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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    Evaluatie van parkhuisvesting voor vleeskonijnen
    Rommers, Jorine ; Jong, Ingrid de; Houwers, Wim ; Hattum, Theo van - \ 2017
    Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1018)
    konijnen - slachtdieren - groepshuisvesting - dierenwelzijn - mestresultaten - schoonmaken - dierlijke productie - huisvesting, dieren - rabbits - meat animals - group housing - animal welfare - fattening performance - cleaning - animal production - animal housing
    In dit rapport wordt verslag gedaan van een onderzoek dat is uitgevoerd op een konijnen praktijkbedrijf en waarbij drie verschillende parksystemen voor vleeskonijnen zijn vergeleken. Gelet is of de systemen voldoen aan de behoefte van konijnen, de productiviteit is gemeten en de hygiëne, de reinigbaarheid en het arbeidsgemak zijn in kaart gebracht.
    Het effect van aminozuuraanbod en -samenstelling van het voer op zoötechnische prestaties van beren gehuisvest onder verschillende sanitaire condities
    Meer, Y. van der; Gerrits, W.J.J. ; Jansman, A.J.M. - \ 2016
    Wageningen UR Livestock Research (Livestock Research rapport 938) - 32
    beren (varkens) - aminozuren - eiwit - voedselsamenstelling - varkensvoeding - mestresultaten - hygiëne - varkenshouderij - zoötechniek - dierlijke productie - boars - amino acids - protein - food composition - pig feeding - fattening performance - hygiene - pig farming - zootechny - animal production
    Dit experiment was opgezet om het effect van eiwitniveau (normaal versus verlaagd) en aminozuursamenstelling in het rantsoen te evalueren op de technische prestaties van beren gehuisvest onder een tweetal sanitaire condities.
    Unveiling causes for growth retardation in piglets
    Paredes Escobar, S. - \ 2014
    Wageningen University. Promotor(en): Leonard den Hartog, co-promotor(en): Martin Verstegen; Walter Gerrits. - Wageningen : Wageningen University - ISBN 9789462571204 - 168
    biggen - groei - mestresultaten - geboortegewicht - speengewicht - voer - groeivertraging - inslineresistentie - varkensvoeding - diervoeding - voedingsfysiologie - piglets - growth - fattening performance - birth weight - weaning weight - feeds - growth retardation - insulin resistance - pig feeding - animal nutrition - nutrition physiology

    The evolution of hyper‐prolific sow breeds has led to a higher number of piglets born per sow per year. This increase in litter size has enlarged the number of light weight (or growth retarded) piglets, increased pre‐weaning mortality and heterogeneity at the end of the nursery phase (ten weeks of age). These poorly performing piglets represent a challenge to the swine industry as their presence in the herd has economic and welfare implications.

    Reducing the heterogeneity at the end of the nursery phase is relevant, as it influences the efficiency of use of the grower and finisher facilities, and/or it reduces penalties for delivering underweight piglets to the slaughterhouse. The focus of this thesis was the end of the nursery phase, as this is the time point where piglets are transferred to the grower and finisher facilities.

    The aim of this thesis was to identify and describe the causes of growth retardation in the nursery phase to provide a basis to look for alternative nutrition or management solutions.

    The database analysis described in Chapter 2 provides a phenotypic definition of growth retardation based on the risk factor analysis approach, and describes season of birth, body weight at birth, at weaning and at six weeks of age as the main factors to predict piglet BW at the end of the nursery phase.

    Based on the algorithm developed to predict piglets’ BW at the end of the nursery phase, our target population was defined as piglets with a birth weight above the mean ‐2 times the SD from the total population and a predicted BW at the end of the nursery phase below the mean ‐1 time the SD from the mean of the total population, considered Low Performing

    piglets LP). We aimed to characterize differences between LP piglets and their heavier counterpart (piglets with a predicted BW at the end of the nursery phase above the mean +1 time the SD from the mean of the total population HP).

    Compared to the HP, the LP piglets grew slower, ate less and were lighter but have an equal gain:feed ratio at ten weeks of age. The LP piglets tended to take more time to touch a novel object and spent more time eating. The LP and HP piglets have an equal macronutrient digestibility, with the exception of NSP. When fed a high fibre diet, both groups have a lower starch and fat apparent total tract digestibility. Yet, the LP piglets have a reduced fermentative capacity, which might place them in disadvantage. Also LP piglets are unable to engage into compensatory gain or compensatory feed intake, as efficiency of nutrient utilization and feed intake per kg BW0.75 was unaffected. In terms of skeletal muscle development, the LP piglets have a low muscularity (total fiber number and fiber cross sectional area), which might be of disadvantage for lean mass accretion in further life and for meat quality. The LP piglets exhibit insulin resistance and a lower pancreatic amylase activity, which might be related to the lower performance. Lastly, in the general discussion a comparison of the main findings with literature characterizing growth retarded piglets is presented. Also based on modelled data, the economic impact of growth retarded piglets is estimated from 10 weeks of age until slaughter weight (110 kg BW).

    The studies reported in this thesis describe a novel method for selecting growth retarded piglets in the nursery phase and provide insight into possible mechanism for growth retardation in the piglet phase.

    Werking dunne fractie mest valt nog tegen
    Verloop, J. ; Geerts, R.H.E.M. ; Hilhorst, G.J. - \ 2013
    V-focus 10 (2013)2. - ISSN 1574-1575 - p. 28 - 29.
    melkveehouderij - mestresultaten - drijfmest - mestverwerking - scheiding - stikstof - ammoniakemissie - dairy farming - fattening performance - slurries - manure treatment - separation - nitrogen - ammonia emission
    Veldproeven op een aantal Koeien & Kansen-bedrijven wijzen uit dat de stikstofwerking van de dunne fractie van gescheiden mest niet duidelijk hoger is dan die van drijfmest. Mogelijk komt dit doordat het gehalte aan minerale stikstof in de dunne fractie niet hoog genoeg is. Een andere mogelijke oorzaak is een hogere emissie van ammoniak uit de dunne fractie. Wat kan de huidige praktijk hier nu mee? En hoe verder met het onderzoek naar mestscheiding?
    Nutrient synchrony in preruminant calves
    Borne, J.J.G.C. van den - \ 2006
    Wageningen University. Promotor(en): Martin Verstegen, co-promotor(en): Walter Gerrits. - [S.l.] : S.n. - ISBN 9789085045243 - 197
    vleeskalveren - diermodellen - kalvervoeding - voedingsstoffenbeschikbaarheid - tijd - eiwitmetabolisme - energiemetabolisme - aminozuren - glucose - synchronisatie - groei - mestresultaten - veal calves - animal models - calf feeding - nutrient availability - time - protein metabolism - energy metabolism - amino acids - glucose - synchronization - growth - fattening performance
    In animal nutrition, the nutrient composition of the daily feed supply is composed to match the nutrient requirements for the desired performance. The time of nutrient availability within a day is usually considered not to affect the fate of nutrients. The aim of this thesis was to evaluate effects of the time of nutrient availability within a day (i.e. nutrient synchrony) on the protein and energy metabolism in preruminant calves. Two types of nutrient synchrony were studied: (1) synchrony between total nutrient supply and requirements within a day, and (2) synchrony between protein and carbohydrate availability. The studies were mainly conducted in heavy preruminant calves, because those animals have a very low efficiency of protein utilization for growth compared with other farm animals, such as pigs and lambs, allowing a large potential for improvement. Increasing the feeding frequency increased the efficiency of protein utilization in preruminant calves. This was however not detected when short-term measurements of amino acid metabolism (12 h urea production and oral leucine oxidation) were considered. Dietary carbohydrates were almost completely oxidized, unaffected by feeding level, in heavy preruminant calves. Glucose homeostasis improved with increasing feeding frequency. In pigs, an asynchronous availability of glucose and amino acids within a day reduced protein utilization but did not affect fat retention. In preruminant calves, however, an asynchronous availability of glucose and amino acids did not decrease the efficiency of protein utilization but substantially increased fat retention. Separating the intake of protein and lactose over meals inhibited postprandial plasma insulin responses, but increased glucose excretion in urine. Intramuscular fat content and oxidative enzyme activity increased with decreasing nutrient synchrony in an oxidative muscle in calves. Oxidative enzyme activity is not an appropriate indicator of whole-body heat production in growing calves.
    Rumen development in veal (preruminant) calves
    Suárez, B.J. - \ 2006
    Wageningen University. Promotor(en): Seerp Tamminga, co-promotor(en): Walter Gerrits; Jan Dijkstra. - [S.l.] : S.n. - ISBN 9789085045366 - 174
    vleeskalveren - pensontwikkeling - pensfermentatie - concentraten - ruwvoer (roughage) - voer - samenstelling - koolhydraten - enzymactiviteit - mestresultaten - kalvervoeding - veal calves - rumen development - rumen fermentation - concentrates - roughage - feeds - composition - carbohydrates - enzyme activity - fattening performance - calf feeding
    Historically, veal calves were fed until slaughter weight with only milk replacer and, in absence of solid feed the physiological development of the forestomachs was limited. In 1997, a new EU legislation stipulated that a minimum amount of solid feed (fiber) has to be provided for the welfare of the calves (solid feed supply reduce abnormal oral behaviors in veal calves; Van Putten, 1982; Veissier et al., 1998); however, no specifications were made about the type and source of feed.

    Rumen development is triggered by the production of VFA resulting from fermentation ofOMin the rumen (Flatt et al., 1958). Butyrate, and to a lesser extent propionate stimulate the development of the rumen mucosa; mostly because of their use as energy sources by the rumen epithelium (Sander et al., 1959; Tamate et al., 1962). In rearing calves, information on rumen fermentation of different sources of dietary carbohydrates is relatively well documented (Davis and Drackley, 1998; Lesmeister and Heinrichs, 2004) but only a few experiments have been conducted in veal calves.

    Based on earlier research (Blokhuis et al., 2000) it was hypothesized that stimulating early rumen development in veal calves would be beneficial to their subsequent performance and health. Therefore in vivo experiments were designed to establish the effects of stimulating an early rumen development in veal calves, aiming to optimize nutrient utilization from rumen fermentation and to prevent health problems in the lower gastrointestinal tract (e.g. ulcers in abomasum). In addition the potential interactions of feeding solid feed with a milk replacer based diet were investigated. Finally but not least, the development and evaluation (comparison) of techniques for estimating fermentation characteristics of different substrates, to facilitate the choice of feed ingredient for veal calves diets was also carried out. 

    Chapter 2:This study was conducted to evaluate the effects of concentrate intake, differing in carbohydrates composition in addition to a milk replacer, on growth performance and rumen fermentation characteristics in veal calves. Accordingly, 160 Holstein Friesian x Dutch Friesian male calves, were fed with one of the following treatments: 1) milk replacer control (CONTROL), 2) pectin-based concentrate (PECTIN), 3) neutral detergent fiber (NDF) based concentrate, 4) starch-based concentrate (STARCH) and 5) mixed concentrate (MIXED) (equal amounts of concentrates of treatments 2, 3, and 4). Concentrate diets were provided in addition to a commercial milk replacer Results: Calves showed an ADG varying between 0.70 and 0.78 kg/d, with a rumen fermentation in concentrates fed calves characterized by a low pH (4.9 - 5.2), relatively low VFA concentrations between 100 and 121 mmol/L and high concentrations of reducing sugars (33-66 g/kg DM). Calves fed the CONTROL diet had higher lactate concentration (21mmol/L) than concentrate fed calves (between 5 and 11 mmol/L). Results indicated that the carbohydrate source can influence intake, growth rate and rumen fermentation in young veal calves.

    Chapter 3:This experiment aimed to gain an insight into the effects of age (calves were euthanized either at the end of 8 or 12 weeks of age) and concentrate supplementation, differing in carbohydrates composition, on rumen development in young veal calves. Moreover, some selected plasma metabolites as predictors of rumen development were evaluated. Diets treatments correspond to those described in Chapter 2. Results: Feeding concentrates differing in carbohydrate composition to veal calves promoted rumen development compared with calves fed milk replacer only. In most calves, a poorly developed rumen mucosa was observed. Coalescing rumen papillae with embedded hair, feed particles and cell debris were found in all calves fed concentrate diets. Calves fed concentrates had significantly heavier rumens than calves fed CONTROL. Although the variation in carbohydrate composition caused variation in rumen development, the latter was generally small. In the dorsal location of the rumen, calves fed concentrate diets showed an increased ratio of mucosa to serosa length (RMSL) than calves fed CONTROL. Mucosa thickness (MCT) and muscle thickness (MST) were bigger in the ventral and in the dorsal locations of the rumen, respectively.

    At 8 weeks, calves fed concentrate diets had higher plasma acetate concentrations than calves on the CONTROL treatment. However, at 12 weeks, only NDF fed calves showed significantly higher plasma acetate concentrations. For plasma BHBA concentration no differences were observed among treatments at 12 weeks. Results from a principal component analysis indicated that veal calves, in addition to rumen volatile fatty acids (VFA) concentrations, other factors are likely to affect rumen development.  

    Chapter 4:This experiment was designed based on the results obtained in experiment 1 (Chapter 2 and 3) where in concentrate-fed veal calves a rumen environment, characterized by a sub clinical acidosis (pH< 5.2), relatively low VFA concentrations (100-120 mmol/L) and a rumen mucosa characterized by poorly shaped papillae with feed and cell debris embedded between them (referred as plaque formation) were observed. Feeding only roughage to young calves generally does not promote rapid papillae development (Nocek and Kesler, 1980); however, roughage consumption and its inherent coarseness stimulate the development of the rumen wall (Tamate et al., 1962) and rumination (Hodgson, 1971) and the healthiness of the rumen mucosa (Haskins et al., 1969). Information concerning the effects of roughage intake on veal calves performance and rumen development is scarce (Blokhuis et al., 2000; Cozzi et al., 2002). Therefore, it was hypothesized that adding small amount of roughage to a concentrate diet will improve and stimulates the development of the rumen wall, without having negative effects on calf's performance. Sixty four male Holstein Friesian x Dutch Friesian veal calves (46 kg ± 3.0 kg), were fed on of the following diets: 1) C100= concentrate only, 2) C70-S30= concentrate (70%) with straw (30%), 3) C70-G30= concentrate (70%) with dried grass (30%), 4) C70-G15-S15= concentrate (70%) with dried grass (15%) and straw (15%), 5) C70-CS30= concentrate (70%) with corn silage (30%), 6) C40-CS60= concentrate (40%) with corn silage (60%), 7) C70-CS30-AL= concentrate (70%) with corn silage (30%) ad libitum, 8) C70-G15-S15-AL= concentrate (70%) with dried grass (15%) and straw (15%) ad libitum. All dietary treatments were provided in addition to a commercial milk replacer. Concentrate was provided as pellets and roughage was chopped. Results: Roughage and intake level affects rumen fermentation and rumen development of veal calves. Substitution of part of the concentrate by roughage did not affect DMI and ADG, but among roughage sources feeding straw reduced DMI and ADG. The addition of roughage did not affect rumen pH (pH >5.3). Rumen fermentation was characterized by high total volatile fatty acids (VFA) and reducing sugars (RS) concentrations. Cobalt recovery, as an indication of milk leakage was found in the rumen, varying between 20.5 and 34.9 %, but it was not affected by dietary treatments. Roughage addition decreased the incidence of plaque formation and the incidence of calves with poorly developed rumen mucosa. However, morphometric parameters of the rumen wall were hardly influenced by the type and level of roughage. Results indicated that in veal calves, the addition of roughage to concentrate diets did not affect growth performance and positively influenced the macroscopic appearance of the rumen wall.

    Chapter 5:Several methodologies have been developed to characterize feedstuffs in terms of digestibility and degradability, comprising in vivo , in situ and in vitro methods.

    The gas production technique (GPT) provides gas production profiles that give an indication of the fermentative characteristics of the feed. The objective of this experiment was to estimate fermentation kinetic parameters of various solid feeds supplied to veal calves using the GPT, and to study the effect of adaptation of the rumen microflora to these solid feeds on their subsequent fermentation patterns. Thus, from the in vivo experiment described in Chapter 2 and 3; three out of five dietary treatments were selected as inoculum sources: pectin ( PECTIN ), neutral detergent fiber ( NDF ), and starch ( STARCH ). Sugar beet pulp ( SBP ), sugar beet pectin ( SBPec) , native corn starch ( NCS ), soy bean hulls ( SBH ) and crystalline cellulose ( AVICEL) were selected as substrates. For the second in vitro experiment, three out of eight dietary treatments (from the in vivo experiment described in Chapter 4) were selected as inocula. The selected diet treatments were: C100= concentrate only, C70-S30 = concentrate (70%) with straw (30%) and C70-CS30 = concentrate (70%) with corn silage (30%). For this gas production experiment, straw ( STRAW ), soy bean hulls ( SBH ), native corn starch ( NCS ) and sugar beet pectin ( SBPec ) were chosen as in vitro substrates.

    For both in vivo experiments, cumulative gas production was measured over time (72 h) as an indicator of the kinetics of fermentation. Fermentation end-products, including volatile fatty acids and ammonia, and organic matter loss, were also measured. Results : In both experiments significant differences between the inoculum sources, in terms of both fermentation kinetics characteristics and end-products of fermentation were observed. Similarly, significant effects were also observed for substrate compositions. Differences between the fermentation characteristics of NCS, SBPec and SBH, were consistent for both experiments. The total VFA production was not different among these substrates in both experiments. Finally, for both experiments, there was a significant inocula and substrate interaction which may indicate differences in the microbial activity occurring between the calves. Therefore, it was concluded that rumen inoculum from adapted animals should be used to obtain a more accurate assessment of feed ingredients in veal calf diets.

    Chapter 6 (General discussion) focused in four points: a) Factors influencing rumen development in rearing and veal calves; b) The importance of ruminal drinking in veal calves fed solids feeds; c) Effects of feeding strategies on ruminal pH and buffering capacity of rumen contents in veal calves; d) comparative analysis of the results obtained from the GPT (results presented in Chapter 5) and the PDE activities (results presented in Chapter 2 and 4).
    N-werking vaste rundermest = The effectiveness of nitrogen of solid cattle manure
    Holshof, G. - \ 2005
    Lelystad : Animal Sciences Group (PraktijkRapport / Animal Sciences Group, Praktijkonderzoek : Rundvee 72) - 20
    rundveehouderij - rundveemest - dierlijke meststoffen - graslanden - graslandbeheer - mestresultaten - samenstelling - stikstofrespons - cattle husbandry - cattle manure - animal manures - grasslands - grassland management - fattening performance - composition - nitrogen response
    The figures of effectiveness of solid cattle manure were determined in the 1950s and 1960s. However, this effectiveness may have changed over the years, due to changes in breed and rations. A study at the Waiboerhoeve showed that the effectiveness of solid manure applied in spring was 13 to 15% in the first cut, which means an arithmetic effectiveness of 1-11% in the remaining growing season
    Literatuurstudie van landbouwkundige aspecten van herinzaai van grasland
    Boer, H.C. de; Hoving, I.E. - \ 2005
    Lelystad : Animal Sciences Group (Praktijkrapport / Animal Sciences Group, Praktijkonderzoek : Rundvee ) - 27
    graslanden - rundveeteelt - zaaien - lolium - opbrengsten - voedingswaarde - voeropname - mestresultaten - literatuuroverzichten - nederland - grasslands - cattle farming - sowing - lolium - yields - nutritive value - feed intake - fattening performance - literature reviews - netherlands
    This survey discusses the effect of reseeding botanically deteriorated grassland on several aspects of grassland use, including dry matter yield, intake of grass during grazing, nutritive value, ensilability, conservation losses, intake of silage and utilisation in the animal. From the survey it appears that a number of relatively small differences on several aspects can result in a 24-30 % higher productivity (beef production) of reseeded grassland compared with botanically deteriorated grassland.
    Dynamisch voeren belooft veel goed, maar... er valt nog wat te sleutelen!
    Harn, J. van; Veldkamp, T. - \ 2005
    De Pluimveehouderij 35 (2005)8. - ISSN 0166-8250 - p. 14 - 15.
    pluimveehouderij - diervoedering - voedingsrantsoenen - voederconversie - mestresultaten - dierenwelzijn - diergezondheid - economische analyse - on-farm research - poultry farming - animal feeding - feed rations - feed conversion - fattening performance - animal welfare - animal health - economic analysis - on-farm research
    Minder voetzoolproblemen bij vleeskuikens: dat was een doel van twee experimenten van Praktijkonderzoek, eind vorig jaar. Een van de experimenten betrof 'dynamisch voeren', waarmee in de praktijk op voerkosten is bespaard en strooiselkwaliteit verbeterde. Reden om het op Het Spelderholt in Lelystad te beproeven
    Heat stress in growing pigs
    Huynh Thi Thanh Thuy, - \ 2005
    Wageningen University. Promotor(en): Martin Verstegen; Bas Kemp, co-promotor(en): Andre Aarnink. -
    varkens - warmtestress - groei - omgevingstemperatuur - dierfysiologie - diergedrag - mestresultaten - afmesten - koelsystemen - pigs - heat stress - growth - environmental temperature - animal physiology - animal behaviour - fattening performance - finishing - cooling systems
    Compared to other species of farm animals, pigs are more sensitive to high environmental temperatures, because they cannot sweat and do not pant so well. Furthermore, fast-growing lean pigs generate more heat than their congeners living in the wild. This, in combination with confined housing, makes it difficult for these pigs to regulate their heat balance. Heat stressed pigs have low performance, poor welfare, and, by pen fouling, they give higher emissions of odour and ammonia.

    Above certain critical temperatures (inflection point temperatures) pigs start to adapt their mechanisms of balancing heat loss and heat production. The inflection point temperatures above which the responses change may well differ depending on which animal parameter is studied. Within this thesis, firstly, these critical temperatures were determined for different physiological, behavioral and production parameters. Secondly, the effect of different cooling systems on these parameters was studied.

    In order of appearance we found inflection point temperatures for lying on slatted floor, respiration rate, evaporative water, ratio of water to feed intake, total heat production, activity heat production, voluntary feed intake and rectal temperature. These inflection point temperatures were different for the different parameters and show the subsequent strategies the pig follows at increasing temperatures. Relative humidity had minor effects on physiological parameters. However, a combination of high relative humidity and high temperature showed a detrimental effect on daily gain.Theavailability of cooling systems, e.g. floor cooling, water bath or sprinklers, had beneficial effects on pigs' performance.

    It is concluded that high ambient temperatures strongly affect physiology, behaviour and performance of growing pigs.The inflection point temperatures found in this study are good indicators of heat stress. These can be used as set points for cooling systems. Cooling systems improve animal performance and welfare under high temperature conditions.

    Alternatieven voor antimicrobiële voerbespaarders (AMGB's) in vleeskuikenvoer = Alternatives for anti microbial growth promoters (AGPs) in the broiler diet
    Veldkamp, T. ; Harn, J. van; Middelkoop, J.H. van - \ 2004
    Lelystad : Animal Sciences Group (PraktijkRapport : Pluimvee ) - 28
    vleeskuikens - pluimveevoeding - voer - groeibevorderaars - antimicrobe-eigenschappen - voedertoevoegingen - vervangmiddelen - mestresultaten - diervoeding - broilers - poultry feeding - feeds - growth promoters - antimicrobial properties - feed additives - substitutes - fattening performance - animal nutrition
    Het Praktijkonderzoek heeft in de afgelopen jaren regelmatig onderzoek gedaan naar mogelijke alternatieven voor antimicrobiële voerbespaarders in vleeskuikenvoer. In vier proeven zijn diverse mogelijke alternatieven onderzocht. Geen van die middelen bood echter een goed alternatief als vervanger van de nog toegelaten AMGB's. In de tussentijd is de industrie doorgegaan met het zoeken naar en het ontwikkelen van mogelijke andere alternatieven. Aangezien het gebruik van AMGB's per 1 januari 2006 wordt verboden, wil de sector graag weten hoe de stand van zaken is met betrekking tot de vraag: Zijn AMGB's te vervangen? Het Praktijkonderzoek heeft in opdracht van het Productschap voor Pluimvee en Eieren (PPE) verder onderzoek gedaan naar alternatieven voor antimicrobiële voerbespaarders in vleeskuikenvoer. In dit onderzoek zijn de twee meest perspectiefvolle alternatieven uit een pilotstudie onder semi-praktijkomstandigheden onderzocht en vergeleken met een voer met AMGB (positieve controle) en een voer zonder AMGB (negatieve controle). De twee onderzochte alternatieven waren Enteroguard® en AviMos™. Avilamycine werd bij de positieve controle toegevoegd als AMGB. Het weglaten van AMGB's in vleeskuikenvoer leidde in dit onderzoek tot een lager eindgewicht op 40 dagen leeftijd. Op 40 dagen leeftijd waren de dieren uit de negatieve controle 30 g (1,3 %) lichter dan de dieren uit de positieve controle. Dit is vooral veroorzaakt in de eindfase. De verminderde groei in de eindfase kon niet worden gecompenseerd door toevoeging van de twee alternatieven. Er was geen verschil in uitval tussen de vier proefgroepen
    Effect van gekleurde verlichting op technische resultaten en welzijn bij vleeskuikens
    Rodenburg, T.B. ; Harn, J. van; Middelkoop, J.H. van - \ 2004
    Lelystad : Animal Sciences Group (PraktijkRapport / Praktijkonderzoek Veehouderij : Pluimvee ) - 13
    vleeskuikens - pluimvee - kunstlicht - kunstmatige verlichting - kleur - mestresultaten - dierenwelzijn - broilers - poultry - artificial light - artificial lighting - colour - fattening performance - animal welfare
    In vleeskuikenstallen kiest men naast TL of gloeilampen tegenwoordig vaak voor gekleurd licht. Er zijn aanwijzingen in de literatuur dat gekleurd licht kan leiden tot betere technische resultaten. De kleur van het licht heeft ook invloed op de activiteit van de dieren en de verdeling van de dieren over de stal. Dit heeft weer invloed op het al dan niet ontstaan van loopproblemen en bevuiling en verwonding van de dieren en daarmee op het welzijn. Gezien de toenemende interesse voor gekleurd licht heeft het Praktijkonderzoek in opdracht van het Productschap Pluimvee en Eieren (PPE) onderzoek verricht naar het effect van gekleurde verlichting op technische resultaten en welzijn van vleeskuikens
    Effect van stikstofaanvoernormen 2003 op technische resultaten en N-excretie bij vleesvarkens
    Krimpen, M.M. van; Bussel-van Lierop, A.H.A.A.M. van; Binnendijk, G.P. - \ 2004
    onbekend : Praktijkonderzoek Veehouderij (PV) (PraktijkRapport / Animal Sciences Group, Praktijkonderzoek : Varkens ) - 18
    varkens - slachtdieren - varkenshouderij - stikstof - reductie - excretie - voer - varkensvoeding - chemische samenstelling - mestresultaten - pigs - meat animals - pig farming - nitrogen - reduction - excretion - feeds - pig feeding - chemical composition - fattening performance
    In het kader van de Europese Nitraatrichtlijn moet de stikstofuitscheiding verder teruggedrongen worden. In 2003 bedraagt de forfaitaire stikstofuitscheidingsnorm 11,7 kg stikstof per vleesvarken per jaar; 1,7 kg lager dan de norm voor 2000. Een van de wegen om de stikstofuitscheiding in de vleesvarkenshouderij verder te verminderen is verlaging van het ruweiwitgehalte (een maat voor het stikstofgehalte) in de voeders van vleesvarkens. Stikstof is echter een belangrijke bouwsteen voor de vorming van vlees en verlaging ervan in het voer kan de dierprestaties verminderen. In opdracht van de Productschappen Vee, Vlees en Eieren heeft Praktijkonderzoek onderzocht of deze lagere norm voor stikstofuitscheiding haalbaar was zonder negatieve effecten op de technische resultaten, slachtkwaliteit, gezondheid, en economische resultaten van vleesvarkens. In het onderzoek dat is uitgevoerd op Praktijkcentrum Sterksel, hebben we vier proefbehandelingen met elkaar vergeleken. Er was een proefgroep met gangbare ruweiwitgehalten in het startvoer en het eindvoer. Bij de overige drie proefgroepen werd het ruweiwitgehalte verlaagd in het startvoer (behandeling 2), of in het eindvoer (behandeling 3) of in beide voeders (behandeling 4). Het ruweiwitgehalte in het gangbare startvoer was berekend op 180 g/kg en in het aangepaste startvoer op 165 g/kg. In het eindvoer was ook een verlaging van 15 gram beoogd (van 165 g/kg naar 150 g/kg). De daadwerkelijk gerealiseerde verlaging van het ruw eiwitgehalte bleek echter 10 en 12 g/kg te zijn in respectievelijk het start- en het eindvoer. Door toevoeging van synthetische aminozuren is er voor gezorgd dat de gehalten aan essentiële darmverteerbare aminozuren gelijk waren in de voeders. De proefvoeders bevatten geen antimicrobiële groeibevorderaars. Per behandeling werden 144 vleesvarkens opgelegd (576 in totaal). De dieren waren gehuisvest met acht varkens per hok.
    Dietary influences on nutrient partitioning and anatomical body composition of growing pigs; modelling and experimental approaches
    Halas, V. - \ 2004
    Wageningen University. Promotor(en): Martin Verstegen; L. Babinszky, co-promotor(en): Jan Dijkstra; Walter Gerrits. - [S.I.] : S.n. - ISBN 9789085040262 - 217
    varkens - voedingsstoffenopname (mens en dier) - lichaamssamenstelling - groeimodellen - groei - mestresultaten - voedingsstoffen - voer - varkensvoeding - diervoeding - pigs - nutrient intake - body composition - growth models - growth - fattening performance - nutrients - feeds - pig feeding - animal nutrition
    Prediction of pig performance from data on nutrient intake and animal properties makes it easier to obtain a better productivity. It provides tools to arrive at desired outputs, or to calculate required inputs. Thus it enables production to be flexible, safe and less erratic. It is to be expected that the results will give a more profitable pig production. In practice, different types of models are used, mostly by feed producers, but also in farm management programmes. Each of these existing models was designed to meet a certain objective. The classification of different types of models, and the benefits of using them, are presented in the literature overview of the thesis. After a general overview of modelling, a critical evaluation was provided on existing models. It was concluded from the literature, that a comprehensive model, which predicts the chemical composition in different parts of the body, like in lean or in the meat, does not exist. It was also concluded that mechanistic approach should be used to modelling growth. The conceptual basis of a mechanistic model was developed in accordance with basic properties of protein and lipid metabolism. Since nutrients are almost exclusively absorbed in the hydrolyzed form, simulation of use of nutrients for growth should, at least to some extent, make use of biochemical pathways. Therefore, a biological approach to simulation of anatomical body composition is pretended as it follows nutrients from ingestion through intermediary metabolism to deposition as body fat and protein, preferably in distinct tissues or tissue groups. Prediction of anatomical body composition therefore has to be based on deposition of the chemical entities.

    Therefore the scope of the present thesis was 1) to develop a mechanistic-dynamic model for growing and fattening pigs which predicts anatomical and chemical body composition at slaughter; 2) to determine which model parameters are sensitive to changes in the model; 3) to determine the model accuracy by quantitative and qualitative prediction of the model tested with independent data; 4) to complete an experiment to define fat production potential of different energy sources at low and high feeding levels, and 5) to study the effect of different energy sources at two feeding levels on the distribution of fat deposition during the fattening period.

    The thesis presents both the description and the evaluation of the growth model. It was concluded that the developed model predicts growth rate as well as chemical and anatomical body compositions of gilts in the 20-105 kg live weight range, from nutrient intake. The model represents partitioning of nutrients from feed intake through intermediary metabolism to synthesis of body protein and body fat. State variables of the model are lysine, acetyl-CoA equivalents, glucose, VFA, and fatty acids as metabolite pools, as well as protein in muscle, hide, bone and viscera and body fat as body constituent pools. It is assumed that fluxes of metabolites follow saturation kinetics depending on metabolite concentrations. Anatomical body composition is predicted from chemical body composition and accretion. Partitioning of protein, fat, water and ash into muscle, organs, hide and bone fractions are described by allometric equations, driven by rates of muscle protein and body fat deposition. Two experiments were used in the model calibration process, one with 95 growing pigs (20-45 kg) fed different ileal digestible lysine intakes at two feeding levels, and another with 100 growing and fattening pigs (20-105 kg), which received different energy intakes. Differential equations were solved numerically for a given set of initial conditions and parameter values. The integration interval used was 0.01 day, with the fourth-order fixed-step-length Runge-Kutta algorithm. The muscle protein and body fat deposition rates were considered in different weight ranges and for the whole fattening period. Results presented were not sensitive to small changes in initial conditions, or to smaller integration step sizes.

    In the model evaluation the predicted response of the pigs to changes in model parameters, and to changes in nutrient intakes, are shown. As a result of the sensitivity analysis, the model was responsive to changes in a number of the model parameters examined. Changes in maintenance energy requirements, and the fractional degradation rate of muscle protein, have the largest impact on tissue deposition rates. The model is highly sensitive to changes in the maximal velocity and steepness parameter of lysine utilisation for muscle protein synthesis. Those parameters which directly affect the size of the lysine pool generally have a considerable influence on model predictions. Furthermore, it should be noted that results of this sensitivity analysis depend on nutrient intakes of the reference simulation. The model was relatively insensitive to changes of parameters regarding energy metabolism. It was concluded that the probable reason was that protein and/or lysine was more limiting within the simulated conditions. The model was further tested by independent published data. In general, the model satisfactorily predicted qualitative pig responses to a wide range of variations in nutrient supply. The predicted chemical and anatomical body composition, and also the distribution of protein and fat, were satisfactory in model testing. In most cases, errors in the predicted parameters attributed to the deviation of the regression slope were minor. It was assumed that the major factors contributing to the relatively large bias, observed for most predicted growth characteristics, was variation in pig performance among genotypes, or differences in environmental conditions. Based on the comparison of model simulations with independent data sets, it was recommended to improve the model regarding prediction of protein and fat deposition rates from nutrient intake of different energy sources.

    It was found that literature data on the effect of different energy sources on fat deposition was limited. In non-protein energy fraction of the diet, dietary lipids, starch and rapidly fermentable non-starch polysaccharides (NSP) are major energy sources. Lipids are absorbed as long-chain fatty acids and starch as glucose. Dietary NSP is fermented and the short-chain fatty acids produced enter intermediary metabolism as an energy source. Equal intakes of energy from glucose, long-chain fatty acids and short-chains fatty acids might result in different fat deposition rates, and quite likely, result in different distributions of body fat over the tissues. There is, however, little quantitative data available on effects of energy source on partitioning of body lipids. Therefore a fattening trial was completed to: 1) study the effect of extra energy intake from fermentable NSP, digestible starch and digestible fat used for fat deposition under protein limiting conditions; 2) determine the location of the fat deposition resulting from extra intake fermentable NSP, digestible starch and digestible fat; 3) determine if the extra fat deposition from different energy sources depends on the level of feed intake, and 4) quantify potential interactions between feed intake level and energy source on the location of extra body fat deposition.

    A total of 58 hybrid individually housed pigs were used in the trial with an initial body weight of 48±4 kg. The experimental treatments were arranged in a 3x2 factorial design, with three energy sources (i.e. fermentable NSP, digestible starch and digestible fat, all added to a control diet) at each of two energy levels. Within each energy level, daily nutrient intakes were the same with regard to digestible protein, ileal digestible lysine and other amino acids, vitamins and minerals. Treatments had an isocaloric proportion of daily nutrient intake derived from each energy source (0.2 MJ DE/kg 0.75 ), in addition to the nutrients from control diet. It was equal with 11 g/kg 0.75 highly fermentable NSP, 11 g/kg 0.75 starch or 5 g/kg 0.75 digestible fat daily. The DE intakes were 2.0 and 3.0 maintenance requirement in control groups. The additional energy from different sources increased DE intake up to 2.4 and 3.4 times maintenance requirement at low and high feeding levels, respectively. To obtain initial values, ten pigs were slaughtered at 48±4 kg and the treatment pigs at 106±3 kg body weight. Each body was dissected into four fractions being: 1) lean, 2) organs, 3) hide and subcutaneous fat, and 4) offal. Chemical body composition was determined in each body fraction. The differences between fat deposition of body parts in the control group, and the other treatments, resulted in the additional energy derived from each energy source. As a conclusion from the study, under protein limiting conditions, extra energy intake from fermentable NSP, digestible starch and digestible fat resulted in similar fat deposition. Preferential deposition of extra energy intake in various fat depots did not depend on the energy source. The extra fat deposition from fermentable NSP, digestible starch and digestible fat deposited as body fat was similar at both the low and high levels of feed intake.

    In the General Discussion, some consequences of the mechanistic approach were discussed and then substantial attention was devoted to the practical aspects of the model. The later part of the General Discussion focuses on representation of different energy sources as an aspect of the model. The energetic efficiency of the different dietary energy sources is discussed, based on data from Chapter 6. The growth model is further evaluated by results of the fattening study. Moreover, data from the fattening study are analysed regarding the distribution of fat deposition. Consequences of the fattening study on the model is discussed regarding the effect of energy sources on energetic efficiency, and on location of fat deposition in the pig. Finally, a new application of the present model is introduced in addition to development of feeding strategies and identifying research priorities.
    Na het seksen mesten? : onderzoek met haantjes van legrassen
    Middelkoop, J.H. van; Harn, J. van; Wiers, W.J. - \ 2003
    De Pluimveehouderij 33 (2003)6. - ISSN 0166-8250 - p. 10 - 11.
    kuikenproductie - geslachtsbepaling - hanen - afmesten - voedering - marketing - mestresultaten - voederconversie - vleesopbrengst - productiekosten - chick production - sex determination - cocks - finishing - feeding - marketing - fattening performance - feed conversion - meat yield - production costs
    Bij het mesten van haantjes van legrassen is er niet alleen het probleem van het vinden van een afzetmarkt die dit economisch haalbaar maakt, maar er is ook het probleem van de pikkerij.
    Lammeren uitscharen: 4 euro tot 15 euro lagere voerkosten
    Verkaik, J.C. - \ 2003
    Praktijkkompas. Rundvee 17 (2003)3. - ISSN 1570-8586 - p. 24 - 25.
    schapenhouderij - lammeren - lammerenvoeding - schapenvoeding - voer - voersamenstelling - voedingsrantsoenen - bijvoeding - aanvullend voer - krachtvoeding - begrazing - afmesten - mestresultaten - prestatieniveau - kosten - agrarische bedrijfsvoering - sheep farming - lambs - lamb feeding - sheep feeding - feeds - feed formulation - feed rations - supplementary feeding - supplementary feeds - force feeding - grazing - finishing - fattening performance - performance - costs - farm management
    Lammeren op het juiste moment afleveren vereist inzicht in voerstrategieën. Het PV constateert dat het weidend afmesten zonder krachtvoer economisch het meest aantrekkelijk is. Vermijd afleververtragingen door managementfouten. Eén week te laat ontwormen betekent vaak een maand later afleveren!
    Sturen op karkaskwaliteit in biologische 'mini'keten
    Enting, I. - \ 2003
    Praktijkkompas. Varkens 17 (2003)3. - ISSN 1570-8578 - p. 23 - 23.
    varkenshouderij - varkens - slachtdieren - biologische landbouw - karkaskwaliteit - karkassamenstelling - mestresultaten - prestatieniveau - prestatie-onderzoek - landbouwkundig onderzoek - dierveredeling - varkensvoeding - ketenmanagement - varkensfokkerij - pig farming - pigs - meat animals - organic farming - carcass quality - carcass composition - fattening performance - performance - performance testing - agricultural research - animal breeding - pig feeding - supply chain management - pig breeding
    Het ideale biologische vleesvarken heeft, net als het gangbare varken, een geslacht gewicht van minimaal 90 kg en een magervleespercentage van minimaal 55 %. Op het Praktijkcentrum voor de biologische varkenshouderij in Raalte onderzoeken we de invloed van de keuze van de eindbeer en de kracht- en ruwvoeropname op de vlees/vet-verhouding in het karkas van biologische varkens
    Bij rustige boer houden varkens energie over
    Mheen, H. van der; Spoolder, H.A.M. - \ 2003
    Praktijkkompas. Varkens 17 (2003)3. - ISSN 1570-8578 - p. 4 - 5.
    varkenshouderij - varkens - dierenwelzijn - agrarische bedrijfsvoering - gedrag - abnormaal gedrag - houding van boeren - prestatieniveau - mestresultaten - karkasgewicht - karkassamenstelling - groei - pig farming - pigs - animal welfare - farm management - behaviour - abnormal behaviour - farmers' attitudes - performance - fattening performance - carcass weight - carcass composition - growth
    Varkenshouders gaan dagelijks met hun dieren om. De manier waarop ze dit doen verschilt. De vraag is of dit iets uitmaakt. Veel mensen zijn van mening dat de manier van omgang wel degelijk een invloed heeft.
    Klein effect van groter oppervlak
    Vermeij, I. ; Enting, I. ; Hoofs, A. - \ 2002
    Praktijkkompas. Varkens 16 (2002)4. - ISSN 1570-8578 - p. 16 - 17.
    varkenshouderij - varkens - afmesten - huisvesting, dieren - vloerruimte - bezettingsdichtheid - prestatieniveau - mestresultaten - voederconversie - groei - kosten - kosten-batenanalyse - bedrijfsresultaten in de landbouw - agrarische bedrijfsvoering - groeisnelheid (slachtvee) - groepsgrootte - pig farming - pigs - finishing - animal housing - floor space - stocking density - performance - fattening performance - feed conversion - growth - costs - cost benefit analysis - farm results - farm management - liveweight gain - group size
    Onderzoek op Praktijkcentrum Sterksel geeft een indicatie dat varkens iets harder groeien en een iets betere voederconversie hebben als ze 1,0 m2 krijgen, maar dit weegt niet op tegen de extra huisvestingskosten.
    Zonder AMGB en koper 30g minder groei
    Krimpen, M. van; Jongbloed, A. - \ 2002
    Praktijkkompas. Varkens 16 (2002)3. - ISSN 1570-8578 - p. 20 - 21.
    varkensvoeding - voersamenstelling - voer - diervoedering - voedertoevoegingen - groeibevorderaars - antibiotica - toevoegingen - koper - biggen - varkens - afmesten - mestresultaten - voederconversie - prestatieniveau - groei - voeropname - rentabiliteit - rendement - kosten-batenanalyse - bedrijfsresultaten in de landbouw - pig feeding - feed formulation - feeds - animal feeding - feed additives - growth promoters - antibiotics - additives - copper - piglets - pigs - finishing - fattening performance - feed conversion - performance - growth - feed intake - profitability - returns - cost benefit analysis - farm results
    Ondanks een hoge gezondheidsstatus blijkt dat gelijktijdig weglaten van AMGB's en verlaging van het kopergehalte in varkensvoer leidt tot verminderde dierprestaties van biggen en vleesvarkens. Het weglaten kost 30 gram groei per dier per dag in zowel de opfokperiode als de vleesvarkensfase. Ook blijkt dat het positieve effect van groeibevorderende stoffen tijdens de opfokperiode volledig verloren gaat als daarna wordt overgeschakeld op voer zonder groeibevorderende stoffen. Het weglaten van AMGB's komt echter wel de economische resultaten ten goede. Het saldo per afgeleverd vleesvarken verbetert met 0,40 Euro wanneer de groeibevorderende stoffen tijdens het hele traject uit het voer worden weggelaten.
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