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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Cardiac and Skeletal Muscle Transcriptome Response to Heat Stress in Kenyan Chicken Ecotypes Adapted to Low and High Altitudes Reveal Differences in Thermal Tolerance and Stress Response
Srikanth, Krishnamoorthy ; Kumar, Himansu ; Park, Woncheoul ; Byun, Mijeong ; Lim, Dajeong ; Kemp, Steve ; Pas, Marinus F.W. te; Kim, Jun Mo ; Park, Jong Eun - \ 2019
Frontiers in Genetics Livestock Genomics 10 (2019). - ISSN 1664-8021
heat stress - hub genes - MAPK signaling - p53 signaling - PPAR signaling - RNA-Seq

Heat stress (HS) negatively affects chicken performance. Agricultural expansion will happen in regions that experience high ambient temperatures, where fast-growing commercial chickens are vulnerable. Indigenous chickens of such regions, due to generations of exposure to environmental challenges, might have higher thermal tolerance. In this study, two indigenous chicken ecotypes, from the hot and humid Mombasa (lowland) and the colder Naivasha (highland) regions, were used to investigate the effects of acute (5 h, 35°C) and chronic (3 days of 35°C for 8 h/day) HS on the cardiac and skeletal muscle, through RNA sequencing. The rectal temperature gain and the number of differentially expressed genes (DEGs) [False Discovery Rate (FDR) < 0.05] were two times higher in the acute stage than in the chronic stage in both ecotypes, suggesting that cyclic exposure to HS can lead to adaptation. A tissue- and stage-specific difference in response to HS was observed, with peroxisome proliferator-activated-receptor (PPAR) signaling and mitogen-activate protein kinase (MAPK) signaling pathways, enriched in heart and skeletal muscle, respectively, and the p53 pathway enriched only in the acute stage in both tissues. The acute and chronic stage DEGs were integrated by a region-specific gene coexpression network (GCN), and genes with the highest number of connections (hub genes) were identified. The hub genes in the lowland network were CCNB2, Crb2, CHST9, SESN1, and NR4A3, while COMMD4, TTC32, H1F0, ACYP1, and RPS28 were the hub genes in the highland network. Pathway analysis of genes in the GCN showed that p53 and PPAR signaling pathways were enriched in both low and highland networks, while MAPK signaling and protein processing in endoplasmic reticulum were enriched only in the gene network of highland chickens. This shows that to dissipate the accumulated heat, to reduce heat induced apoptosis, and to promote DNA damage repair, the ecotypes activated or suppressed different genes, indicating the differences in thermal tolerance and HS response mechanisms between the ecotypes. This study provides information on the HS response of chickens, adapted to two different agro climatic environments, extending our understanding of the mechanisms of HS response and the effect of adaptation in counteracting HS.

Development of the ‘animal welfare’ dimension within the Greenwell sustainability assessment model. 1.: Justification of the selection of indicators
Jong, I.C. de - \ 2019
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research report 1194) - 66
The current report describes the development of the ‘animal welfare dimension’ (‘welfare assessment model’) within the overall Greenwell sustainability model. As we apply the framework of Welfare Quality®, in which animal health is considered one of the aspects of animal welfare, the model also includes health indicators. The model has been developed according to two steps: definition of long-lists of indicators for the broiler breeder, hatchery, broiler on-farm and broiler end-of-life stage, and the selection of key indicators from these long-lists, as well as whether these need to be measured real-time or can be estimated by a representative sample or literature value.
Literature update on effective environmental enrichment and light provision in broiler chickens
Souza da Silva, C. ; Jong, I.C. de - \ 2019
Wageningen : Wageningen Livestock Research (Report / Wageningen Livestock Research 1204) - 46
The results of a literature study to the effect of different types of environmental enrichment and light conditions on broiler chickens welfare are described, in order to attempt to provide an environment to slow-growing broiler chickens that better meets their behavioural requirements. With respect to environmental enrichment, a review paper has been used as a starting point and more recent information has been collected and summarised. With respect to lighting, in consultation with stakeholders we chose to limit the literature study to a fewpotential interesting areas of research (e.g. natural light provisionand its variation across the broiler house). There are several research questions in relation to enrichment provision, e.g., optimal perch design, multiple use of enrichments and the actual number of enrichments that should be provided. Currently, little is known about the need for light in slow-growing broiler chickens and how this interacts with the environmental enrichment offered. Future research priorities include theoptimization of methods of natural light provision (which is often applied in higher welfare indoor systems with slow-growing breeds), testing effects of ultraviolet wavelengths on chicken behaviour,and light colour preferences in slow-growing breeds.
Broeders mijden de publiciteit
Jong, I.C. de - \ 2019
화훼,원예농업의 선진국 네덜란드는?[목포MBC 특집다큐]
Jong, Rick de - \ 2019
Broiler welfare trade-off: A semi-quantitative welfare assessment for optimised welfare improvement based on an expert survey
Bracke, Marc B.M. ; Koene, Paul ; Estevez, Inma ; Butterworth, Andy ; Jong, Ingrid C. de - \ 2019
PLoS ONE 14 (2019)10. - ISSN 1932-6203

In order to support decision making on how to most effectively improve broiler welfare an innovative expert survey was conducted based on principles derived from semantic modelling. Twenty-seven experts, mainly broiler welfare scientists (n = 20; and 7 veterinarians), responded (response rate 38%) by giving welfare scores (GWS, scale 0–10) to 14 benchmarking housing systems (HSs), and explaining these overall scores by selecting, weighing and scoring main welfare parameters, including both input and output measures. Data exploration followed by REML (Linear Mixed Model) and ALM (Automatic Linear Modelling) analyses revealed 6 clusters of HSs, sorted from high to low welfare, i.e. mean GWS (with superscripts indicating significant differences): 1. (semi-natural backyard) Flock (8.8a); 2. Nature (7.7ab), Label Rouge II (7.4ab), Free range EU (7.2ab), Better Life (7.2ab); 3. Organic EU (7.0bc), Freedom Food (6.2bc); 4. Organic US (5.8bcd), Concepts NL (5.6abcdef), GAP 2 (4.9bcd); 5. Conventional EU (3.7de), Conventional US (2.9ef), Modern cage (2.9abcdef); 6. Battery cage (1.3f). Mean weighting factors (WF, scale 0–10) of frequently (n> = 15) scored parameters were: Lameness (8.8), Health status (8.6), Litter (8.3), Density (8.2), Air quality (8.1), Breed (8.0), Enrichment (7.0) and Outdoor (6.6). These did not differ significantly, and did not have much added value in explaining GWS. Effects of Role (Scientist/Vet), Gender (M/F) and Region (EU/non-EU) did not significantly affect GWS or WF, except that women provided higher WF than men (7.2 vs 6.4, p<0.001). The contribution of welfare components to overall welfare has been quantified in two ways: a) using the beta-coefficients of statistical regression (ALM) analyses, and b) using a semantic-modelling type (weighted average) calculation of overall scores (CalcWS) from parameter level scores (PLS) and WF. GWS and CalcWS were highly correlated (R = ~0.85). CalcWS identified Lameness, Health status, Density, Breed, Air quality and Litter as main parameters contributing to welfare. ALM showed that the main parameters which significantly explained the variance in GWS based on all PLS, were the output parameter Health status (with a beta-coefficient of 0.38), and the input parameters (stocking) Density (0.42), Litter (0.14) and Enrichment (0.27). The beta-coefficients indicated how much GWS would improve from 1 unit improvement in PLS for each parameter, thus the potential impact on GWS ranged from 1.4 welfare points for Litter to 4.2 points for Density. When all parameters were included, 81% of the variance in GWS was explained (77% for inputs alone; 39% for outputs alone). From this, it appears that experts use both input and output parameters to explain overall welfare, and that both are important. The major conventional systems and modern cages for broilers received low welfare scores (2.9–3.7), well below scores that may be considered acceptable (5.5). Also, several alternatives like GAP 2 (4.9), Concepts NL (5.6), Organic US (5.8) and Freedom Food (6.2) are unacceptable, or at risk of being unacceptable due to individual variation between experts and farms. Thus, this expert survey provides a preliminary semi-quantified decision-support tool to help determine how to most effectively improve broiler welfare in a wide range of HSs.

Inbreeding depression due to recent and ancient inbreeding in Dutch Holstein-Friesian dairy cattle
Doekes, Harmen P. ; Veerkamp, Roel F. ; Bijma, Piter ; Jong, Gerben de; Hiemstra, Sipke J. ; Windig, Jack J. - \ 2019
Genetics, Selection, Evolution 51 (2019)1. - ISSN 0999-193X - 16 p.

BACKGROUND: Inbreeding decreases animal performance (inbreeding depression), but not all inbreeding is expected to be equally harmful. Recent inbreeding is expected to be more harmful than ancient inbreeding, because selection decreases the frequency of deleterious alleles over time. Selection efficiency is increased by inbreeding, a process called purging. Our objective was to investigate effects of recent and ancient inbreeding on yield, fertility and udder health traits in Dutch Holstein-Friesian cows. METHODS: In total, 38,792 first-parity cows were included. Pedigree inbreeding ([Formula: see text]) was computed and 75 k genotype data were used to compute genomic inbreeding, among others based on regions of homozygosity (ROH) in the genome ([Formula: see text]). RESULTS: Inbreeding depression was observed, e.g. a 1% increase in [Formula: see text] was associated with a 36.3 kg (SE = 2.4) decrease in 305-day milk yield, a 0.48 day (SE = 0.15) increase in calving interval and a 0.86 unit (SE = 0.28) increase in somatic cell score for day 150 through to 400. These effects equalled - 0.45, 0.12 and 0.05% of the trait means, respectively. When [Formula: see text] was split into generation-based components, inbreeding on recent generations was more harmful than inbreeding on more distant generations for yield traits. When [Formula: see text] was split into new and ancestral components, based on whether alleles were identical-by-descent for the first time or not, new inbreeding was more harmful than ancestral inbreeding, especially for yield traits. For example, a 1% increase in new inbreeding was associated with a 2.42 kg (SE = 0.41) decrease in 305-day fat yield, compared to a 0.03 kg (SE = 0.71) increase for ancestral inbreeding. There were no clear differences between effects of long ROH (recent inbreeding) and short ROH (ancient inbreeding). CONCLUSIONS: Inbreeding depression was observed for yield, fertility and udder health traits. For yield traits and based on pedigree, inbreeding on recent generations was more harmful than inbreeding on distant generations and there was evidence of purging. Across all traits, long and short ROH contributed to inbreeding depression. In future work, inbreeding depression and purging should be assessed in more detail at the genomic level, using higher density information and genomic time series.

Substraat voorkeur voor foerageergedrag leghennen : pilotstudie
Neijenhuis, Francesca ; Wijhe-Kiezebrink, Maudia van; Jong, Ingrid de - \ 2019
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1193) - 25
The project "Health for humans and animals through system change in poultry farming" is working on alternatives to the current litter as foraging substrate, from which manure can be removed to reduce particulate matter and ammonia emissions. In a pilot study, carried out during three weeks on one commercial laying hen farm with a wintergarden and outdoor range, 10 different possible foraging substrates were offered in 6 bins. This pilot shows that diatomaceous earth, peat, shells and buckwheat hulls meet the foraging requirements of laying hens better than wood shavings, hydro pellets, bark and lava stones. But there was no significant difference in use between diatomaceous earth, peat, shells, chopped straw, or buckwheat hulls for foraging.
Effectmodules in het Deltaprogramma Zoetwater : van hydrologisch effect naareconomisch effect van droogte
Schasfoort, Femke ; Jong, Jurjen de; Meijers, Erwin ; Mulder, Martin - \ 2019
Delft : Deltares - 98
Maternale antilichamen tegen Campylobacter in eieren van verschillende merken kippen
Koene, M.G.J. ; Goot, J.A. van der; Cornelissen, J.B.W.J. ; Jong, Ingrid de; Kollenstart, Johan ; Hartog, Mark den - \ 2019
Wageningen Bioveterinary Research
Associations between carcass weight uniformity and production measures on farm and at slaughter in commercial broiler flocks
Vasdal, Guro ; Granquist, Erik Georg ; Skjerve, Eystein ; Jong, Ingrid C. de; Berg, Charlotte ; Michel, Virginie ; Moe, Randi Oppermann - \ 2019
Poultry Science 98 (2019)10. - ISSN 0032-5791 - p. 4261 - 4268.
chicken - health - indicator - poultry - welfare

In poultry flocks, flock weight uniformity is often defined as the percent individuals within 10% of the mean body weight (BW) and the variability of this uniformity can be expressed as the CV of BW. Flock weight uniformity is a standardized and objective measured, and could potentially be used as a welfare indicator; however, little is known about the relationship between flock uniformity and other production measures on-farm or at slaughter. The aim of this study was to investigate the associations between carcass weight uniformity (CV of BW) and production measures on-farm and at slaughter in Norwegian commercial broiler flocks. A total of 45 randomly selected mixed-sex Ross 308 broiler flocks were visited prior to slaughter at 28 to 30 D of age (average slaughter age 30.6 D). All flocks were raised under similar farm management systems. The Welfare Quality protocol for broilers was used to assess different animal welfare indicators in each flock. All production data from the slaughterhouse were collected for each flock, including carcass weight uniformity (%), mortality (%), growth rate (g), feed conversion ratio (FCR), and rejected birds (%) in different rejection categories. Univariable and multivariable linear regression models were used to investigate the associations between flock weight uniformity and production and welfare measures. The results showed that flock uniformity varied from 11% to 18% between flocks within the same hybrid, similar management standards, and similar slaughter age (day 29 to 32). Poorer uniformity (i.e., high CV) was associated with increased first week mortality (P < 0.004, r = 1.48, increased total mortality (P < 0.013, r = 0.01), increased FCR (i.e., less efficient growth) (P < 0.024, r = 0.06), reduced growth rate (P < 0.0012, r = -0.01), and a reduced rejection rate at slaughter (P < 0.006, r = -0.01). The results show that flock uniformity varies across broiler flocks, and is associated with several production measures.

Plukrobot leeft zich uit op muur van fruit
Jong, P.F. de - \ 2019
Promoting parenting strategies to improve tooth brushing in children: Design of a non-randomised cluster-controlled trial
Jong-Lenters, Maddelon De; Hoir, Monique L'; Polak, Erica ; Duijster, Denise - \ 2019
BMC Oral Health 19 (2019)1. - ISSN 1472-6831
Dental caries - Intervention - Parenting - Prevention - Self-efficacy - Tooth brushing

Background: Tooth brushing with fluoride toothpaste is a key recommendation in evidence-based guidelines for caries prevention. Parents generally have sufficient knowledge to practice tooth brushing for their child, yet many experience barriers to actually implement the behaviour. Common barriers are associated with difficult child behaviour, stress, poor family organisation and management of routines. These underlying determinants of tooth brushing behaviour should be addressed in caries-preventive interventions. The 'Uitblinkers' intervention is a semi-structured interview method developed for oral healthcare professionals (OHPs), with the aim to improve the practice of twice daily tooth brushing in children. The interview method focusses on 1) identifying parents' barriers to tooth brushing, and 2) promoting parenting strategies (related to tooth brushing) to tackle the identified barriers. The intervention applies principles from learning theory, including stimulus control, operant conditioning and authoritative parenting. This paper describes a study protocol to evaluate the effect of the intervention. Methods: This non-randomised cluster-controlled trial will be conducted in 40 general dental practices in The Netherlands. Intervention practices will implement the intervention in addition to care as usual, while control practices will only provide care as usual. From each dental practice, a random sample of 3 to 4-year-old children will be recruited. The intervention consists of three sessions between an OHP and parent, in which parenting strategies for identified barriers are discussed. The primary study outcome is children's dental caries experience after 24 months. Secondary outcomes include parents' self-efficacy in brushing their children's teeth, tooth brushing frequency in children and children's dental plaque scores. Differences in outcomes between the intervention and control group will be assessed using logistic and negative binomial regression. The feasibility of the intervention will be assessed through process evaluation. Discussion: Findings of this study will ascertain whether promoting parenting strategies is a successful method to improve tooth brushing in children and to prevent childhood dental caries in a clinical dental setting. Trial registration: This trial is registered with the Netherlands National Trial Register (registration date: 7 September 2018; trial registration number: NTR7469).

Virus Shedding of Avian Influenza in Poultry: A Systematic Review and Meta-Analysis
Germeraad, Evelien A. ; Sanders, Pim ; Hagenaars, Thomas J. ; Jong, Mart C.M. de; Beerens, Nancy ; Gonzales, Jose L. - \ 2019
Viruses 11 (2019)9. - ISSN 1999-4915
avian influenza - meta-analysis - poultry - systematic review - virus shedding

Understanding virus shedding patterns of avian influenza virus (AIV) in poultry is important for understanding host-pathogen interactions and developing effective control strategies. Many AIV strains were studied in challenge experiments in poultry, but no study has combined data from those studies to identify general AIV shedding patterns. These systematic review and meta-analysis were performed to summarize qualitative and quantitative information on virus shedding levels and duration for different AIV strains in experimentally infected poultry species. Methods were designed based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Four electronic databases were used to collect literature. A total of 1155 abstract were screened, with 117 studies selected for the qualitative analysis and 71 studies for the meta-analysis. A large heterogeneity in experimental methods was observed and the quantitative analysis showed that experimental variables such as species, virus origin, age, inoculation route and dose, affect virus shedding (mean, peak and duration) for highly pathogenic AIV (HPAIV), low pathogenic AIV (LPAIV) or both. In conclusion, this study highlights the need to standardize experimental procedures, it provides a comprehensive summary of the shedding patterns of AIV strains by infected poultry and identifies the variables that influence the level and duration of AIV shedding.

Possible improvement of measures within the principle ‘appropriate behaviour’ of the Welfare Quality® boiler assessment protocol
Jong, Ingrid de; Riel, Johan van; Hoevenaar, Tosca ; Niekerk, Thea van - \ 2019
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research report 1192) - 35
The aim of the current study was two-fold. First, we tested whether or not a scan sampling technique can be used as a relatively quick, simple scoring of the behaviour in commercial-size broiler chicken flocks, and could thus be included as a measure of appropriate behaviour in the Welfare Quality® broiler assessment protocol. Four existing datasets were analysed, these were collected for different purposes but were based on the same sampling technique, i.e. counting the number of broilers engaged in different behaviours using direct observations, at different time intervals and at different locations in the house. Analysis showed that various factors affected the outcome. Whereas those such as observer, time of the day and location could be taken into account when designing an observation protocol (e.g. by training, by selection of different observation locations and times), it must first be determined how to take into account the effect of subsequent scans, the apparent difference between flocks and genetic strains, and the effects of different behaviours. This is important when e.g. thresholds need to be set or scores reliably assigned regarding the prevalence of birds showing certain behaviours during a farm visit. Second, it was tested whether alternative measures (rather than distance to observer or a novel object) could be used as indicators of fear in broiler chickens. Previous research suggested a possible relationship between walking ability and the number of birds within arm’s reach in the touch test, thus implying that the touch test may be confounded by impaired walking ability and might thus be a suboptimal method of assessing fear of humans in broilers. The present study was carried out at an experimental farm and reported in detail in a student thesis. An extended summary is included in this report. The results showed that both distance to observer or novel object and behaviour of the bird (alert body posture, neck posture, body position towards object or observer) seemed to be valid indicators of fear, however, when a relatively short time is available for testing, the birds’ behaviour should always be measured as older broilers need more time to move away.
Een schoolplein mag niet op een parkeerplaats lijken
Vries, Sjerp de; Goossen, Martin - \ 2019
Preparing for Virus X
Kortekaas, J.A. ; Poel, W.H.M. van der; Jong, M.C.M. de - \ 2019
Hydrographic and Biological Survey of a Surface-Intensified Anticyclonic Eddy in the Caribbean Sea
Boog, C.G. van der; Jong, M.F. de; Scheidat, M. ; Leopold, M.F. ; Geelhoed, S.C.V. ; Schulz, K. ; Dijkstra, H.A. ; Pietrzak, J.D. ; Katsman, C.A. - \ 2019
Journal of Geophysical Research: Oceans 124 (2019)8. - ISSN 2169-9275 - p. 6235 - 6251.
anticyclone - barrier layer - Caribbean Sea - ecology - hydrographic - thermohaline staircases

In the Caribbean Sea, mesoscale anticyclonic ocean eddies impact the local ecosystem by mixing of low salinity river outflow with the nutrient-rich waters upwelling along the Venezuelan and Colombian coast. To gain insight into the physics and the ecological impact of these anticyclones, we performed a combined hydrographic and biological survey of one Caribbean anticyclone in February 2018. We found that the anticyclone had a radius of 90 km and was surface intensified with the strongest velocities (0.72 m/s) in the upper 150 m of the water column. Below, isopycnal displacements were found down to 700 dbar. The core of the anticyclone entrained waters from the Orinoco River plume and contained slightly elevated chlorophyll concentrations compared to the surroundings. At the edge of the anticyclone we observed higher densities of flying fish but not higher densities of predators like seabirds and cetaceans. Below the surface, a strong temperature inversion (0.98 °C) was present within a barrier layer. In addition, we found thermohaline staircases that originated from double diffusion processes within Tropical Atlantic Central Water.

Quantifying transmission of Mycobacterium avium subsp. paratuberculosis among group-housed dairy calves
Corbett, Caroline S. ; Jong, Mart C.M. De; Orsel, Karin ; Buck, Jeroen De; Barkema, Herman W. - \ 2019
Veterinary Research 50 (2019)1. - ISSN 0928-4249

Johne's disease (JD) is a chronic enteritis caused by Mycobacterium avium subsp. paratuberculosis (MAP), with control primarily aimed at preventing new infections among calves. The aim of the current study was to quantify calf-to-calf transmission of MAP among penmates in an experimental trial. Newborn Holstein bull calves (n = 32) were allocated into pens of 4, with 2 inoculated (IN) calves and 2 calves that were contact exposed (CE). Calves were group-housed for 3 months, with frequent collection of fecal and blood samples and tissue collection after euthanasia. The basic reproduction ratio (R0) was estimated using a final size (FS) model with a susceptible-infected model, based on INF-γELISA and tissue culture followed by qPCR. In addition, the transmission rate parameter (β) for new shedding events was estimated using a general linearized method (GLM) model with a susceptible-infected-susceptible model based on culture, followed by qPCR, of fecal samples collected during group housing. The R0 was derived for IN and CE calves separately, due to a difference in susceptibility, as well as differences in duration of shedding events. Based on the FS model, interferon-γresults from blood samples resulted in a R 0 IG of 0.90 (0.24, 2.59) and tissue culture resulted in a R 0 T of 1.36 (0.45, 3.94). Based on the GLM model, the R0 for CE calves to begin shedding (R 0 CE) was 3.24 (1.14, 7.41). We concluded that transmission of MAP infection between penmates occurred and that transmission among calves may be an important cause of persistent MAP infection on dairy farms that is currently uncontrolled for in current JD control programs.

Global prospects of the cost-efficiency of broiler welfare in middle-segment production systems
Vissers, Luuk S.M. ; Jong, Ingrid C. de; Horne, Peter L.M. van; Saatkamp, Helmut W. - \ 2019
Animals 9 (2019)7. - ISSN 2076-2615
Animal welfare - Broiler production - Cost-efficiency

In the 2000s, the idea of a so-called middle-segment arose in North-West Europe to address the criticism on intensive broiler production systems. Middle-segment systems being indoor housing of slower-growing broiler strains at a stocking density ≤38 kg/m2. Previous literature showed that Dutch middle-segment systems entail a relatively large gain in animal welfare at a relatively low increase in costs, i.e., have a high cost-efficiency. The question is to what extent these findings are applicable to other countries. Therefore, the aim of this study is to gain insight in the global prospects of middle-segment systems by exploring the cost-efficiency of these systems in other parts of the world. A set of representative countries, containing the Netherlands, United States and Brazil were selected. Cost-efficiency was defined as the ratio of the change in the level of animal welfare and the change in production costs. The level of animal welfare was measured by the Welfare Quality (WQ) index score. Data was collected from literature and consulting experts. Results show that in the Netherlands, United States and Brazil a change from conventional towards a middle-segment system improves animal welfare in a cost-efficient manner (the Netherlands 9.1, United States 24.2 and Brazil 12.1). Overall, it can be concluded that in general middle-segment production systems provide a considerable increase in animal welfare at a relatively small increase in production costs and therefore offer good prospects for a cost-efficient improvement of broiler welfare.

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