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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    Regio heeft grote invloed op levensvatbaarheid
    Pellikaan, F. ; Ouweltjes, W. ; Windig, J.J. ; Muskens, J. ; Linden, R. van der; Pelt, M.L. van; Calus, M.P.L. - \ 2014
    Veeteelt 31 (2014)14. - ISSN 0168-7565 - p. 10 - 13.
    melkveehouderij - kalveren - levensvatbaarheid - geboorte - vaarzen - grote landbouwbedrijven - bedrijfsgrootte in de landbouw - landbouwstatistieken - bedrijfsvergelijking in de landbouw - invloeden - dairy farming - calves - viability - birth - heifers - large farms - farm size - agricultural statistics - farm comparisons - influences
    Een afname van zes procent levend geboren kalveren van vaarzen tussen 1995 en 2010 was aanleiding voor nieuw sectoronderzoek. Uit de inventarisatie blijkt dat naast bekende factoren als draagtijd en geboorteverloop de regio waar het bedrijf is gehuisvest en het seizoen van afkalven zorgen voor opmerkelijke verschillen in levensvatbaarheid van kalveren.
    Behaviour of heifers during long distance transport : comparison between two different transportation schemes
    Visser, K.J. ; Werf, J.T.N. van der; Gunnink, H. ; Hindle, V.A. ; Riel, J.W. van; Dixhoorn, I.D.E. van; Gerritzen, M.A. - \ 2014
    Wageningen : Wageningen UR Livestock Research (Livestock research report 787) - 61
    melkvee - vaarzen - dierlijke productie - veevervoer - transport - diergedrag - diergezondheid - dierenwelzijn - dairy cattle - heifers - animal production - transport of animals - transport - animal behaviour - animal health - animal welfare
    This current study aimed to test if the welfare of heifers transported in commercial transports and under Cattle Cruiser conditions was increased if animals were allowed a 9-hour overnight stop (feeding and resting) on the vehicle compared to the common practice in which animals were rested (and fed) at least 1 hour after 14 hours of transport. The results of the study are intended as hypothesis forming and are only applicable to the Cattle Cruiser conditions under which the animals were transported in vehicles with the specifications outlined in Appendix 2.
    Familiekuddes : Judith Poelarends over de jong volwassen kudde
    Livestock Research, - \ 2012
    Wageningen : Wageningen UR Livestock Research
    melkveehouderij - dierenwelzijn - melkvee - dierlijke productie - diergezondheid - diergedrag - melkveestapel - kuddes (herds) - vaarzen - huisvesting, dieren - lactatie - stallen - duurzame veehouderij - biologische landbouw - dairy farming - animal welfare - dairy cattle - animal production - animal health - animal behaviour - dairy herds - herds - heifers - animal housing - lactation - stalls - sustainable animal husbandry - organic farming
    In de huidige melkveehouderij ervaren de vaarzen behoorlijk veel stress als ze in de koppel worden geïntroduceerd na het afkalven. Een groot deel van de dieren begint niet eens aan een tweede lactatie en verlaten het bedrijf omdat ze tegenvallen. We denken dat een 'jong volwassen kudde', waarbij vaarzen al veel eerder voor het afkalven in de kudde worden geïntroduceerd (bijvoorbeeld al na dekking of inseminatie of 2 tot 3 maanden voor afkalven) een positieve invloed heeft op deze groep dieren. Ze maken immers onderdeel uit van de kudde en de rangorde en raken gewend aan het management. Meer over de familiekudde op: http://www.familiekuddes.nl
    Pijnsignalen, wat doen we ermee?
    Driesse, M. ; Kluivers-Poodt, M. - \ 2010
    Veehouder en Dierenarts 24 (2010)1. - ISSN 1381-8007 - p. 22 - 23.
    melkveehouderij - melkkoeien - vaarzen - kalven - pijnstillende middelen - dierenartsen - pijn - dierenwelzijn - dairy farming - dairy cows - heifers - calving - analgesics - veterinarians - pain - animal welfare
    Dieren, dus ook koeien, laten niet snel merken dat ze pijn hebben. Want daarmee laten ze zien dat ze verzwakt zijn en dus een gemakkelijke prooi vormen. Hoogleraar veterinaire anesthesiologie prof. dr. Ludo Hellebrekers zei het vorig jaar tijdens een voordracht voor dierenartsen over pijn als volgt: “De grootste valkuil is: ik zie geen abnormaal gedrag, dus het dier heeft geen pijn.”
    Laag celgetal bij eerste afkalving betaalt zich terug
    Smolders, E.A.A. ; Wagenaar, J.P. - \ 2008
    V-focus 5 (2008)5. - ISSN 1574-1575 - p. 20 - 21.
    melkveehouderij - vaarzen - melkproductie - uiers - diergezondheid - biologische landbouw - celgetal - kalven - dairy farming - heifers - milk production - udders - animal health - organic farming - somatic cell count - calving
    De uiergezondheid van meer dan 7.500 vaarzen van ruim 100 biologische melkveebedrijven zijn beoordeeld op basis van MPR-gegevens (MelkProductieRegistratie 2003-2007). Het celgetal in de eerste MPR na afkalven was gemiddeld 82.000 en was het laagst bij dieren die afkalfden in het begin van de stalperiode. Afkalven op oudere leeftijd had geen gunstige invloed op het celgetal. Vaarzen die afkalfden met een laag celgetal hielden een lager celgetal tijdens de lactatie en werden minder snel afgevoerd
    Een vaarskalfje meer of minder : extra opfok jongvee op extensief bedrijf aantrekkelijker dan op intensief bedrijf
    Saatkamp, H.W. ; Ouweltjes, W. ; Walle, K. van der; Hogeveen, H. - \ 2003
    Veeteelt 20 (2003)11. - ISSN 0168-7565 - p. 28 - 30.
    melkveehouderij - melkvee - kalveren - vaarzen - kalvervoeding - agrarische bedrijfsvoering - bedrijfsvergelijking in de landbouw - intensieve veehouderij - extensieve veehouderij - dairy farming - dairy cattle - calves - heifers - calf feeding - farm management - farm comparisons - intensive livestock farming - extensive livestock farming
    In dit 2e artikel van een serie over jongvee en vervangingsbeleid aandacht voor 't opfokbeleid met cijfers over het aanhouden van verschillende aantallen jongvee op zowel een extensief als op een intensief melkveebedrijf
    Modelling epidemiological and economic consequences of bovine respiratory disease in dairy heifers
    Fels-Klerx, H.J. van der - \ 2001
    Wageningen University. Promotor(en): A.A. Dijkhuizen; R.B.M. Huirne; J. Verhoeff. - S.l. : S.n. - ISBN 9789058085375 - 167
    melkvee - vaarzen - rundveeziekten - ademhalingsziekten - melkveebedrijven - kostenanalyse - melkresultaten - computersimulatie - simulatiemodellen - epidemiologie - agrarische economie - nederland - dairy cattle - heifers - cattle diseases - respiratory diseases - dairy farms - cost analysis - dairy performance - computer simulation - simulation models - epidemiology - agricultural economics - netherlands

    Bovine respiratory disease (BRD) is an important health problem in dairy heifers. BRD causes considerable losses, particularly on farms that experience high levels of the disease. However, an exact quantification of the economic losses due to BRD was not available yet. Despite this lack of economic insight, dairy farmers have to make decisions with regard to prevention of the disease. To make these decisions as economically sound as possible, more accurate insight is necessary into the economic consequences of BRD on the individual dairy farm.

    The main objective of the research project described in this thesis was to obtain insight into the on-farm economic consequences of BRD in dairy heifers by means of a PC-based simulation model. The second objective was to collect information on the epidemiological consequences of the disease indispensable for model input.

    The research started with a literature review aimed at obtaining the necessary qualitative and quantitative information on both the effects of BRD on the productivity of dairy heifers and risk factors of the disease. Because relevant literature turned out to be scarce, a formal expert judgement study was held to obtain additional data on the(se) variables of interest.

    As a next step, a simulation model was developed that calculates the economic losses due to BRD in dairy heifers for individual dairy farm conditions in the Netherlands. Following the results of the expert judgement study, the model distinguishes between two BRD types, being calf pneumonia and a seasonal BRD outbreak.

    Model calculations showed that for most dairy farms in the Netherlands the economic losses due to BRD will be relatively small: around 1 % of the farm's net return to labour and management for average situations, increasing up to 3-4 % at worst. For individual farms that experience high levels of BRD, the associated losses can be as high as 10-15 % of the farm's net return to labour and management, up to 25 % for large farms. Besides for calculation of the economic losses due to BRD, the model showed also to be useful for evaluation of the on-farm cost-effectiveness of prevention of the disease. Moreover, the model is flexible and user-friendly, hence, can be used as a tool to support decision-making in dairy practice.

    Economic modelling to optimize dairy heifer management decisions
    Mourits, M.C.M. - \ 2000
    Agricultural University. Promotor(en): A.A. Dijkhuizen; R.B.M. Huirne; D.T. Galligan. - S.l. : S.n. - ISBN 9789058081551 - 149
    koeien - melkkoeien - vaarzen - opfoktechnieken - rundvee - bedrijfsvoering - dynamisch programmeren - economie - modellen - cows - dairy cows - heifers - rearing techniques - cattle - management - dynamic programming - economics - models

    The objective of heifer rearing within a dairy farm is to produce high quality dairy replacements at low costs. Heifer management decisions interact with the biological aspects of growth, thereby influencing the future profitability of the heifer. To maximize profitability farmers need to be aware of the potential impacts of these management decisions. However, this is a field of research that received only little attention. The objective of the research described in this thesis was to obtain insight into the technical and economic consequences of various dairy heifer rearing strategies by means of a stochastic dynamic optimization model.

    The research was started with a literature review to identify the key issues in heifer rearing and a large field survey to evaluate the present heifer rearing performance of dairy farmers in the Netherlands. Based on the insights obtained, a stochastic dynamic optimization model was developed, using the hierarchic Markov process technique. Within the model heifers were described in terms of age, season, body weight, reproductive state and prepubertal growth rate. Management decisions with respect to growth rate, time of insemination and replacement were optimized under maximization of discounted net returns per heifer place per year. Model behaviour was studied by the evaluation of a basic Dutch production situation. Within the default situation, the optimal rearing policy resulted in an average calving age of 22.6 months and an average calving body weight of 564 kg. Discounted net returns coincided with Dfl 337 per heifer per year. Extensive sensitivity analyses were carried out to evaluate the consequences of variation in price and production variables on the optimization outcomes.

    Additionally, the basic model was extended to determine the extent to which heifer rearing activities influence the environmental problems on a Dutch dairy farm and to study the sensitivity of the optimal rearing policy for environmental measures as the Dutch mineral accounting system (MINAS) or the use of least mineral rations. In the final phase, application of the model under other production circumstances was studied by an evaluation of a rearing situation typical for a Pennsylvanian (US) dairy herd.

    The potential of improving napier grass under smallholder farmers' conditions in Kenya
    Kariuki, J.N. - \ 1998
    Agricultural University. Promotor(en): S. Tamminga; C.K. Gachuiri; G.K. Gitau. - Naivasha : Kariuki - ISBN 9789054859642 - 197
    melkvee - pennisetum purpureum - melkveehouderij - gemengde landbouw - herkauwersvoeding - voedingsstoffenverbetering - voedingswaarde - voedersupplementen - voeropname - verteerbaarheid - groeitempo - vaarzen - kenya - dairy cattle - pennisetum purpureum - dairy farming - mixed farming - ruminant feeding - nutrient improvement - nutritive value - feed supplements - feed intake - digestibility - growth rate - heifers - kenya

    Dairy farming is the main livestock enterprise in the mixed crop/livestock farming system in the high rainfall areas of Kenya. These areas are characterised by a high human population density and very small farms. As a consequence, napier grass ( Pennisetum purpureum ) has been widely adopted because of its relatively high dry matter yield and suitability as a cut fodder. The conventional methods of improving napier grass quality through fertilization or use of concentrates to supplement napier grass diets is limited because most farmers cannot afford these inputs. This has led to poor animal performance mostly attributed to the low protein content in napier grass.

    The most vulnerable group are heifers which receive far less attention compared to calves and cows. This is reflected by low weight gain (less than 0.25 kg day -1) and poor reproductive and life-time performance. Fortunately, several protein-rich forages (PRF) which have the potential to improve the quality of napier grass-based diets have been identified. These include Desmodium spp., Calliandra calothyrsus, Leucaena leucocephala, Ipomoea batatas, Medicago sativa, Musa sapienta, Trifolium semipilosum and Canna edulis .

    The benefits of using PRF include improved rumen function, increased energy and protein intake, improved feed efficiency, increased availability of minerals and vitamins, and generally enhanced animal performance. Appropriate and adequate information on the nutritive value of napier grass at different stages of growth and the PRF would facilitate ration formulation, allow more reliable prediction of subsequent animal performance and assist in the planning of suitable feeding strategies for the resource poor dairy farmers. Therefore, the overall objective of the study was to evaluate the nutritive value of napier grass and determine the potential for improvement in animal performance using PRF. Results from this thesis indicated that intake and utilization can be improved by manipulating the cutting regime of napier grass and varying the levels of PRF supplements.

    Indeed, PRF had a profound effect on fermentation and subsequently improved the intake of organic matter fermented in the rumen by up to 50%. Protein supplementation strategies for low crude protein tropical grasses should first target at optimising microbial protein production and then consider supplements containing a combination of ruminally degradable and bypass protein for high animal performance. Inadequately fed heifers grow poorly and show poor reproductive performance. The positive growth response obtained from the supplemented heifers were attributed to additional rumen degradable protein and/or bypass protein from PRF that overcame protein deficiency in napier grass.

    It was concluded that PRF could play an important role in the improvement of the utilization of napier grass and the subsequent animal performance. The data provided in this study, on the nutritive value of these forages will, consequently, facilitate making appropriate choices for diet formulation at the farm level.

    Sensorisch onderzoek van rundvlees
    Mazijk-Bokslag, D.M. van; Cramwinckel, A.B. ; Herstel, H. - \ 1991
    Wageningen : RIKILT (Rapport / RIKILT 91.09) - 17
    sensorische evaluatie - sensorische wetenschappen - rundvlees - vaarzen - sensory evaluation - sensory sciences - beef - heifers
    Op verzoek van het Instituut voor Veeteeltkundig Onderzoek "Schoonoord" (IVO) is de derde ronde van het onderzoek naar de geschiktheid van Piernontese kruislingvaarsen als vleesvaars uitgevoerd. In deze derde ronde is opnieuw nagegaan of er aantoonbare verschillen in "eetkwaliteit" zijn tussen vlees van kruislingvaarzen die op verschillende tijdstippen na het afkalven zijn geslacht en verschillend zijn gevoederd. Als vergelijkingsmateriaal is het vlees van stieren onderzocht. De monstername is door het IVO uitgevoerd en het vlees is in porties diepgevroren bij het RIKILT afgeleverd. Het sensorisch onderzoek is met behulp van een schaalmethode met dezelfde termen, die bij de voorgaande onderzoeken gebruikt zijn, uitgevoerd. De monsters zijn gecodeerd en gerandomiseerd aan een panel van zestien personen in tien sessies aangeboden.
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