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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    Embryo temperature during incubation: practice and theory
    Lourens, A. - \ 2008
    Wageningen University. Promotor(en): Bas Kemp, co-promotor(en): Henry van den Brand; R. Meijerhof. - S.l. : S.n. - ISBN 9789085852582 - 131
    kuikens - embryo's - temperatuur - broeden - embryonale ontwikkeling - warmteproductie - warmteverlies - eierschaal - incubators - pluimveehouderij - chicks - embryos - temperature - incubation - embryonic development - heat production - heat loss - egg shell - incubators - poultry farming
    (Key words: incubation, embryo temperature, embryonic development, heat production, heat loss)

    Until recently, all incubator studies were performed using a constant machine temperature (MT). But it is embryo temperature (ET) that is of importance to the embryo, and not MT. In practice, MT is often measured at one location within the incubator, while ET can vary between eggs within an incubator. Furthermore, ET is the result of the balance between heat production (HP) and heat loss, and if HP or heat loss is affected it may have consequences for ET. Aim of this dissertation was to identify the causes of variable ET and to describe the consequences of variable ET on embryonic development, hatchability, HP and chick quality. Because the direct measurement of ET is destructive, it was chosen in this dissertation to use eggshell temperature (EST) measurements as a reflection of ET.
    Long term deviations of 1.1ºC away from a constant EST of 37.8ºC decreased embryonic growth, development, hatchability, and the ability of young chicks to maintain high body temperatures after hatching, especially under cold stress. HP was considered to be positively related to embryonic development, because when more energy is used for growth, HP during incubation will increase and chicks will subsequently hatch with a larger yolk free body and with a lower amount of energy left over in the residual yolk. Within the EST zone of 1.0ºC below and above 37.8ºC it was observed that HP increased linearly with short term EST increments, and the response of the embryos to EST variations was identical in young, mid term and late term embryos. Maximizing HP based on metabolic responses to EST fluctuations will therefore increase EST above the studied EST zone, leading to decreased embryonic growth and increased embryonic mortality. High EST increases the demand for oxygen, so oxygen availability was expected to limit HP and embryonic growth more at higher EST profiles than at EST of 37.8ºC. However, despite the fact that HP at day 18 was highest for the combination of high EST with high oxygen concentration, embryonic development did not show the same relationship. At EST above 37.8ºC, the amount of energy utilized from the egg content remained the same, but the efficiency of energy transfer (EYFB) between egg and embryo decreased. Factors as egg size, breed, and oxygen availability affected HP through changes in energy utilization, and had no effect on EYFB.
    In this thesis, the importance was shown to measure and control ET during incubation and not MT. Factors were identified that affect ET through changes in HP and heat loss. When ET is controlled and maintained at a constant level of 37.8ºC, embryonic development may be improved by measures that increase energy utilization through increments in gas exchange, which will increase HP.
    Metingen naar de verschillende tussen uitkomstbakken: het belang van luchtbeweging
    Lourens, A. - \ 2001
    De Pluimveehouderij 31 (2001)10. - ISSN 0166-8250 - p. 18 - 19.
    pluimveehouderij - eieren - uitbroeden - broedmachines - luchttemperatuur - eierschaal - temperatuur - poultry farming - eggs - hatching - brooders - air temperature - egg shell - temperature
    Bij het analyseren van broeduitkomsten worden er grote verschillen gevonden in aantallen eerste en tweede soort kuikens en liggenblijvers tussen uitkomst bakken. De relatie tussen broeduitkomsten en de broedomstandigheden zoals die op verschillende plaatsen in de voorbroedmachine kunnen voorkomen wordt beschreven als mogelijke verklaring van de verschillen (luchttemperatuur, luchtsnelheid, eischaaltemperatuur)
    Effect eischaaltemperatuur tijdens broedproces op broeduitkomsten en vleeskuikenprestatie
    Lourens, S. ; Middelkoop, J.H. van - \ 2000
    Beekbergen : Praktijkonderzoek Pluimveehouderij (PP uitgave : praktijkonderzoek pluimveehouderij 89) - 24
    vleeskuikens - broeden - broedfactoren - temperatuur - eierschaal - kuikenembryo's - embryonale ontwikkeling - vleeskuikenproductie - broedeieren - vleeskuikenouderdieren - broilers - incubation - hatching factors - temperature - egg shell - chick embryos - embryonic development - broiler production - hatching eggs - broiler breeders
    In dit onderzoek zijn de broedresultaten bij vier verschillende temperatuurinstellingen vergeleken. Hiertoe werd de temperatuur op de eischaal gemeten, en aan de hand daarvan de instellingen van de broedmachine geregeld. Van twee temperatuurinstellingen zijn zowel hen- als haankuikens gevolgd tijdens de mestperiode.
    Uitwendige eikwaliteit en huisvesting
    Niekerk, Th.G.C.M. van - \ 1992
    Praktijkonderzoek voor de Pluimveehouderij 3 (1992)2. - ISSN 0924-9087 - p. 9 - 12.
    huisvesting, dieren - dierlijke producten - dierenwelzijn - eierschaal - hennen - pluimveehokken - kwaliteit - animal housing - animal products - animal welfare - egg shell - hens - poultry housing - quality
    In het vorige periodiek (92/1) is ingegaan op de inwendige kwaliteit van consumptie-eieren in relatie tot het type huisvesting van de leghen. In dit artikel zal de relatie uitwendige eikwaliteit - huisvesting aan de orde komen.
    Ervaringen met beeldverwerking.
    Meuleman, J. - \ 1989
    Landbouwmechanisatie 40 (1989)12. - ISSN 0023-7795 - p. 27 - 29.
    analyse - dierlijke producten - appels - toepassingen - automatische regeling - automatisering - controle - voertuigen zonder bestuurder - eierschaal - proefstations - landbouwwerktuigen - voedselkwaliteit - voedingsmiddelen - frankrijk - fruitgewassen - oogsten - instrumentatie - malus - kwaliteitscontroles - regulatie - remote sensing - onderzoeksinstituten - besturen - systemen - technologie - testen - groenten - procesbewaking - machines - analysis - animal products - apples - applications - automatic control - automation - control - driverless vehicles - egg shell - experimental stations - farm machinery - food quality - foods - france - fruit crops - harvesting - instrumentation - quality controls - regulation - research institutes - steering - systems - technology - testing - vegetables - process control
    Verslag van een werkbezoek aan het Franse instituut Cemagref, met nadruk op beeldverwerking. Toepassingen van beeldverwerking zijn onder andere: een plukrobot voor appels; het detecteren van oppervlaktebeschadigingen bij appels; het detecteren van breuk in eieren; remote sensing
    De relatie tussen kooiconstructievariabelen en het ontstaan van eischaalbreuk
    Oosterwoud, A. - \ 1985
    Beekbergen : COVP (COVP onderzoeksverslag no. 231) - 37
    batterijkooien - kooien - eierschaal - intensieve landbouw - nederland - battery cages - cages - egg shell - intensive farming - netherlands
    Eggshell strength: The causes of egg breakage in relation to nutrition, management and environment. B Part two
    Boushy, A.R. El; Raterink, R. - \ 1985
    Feedstuffs 57 (1985)34. - ISSN 0014-9624 - p. 7 - 9.
    diervoedering - huisvesting, dieren - calcium - eierproductie - eierschaal - agrarische bedrijfsvoering - voer - hennen - mineralen - fosfor - animal feeding - animal housing - egg production - egg shell - farm management - feeds - hens - minerals - phosphorus
    Een rantsoen met 4% oesterschelpen en 3.5% krijt garandeert een voldoende opname voor calcium gedurende de gehele dag. Voor een goede eiproduktie met voldoende schaalsterkte is 0.3% Fosfor en 3.5% calcium aan te bevelen. Toevoeging van 50 ppm Vitamine C is aan te bevelen bij hoge temperatuur en relatieve vochtigheid. Goede hokinrichting en goed management kunnen eischaalbreuk in gunstige zin beinvloeden
    Eggshell strength: The causes of egg breakage in relation to nutrition, management and environment. A Part one
    Boushy, A.R. El; Raterink, R. - \ 1985
    Feedstuffs 57 (1985)33. - ISSN 0014-9624 - p. 18 - 21.
    diervoedering - eierschaal - voer - dierverzorging - animal feeding - egg shell - feeds - care of animals
    Beschrijving van voedings-, management- en klimaatsinvloeden op de eischaalkwaliteit. Als voedingsinvloeden worden calcium (bron en hoeveelheid), fosfor en vitamine a genoemd. Management-invloeden betreffen leeftijd van het dier, kooiconstructie, bezettingsdichtheid, vervoer, wassen en andere behandelingen van eieren. Verder wordt er op gewezen, dat een hoge omgevingstemperatuur en een hoog vochtigheidsgehalte een ongunstige invloed op de schaalkwaliteit hebben
    Ultrastructure of the hen eggshell and its physiological interpretation
    Simons, P.C.M. - \ 1971
    Landbouwhogeschool Wageningen. Promotor(en): A.M. Frens. - Wageningen : Centre for Agricultural Publishing and Documentation - ISBN 9789022003411 - 90
    eierproducten - eierschaal - eieren - zoölogie - egg products - egg shell - eggs - zoology

    Financial losses from egg breakage have increased over the years. To seek any relation with shell strength, the structure of eggshell and shell membranes were examined by light microscope, transmission electron microscope and scanning electron microscope. They were taken from eggs laid by laying hens, from eggs removed from the oviduct and from eggs laid prematurely, and occasionally from incubated hen eggs and eggs of guinea-fowl, duck, turkey, emu and ostrich.

    The results with different methods of measurement showed how shell membranes vary in thickness, how some structural properties of shell may influence shell strength, how the shell and shell membranes form and how they are destroyed during incubation and what factors influence the cuticular surface of the eggs.

    Egg shell quality and microstructure as affected by vitamin C, other feed additives and high environmental temperatures
    El-Boushy, A.R. - \ 1966
    Wageningen University. Promotor(en): A.M. Frens. - Wageningen : Veenman - 79
    dierfysiologie - eierschaal - pluimvee - kippen - kwaliteit - prestatieniveau - voer - samenstelling - milieufactoren - immunologie - antigenen - voedertoevoegingen - dierverzorging - animal physiology - egg shell - poultry - fowls - quality - performance - feeds - composition - environmental factors - immunology - antigens - feed additives - care of animals
    The effects of climatic stress on egg formation (weight, shape, formation period, clutch size and blood calcium) and shell quality were estimated in White Leghorn and White Plymouth Rock hens. Constant environments were used with 85°F 75- 80% r.h., 75-77°F 50-60% r.h. and 55°F 50-60% r.h. as well as a fluctuating environment with 10 h (day) 85°F 75-80% r.h. and 14 h (night) 65-70°F 50-60% r.h. The effects of dietary vitamin C (50 or 100 mg/kg feed), NaHCO 3 2.1 % and antibiotics were also tested.

    The author concluded the following. Fluctuating temperature had no effect. In heat-stressed hens vitamin C improved the diminished shell quality and raised blood calcium.

    At 75°F vitamin C and NaHCO 3 increased egg weight and shell quality. Combinations of antibiotics improved egg and shell weight. Microscopy of ground sections of the shell showed that heat diminished shell thickness and impaired the crystal structure of the calcified shell; vitamin C addition improved shell thickness.

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