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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    What do animal want?
    Bokkers, E.A.M. - \ 2020
    Three ASG colleagues, including Eddie Bokkers en Bas Rodenburg, will give a pitch on what they think animals want, and where they see opportunities to enrich the societal debate with scientific knowledge.
    With you, we want to explore these questions further. What do answers to these questions tell us about the relation between science and societal concerns when it comes to sustainable and responsible treatment of animals? How should we as scientists engage with these societal questions? What does that require in terms of our research and communication? And what role can society play to support the scientific understanding of animals?
    What do animals want?
    Bokkers, E.A.M. - \ 2020
    Op donderdag 10 december 15: 30-17: 00 uur organiseert het Centre for Sustainable Animal Stewardship (CenSAS: een samenwerking tussen de Faculteit Diergeneeskunde van de Universiteit Utrecht en de WUR Animal Sciences Group) een Teamsmeeting voor alle collega's binnen ASG die mee willen praten en denken over verantwoord omgaan met dieren.

    Drie ASG collega's - onder wie Eddie Bokkers en Bas Rodenburg - geven een pitch over wat zij denken dat dieren willen, en waar zij kansen zien om het maatschappelijke debat te verrijken met wetenschappelijke kennis.

    Samen met jou willen we deze vragen verder onderzoeken. Wat vertellen antwoorden op deze vragen ons over de relatie tussen wetenschap en maatschappelijke zorgen als het gaat om duurzame en verantwoorde omgang met dieren? Hoe moeten we als wetenschappers omgaan met deze maatschappelijke vragen? Wat betekent het voor ons onderzoek en onze communicatie? En welke rol kan de samenleving spelen om de wetenschappelijke kennis over dieren uit te bouwen?
    Influence of the punisher on the feasibility and sensitivity of a Judgment Bias Task for cattle
    Kremer, L.A.M. ; Webb, L.E. ; Bokkers, Eddy ; Werf, J.T.N. van der; Engel, B. ; Schnabel, S.K. ; Reenen, C.G. van - \ 2020
    In: ISAE Benelux meeting 2020. - International Society for Applied Ethology (ISAE) - p. 7 - 7.
    Affect influences decision-making: individuals experiencing positive affect interpret ambiguous situations more positively than individuals experiencing negative affect. In animals, decision-making under ambiguity, hence affect, is assessed using judgment bias tasks (JBTs). Since JBT has not yet been designed for cows, we aimed to develop a feasible and sensitive task for cows. Cows were allocated to one of three punishers: “no-reward” (NOTH, n=12), an air puff (AIR, n=12), or an electric shock (ELEC, n=12). Cows were trained to discriminate a positive (P) from a negative (N) cue based on feeder location. Cows learnt to reach (P) within 20s to get concentrates and to not reach (N) during 90s to avoid punisher. Percentage of correct responses to (N) was used to assess JBT feasibility. Data were analyzed using GLMM including the fixed effects of batch and punisher. Cows then faced three ambiguous cues placed between (P) and (N). Latencies to reach these cues were recorded. In a sensitive test, a linear relationship is expected between latencies and distance of the cues from (P) – i.e. latencies decrease when cues are closer to (P). Area between the theoretical line and the experimental profile of responses obtained for each punisher was calculated to assess JBT sensitivity. Data were analyzed using Wilcoxon tests. Percentage of correct responses to (N) was lower for NOTH- compared with AIR- (p=0.032) and ELECcows (p<0.001) (46 ± 4.7%, 66 ± 7.0% and 84.6 ± 2.1%, respectively) during training. Thus, “no-reward” is a less suitable punisher for a feasible JBT since NOTH-cows kept responding to (N). Area between the theoretical and the experimental profiles of responses was smaller for trained AIR-cows than trained ELEC-cows (p<0.001, -0.20 ± 0.186, 0.96 ± 0.140, respectively) indicating that air puff led to a more sensitive test. We therefore advise using air puff as a punisher in JBTs for cows.
    The effects of manual and automated milk feeding methods on group-housed calf health, behaviour, growth and labour
    Sinnott, Alison M. ; Kennedy, Emer ; Bokkers, Eddie A.M. - \ 2020
    Livestock Science (2020). - ISSN 1871-1413
    Automation - Calf - Feeding Systems - Health - Labour - Welfare

    It has been suggested that the integration of automatic feeding systems into calf rearing programmes has the potential to improve calf behaviour, growth and the associated labour. Thus, the objective of this study was to compare the effects of automatic and manual feeding systems on calf health, behaviour, growth and labour. A population of 60 dairy heifer calves was used: 44 Holstein-Friesian (HF) and 16 HF x Jersey (JE), balanced for birth weight (33 ± 4.1 kg), birth date (26 January ± 3.2 days) and breed. The experiment was a randomised block design including two treatments; i) automated calf feeding system (AFS) and ii) manual calf feeding system (MFS). Each treatment was replicated once, so a total of four balanced groups of 15 heifer calves were created. Milk replacer was offered at a rate of 6 L per calf/day (reconstitution rate 15%), with fresh water, ad-libitum concentrates and hay offered from three days old. Calves were weaned based on weight (90 kg for HF and 85 kg for HF x JE). Total labour input/day was consistently less for AFS compared to MFS (-00:01:06 per calf/day). Automatic feeding systems had a higher labour requirement for health inspections and training to the system (+00:00:15 per calf/day and +00:02:06 per calf/day, respectively), on a per calf basis, compared to MFS. The MFS-calves had an increased likelihood of experiencing faecal scores > 0 (Odds Ratio (OR) = 2.009; Confidence Interval (CI) = 1.463 – 2.759). The MFS-calves were also more likely to defecate and urinate (OR= 1.450; CI = 1.080-1.945), eat (OR= 1.281; CI = 1.140 – 1.439) and socially interact (OR= 1.300; CI = 1.111 – 1.521), compared to standing. There was no difference in number of days from birth to weaning (80.8 days) and weight at weaning (92.9 kg); average daily gain in both the pre (81 days) and post weaning (79 days) periods was similar between the two treatments (0.74 and 0.70 kg/day, respectively). Patterns for behaviours such as lying and playing were similar and low levels of abnormal behaviours were found in both treatments. Calves in both treatments exhibited good health and normal behavioural patterns as well as similar growth rates. Thus, when managed appropriately, the saving of labour is a distinct advantage automated feeding systems have over their manual counterparts when rearing group-housed calves.

    Provisioning of live black soldier fly larvae (Hermetia illucens) benefits broiler activity and leg health in a frequency- and dose-dependent manner
    Ipema, Allyson ; Gerrits, W.J.J. ; Bokkers, Eddie ; Kemp, B. ; Bolhuis, J.E. - \ 2020
    Applied Animal Behaviour Science 230 (2020). - ISSN 0168-1591
    Fast-growing broilers spend most their time inactive and are therefore prone to experience leg problems. Environmental enrichment which facilitates intrinsically motivated behaviour scan potentially promote activity and reduce leg problems, thereby improving broiler welfare. A promising environmental enrichment method is the scattering of desired feed items, such as insects which are highly attractive to broilers. We studied the effect of providing live black soldier fly larvae (BSFL) scattered on the litter on broiler behaviour, leg health and performance. One-day-old male broilers were assigned to one of five treatments(eight pens/treatment, nine broilers/pen): a control without BSFL and four treatments with BSFL in different amounts (5% or 10% of estimated dietary dry matter intake; A5 andA10 respectively) and frequencies (two or four times a day; F2 and F4 respectively). All broilers were fed diets formulated to ensure a similar energy and nutrient intake. Broiler weight and leg health were determined on day 42. The behavioural time budget was determined weekly by observations for 7 h per day using 12-min scan sampling, and activity around larval provisioning was determined by 3-min scan sampling from 9 min before, until 30 min after larval provisioning on day 15/16, 29/30 and 40/41. Broilers in all larval provisioning treatments had a different behavioural time budget than controls, with higher levels of foraging behaviour, walking, standing idle and general activity during at least three of the five observation days (p<0.05 compared to controls). Generally, active behaviours were most profoundly increased in A10F4 broilers. Time spent active and in standing posturedeclined from week 4 onwards in A10F4, whereas for all other treatments this decline occurred already in week 2. Activity during 30 minutes after larval provisioning was higher for A10 than A5 treatments (p<0.05 for all days) but overall not affected by frequency of larval provisioning. Hock burn occurred less in A10 birds than in controls (p<0.05), and lameness occurred less in A10 and A5F4 birds than in controls (p<0.01). Only A10F2 birds had a lower final weight than controls (p<0.05). In conclusion, the largest amount combined with the highest frequency of larval provisioning applied in this study resulted in a prolonged increase in activity and better leg health, without significantly affecting broiler performance.
    KDV start onderzoek naar licht in varkensstal
    Boumans, Iris ; Bokkers, E.A.M. - \ 2020

    De Keten Duurzaam Varkensvlees (KDV) start een onderzoeksproject naar de effecten van lichtintensiteit en lichtkleur op varkens.

    Rol van licht fundamenteel belicht
    Bokkers, E.A.M. - \ 2020

    Licht heeft een grote invloed op het gedrag, de gezondheid, de groei en dus het welzijn van varkens. Toonaangevende bedrijven en instituten gaan samen een duurzaam en innovatief lichtconcept voor de varkenshouderij ontwikkelen. Leider van het project 'Enlighted Pigs' is Eddie Bokkers van de groep Dierlijke Productiesystemen van Wageningen University & Research.

    De Hoeve en Westfort starten project 'Verlichte varkens'
    Bokkers, E.A.M. ; Boumans, Iris - \ 2020

    Varkenshouderijbedrijf De Hoeve en slachterij Westfort zijn onlangs het project 'Verlichte varkens' gestart. Bij het project wordt licht geïntegreerd in een diervriendelijke, duurzame veehouderij zoals de Keten Duurzaam Varkensvlees (KDV) die voorstaat.

    Feeding patterns as real-time indicator of growing-finishing pig welfare
    Bus, J.D. ; Boumans, I.J.M.M. ; Webb, L.E. ; Bokkers, Eddy - \ 2020
    In: ISAE Benelux meeting 2020: Elevating animal Lives: Virtual conference. - International Society for Applied Ethology (ISAE) - p. 6 - 6.
    Feeding patterns, encompassing feed intake, feeding frequency, duration and rate, may show rapid and extensive deviation from basal levels during welfare challenges. As feeding patterns can be continuously recorded by electronic feeding stations, they may serve as feasible, real-time indicators of welfare. We systematically reviewed the literature on the relation between feeding patterns and growing-finishing pig welfare, covering both negative states, i.e. health and behavioural issues, and positive states. Studies on health issues have focused on the impact of clinical disease and thermal stress on feed intake, while other health issues and the behaviours underlying intake have received less attention (e.g. subclinical disease & skin lesions, feeding frequency & duration). Moreover, feeding patterns are commonly reported at group level and with a daily time step, despite extensive variation in feeding behaviour between pigs and across the day, suggesting that some individual- or time-specific impacts on feeding patterns may have been overlooked. Regarding behavioural issues, tail biting alters feeding frequency during the weeks preceding an outbreak, but may not alter feeding patterns once the outbreak has commenced. Feed competition strongly alters feeding patterns of both dominant and subordinate pigs, but it is unclear which changes reflect appropriate adaptation to the social environment and which indicate severe social stress. Few studies have considered feeding patterns and positive states concomitantly. Feed intake differences have been reported between pigs housed in barren or enriched environments, but studies using animal-based indicators of positive states, such as play or tail posture, are currently absent. We conclude that feeding patterns are promising indicators of real-time pig welfare, especially if several feeding behaviours are included, with short time steps (e.g. hourly) at the level of the individual pig. We propose that negative states may induce deviations from basal patterns, while positive states may be characterised by stable patterns.
    Long-term access to live black soldier fly larvae (Hermetia illucens) stimulates activity and reduces fearfulness of broilers, without affecting health
    Ipema, Allyson F. ; Bokkers, Eddie A.M. ; Gerrits, Walter J.J. ; Kemp, Bas ; Bolhuis, Liesbeth - \ 2020
    Scientific Reports 10 (2020)1. - ISSN 2045-2322

    Commercially housed broilers frequently experience limited environmental stimulation and various health issues, compromising their welfare. Providing environmental enrichment can alleviate these problems by facilitating natural behaviour and activity. We investigated the effect of providing live black soldier fly larvae (BSFL) to broilers housed at commercial densities (33 kg/m2) on behaviour, fearfulness, health and performance. One-day-old broilers were distributed over five treatments with eight pens/treatment: a control treatment without BSFL; two treatments where 5% of the daily nutrient intake was replaced with live BSFL, provided four or seven times a day; and two treatments where 10% of the daily dietary intake was replaced with live BSFL provided four times a day or in transparent, movable tubes with holes. In all BSFL treatments foraging behaviour, and thereby broiler activity, was increased. Prolonged access to live BSFL, either by providing larvae seven times a day or in tubes, caused the largest increase in activity while also decreasing the time spend in tonic immobility, indicating reduced fearfulness. Broiler final weight and health were not affected. Overall, long-term access to live BSFL seems most effective in improving broiler welfare by facilitating natural behaviour and reducing fearfulness, without hindering broiler performance and health.

    Effect of cow-calf contact on cow motivation to reunite with their calf
    Wenker, Margret L. ; Bokkers, Eddie A.M. ; Lecorps, Benjamin ; Keyserlingk, Marina A.G. von; Reenen, Cornelis G. van; Verwer, Cynthia M. ; Weary, Daniel M. - \ 2020
    Scientific Reports 10 (2020)1. - ISSN 2045-2322

    Early cow-calf separation prevents much of cows’ natural maternal behaviour. Early separation is thought to prevent the development of a cow-calf bond. To assess this bond, we measured motivation of dairy cows to reunite with their calf. To vary the degree of bonding, some cows were allowed continued contact with their calf and others were separated from their calf soon after birth, following standard practice on most farms. Among cows allowed continued contact, some were able to suckle their calf and others were prevented from suckling (by covering the cow’s udder with an udder net). Cows were habituated to the weighted-gate apparatus before calving by daily training with the (un-weighted) gate. After calving, cow willingness to use the gate was assessed by determining if she would push open the gate to access to her own calf. Testing occurred once daily, with weight on the gate gradually increased. After passing through the gate, the dam’s calf-directed behaviour was recorded. Suckled cows pushed a greater maximum weight (45.8 ± 7.8 kg) than separated cows (21.6 ± 6.7 kg) and non-suckled cows (24.3 ± 4.5 kg), with no differences between separated and non-suckled cows. Once reunited, latency to make nose contact and duration of licking did not differ between treatments. We conclude that motivation for calf contact is greater for cows that are suckled.

    Herders and livestock professionals' experiences and perceptions on developments and challenges in yak farming in Bhutan
    Dorji, Nedup ; Derks, Marjolein ; Dorji, Phub ; Groot Koerkamp, Peter W.G. ; Bokkers, Eddie A.M. - \ 2020
    Animal Production Science 60 (2020)17. - ISSN 1836-0939 - p. 2004 - 2020.
    policy - welfare

    Context: The yak-based transhumant system is influenced by socioeconomic developments, regulations and environmental changes. Little is known about the impact of this on yak farming practices among different regions in Bhutan. Aim and methods: The experienced changes in yak farming practices over the years and perceptions on developments were assessed through interviews with yak herders in three regions (west, n = 22; central, n = 20; east, n = 25) and with livestock extensionists (n = 28). Key results: At present, forage shortage in the rangeland, yak mortality mainly due to (endangered) wild predators and, to a lesser extent, labour availability are the main concerns in all yak farming regions. These concerns have increased due to socioeconomic developments (e.g. education and other sources of income) and strong conservation policy, which affects the living environment of the yaks. Overall, the market to sell yak products and livestock extension services has improved, but forage shortage and yak mortality has increased over the years. However, some factors causing forage shortage are more specific to certain regions, e.g. competition with the horse population (west), cattle and cattle-yak hybrids (east), cordyceps collection (west and central) and prohibited burning of rangelands (central and east). Family labour available to herd yaks has slightly decreased, and the number of young family members (successors) to take over yak farming has decreased over the years. Conclusions: On the basis of the experiences and perceptions of yak herders and extensionists, we conclude that increasing forage shortage in the rangelands, decreasing numbers of successors, and increasing yak predation by wild animals are the major threats to yak farming. Implications: This study demonstrates that yak farming in Bhutan experiences an increasing pressure to sustain. Differences between regions make clear that a one blanket-policy will not be effective to preserve yak farming for the future.

    Associating mobility scores with production and reproductive performance in pasture-based dairy cows
    O'Connor, A.H. ; Bokkers, E.A.M. ; Boer, I.J.M. de; Hogeveen, H. ; Sayers, R. ; Byrne, N. ; Ruelle, E. ; Shalloo, L. - \ 2020
    Journal of Dairy Science 103 (2020)10. - ISSN 0022-0302 - p. 9238 - 9249.
    culling - lameness - locomotion - milk production - reproduction

    Lameness in dairy cows can have significant effects on cow welfare, farm profitability, and the environment. To determine the economic and environmental consequences of lameness, we first need to quantify its effect on performance. The objective of this study, therefore, was to determine the associations of various production and reproductive performance measurements (including milk, fat, and protein yield, somatic cell count, calving interval, cow death, or cow slaughter), and mobility scores in spring-calving, pasture-based dairy cows. We collected mobility scores (0 = good, 1 = imperfect, 2 = impaired, and 3 = severely impaired mobility), body condition scores, and production data for 11,116 cows from 68 pasture-based dairy herds. Linear mixed modeling was used to determine the associations between specific mobility scores and milk, fat and protein yield, and somatic cell count and calving interval. Binomial logistic regression was used to determine the association between mobility score and cow death, or slaughter. Significant yield losses of up to 1.4% of the average yield were associated with mobility score 2 and yield losses of up to 4.7% were associated with mobility score 3 during the early scoring period. Elevated somatic cell count was associated with all levels of suboptimal mobility during the late scoring period. Cows with a mobility score of 2 during the early scoring period were associated with longer calving interval length, whereas only cows with a mobility score of 3 during the late scoring period were associated with longer calving interval length. Cows with a mobility score ≥1 were more likely to be culled during both scoring periods. Our study, therefore, shows an association between specific mobility scores and production and reproductive performance in spring-calving, pasture-based dairy cows scored during the summer grazing period.

    Pre-weaning management of calves on commercial dairy farms and its influence on calf welfare and mortality
    Barry, J. ; Bokkers, E.A.M. ; Boer, I.J.M. De; Kennedy, E. - \ 2020
    Animal 14 (2020)12. - ISSN 1751-7311 - p. 2580 - 2587.
    health treatments - hygiene - post-colostrum feeding - space allowance - transition milk

    Welfare and management of calves is of increasing interest and also influences performance of these animals in later life. The aim of this study was to assess management and environmental conditions under which pre-weaned dairy calves are reared on commercial Irish dairy farms. We included 47 spring-calving, pasture-based herds in this study. Herd and animal-specific data, such as mortality rate, age and breed, were gathered from all participants via the HerdPlus® database. Information pertaining to management practices was collected by conducting an interview with the principal calf rearer, while an assessment of calf housing facilities was conducted to identify conditions calves were reared in. The environmental assessment included measurements of space allowance per calf, as well as feeding equipment hygiene. To assess calf behaviour video observations were used, while accounting for the number of calves present in a group and the space available per calf. Faecal samples were also collected to determine the presence of enteric pathogens among calves. To compare calf space allowance, group size and presence of enteric pathogens early and late in the calving season each farm was visited twice. Calf mortality was not associated with either herd size, space allowance per calf or post-colostrum feeding practices. Higher calf mortality was identified among herds which reported experiencing an on-set of calf pneumonia during weeks 8 to 10 of the calving season. This study demonstrates that factors associated with calf welfare on commercial Irish dairy farms (e.g. space allowance, mortality rate) are independent of herd size. Some management practices however, such as methods used for treating health issues can affect rates of calf mortality experienced. Calf mortality, for example, was lower in herds which treated diarrhoea cases by administering electrolytes, while continuing to offer milk. Behavioural observations indicate that smaller group sizes could promote expression of positive behaviours, potentially resulting from an overall improvement in welfare. Space allowance per calf was not associated with observed behaviour frequencies. We also identified that similar rates of calf mortality are experienced across herds of different sizes.

    Cow and herd-level risk factors associated with mobility scores in pasture-based dairy cows
    O'Connor, A.H. ; Bokkers, E.A.M. ; Boer, I.J.M. de; Hogeveen, H. ; Sayers, R. ; Byrne, N. ; Ruelle, E. ; Engel, B. ; Shalloo, L. - \ 2020
    Preventive Veterinary Medicine 181 (2020). - ISSN 0167-5877
    Animal-health - Grass-based - Lameness - Locomotion - Risk-factors

    Lameness in dairy cows is an area of concern from an economic, environmental and animal welfare point of view. While the potential risk factors associated with suboptimal mobility in non-pasture-based systems are evident throughout the literature, the same information is less abundant for pasture-based systems specifically those coupled with seasonal calving, like those in Ireland. Therefore, the objective of this study was to determine the potential risk factors associated with specific mobility scores (0 = good, 1 = imperfect, 2 = impaired, and 3 = severely impaired mobility) for pasture-based dairy cows. Various cow and herd-level potential risk factors from Irish pasture-based systems were collected and analyzed for their association with suboptimal mobility, whereby a mobility score of 0 refers to cows with optimal mobility and a mobility score ≥ 1 refers to a cow with some form of suboptimal mobility. Combined cow and herd-level statistical models were used to determine the increased or decreased risk for mobility score 1, 2, and 3 (any form of suboptimal mobility) compared to the risk for mobility score 0 (optimal mobility), as the outcome variable and the various potential risk factors at both the cow and herd-level were included as predictor type variables. Cow-level variables included body condition score, milk yield, genetic predicted transmitting ability for ‘lameness’, somatic cell score, calving month and cow breed. Herd-level variables included various environmental and management practices on farm. These analyses have identified several cow-level potential risk factors (including low body condition score, high milk yield, elevated somatic cell count, stage of lactation, calving month, and certain breed types), as well as various herd-level potential risk factors (including the amount of time taken to complete the milking process, claw trimmer training, farm layout factors and foot bathing practices) which are associated with suboptimal mobility. The results of this study should be considered by farm advisors when advising and implementing a cow/herd health program for dairy cows in pasture-based systems.

    An overview of current animal welfare research
    Bokkers, E.A.M. - \ 2020
    During the seminar: Listening to farmed animals in welfare research and ethics - the case of animal agency
    Effects of Dutch livestock production on human health and the environment
    Post, Pim M. ; Hogerwerf, Lenny ; Bokkers, Eddie A.M. ; Baumann, Bert ; Fischer, Paul ; Rutledge-Jonker, Susanna ; Hilderink, Henk ; Hollander, Anne ; Hoogsteen, Martine J.J. ; Liebman, Alex ; Mangen, Marie-Josée J. ; Manuel, Henk Jan ; Mughini-Gras, Lapo ; Poll, Ric van; Posthuma, Leo ; Pul, Addo van; Rutgers, Michiel ; Schmitt, Heike ; Steenbergen, Jim van; Sterk, Hendrika A.M. ; Verschoor, Anja ; Vries, Wilco de; Wallace, Robert G. ; Wichink Kruit, Roy ; Lebret, Erik ; Boer, Imke J.M. de - \ 2020
    Science of the Total Environment 737 (2020). - ISSN 0048-9697
    Animal production - Climate impact - Disability-adjusted life year (DALY) - Environmental impact - Livestock farming

    Observed multiple adverse effects of livestock production have led to increasing calls for more sustainable livestock production. Quantitative analysis of adverse effects, which can guide public debate and policy development in this area, is limited and generally scattered across environmental, human health, and other science domains. The aim of this study was to bring together and, where possible, quantify and aggregate the effects of national-scale livestock production on 17 impact categories, ranging from impacts of particulate matter, emerging infectious diseases and odor annoyance to airborne nitrogen deposition on terrestrial nature areas and greenhouse gas emissions. Effects were estimated and scaled to total Dutch livestock production, with system boundaries including feed production, manure management and transport, but excluding slaughtering, retail and consumption. Effects were expressed using eight indicators that directly express Impact in the sense of the Drivers-Pressures-State-Impact-Response framework, while the remaining 14 express Pressures or States. Results show that livestock production may contribute both positively and negatively to human health with a human disease burden (expressed in disability-adjusted life years) of up to 4% for three different health effects: those related to particulate matter, zoonoses, and occupational accidents. The contribution to environmental impact ranges from 2% for consumptive water use in the Netherlands to 95% for phosphorus transfer to soils, and extends beyond Dutch borders. While some aggregation across impact categories was possible, notably for burden of disease estimates, further aggregation of disparate indicators would require normative value judgement. Despite difficulty of aggregation, the assessment shows that impacts receive a different contribution of different animal sectors. While some of our results are country-specific, the overall approach is generic and can be adapted and tuned according to specific contexts and information needs in other regions, to allow informed decision making across a broad range of impact categories.

    The future of yak farming from the perspective of yak herders and livestock professionals
    Dorji, Nedup ; Derks, Marjolein ; Groot Koerkamp, Peter W.G. ; Bokkers, Eddie A.M. - \ 2020
    Sustainability 12 (2020)10. - ISSN 2071-1050
    Future - Opinions - Perceived concern - Sustainability - Yak farming

    The declining number of yak farming families is perceived as a socio-political and economic concern in Bhutan. However, there is limited understanding of what influences herders' plans and decisions on yak farming. We studied factors determining future perspectives of yak farming by interviewing yak herders and livestock professionals. We analysed relationships between herders' characteristics and level of concerns, and future plans related to yak farming. Furthermore, relationships between level of concern and future plans were analysed. Most of the herder characteristics did not influence their future plans with yak farming. Age and level of perceived concern of the herders was associated with their wish for their children to continue yak farming in the future. Nevertheless, they expect that the number of yak farming families will decline in the next ten years. Additionally, most of the livestock professionals believe that the number of yak farming families will decline in the future. No differences were observed between the aggregated score of concern of herders and livestock professionals. The most important factors threatening the future of yak farming in Bhutan according to herders and livestock professionals are forage shortage, predation and no successor to take up yak farming.

    Herders’ and livestock professionals’ experiences on past and future developments in yak farming in Bhutan
    Dorji, Nedup ; Derks, M. ; Dorji, P. ; Groot Koerkamp, P.W.G. ; Bokkers, Eddie - \ 2020
    In: Wias Annual Conference 2020. - WIAS - p. 48 - 48.
    In Bhutan yak-based transhumant systems are influenced by socioeconomic developments,regulations, and environmental changes. Little is known about the impact of thesefactors on yak farming practices. The aim was to study perceptions and experiences ofyak herders and livestock professionals on past and future developments in yak farming.Yak herders in three regions (west, n = 22; central, n = 20; east, n = 25) and livestock professionals(n = 28) were interviewed using a semi-structured questionnaire. Our results showthat at present forage shortage in the rangeland (herders, 93%; livestock professionals,96%), yak mortality (herders, 96%; livestock professionals, 96%) and to a lesser extent labouravailability (herders, 30%; livestock professionals, 96%) are the main concerns in yakfarming. Some factors causing forage shortage, however, are specific to certain regions,e.g. competition with the horse population (west, 91%) and prohibited burning of rangelands(central, 80%; east, 76%). Overall, the market to sell yak products and livestock extensionservices has improved, whereas forage shortage and yak mortality has increased over the years. In addition, family labour available to herd yaks, as well as the number of young family members to take over yak herding has decreased over the years. These key concerns have increased due to socioeconomic developments and strong conservation policy, which also affects the living environment of the yaks. Despite the challenges experienced by herders in yak farming, the majority of herders (81%) wish their children to take up yak farming in the future. About half of the respondents (57%), however, think that yak farming households will decline in the next 10 years. For a sustainable future of yak farming in Bhutan active policy involvement seems to be required to reduce uncertainties and increase livelihood perspectives.
    Provisioning of live black soldier fly larvae (Hermetia illucens) benefits broiler activity and leg health in a frequency and dose-dependent manner
    Ipema, Allyson ; Gerrits, W.J.J. ; Bokkers, Eddie ; Kemp, B. ; Bolhuis, J.E. - \ 2020
    In: WIAS Annual Conference 2020 WIAS - p. 33 - 33.
    Fast-growing broilers spend most their time inactive and are therefore prone to experience leg problems. Environmental enrichment which facilitates intrinsically motivated behaviour scan potentially promote activity and reduce leg problems, thereby improving broiler welfare. A promising environmental enrichment method is the scattering of desired feed items, such as insects which are highly attractive to broilers. We studied the effect of providing live black soldier fly larvae (BSFL) scattered on the litter on broiler behaviour, leg health and performance. One-day-old male broilers were assigned to one of five treatments(eight pens/treatment, nine broilers/pen): a control without BSFL and four treatments with BSFL in different amounts (5% or 10% of estimated dietary dry matter intake; A5 andA10 respectively) and frequencies (two or four times a day; F2 and F4 respectively). All broilers were fed diets formulated to ensure a similar energy and nutrient intake. Broiler weight and leg health were determined on day 42. The behavioural time budget was determined weekly by observations for 7 h per day using 12-min scan sampling, and activity around larval provisioning was determined by 3-min scan sampling from 9 min before, until 30 min after larval provisioning on day 15/16, 29/30 and 40/41. Broilers in all larval provisioning treatments had a different behavioural time budget than controls, with higher levels of foraging behaviour, walking, standing idle and general activity during at least three of the five observation days (p<0.05 compared to controls). Generally, active behaviours were most profoundly increased in A10F4 broilers. Time spent active and in standing posturedeclined from week 4 onwards in A10F4, whereas for all other treatments this decline occurred already in week 2. Activity during 30 minutes after larval provisioning was higher for A10 than A5 treatments (p<0.05 for all days) but overall not affected by frequency of larval provisioning. Hock burn occurred less in A10 birds than in controls (p<0.05), and lameness occurred less in A10 and A5F4 birds than in controls (p<0.01). Only A10F2 birds had a lower final weight than controls (p<0.05). In conclusion, the largest amount combined with the highest frequency of larval provisioning applied in this study resulted in a prolonged increase in activity and better leg health, without significantly affecting broiler performance.
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