivo CH4 when expressed per unit of eRFOM (R2 = 0.54), but not when expressed per unit of organic matter ingested (R2 = 0.04). In the same experiment, results showed that incubation of the same substrate with rumen inocula obtained from donor cows adapted to different diets produced a variable amount of CH4 suggesting that it is important to consider the diet of the donor animal when collecting rumen inocula for in vitro incubation. Even though the in vitro technique has limitations to represent in vivo conditions, it is useful for screening of large sets of animal feeds or feed additives to be used as a CH4 mitigation strategy. In this thesis, two in vitro experiments were conducted to examine the effects of variation in structural composition of condensed tannins (CT) in sainfoin accessions collected from across the world on CH4 production, and CT extracts obtained from a selected sainfoin accessions on CH4 production. Results revealed substantial variation among CT in their effect on in vitro CH4 production and this variation was attributed to differences in chemical structure of CT. Condensed tannins evaluated in this thesis showed to have potential to reduce in vitro CH4 production, but require further investigations to fully evaluate their in vivo effects.

    In conclusion, results from the research work conducted in this thesis show that changes in the basal diet of dairy cows and in roughage production management can substantially reduce the amount of enteric CH4 produced and thereby influence the impact of dairy production on the environment.

    Fokwaarde voeropname : introductie van fokwaarde voor voeropname in Nederland
    Haas, Y. de; Veerkamp, R.F. - \ 2015
    Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 837) - 17
    fokwaarde - melkveehouderij - melkproductie - voeropname - dierveredeling - rundveehouderij - rundveevoeding - breeding value - dairy farming - milk production - feed intake - animal breeding - cattle husbandry - cattle feeding
    Feed costs represent above 50% of the total costs of dairy production, so reducing costs by improving dairy cow feed efficiency is a way to increase profitability. Therefore it is important to improve efficiency of that dairy cattle population. This project has shown that it is possible to breed for more efficient animals, resulting in permanent and cumulative changes in the genetic merit of dairy cows. The breeding value for feed intake is currently integrated in the Better Life Efficiency index for all sires of CRV, and it is under discussing if it will be included in the national index (published by GES) for all bulls in the Netherlands and Flanders.
    Ruimtelijke optimalisatie van voederstromen in de Peel : nieuwe landgebruiksvormen en clustering ten behoeve van regionale productie van veevoer
    Walsum, P.E.V. van; Galama, P.J. ; Roelsma, J. ; Cormont, A. ; Hack-ten Broeke, M.J.D. - \ 2014
    Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2615) - 49
    melkveehouderij - milieueffect - krachtvoeding - rundveevoeding - voedergewassen - duurzaamheid (sustainability) - ruimtelijke verdeling - nutriëntenuitspoeling - duurzaam bodemgebruik - regionaal landbouwbeleid - veevoederindustrie - de peel - dairy farming - environmental impact - force feeding - cattle feeding - fodder crops - sustainability - spatial distribution - nutrient leaching - sustainable land use - regional agricultural policy - feed industry - de peel
    In een eerdere studie werd verkend in hoeverre het economische en milieutechnisch haalbaar zou zijn om in regio De Peel krachtvoervervangers regionaal te verbouwen. In de in dit rapport beschreven studie stelden we ons de vraag of ruimtelijke optimalisatie wel tot milieuwinst zou kunnen leiden en vervolgens hoe regionale voercentra kunnen bijdragen en op welke locatie deze zouden moeten liggen.
    IAG ring test animal proteins 2014
    Raamsdonk, L.W.D. van; Pinckaers, V.G.Z. ; Scholtens-Toma, I.M.J. ; Prins, T.W. ; Voet, H. van der; Vliege, J.J.M. - \ 2014
    Wageningen : RIKILT Wageningen UR (RIKILT report 2014.011) - 35
    ringtest - microscopie - dierlijke eiwitten - rundveevoeding - pluimveevoeding - diergezondheid - ring test - microscopy - animal proteins - cattle feeding - poultry feeding - animal health
    A ring test was organized for the detection of animal proteins in animal feed by microscopy in the framework of the annual ring tests of the IAG – International Association for Feeding stuff Analysis, Section Feeding stuff Microscopy. The aim of the ring study was to provide the participants information on the performance of the local implementation of the detection method for their local quality systems. A further aim was to gather information about the application of the microscopic method.
    Update of an extant master plan for the development of a nutrient-based feed evaluation system that predicts dairy cow response to nutrition
    Bannink, A. ; Dijkstra, J. - \ 2014
    Lelystad : Wageningen UR Livestock Research (Report / Wageningen UR Livestock Research 763) - 17
    voederwaardering - dynamisch modelleren - melkkoeien - voedingswaarde - rundveevoeding - rundvee - spijsvertering - feed evaluation - dynamic modeling - dairy cows - nutritive value - cattle feeding - cattle - digestion
    Recent modelling efforts are discussed in view of the master plan for a nutrient based feed evaluation system for dairy cows. Digestive modules have been developed; more recently modules of post-absorptive nutrient (mainly amino acid) metabolism became available. The modelling efforts do not demand a basal change of the original master plan.
    Handboek melkveehouderij 2013
    Remmelink, G.J. ; Dooren, H.J.C. van; Middelkoop, J.C. van; Ouweltjes, W. ; Wemmenhove, H. - \ 2013
    Lelystad : Wageningen UR Livestock Research [etc.] (Handboek / Wageningen UR Livestock Research 26) - 392
    melkveehouderij - agrarische bedrijfsvoering - graslandbeheer - bemesting - rundveevoeding - dierveredeling - diergezondheid - melk- en zuivelapparatuur - huisvesting van koeien - landbouwwerktuigen - bedrijfsontwikkeling in de landbouw - handboeken - dairy farming - farm management - grassland management - fertilizer application - cattle feeding - animal breeding - animal health - dairy equipment - cow housing - farm machinery - farm development - handbooks
    Het digitale Handboek Melkveehouderij 2013 is geactualiseerd met de laatste ontwikkelingen in de melkveehouderij, zoals in de hoofdstukken: - Bemesting; - Grasland en voedergewassen; - Voederwinning; - Rundveeverbetering; - Gezondheid; - Melkwinning; - Bedrijfsgebouwen; - Mechanisatie.
    Variation of milk urea in dairy cattle : a study on factors that affect the relationship between urea concentration in milk and urea excretion in urine
    Spek, J.W. - \ 2013
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Jan Dijkstra; Andre Bannink. - S.l. : s.n. - ISBN 9789461736642 - 156
    melkkoeien - melkvee - ureum - melk - concentratie - urinering - excretie - stikstof - meta-analyse - natriumchloride - opname (intake) - diervoeding - rundveevoeding - voedingsfysiologie - dairy cows - dairy cattle - urea - milk - concentration - urination - excretion - nitrogen - meta-analysis - sodium chloride - intake - animal nutrition - cattle feeding - nutrition physiology

    The aim of this thesis was to increase the applicability of milk urea nitrogen concentration (MUN) as a predictor of urinary urea nitrogen excretion (UUN) by identifying and quantifying factors that can explain variation in MUN that is not related to UUN. A literature study was conducted in order to identify these factors that affect the relationship between MUN and UUN. In this literature review a number of factors were established that affect the relationship between MUN and urinary N-excretion (UN) or UUN, such as dietary crude protein content (CP), intake of dietary salt and water, body weight, diurnal variation in plasma urea nitrogen concentration (PUN), exchange of urea between blood and milk, and heritability of MUN. Results of a quantitative meta-analysis where the effect of various physiological and dietary factors on the relationship between MUN and UN or UUN were studied confirmed the fact that CP affects the relationship between MUN and UUN and showed that by using information on MUN and CP more variation in UUN could be explained compared to using information on either MUN or CP alone. One of the factors established in the literature review that can affect the relationship between MUN and UUN is dietary salt content or drink water intake. In order to quantify the effect of dietary salt on MUN and UUN an experiment was carried out that investigated the effect of four dietary levels of sodium chloride (NaCl) on urea levels in blood plasma and milk and on UN and UUN. The results from this trial clearly showed a negative relationship between dietary NaCl content and MUN whereas UUN was not affected by NaCl intake and UN was slightly increased by increasing NaCl intake levels. The question arose whether the effect of dietary salt on MUN would be similar at high and low dietary protein levels as the renal mechanism of excretion and reabsorption of urea is affected by both dietary protein and salt intake. Therefore, the interaction between dietary salt and protein on UUN was tested in an experiment with two CP levels and two dietary NaCl levels. No interaction between dietary NaCl and CP on MUN was observed. However, the relationship between MUN and UUN was altered by the effect of salt intake. The literature review showed that diurnal variation in PUN and MUN can be substantial, and that this variation depends on factors such as time and frequency of feeding and milking. Insight in the dynamics of urea transport between blood of milk is important in order to model and predict variation in MUN over time under various feeding and milking regimes. To obtain quantitative insight in urea fluxes between blood and milk two experiments were conducted in which urea transport from blood to milk and vice versa was investigated by means of pulse dose injections of labeled [15N15N]urea in milk cisterns at various time intervals before milking. The results showed a rapid distribution of injected labeled urea throughout the milk in the mammary gland and substantial urea transport from milk to blood.

    It is concluded that various factors that are discussed in this thesis contribute to variation in MUN that is not related to UUN. Taking these factors into account increases the applicability of MUN as a predictor of UUN.

    Passage of feed in dairy cows : use of stable isotopes to estimate passage kinetics through the digestive tract of dairy cows
    Warner, D. - \ 2013
    Wageningen University. Promotor(en): Wouter Hendriks, co-promotor(en): Wilbert Pellikaan; Jan Dijkstra. - S.l. : s.n. - ISBN 9789461736833 - 163
    melkkoeien - melkvee - voer - voedingsstoffen - spijsvertering - spijsverteringskanaal - kinetica - stabiele isotopen - verteerbaarheidsmerkers - rundveevoeding - diervoeding - voedingsfysiologie - dairy cows - dairy cattle - feeds - nutrients - digestion - digestive tract - kinetics - stable isotopes - digestibility markers - cattle feeding - animal nutrition - nutrition physiology

    Dairy cows possess a unique digestive system to digest fibre-rich diets. Ingested feed is retained and degraded in the rumen by the enteric microbial population and is passed from the rumen to the following segments of the digestive tract. Passage of feed determines energy and protein supply to the animal and is a key parameter in several feed evaluation models for ruminants. Yet, quantitative data on passage of feed and particularly of single feed components are limited. Common techniques used to determine fractional passage rates of feed typically include indigestible markers that are not able to describe passage of distinct feed components. This thesis describes the use of stable isotope labelled feed components as a novel marker to determine feed type and feed component specific fractional passage rates. In a series of in vivoexperiments, fractional passage rates of a typical dairy ration, including grass silage, maize silage and concentrates, were determined. The use of carbon (13C) and nitrogen (15N) stable isotopes as an internal marker inherent to the diet allowed to specifically determine fractional passage rates of plant cell walls such as structural fibre, fibre-bound nitrogen, n-alkanes, and intracellular components such as starch and total nitrogen. For grass silage and maize silage, stable isotopes gave slower fractional rumen passage rates compared to the commonly used external marker chromium mordanted fibre; for concentrates, stable isotopes gave faster rates than the external marker. Among isotopic labelled fractions, 13C-labelled fibre and 15N-labelled fibre-bound nitrogen gave the slowest rates. The isotopic signature of single feed components and further application of stable isotopes on a wider range of feeds and feed components offers scope for the future for a more detailed insight into nutrient-specific passage kinetics. This will ultimately allow to quantify nutrient supply in response to changes in diet composition and quality, and model animal response in relation to optimal animal performance, environmental and animal-health issues.

    Nieuwe technieken, nog meer reductie
    Haan, M.H.A. de; Hilhorst, G.J. ; Vegte, D.Z. van der; Booij, A. - \ 2013
    Veeteelt 30 (2013)11. - ISSN 0168-7565 - p. 36 - 37.
    melkveehouderij - broeikasgassen - innovaties - proefboerderijen - mestverwerking - methaan - emissie - rundveevoeding - voersamenstelling - nitraat - onderzaaien - grassen - dairy farming - greenhouse gases - innovations - experimental farms - manure treatment - methane - emission - cattle feeding - feed formulation - nitrate - undersowing - grasses
    Gras crushen, mest raffineren, toevoegmiddelen voor voer en kuil; op praktijkcentrum De Marke in het Gelderse Hengelo worden verschillende innovatietechnieken uitgeprobeerd om de broeikasgassen verder te verminderen. Praktijkrijp zijn ze nog niet.
    Kleinschalige bioraffinage in de Achterhoek; een duurzame oplossing voor het mestprobleem
    Sanders, J.P.M. ; Doorn, W.J. van; Krimpen, M.M. van; Cremers, H. - \ 2013
    Wageningen : Wageningen Universiteit, Livestock Research - 34
    voedermiddelbewerking - grasmaaisel - maïs - bioraffinage - nutriëntengebruiksefficiëntie - mestoverschotten - regionale ontwikkeling - rundveevoeding - varkensvoeding - melkveehouderij - achterhoek - nederland - biobased economy - feed processing - grass clippings - maize - biorefinery - nutrient use efficiency - manure surpluses - regional development - cattle feeding - pig feeding - dairy farming - achterhoek - netherlands - biobased economy
    We kampen in Nederland al decennia met een mestprobleem, in feite een mest overschot. In dit rapport worden nieuwe aanpakken van dit probleem voorgesteld, gedeeltelijk gecombineerd met verlaging van mineralen in het voer. De nieuwe aanpak wordt mogelijk indien we er in slagen de efficiëntie van de diervoeders te verbeteren en indien we de belangrijkste componenten van het diervoeder, eiwit en de energie behoefte van de dieren, in Nederland zelf te produceren. Bioraffinage van met name gras en in op termijn ook van mais, is doorslaggevend omdat we daarmee de componenten voor de rundveevoeders kunnen ontsluiten waardoor een hoger rendement wordt bereikt. Door graseiwit in te zetten als varkensvoeder zijn we niet langer afhankelijk van de import van sojaschroot en andere restproducten uit de plantaardige olie verwerkende industrie. Wanneer we deze bioraffinage uitvoeren in kleinschalige fabriekjes, voor de maisraffinage het liefst gekoppeld aan een biogas vergistingsinstallatie, dan kunnen de mineralen die niet voor het dier nodig zijn, direct zonder dure concentreringsbehandelingen naar het agrarische veld terug gebracht worden als bemesting.
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