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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    We will mail you new results for this query: keywords==reproductive efficiency
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Vroege detectie van dracht bij koeien door Proteomics Biomerkers in melk = Early pregnancy detection using proteomics biomarkers in milk
Pas, M.F.W. te; Kruijt, L. ; Wit, A.A.C. de; Hulsegge, B. ; Riel, J.W. van; Heeres-van der Tol, J.J. ; Sulkers, H. ; Woelders, H. - \ 2014
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research nr. 747) - 10
melkkoeien - zwangerschap - eiwitexpressieanalyse - merkers - melkproductie - melkveehouderij - rundveehouderij - productiebeperkingen - optimalisatie - voortplantingsefficiëntie - dairy cows - pregnancy - proteomics - markers - milk production - dairy farming - cattle husbandry - production restrictions - optimization - reproductive efficiency
The aim of this study is to develop an accurate, fast, cheap, and reliable test to detect pregnancy before day 35 on the basis of markers in milk. The ultimate goal is to have a method that can be implemented in a practical setting.
Slechte bevedering werkt als anticonceptie: inventarisatie reproductieproblematiek VB-sector
Emous, R.A. van - \ 2007
De Pluimveehouderij 37 (2007)21. - ISSN 0166-8250 - p. 16 - 17.
pluimvee - pluimveehouderij - voortplanting - voortplantingsefficiëntie - bevederingspercentage - poultry - poultry farming - reproduction - reproductive efficiency - feathering rate
Animal Sciences Group inventariseert de reproductieproblematiek in de vermeerderingssector. De belangrijkste factoren die voor problemen zorgen, worden in een serie artikelen uit de doeken gedaan. In dit artikel wordt de bevedering van de hennen onder de loep genomen
Natural mating in Nile tilapia (Oreochromis niloticus L.) : implications for reproductive success, inbreeding and cannibalism
Fessehaye, Y. - \ 2006
Wageningen University. Promotor(en): Johan Verreth; Johan van Arendonk, co-promotor(en): Hans Komen; Henk Bovenhuis. - [S.l.] : S.n. - ISBN 9085045401 - 149
oreochromis niloticus - tilapia - natuurlijke paring - voortplantingsefficiëntie - inteelt - kannibalisme - genetische verbetering - visteelt - natural mating - reproductive efficiency - inbreeding - cannibalism - genetic improvement - fish culture
Meer biggen met bietenpulp in zeugenvoer
Peet-Schwering, C. van der; Binnendijk, G. - \ 2002
Praktijkkompas. Varkens 16 (2002)6. - ISSN 1570-8578 - p. 16 - 17.
varkens - varkenshouderij - zeugen - varkensvoeding - voer - voersamenstelling - zwangerschap - lactatie - voortplanting - voortplantingsefficiëntie - voortplantingsvermogen - prestatieniveau - bietenpulp - pigs - pig farming - sows - pig feeding - feeds - feed formulation - pregnancy - lactation - reproduction - reproductive efficiency - reproductive performance - performance - beet pulp
Het geven van een bietenpulp voer tijdens de dracht en een zetmeelrijk voer tijdens de lactatie is een goede voerstrategie voor zeugen. Voer met 40% bietenpulp tijdens de dracht verhoogt het aantal levend geboren biggen met 0,5 big. Het verstrekken van een zetmeelrijk voer tijdens de lactatie verhoogt de voeropname van de zeugen met 0,4 kg per dag. De verplichting om guste en drachtige zeugen dagelijks enig ruwvoer te geven kan dus een positief effect hebben op de reproductie van zeugen
Optimising insemination strategies in pigs
Steverink, D. - \ 1999
Agricultural University. Promotor(en): J.P.T.M. Noordhuizen; Bas Kemp; Nicoline Nieuwenhuizen-Soede. - S.l. : S.n. - ISBN 9789058080950 - 147
zeugen - varkens - kunstmatige inseminatie - voortplanting - voortplantingsefficiëntie - bevruchting - spermatozoön - dosering - sperma - oestrus - ovulatie - tijd - wiskundige modellen - simulatiemodellen - commerciële landbouw - sows - pigs - artificial insemination - reproduction - reproductive efficiency - fertilization - spermatozoa - dosage - semen - ovulation - time - mathematical models - simulation models - commercial farming
<p>INTRODUCTION<p>Reproductive efficiency shows large variation between farms. The origin of the variation between farms, with respect to these reproduction results, is very complex. Factors like health status, husbandry system, management and breed can have an influence on reproduction results. One of the management factors is timing of insemination, which influences reproduction results by affecting fertilisation.<p>The research described in this thesis deals with the possibility of developing a method to optimise insemination strategies for individual farms. Therefore three objectives were formulated: the <u>first objective</u> is increasing insight in the effects of the interval between insemination and ovulation on fertilisation results. The <u>second objective</u> is increasing knowledge on the possibilities of predicting the moment of ovulation of sows at a farm. The <u>final objective</u> is developing a method which can be used for optimising insemination strategies at commercial farms.<p>FERTILISATION IN RELATION TO INSEMINATION AND OVULATION<p>In Chapter 2 the sensitivity of the relation of the insemination to ovulation interval (IO) and fertilisation results is studied. Fertilisation results are not very sensitive to variation in the number of inseminated sperm cells in the range of 1 x 10 <sup>9</sup> to 6 x 10 <sup>9</sup> sperm cells (Chapter 2.1). Sows with more than 4 ml backflow of semen during insemination had reduced fertilisation results when the sows were inseminated with 1 x 10 <sup>9</sup> sperm cells, but this was not seen with an insemination dosage of 3 x 10 <sup>9</sup> or 6 x 10 <sup>9</sup> sperm cells (Chapter 2.2). Backflow of semen after insemination did not affect fertilisation results. It could be concluded that sub-optimal circumstances like a combination of a low dosage and loss of sperm cells due to backflow during insemination, lead to sub-optimal fertilisation results.<p>Fertilisation is a complex process, resulting in no, partial or complete fertilisation of the oocytes. The variation in conception (at least one oocyte fertilised) and fertilisation rate between sows is high, but a large part of the variation is related to the interval between insemination and ovulation. A mathematical model for conception and fertilisation is described in Chapter 2.3. The data used for estimating the parameters in the model were derived from multiparous sows that were inseminated once with a commercial sperm dose of 3 x 10 <sup>9</sup> sperm cells of proven quality which was stored for less than 48 h and with sperm cells. In the model, the probability of conception is maximal (98%), when insemination is performed between 29 and 3 h before ovulation. The probability of complete fertilisation (all oocytes fertilised) is maximal when insemination was performed at 9.6 h before ovulation. At this optimal fertilisation point, the probability of partial fertilisation is 21% which increases beyond this point.<p>PREDICTION OF OVULATION<p>Fertilisation results are related to the interval between insemination and ovulation. Therefore, the moment of ovulation is a crucial moment for timing of insemination. Many potential ovulation predictors have been studied, but only oestrus duration is a reasonable estimate (retrospectively) for ovulation. Ovulation takes place at on average twothirds of oestrus. Unfortunately oestrus duration is very variable.<p>The average oestrus duration is different between farms ranging between 31 and 64 h (Chapter 3.1). Moreover, oestrus duration is consistent from month to month within a farm with a repeatability of 86%. Furthermore, oestrus duration is negatively related to the weaning to oestrus interval. This relation differs among farms. These specific farm parameters can be used to predict the oestrus duration and from that the ovulation can be predicted. These farm parameters (average oestrus duration and the relation of weaning to oestrus interval and oestrus duration) can be used to define a specific insemination strategy for each farm.<p>DEVELOPMENT OF A MODEL FOR INSEMINATION STRATEGIES<p>There are a variety of factors influencing the reproduction process. The complexity of this reproduction process makes a modelling and simulation approach valuable because effects of the underlying processes can be controlled. A PIG Simulation model for Insemination strategies (PIGSIS) was developed which consists of two parts: (1) the reproduction events from the number of ovulated oocytes until the number of piglets at farrowing and (2) timing of insemination relative to ovulation based on the farm parameters (weaning to oestrus interval, oestrus duration, etc.). PIGSIS simulates the reproduction results at day 1, 5, 10, 15, 35 and 110 of pregnancy. Many physiological processes are included in PIGSIS e.g. fertilisation, embryonic mortality (degeneration, maternal recognition of pregnancy, embryonic uterine capacity) and foetal mortality (foetal uterine capacity). After verification and validation it could be concluded that PIGSIS is a robust model that reasonably simulates reproduction results. Under the basic situation (average oestrus duration of 47 h and average parity of 4.2) and when insemination was applied between 0 and 24 h before ovulation PIGSIS simulates 12.9 total born piglets and a farrowing rate of 94.9%. Under these conditions the average embryonic and foetal mortality of the conceptuses was 34.9% and 3.0%, respectively. The effect of insemination to ovulation interval on fertilisation results is clear, but the effect becomes less clear as gestation proceeds resulting in a more pronounced effect on litter size than on farrowing rate.<p>In the General discussion the results of the studies are discussed and an illustration of the usability of PIGSIS is given. Verification and partial validation gave confidence in the model. However, a further validation is required to evaluate the model as a whole. Therefore PIGSIS is still in its developing stage and reservations has to be taken into account at this stage by using PIGSIS for defining optimal insemination strategies on farms<br/>
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