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Antimicrobial use and farmers' attitude toward mastitis treatment on dairy farms with automatic or conventional milking systems
No full textMastitis is one of the major causes for antimicrobial use on dairy cattle farms. On farms with an automatic milking system (AMS), diagnostics differ from those with a conventional milking system (CMS), with potentially a different attitude toward mastitis treatment. This may result in differences in antimicrobial usage (AMU) between these 2 types of farms. The aims of this study were (1) to compare AMU between AMS and CMS farms, (2) to identify variables associated with AMU in both types of herds, and (3) to describe the distribution of mastitis-causing pathogens and their antimicrobial resistance patterns. Data on AMU was collected for 42 AMS and 254 CMS farms in the Netherlands and was expressed as animal-defined daily dose (ADDD). The ADDD variables were total usage (ADDDTOTAL), intramammary usage during lactation (ADDDIMM), usage for dry cow therapy (ADDDDCT), and usage by injection (ADDDINJ). Eighteen AMS farms and 24 CMS farms participated in a survey on factors potentially related to AMU. These farmers collected 5 quarter milk samples from quarters with clinical mastitis or high somatic cell count, which were subjected to bacteriological culture and antimicrobial susceptibility testing. In addition, routinely collected udder health data of these farms were used in the analysis. Nonlinear principal component analysis (NLPCA) was used to explore associations between AMU, udder health, and questionnaire variables. The ADDDTOTAL and ADDDDCT were comparable between AMS and CMS farms, whereas ADDDIMM tended to be lower and ADDDINJ higher on AMS farms than on CMS farms. The NLPCA yielded 3 principal components (PC) that explained 48% of the variation in all these variables. The AMS farms were not distinguished from CMS farms in the principal component space. The 3 PC represented different aspects of udder health, ADDDTOTAL, and treatment strategy. Differences in treatment strategy were unrelated to total antimicrobial usage or overall udder health. The distribution of mastitis-causing pathogens and their antimicrobial resistance were comparable between AMS and CMS farms. In conclusion, our study shows that AMU on AMS farms was similar to that of CMS farms, but AMS farmers tend to apply more injectable and fewer intramammary treatments during lactation than CMS farmers. Across both farm types, farmers' attitudes toward udder health in general and toward mastitis treatment are associated with AMU.</p
Benthic effects of offshore renewables: identification of knowledge gaps and urgently needed research
No full textAs the EU's commitment to renewable energy is projected to grow to 20% of energy generation by 2020, the use of marine renewable energy from wind, wave and tidal resources is increasing. This literature review (233 studies) (i) summarizes knowledge on how marine renewable energy devices affect benthic environments, (ii) explains how these effects could alter ecosystem processes that support major ecosystem services and (iii) provides an approach to determine urgent research needs. Conceptual diagrams were set up to structure hypothesized cause-effect relationships (i.e. paths). Paths were scored for (i) temporal and spatial scale of the effect, (ii) benthic sensitivity to these effects, (iii) the effect consistency and iv) scoring confidence, and consecutively ranked. This approach identified prominent knowledge gaps and research needs about (a) hydrodynamic changes possibly resulting in altered primary production with potential consequences for filter feeders, (b) the introduction and range expansion of non-native species (through stepping stone effects) and, (c) noise and vibration effects on benthic organisms. Our results further provide evidence that benthic sensitivity to offshore renewable effects is higher than previously indicated. Knowledge on changes of ecological functioning through cascading effects is limited and requires distinct hypothesis-driven research combined with integrative ecological modelling
Effects of strip width on yields in relay-strip intercropping: A simulation study
No full textIntercropping is the cultivation of multiple crop species on the same land. Relay strip intercropping is an intercropping system in which the component species are grown in strips, while the growing periods of the crop species overlap only partially. The effects of strip width on yields in relay-strip intercropping are still poorly understood. Here in a case study on wheat-maize relay intercropping a simple strip intercropping model was applied to quantify intercropping performance as a function of a wide range of strip widths. Simulations showed that (1) the optimum strip width is less than 1 meter and (2) benefits of intercropping rapidly drop as strips become wider. Most previous experimental work was also done at narrow configurations, with strips less than 3 meters wide. Benefits of intercropping may therefore be less than what would be expected from experiments if narrow configurations are not attainable because of lack of mechanisation. All optimised strip configurations showed a Land Equivalent Ratio (LER) larger than 1 indicating benefits of intercropping, irrespective of assumptions that were made on radiation use efficiency in intercropped species as compared to sole crops. At current prices of wheat and maize, however, intercropping gross margin exceeded sole cropping gross margin only if the intercrop RUE was larger than sole crop RUE for both species. This study shows that strip crop growth models can be used to specify needs for future machinery, that will enable farmers to attain benefits from intercropping.</p
Youngest versus oldest child: why does mothers’ snack choice differ?
No full textYoung children frequently consume energy dense snacks, which is one of the factors contributing to childhood overweight. The consumption of more healthy snacks could help in meeting the dietary intake requirements of children. Previous research suggested that mothers of first children showed more health-conscious food behavior compared to mothers of not-first children. However, what is missing from earlier research is an in-depth exploration of differences in considerations to choose a snack and the reasons connected. Therefore, this study aims to characterize differences in mothers' snack choice for their youngest child at 2–3 years and their oldest child when he/she was of the same age. Moreover, this study aims to identify reasons for these differences. A grounded theory approach was used for data collection and analysis. Semi-structured interviews were carried out with 17 Dutch mothers with two or three children. All mothers indicated differences between snacks provided to their youngest child (2–3 years) and their oldest child when it was of the same age. Most frequently mentioned differences were youngest children receive unhealthy snacks at a younger age, the structure regarding snack providing is more fixed, and that youngest children receive less age-specific snacks. Most frequently mentioned reasons for these differences were role-modelling, novelty of the first-born, availability of other types of snacks at home, and school hours of the oldest child. The study provided insights into the possible role of siblings in shaping snack consumption. Results might be relevant for the development of intervention strategies to increase mothers' awareness and to help to meet children's dietary requirements.</p
Chronic simultaneous exposure of common carp (Cyprinus carpio) from embryonic to juvenile stage to drospirenone and gestodene at low ng/L level caused intersex
No full textSynthetic progestins are emerging contaminants of the aquatic environment with endocrine disrupting potential. The main aim of the present study was to investigate the effects of the synthetic progestins gestodene, and drospirenone on sex differentiation in common carp (Cyprinus carpio) by histological analysis. To gain insights into the mechanisms behind the observations from the in vivo experiment on sex differentiation, we analyzed expression of genes involved in hypothalamus–pituitary–gonad (HPG) and hypothalamus–pituitary–thyroid (HPT) axes, histology of hepatopancreas, and in vitro bioassays. Carp were continuously exposed to concentrations of 2 ng/L of single progestins (gestodene or drospirenone) or to their mixture at concentration 2 ng/L of each. The exposure started 24 h after fertilization of eggs and concluded 160 days post-hatching. Our results showed that exposure of common carp to a binary mixture of drospirenone and gestodene caused increased incidence of intersex (32%) when compared to clean water and solvent control groups (both 3%). Intersex most probably was induced by a combination of multiple modes of action of the studied substances, namely anti-gonadotropic activity, interference with androgen receptor, and potentially also with HPT axis or estrogen receptor.</p
Risk assessment of Clostridium perfringens in Cornish pasties in the UK
No full textTo assess the risk of C. perfringens toxico-infections related to the consumption of Cornish pasties in the United Kingdom, a stochastic risk assessment model was created. Exposure to the pathogen was modelled as the result of contamination of different ingredients (i.e. beef and pepper), application of different cooling scenarios at room temperature and considering pasties of a number of common sizes. The model predicted a mean of 213 cases of gastroenteritis per million people in the UK per year (95% CI: 128–317), which might explain a significant proportion of annual C. perfringens toxico-infections according to epidemiological data. Major factors influencing this estimate and possible targets for interventions were the time to consumption and the concentration of the pathogen in contaminated ingredients, the impact of which in reducing the risk was tested in different intervention scenarios. The results of the model together with a number of possible risk mitigation measures are used as a basis to discuss the potential of setting of risk-based metrics as a risk management option in the context of food safety decision-making.</p
Camera trapping reveals trends in forest duiker populations in African National Parks
No full textBushmeat hunting is widely cited as cause for declines of wildlife populations throughout Africa. Forest duikers (Bovidae, Cephalophinae) are among the most exploited species. Whether current harvest rates imperil duikers is debated because of the difficulty of accurately assessing population trends. To assess population trends, we first reviewed literature for historical duiker population estimates. Second, we used systematic camera-trap monitoring to assess population trends for 15 populations of nine duiker species in six national parks in Central and East Africa. We analysed annual monitoring data using Royle-Nichols heterogeneity-induced occupancy models to estimate abundance/sample point and derive occupancy estimates. Published density estimates indicate that duiker populations declined significantly throughout Africa between 1973 and 2013. There was a wide range of densities depending on species ((Formula presented.) range: 0.26–20.6 km−1) and whether populations were hunted ((Formula presented.) =6.3 km−1) or unhunted ((Formula presented.) = 16.3 km−1). More recent analysis of camera-trap monitoring produced different results. Estimated mean point abundance over time was between 0 and 0.99 individuals/point for four populations, between 1.0 and 1.99 for six populations, and greater than 2.0 for five populations. We observed five populations of duikers with negative trends in point abundances, although only one trend was significant and point abundance estimates for three populations were above 2.0 in the final survey year. Six populations showed positive trends in point abundance (three significant), and the remaining populations displayed no trends. Average occupancy was high (Ψ > 0.60) except for three populations. While literature indicates that historical population declines have occurred, most duiker populations appear relatively healthy in monitored parks. Our results indicate that these parks are effective in protecting most duikers despite hunting pressure. We recommend that systematic, standardized camera-trap monitoring be initiated in other African parks in combination with point-abundance models to objectively assess forest ungulate population trends.</p
Non-target screening reveals the mechanisms responsible for the antagonistic inhibiting effect of the biocides DBNPA and glutaraldehyde on benzoic acid biodegradation
No full textThe desalination and reuse of discharged cooling tower water (CTW) as feed water for the cooling tower could lower the industrial fresh water withdrawal. A potential pre-treatment method before CTW desalination is the use of constructed wetlands (CWs). Biodegradation is an important removal mechanism in CWs. In the present study, the impact of the biocides 2,2-dibromo-2-cyanoacetamide (DBNPA) and glutaraldehyde on the biodegradation process by CW microorganisms was quantified in batch experiments in which benzoic acid was incubated with realistic CTW biocide concentrations. DBNPA had a stronger negative impact on the biodegradation than glutaraldehyde. The combination of DBNPA and glutaraldehyde had a lower impact on the biodegradation than DBNPA alone. UHPLC-qTOF-MS/MS non-target screening combined with data-analysis script ‘patRoon’ revealed two mechanisms behind this low impact. Firstly, the presence of glutaraldehyde resulted in increased DBNPA transformation to the less toxic transformation product 2-bromo-2-cyanoacetamide (MBNPA) and newly discovered 2,2-dibromopropanediamide. Secondly, the interaction between glutaraldehyde and DBNPA resulted in the formation of new products that were less toxic than DBNPA. The environmental fate and toxicity of these products are still unknown. Nevertheless, their formation can have important implications for the simultaneous use of the biocides DBNPA and glutaraldehyde for a wide array of applications.</p
Effects of early life and current housing on sensitivity to reward loss in a successive negative contrast test in pigs
No full textAnimals in a negative affective state seem to be more sensitive to reward loss, i.e. an unexpected decrease in reward size. The aim of this study was to investigate whether early-life and current enriched vs. barren housing conditions affect the sensitivity to reward loss in pigs using a successive negative contrast test. Pigs (n = 64 from 32 pens) were housed in barren or enriched conditions from birth onwards, and at 7 weeks of age experienced either a switch in housing conditions (from barren to enriched or vice versa) or not. Allotting pigs to the different treatments was balanced for coping style (proactive vs. reactive). One pig per pen was trained to run for a large reward and one for a small reward. Reward loss was introduced for pigs receiving the large reward after 11 days (reward downshift), i.e. from then onwards, they received the small reward. Pigs housed in barren conditions throughout life generally had a lower probability and higher latency to get the reward than other pigs. Proactive pigs ran overall slower than reactive pigs. After the reward downshift, all pigs ran slower. Nevertheless, reward downshift increased the latency and reduced the probability to get to the reward, but only in pigs exposed to barren conditions in early life, which thus were more sensitive to reward loss than pigs from enriched early life housing. In conclusion, barren housed pigs seemed overall less motivated for the reward, and early life housing conditions had long-term effects on the sensitivity to reward loss.</p
Underwater adhesion: a complex (coacervate) affair
No full textUnderwater adhesion is technically challenging mainly because of the presence of water which drastically weakens the mechanical properties of a glue and prevents a good contact with the surface. This strongly limits the development of injectable adhesives for wet environments, such as the human body: the medical field, especially when regarding soft tissue repair and wound closure, would have much to gain from the development of glues that would replace patient and surgeon-unfriendly techniques such as suturing and stapling. However, this challenge has been solved long time ago by many natural organisms, such as mussels and sandcastle worms. These underwater living animals are able to release a fluid phase underwater. This substance successively hardens due to a change in the environmental conditions (pH, ionic strength), enabling the organisms to attach to different kinds of surfaces. The natural glue is mainly composed of oppositely charged protein domains and stored in the form of complex coacervate, a fluid and water-immiscible phase. Taking nature as a source of inspiration, in this thesis we report the development of an adhesive by mixing aqueous solutions of oppositely charged polymers modified with thermosensitive units. In the first part of the thesis, we show that the material, liquid-like at preparation conditions, turns immediately into a solid when released in a physiological environment, where the adhesive experiences a gradient in both temperature and salinity. The liquid-to-solid transition is ascribed to the collapse of the thermoresponsive chains at the human body temperature and to the strengthening of the electrostatic interactions in a lower ionic strength medium, resulting in higher toughness and strength. When tested underwater, the material shows high adhesive properties, sticking strongly to many different surfaces like glass, teflon or charged surfaces. In addition to that, in the second part of the thesis, we report the optimization of the material, which can be achieved by properly controlling parameters such as the polymer composition, salt concentration, water content and incorporation of nanofillers