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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    Effect of temperature on biomass allocation in seedlings of two contrasting genotypes of the oilseed crop Ricinus communis
    Ribeiro de Jesus, P.R. ; Zanotti, R.F. ; Deflers, C. ; Fernandez, L.G. ; Castro, R.D. De; Ligterink, W. ; Hilhorst, H.W.M. - \ 2015
    Journal of Plant Physiology 185 (2015). - ISSN 0176-1617 - p. 31 - 39.
    abiotic stress tolerance - plant-responses - heat-stress - castor-oil - acid gaba - growth - metabolomics - arabidopsis - pathways - moisture
    Ricinus communis is becoming an important crop for oil production, and studying the physiological and biochemical aspects of seedling development may aid in the improvement of crop quality and yield. The objective of this study was to assess the effect of temperature on biomass allocation in two R. communis genotypes. Biomass allocation was assessed by measuring dry weight of roots, stems, and cotyledons of seedlings grown at three different temperatures. Root length of each seedling was measured. Biomass allocation was strongly affected by temperature. Seedlings grown at 25 ¿C and 35 ¿C showed greater biomass than seedlings grown at 20 ¿C. Cotyledon and stem dry weight increased for both genotypes with increasing temperature, whereas root biomass allocation showed a genotype-dependent behavior. Genotype MPA11 showed a continuous increase in root dry weight with increasing temperature, while genotype IAC80 was not able to sustain further root growth at higher temperatures. Based on metabolite and gene expression profiles, genotype MPA11 increases its level of osmoprotectant molecules and transcripts of genes encoding for antioxidant enzymes and heat shock proteins to a higher extent than genotype IAC80. This might be causal for the ability to maintain homeostasis and support root growth at elevated temperatures in genotype MPA11.
    Thermal comfort of outdoor spaces in Lahore Pakistan: Lessons for bioclimatic urban design in the context of global climate change
    Mazhar, N. ; Brown, R.D. ; Kenny, N. ; Lenzholzer, S. - \ 2015
    Landscape and Urban Planning 138 (2015). - ISSN 0169-2046 - p. 110 - 117.
    heat-stress - model
    Humans interact with urban microclimates through exchanges of energy. A surplus of energy can create thermal discomfort and be detrimental to human health. Many cities in warm regions all over the world are forecast to become very hot through global climate change. Some cities already experience extreme heat and have done so for centuries. We conducted a study of one such city in order to generate design guidelines for creating thermally comfortable outdoor places. In the hot, dry city of Lahore, Pakistan we compared the microclimates of two very different outdoor spaces. The first place was the 16th century Shalimar Garden, which contains much green infrastructure and water features. The other example was the hard-surfaced courtyard of the contemporary Alhamra Art Centre. In both places we measured the microclimatic characteristics and used those data to simulate thermal sensation through the energybudget model COMFA. The measured air temperature and humidity in both spaces was similar. However, the solar radiation that would be received by a person in the Alhamra courtyard was much higher than in Shalimar Garden and was the main determinant of thermal discomfort. Results from this study can inform other cities in hot, dry climates about design responses that provide more outdoor thermal comfort and prevent health-threatening heat. (C) 2015 Elsevier B.V. All rights reserved.
    Designing urban parks that ameliorate the effects of climate change
    Brown, R.D. ; Vanos, J. ; Kenny, N. ; Lenzholzer, S. - \ 2015
    Landscape and Urban Planning 138 (2015). - ISSN 0169-2046 - p. 118 - 131.
    outdoor thermal comfort - green space - heat-stress - united-states - cool island - temperature - health - mortality - cities - environments
    Many inhabitants of cities throughout the world suffer from health problems and discomfort that are caused by overheating of urban areas, and there is compelling evidence that these problems will be exacerbated by global climate change. Most cities are not designed to ameliorate these effects although it is well-known that this is possible, especially through evidence-based climate-responsive design of urban open spaces. Urban parks and green spaces have the potential to provide thermally comfortable environments and help reduce vulnerability to heat stress. However, in order for them to provide this function, parks must be designed within the context of the prevailing climate and predicted future climates. To analyze the effects of elements that alter microclimate in parks, we used human energy budget simulations. We modelled the outdoor human energy budget in a range of warm to hot climate zones and interpreted the results in terms of thermal comfort and health vulnerability. Reduction of solar radiant input with trees had the greatest effect in all test cities. Reduction in air temperature was the second-most important component, and in some climates was nearly as important as incorporating shade. We then conducted similar modelling using predicted climates for the middle of the century, emphasizing the importance of city-level efforts for park design to assist in minimizing future climate-related urban health risks. These simulations suggested that heat waves in many climates will produce outdoor environments where people will be in extreme danger of heat stress, but that appropriately designed parks can reduce the threat
    Improved climate risk simulations for rice in arid environments
    Oort, P.A.J. van; Vries, M. de; Yoshida, H. ; Saito, K. - \ 2015
    PLoS ONE 10 (2015)3. - ISSN 1932-6203 - 27 p.
    oryza-sativa l. - temperature-induced sterility - induced spikelet sterility - irrigated rice - exploring options - modeling approach - solar-radiation - air-temperature - lowland rice - heat-stress
    We integrated recent research on cardinal temperatures for phenology and early leaf growth, spikelet formation, early morning flowering, transpirational cooling, and heat- and cold-induced sterility into an existing to crop growth model ORYZA2000. We compared for an arid environment observed potential yields with yields simulated with default ORYZA2000, with modified subversions of ORYZA2000 and with ORYZA_S, a model developed for the region of interest in the 1990s. Rice variety ‘IR64’ was sown monthly 15-times in a row in two locations in Senegal. The Senegal River Valley is located in the Sahel, near the Sahara desert with extreme temperatures during day and night. The existing subroutines underestimated cold stress and overestimated heat stress. Forcing the model to use observed spikelet number and phenology and replacing the existing heat and cold subroutines improved accuracy of yield simulation from EF = -0.32 to EF =0.70 (EF is modelling efficiency). The main causes of improved accuracy were that the new model subversions take into account transpirational cooling (which is high in arid environments) and early morning flowering for heat sterility, and minimum rather than average temperature for cold sterility. Simulations were less accurate when also spikelet number and phenology were simulated. Model efficiency was 0.14 with new heat and cold routines and improved to 0.48 when using new cardinal temperatures for phenology and early leaf growth. The new adapted subversion of ORYZA2000 offers a powerful analytic tool for climate change impact assessment and cropping calendar optimisation in arid regions.
    Effect of daily environmental temperature on farrowing rate and total born in dam line sows
    Bloemhof, S. ; Mathur, P.K. ; Knol, E.F. ; Waaij, E.H. van der - \ 2013
    Journal of Animal Science 91 (2013)6. - ISSN 0021-8812 - p. 2667 - 2679.
    heat-stress - genetic-parameters - primiparous sows - pigs - reproduction - traits - gilts - progesterone - lactation - tolerance
    Heat stress is known to adversely affect reproductive performance of sows. However, it is important to know on which days or periods during the reproduction cycle heat stress has the greatest effects for designing appropriate genetic or management strategies. Therefore, this study was conducted to identify days and periods that have greatest effects on farrowing rate and total born of sows using 5 different measures of heat stress. The data consisted of 22,750 records on 5024 Dutch Yorkshire dam line sows from 16 farms in Spain and Portugal. Heat stress on a given day was measured in terms of maximum temperature, diurnal temperature range and heat load. The heat load was estimated using 3 definitions considering different upper critical temperatures. Identification of days during the reproduction cycle that had maximum effect was based on the Pearson correlation between the heat stress variable and the reproduction trait, estimated for each day during the reproduction cycle. Polynomial functions were fitted to describe the trends of these correlations and the days with greatest negative correlation were considered as days with maximum effect. Correlations were greatest for maximum temperature, followed by those for heat load and diurnal temperature range. Correlations for both farrowing rate and total born were stronger in gilts than in sows. This implies that heat stress has a stronger effect on reproductive performance of gilts than of sows. Heat stress during the third week (21 to 14 d) before first insemination had largest effect on farrowing rate. Heat stress during the period between 7 d before successful insemination until 12 d after that had largest effect on total born. Correlations between temperatures on consecutive days during these periods were extremely high ( > 0.9). Therefore, for farrowing rate the maximum temperature on 21 d before first insemination and for total born the maximum temperature at day of successful insemination can be used as predictive measures of heat stress in commercial sow farms. Additionally, differences between daughter groups of sires were identified in response to high temperatures. This might indicate possibilities for genetic selection on heat tolerance.
    Merino ewes can be bred for body weight change to be more tolerant to uncertain feed supply
    Rose, I.J. ; Kause, A. ; Mulder, H.A. ; Werf, J.H.J. van der; Thompson, A.N. ; Ferguson, M.B. ; Arendonk, J.A.M. van - \ 2013
    Journal of Animal Science 91 (2013)6. - ISSN 0021-8812 - p. 2555 - 2565.
    random regression-models - parameter-estimation - heat-stress - environment - covariance - liveweight - survival - climate - cattle
    Sheep in Australia experience periods with different feed supply causing them to gain and lose BW during the year. It is more efficient if ewes lose less BW during periods of poor nutrition and gain more BW during periods of good nutrition. We investigated whether BW loss during periods of poor nutrition and BW gain during periods of good nutrition are genetically different traits. We used BW measurements from 2,336 adult Merino ewes managed over 5 yr in a Mediterranean climate in Katanning, Australia. Body weight loss is the difference between 2 BW measured 42 d apart during mating, a period of poor nutrition. Body weight gain is the difference between 2 BW measured 131 d apart during a period of good nutrition between prelambing and weaning. We estimated variance compnents of BW change using 3 methods: 1) as a trait calculated by subtracting the first BW from the second, 2) multivariate analysis of BW traits, and 3) random regression analysis of BW. The h(2) and genetic correlations (rg) estimated using the multivariate analysis of BW and the BW change trait were very similar whereas the random regression analysis estimated lower heritabilities and more extreme negative genetic correlations between BW loss and gain. The multivariate model fitted the data better than random regression based on Akaike and Bayesian information criterion so we considered the results of the multivariate model to be more reliable. The heritability of BW loss (h(2) = 0.05-0.16) was smaller than that of BW gain (h(2) = 0.14-0.37). Body weight loss and gain can be bred for independently at 2 and 4 yr of age (rg = 0.03 and -0.04) whereas at 3 yr of age ewes that genetically lost more BW gained more BW (rg = -0.41). Body weight loss is genetically not the same trait at different ages (rg range 0.13-0.39). Body weight gain at age 3 yr is genetically the same trait at age 4 yr (rg = 0.99) but is different between age 2 yr and the older ages (rg = 0.53 and 0.51). These results suggest that as the ewes reach their mature BW, BW gain at different ages becomes the same trait. This does not apply to BW loss. We conclude that BW change could be included in breeding programs to breed adult Merino ewes that are more tolerant to variation in feed supply.
    Exploring breeding opportunities for reduced thermal sensitivity of feed intake in the lactating sow
    Bergsma, R. ; Hermesch, S. - \ 2012
    Journal of Animal Science 90 (2012)1. - ISSN 0021-8812 - p. 85 - 98.
    genetic-parameters - heat-stress - covariance functions - selection - environment - traits - performance - genotype - cattle - model
    The aims of this study were, first, to evaluate the effects of climatic variables on daily feed intake of lactating sows and, second, to establish whether the response of sows to variation in temperature on feed intake during lactation was heritable. A total of 82,614 records for daily feed intake during lactation were available for 848 sows with 3,369 litters farrowing from January 2000 to December 2007. Climatic parameters available from the nearest weather station were maximum 24 h outside temperature, day length changes, and humidity. Although ambient room temperature was modified at the animal level in the farrowing shed, these climatic variables still had a significant effect on feed intake during lactation. Regression coefficients temperature and humidity were 0.01385 ± 0.00300 (temperature) - 0.00031 ± 0.00009 (temperature2) and 0.01443 ± 0.00620 (humidity) - 0.00009 ± 0.00004 (humidity2). There was an interaction between temperature and humidity, partly due to the climate control in the farrowing shed. At low temperature, feed intake increased considerably with greater humidity, in contrast to a small reduction in feed intake with greater humidity at high temperature. Day length change was modeled with a cosine function. At the start of autumn (September 21), sows ate 0.36 ± 0.056 kg/d less feed than at the start of spring (March 21). Daily feed intake during lactation was described as a function of days in lactation and as a function of both days in lactation and temperature using random regression models. The average heritability and repeatability summarized over the day in lactation at the mean temperature were 0.21 and 0.69, respectively. Genetic variance of temperature response on feed intake was less than 20% of the day effect. The permanent environmental variance was 2-fold (day) and 4-fold (temperature) greater than the corresponding additive genetic variance. Heritabilities of daily feed intake were greater during the first week of lactation compared with the rest of lactation. The genetic correlation between days decreased as time increased down to about 0.2 between the first and last day in lactation. The genetic correlation between feed intake records at the extreme temperatures decreased to about -0.35. It was concluded that random regression models are useful for research and results may be used to develop simpler models that can be implemented in practical breeding programs. An effect of temperature on lactation feed intake was found even in this climate-controlled environment located in a temperate climate zone. Larger effects are expected in more extreme climatic conditions with less temperature-controlled farrowing sheds.
    An attempt to define the sodium requirements of lactating dairy cows in a tropical environment
    Thiangtum, W. ; Yawongsa, A. ; Schonewille, J.T. ; Rukkwamsuk, T. ; Yuangklang, C. ; Verstegen, M.W.A. ; Hendriks, W.H. - \ 2011
    Journal of the Science of Food and Agriculture 91 (2011)13. - ISSN 0022-5142 - p. 2333 - 2337.
    acid-base status - potassium-chloride - mineral metabolism - dietary-sodium - heat-stress - responses - supplementation - magnesium - bicarbonate - absorption
    BACKGROUND: Lactating dairy cattle in the tropics may require more sodium (Na) owing to the hot and humid climatic conditions. It is unknown whether the current recommendations on Na for lactating cows can be quantitatively used in tropical countries. This study attempted to define the Na requirement of lactating dairy cows under tropical conditions by measuring Na levels in saliva, milk and faeces. RESULTS: The concentrations of Na and potassium (K) in milk, faeces and serum were not affected by dietary treatments. The amount of Na absorbed by cows fed the basal (low-Na) diet containing 0.4 g Na kg-1 dry matter (DM) was equal to the amount of Na lost in the milk, showing that these animals were fed an Na-deficient ration. This observation was corroborated by salivary Na and K levels, with the cows on the low-Na diet having salivary Na concentrations below 120 mmol L-1 in combination with salivary K concentrations above 20 mmol L-1 (P <0.05). CONCLUSION: Consumption of a daily ration formulated to contain the current Na requirement set by the NRC appears to provide too much Na for lactating cows under tropical conditions. A tentative value of 1.2 g kg-1 DM is proposed as the Na requirement for dairy cows under tropical conditions. Copyright © 2011 Society of Chemical Industry
    A methodology for model-based greenhouse design: Part 2, description and validation of a tomato yield model
    Vanthoor, B.H.E. ; Visser, P.H.B. de; Stanghellini, C. ; Henten, E.J. van - \ 2011
    Biosystems Engineering 110 (2011)4. - ISSN 1537-5110 - p. 378 - 395.
    temperature regimes - night-temperature - heat-stress - growth - plants - calibration - environment
    With the aim of developing a model-based method to design greenhouses for a broad range of climatic and economic conditions, a tomato yield model that describes the effects of greenhouse climate on yield was described and validated. A literature survey of temperature effects on tomato yield was performed and the main temperature effects were implemented in the model. Subsequently, the yield model was validated for four temperature regimes. Results demonstrated that the tomato yield was simulated accurately for both near-optimal and non-optimal temperature conditions in the Netherlands and southern Spain, respectively, with varying light and CO2-concentrations. In addition, the adverse effects of extremely low as well as high mean temperatures on yield and timing of first fruit harvest were simulated with fair accuracy. The simulated yield response to extreme diurnal temperature oscillations were in agreement with literature values. Given these results, the model is considered to be sufficiently accurate to be used for developing a model-based greenhouse design method. Therefore, the presented model will be integrated in a model-based design method with the aim to design the best greenhouse for local climate and economic conditions
    Gene Expression Modifications by Temperature-Toxicants Interactions in Caenorhabditis elegans
    Vinuela Rodriguez, A. ; Snoek, L.B. ; Riksen, J.A.G. ; Kammenga, J.E. - \ 2011
    PLoS ONE 6 (2011)9. - ISSN 1932-6203 - 11 p.
    zebrafish-danio-rerio - cdna microarray data - organophosphorus pesticides - developmental neurotoxicity - chemical-mixtures - binary-mixtures - heat-stress - c-elegans - toxicity - chlorpyrifos
    Although organophosphorus pesticides (OP) share a common mode of action, there is increased awareness that they elicit a diverse range of gene expression responses. As yet however, there is no clear understanding of these responses and how they interact with ambient environmental conditions. In the present study, we investigated genome-wide gene expression profiles in the nematode Caenorhabditis elegans exposed to two OP, chlorpyrifos and diazinon, in single and combined treatments at different temperatures. Our results show that chlorpyrifos and diazinon induced expression of different genes and that temperature affected the response of detoxification genes to the pesticides. The analysis of transcriptional responses to a combination of chlorpyrifos and diazinon shows interactions between toxicants that affect gene expression. Furthermore, our combined analysis of the transcriptional responses to OP at different temperatures suggests that the combination of OP and high temperatures affect detoxification genes and modified the toxic levels of the pesticides
    Simultaneous estimation of genotype by environment interaction accounting for discrete and continuous environmental descriptors in Irish dairy cattle
    Windig, J.J. ; Mulder, H.A. ; Bohte-Wilhelmus, D.I. ; Veerkamp, R.F. - \ 2011
    Journal of Dairy Science 94 (2011)6. - ISSN 0022-0302 - p. 3137 - 3147.
    milk-production traits - genetic correlations - herd environment - reaction norms - holstein cows - heat-stress - fertility - health - sensitivity - management
    Genotype by environment interaction can be analyzed by using a multi-trait model in which a trait measured in different environments is considered as separate traits. Alternatively, it can be analyzed by using a reaction norm model, in which the trait is considered a function of an environmental descriptor. Here, a model is developed where the 2 approaches are combined such that the effect of a continuous environmental descriptor can be analyzed in 2 or more discrete environments. The model is applied to somatic cell score (SCS) in relation to average herd milk production in 2 production environments: spring calving and year-round calving in Ireland. Heritabilities and additive genetic variances for SCS increased somewhat with increasing milk production and were higher in year-round calving. Under the combined model, the genetic correlation between spring and year-round calving was estimated at 0.82 to 0.84, clearly lower than obtained in a bivariate analysis ignoring effects of herd milk production. Thus, when estimating the genetic correlation between environments, effects of one environmental descriptor may be obscured by another, but can be disentangled in an analysis combining the reaction norm and the multi-trait approach. Such models will be especially useful for analyzing questions such as whether the effect of increasing production or temperature is more severe in different production systems or geographic regions.
    Quantifying abortion rates of reproductive organs and effects of contributing factors using time-to-event analysis
    Wubs, A.M. ; Heuvelink, E. ; Marcelis, L.F.M. ; Hemerik, L. - \ 2011
    Functional Plant Biology 38 (2011)5. - ISSN 1445-4408 - p. 431 - 440.
    capsicum-annuum l. - fruit-development - sweet-pepper - survival analysis - yield components - sink strength - heat-stress - seed set - flower - age
    Time-to-event analysis, or survival analysis, is a method to analyse the timing of events and to quantify the effects of contributing factors. We apply this method to data on the timing of abortion of reproductive organs. This abortion often depends on source and sink strength. We hypothesise that the effect of source and sink strength on abortion rate can be quantified with a statistical model, obtained via survival analysis. Flower and fruit abortion in Capsicum annuum L., observed in temperature and planting density experiments, were analysed. Increasing the source strength as well as decreasing the sink strength decreased the abortion rate. The effect was non-linear, e.g. source strengths above 6 g CH2O per plant per d did not decrease abortion rates further. The maximum abortion rate occurred around 100 degree-days after anthesis. Analyses in which sink strength was replaced with the number of fruits in a specified age category had an equal or better fit to the data. We discuss the advantages and disadvantages of using survival analyses for this kind of data. The technique can also be used for other crops showing reproductive organ abortion (e.g. soybean (Glycine max L.), cucumber (Cucumis sativus L.)), but also on other event types like bud break or germination.
    Dietary amino acid levels and feed restriction affect small intestinal development, mortality, and weight gain of maile broilers
    Wijtten, P.J.A. ; Hangoor, E. ; Sparla, J.K.W.M. ; Verstegen, M.W.A. - \ 2010
    Poultry Science 89 (2010)7. - ISSN 0032-5791 - p. 1424 - 1439.
    adult rooster - young chicks - ascites syndrome - gastrointestinal-tract - lysine requirement - digestive-tract - crude protein - heat-stress - maintenance - growth
    This study investigated the effect of 2 different dietary amino acid treatments and feed restriction in early life versus a control treatment on development of the small intestine segments (weights), mortality, and broiler performance. Each treatment was applied to 6 cages with Ross 308 male broilers and to 6 cages with Cobb 500 male broilers with 24 birds per cage. A control treatment (100% ideal protein) was compared with a treatment with 30% extra ideal protein, a treatment with daily adjustment of the dietary amino acid level and profile, and a feed restriction treatment. The protein treatments were applied from 0 to 14 d of age. The feed restriction was applied from 4 to 21 d of age. Restriction was 15% from d 4 to 14 of age and diminished with equal daily steps thereafter to 5% at 21 d of age. Birds were weighed and dissected for evaluation of small intestine weights at 6, 9, 14, and 36 d of age. Feed intake restriction reduced leg problems in Ross and Cobb broilers. Extra dietary protein reduced leg problems in Ross broilers only. The present experiment does not show that small intestinal weight development is related to mortality. Thirty percent extra dietary ideal protein increased duodenum weight between 6 and 9 d of age. This was not further increased by the daily optimization of the dietary amino acid level and profile. The increased duodenum weights coincided with an improved BW gain. This indicates that duodenum weight may be important in facilitating BW gain in young broilers. Thus, it may be worthwhile to pay more attention to the relation between nutrition and duodenum weight and duodenum function in further studies.
    Plant molecular stress responses face climate change. Trends in Plants
    Ahuja, I. ; Vos, R.C.H. de; Bones, A.M. ; Hall, R.D. - \ 2010
    Trends in Plant Science 15 (2010)12. - ISSN 1360-1385 - p. 664 - 674.
    transgenic arabidopsis plants - elevated atmospheric co2 - drought-stress - abiotic stress - transcription factor - gene-expression - heat-stress - systems biology - carbon metabolism - plasma-membrane
    Environmental stress factors such as drought, elevated temperature, salinity and rising CO2 affect plant growth and pose a growing threat to sustainable agriculture. This has become a hot issue due to concerns about the effects of climate change on plant resources, biodiversity and global food security. Plant adaptation to stress involves key changes in the ‘-omic’ architecture. Here, we present an overview of the physiological and molecular programs in stress adaptation focusing on how genes, proteins and metabolites change after individual and multiple environmental stresses. We address the role which ‘-omics’ research, coupled to systems biology approaches, can play in future research on plants seemingly unable to adapt as well as those which can tolerate climatic change.
    Temperature manipulation during layer chick embryogenesis
    Walstra, I. ; Napel, J. ten; Kemp, B. ; Brand, H. van den - \ 2010
    Poultry Science 89 (2010)7. - ISSN 0032-5791 - p. 1502 - 1508.
    incubation-temperature - thermal manipulations - body-temperature - broiler chicks - muscovy duck - heat-stress - thermoregulation - embryos - hatchability - performance
    The current study investigated the effects of temperature manipulation (TM) during late embryogenesis on temperature preference, response to high environmental temperature, behavior, and performance in young layer chicks. Control (CC) embryos (n = 96) were incubated at 37.8°C eggshell temperature throughout incubation. Thermally manipulated embryos (n = 96) were incubated at 37.8°C eggshell temperature throughout incubation and were exposed to 40°C for 4 h/d from embryonic d 14 to 18 (TM chicks). After hatch, chicks from each treatment were divided into 3 subgroups (n = 32 per group) and were subjected to a temperature preference test at d 1, 7, or 33. One day after the temperature preference test, each subgroup was exposed to 1 thermal challenge for 4 h (d 2, 40°C; d 8, 40°C; or d 34, 35°C). Effects of TM on (fearfulness) behavior of chicks were investigated in a tonic immobility test and during home pen observations. Temperature manipulation decreased incubation time with 7 h (P <0.0001) and body temperature at hatch with 0.2°C (P = 0.002). The TM chicks preferred a lower ambient temperature in the temperature preference test (P <0.05) and showed a higher body temperature response than CC chicks to the thermal challenge at d 2 and 8 (P <0.05). No effects of TM on behavior and performance were observed. Because most TM studies are conducted in broilers, this study is the first attempt to unravel the effects of TM during late embryogenesis on posthatch environmental adaptation in layer chicks. The results demonstrated that effects of our TM on postnatal temperature preference and response to high environmental temperatures are only found until d 8 of age. This may suggest 1 of 3 options: a) the timing or the level, or both, of TM and duration were not at the sensitive period of embryogenesis or not sufficient, or both, respectively; b) the level of the postnatal thermal challenge was not strong enough to induce a hyperthermic response; and c) the postnatal effects of TM in layers are limited in time
    Trends for monthly changes in days open in Holsteins
    Pszczola, M.J. ; Aguilar, I. ; Misztal, I. - \ 2009
    Journal of Dairy Science 92 (2009)9. - ISSN 0022-0302 - p. 4689 - 4696.
    heat-stress - reproductive-performance - dairy-cattle - genetic-parameters - us holsteins - milk-yield - new-york - cows - herds - fertility
    A reaction norm approach was used to estimate trends for days open (DO) with a model that indirectly accounted for heat stress. Data included 3.4 million first-parity records of DO of US Holsteins. A fixed effect model included herd-year, month of calving within region (MOC), age class, and regression on 305-d milk yield. An index calculated from the standardized solutions to MOC derived from the fixed effect model was treated as a proxy for an index on heat stress (SI). The lowest index for any region was set to zero. The highest index was 1.00 for the Southeast, 0.56 for the Northeast, 0.54 for the Midwest, 0.33 for the Northwest, and 0.42 for the Southwest. In all regions except the Northwest, the highest DO and the corresponding highest indices were in March-April. Compared with the fixed model, the reaction norm model also included the effect of an animal and a random regression on the SI; the 2 animal solutions are subsequently referred to as an intercept and a slope. Genetic trends were calculated for cows and sires separately. For cows, the trend for the intercept was - 0.1 d/yr, whereas the trend for the slope was 1 d/yr. For sires, the same trends were - 0.3 and 1.5, respectively. Official proofs were used to characterize the 100 top and 100 bottom bulls with at least 50 daughters for the intercept and the slope. Compared with the top bulls, the bottom bulls for the intercept gave 56 kg more milk and their type performance index was higher by 212 points. For the slope, the same numbers were - 435 kg and - 242 points, respectively. Trends for seasonal changes of days open are unfavorable.
    Effects of early life thermal conditioning and immune challenge on thermotolerance and humoral immune competence in adult laying hens
    Star, L. ; Juul-Madsen, H.R. ; Decuypere, E. ; Nieuwland, M.G.B. ; Vries Reilingh, G. de; Brand, H. van den; Kemp, B. ; Parmentier, H.K. - \ 2009
    Poultry Science 88 (2009)11. - ISSN 0032-5791 - p. 2253 - 2261.
    mannan-binding lectin - 4 layer lines - male broiler-chickens - hygienic stress - early-age - molecular-patterns - heat-stress - temperature - performance - responses
    Effects of early life experience with climatic (heat) and hygienic [lipopolysaccharide (LPS)] stress on adaptability to the same stressors in later life were studied in laying hens. Chicks were exposed to 37°C for 24 h at d 5 of age (n = 12) or were i.v.-administered once with 1 mg/kg of BW of LPS at 6 wk of age (n = 12), whereas a control group was reared under standard conditions receiving a placebo treatment of PBS (n = 36). At 24 wk of age, hens treated in early life were reexposed to the same stressor. Early life control hens were exposed to heat stress (n = 12), i.v.-administered with LPS (n = 12), or not exposed (n = 12). To evaluate improvement of adaptability, effects of climatic and hygienic stress on performance, humoral immune competence, and endocrine responsiveness were investigated in hens with early life experience to the stressors and hens only exposed to the stressors in later life. Early life heat exposure did not affect performance, immune, and endocrine parameters. Treatment x time interactions were found for level of antibody (Ab) binding to LPS and keyhole limpet hemocyanin (KLH) after LPS administration, indicating that hens with early life LPS experience differed in response level (Ab binding to LPS) and response pattern (Ab binding to LPS and KLH) compared with hens administered with LPS only at adult age. Our data suggest that early life heat stress exposure did not affect adaptability of laying hens to heat stress in later life. However, early life LPS exposure affected kinetics and magnitude of Ab levels binding to LPS and KLH, indicating that early life LPS exposure can enhance the status of immune reactivity or induce a higher sensitivity to LPS
    Effect of Single or Combined Climatic and Hygienic Stress in Four Layer Lines: 1. Performance
    Star, L. ; Kemp, B. ; Anker, I. van den; Parmentier, H.K. - \ 2008
    Poultry Science 87 (2008)6. - ISSN 0032-5791 - p. 1022 - 1030.
    multiple-hen cages - male broiler-chickens - laying hens - heat-stress - group selection - immune response - early-age - adaptation - lipopolysaccharide - thermotolerance
    Effects of long-term climatic stress (heat exposure), short-term hygienic stress [lipopolysaccharide (LPS)], or a combination of both challenges on performance of 4 layer lines were investigated. The lines were earlier characterized by natural humoral immune competence and survival rate. At 22 wk of age, 80 hens per line were randomly divided over 2 identical climate chambers and exposed to a constant high temperature (32°C) or a control temperature (21°C) for 23 d. Half of the hens housed in each chamber were i.v. injected with LPS at d 1 after the start of the heat stress period. The effect of heat, LPS, or a combined challenge on feed intake, BW, hen-day egg production, egg weight, and egg shell thickness were investigated. Feed intake, BW, hen-day egg production, egg weight, and egg shell thickness were significantly reduced by heat stress. Administration of LPS significantly reduced feed intake, BW (LPS x time interaction), hen-day egg production, and egg weight (LPS x time interaction). Hens were able to recover from LPS administration but did not completely adapt to heat stress. Hens still lost weight, had a lower feed intake and hen-day egg production after 23 d of continuous exposure to heat stress. These data suggest a different nature of short-term LPS exposure versus long-term heat exposure affecting performance parameters of laying hens, and different adaptation mechanisms of hens toward these stressors. Neither natural humoral immune competence nor survival rate, for which the lines had been earlier characterized, were indicative of the response to different stressors. However, significant line x heat interactions were found for feed intake and hen-day egg production, and a line x heat x time interaction for BW, whereas a line x LPS interaction was found for hen-day egg production and a line x LPS x time interaction for BW. The lines had similar response patterns, but differed in response levels, suggesting that some lines were better able to adapt to stressors than others
    Effect of Single or Combined Climatic and Hygienic Stress on Natural and Specific Humoral Immune Competence in Four Layer Lines
    Star, L. ; Nieuwland, M.G.B. ; Kemp, B. ; Parmentier, H.K. - \ 2007
    Poultry Science 86 (2007)9. - ISSN 0032-5791 - p. 1894 - 1903.
    red-blood-cells - heterophil-lymphocyte ratio - antibody-responses - heat-stress - escherichia-coli - feed restriction - endotoxin-shock - chickens - lipopolysaccharide - responsiveness
    Effects of long-term climatic stress (heat exposure), short-term hygienic stress [lipopolysaccharide (LPS)], or a combination of both challenges on the immune competence of 4 layer lines was investigated. The lines were earlier characterized for natural humoral immune competence and survival rate. Eighty hens per line were randomly divided over 2 identical climate chambers and exposed to a constant high temperature (32°C) or a control temperature (21°C) for 23 d. Half of the hens housed in each chamber were i.v. injected with LPS at d 1 after the start of the heat stress period. Within each of the treatment groups, half of the hens were s.c. immunized with human serum albumin (HuSA) at d 2 after the start of the heat stress period to measure specific antibody (Ab) titers to HuSA. The effect of heat, LPS, or a combined challenge on specific Ab titers to HuSA, natural Ab titers to keyhole limpet hemocyanin or HuSA (in hens that were not immunized with HuSA), and activity of the classical and alternative complement pathways were investigated. Heat stress enhanced specific and natural immune responses. Administration of LPS enhanced natural immune responses but decreased specific immune responses. The lack of interaction between heat stress and LPS administration, except for natural Ab titers to HuSA, suggest that these were 2 independent stressors. The lines had a similar response pattern but differed in the response level. Neither natural humoral immune competence nor survival rate, for which the lines had been characterized, was indicative of the specific and natural immune response to different stressors. Lipopolysaccharide and heat stress initiated sequential responses over time, with an earlier effect of short-term LPS exposure (within the first and second week) and a later effect of long-term heat exposure (within the second and third week). These data suggest that LPS and heat stress affect the natural and specific immune competence of laying hens.
    Effects of tropical climate and water cooling methods on growing pigs' responses
    Huynh, T.T.T. ; Aarnink, A.J.A. ; Truong, C.T. ; Kemp, B. ; Verstegen, M.W.A. - \ 2006
    Livestock Science 104 (2006)3. - ISSN 1871-1413 - p. 278 - 291.
    heat-stress - high-temperature - lying behavior - performance - humidity - swine - sow
    We report a study on crossbred growing pig ((Duroc x Pietrain) x Large White) that measured the effect of tropical conditions on respiration rate (RR), skin temperature (ST), rectal temperature (RT) and productivity and determined the efficacy of two simple cooling methods. The experiment was a randomized complete block design using 120 growing pigs. The factors were cooling system and pen design. The effects of two cooling systems (water bath (WB) and sprinkling (S)) were evaluated and compared with a control (CON). Cooling systems were tested in pens with (Y) or without an additional outdoor yard (NY). The pens were similar to those used in small-scale pig keeping in South-East Asia. The inside pen size was 2.5 x 3 m, the yard was 2.5 x 2 m. The same experimental design was used in two blocks: one block was in the wet season with average ambient temperature (T) of 27.5 degrees C and average relative humidity (RH) of 74.7% and the other was in the dry season with average T of 28.7 degrees C and average PH of 62.8%. In each block a batch of 60 pigs was reared in 12 pens (five pigs per pen). Pigs had free access to feed and water. Results showed that cooling and pen type significantly affected most parameters. The bath and S reduced RR by 4.2 and 5.2 min(-1), respectively (P <0.01), and ST by 0.3 and 0.4 degrees C, respectively, (P <0.05). Rectal temperature was not influenced by any treatment. The bath significantly reduced number of defecations and urinations in the resting area in pens NY (P <0.001). A yard reduced the number of excretions in the resting area (P <0.01). There were significant interaction effects of cooling and pen type on lying, lateral lying, and huddling (P <0.01; P <0.001; P <0.01, respectively). Daily weight gain was 6 g d(-1) more with WB and 50 g d(-1) more with S (P <0.05). The biggest daily weight gain was achieved when S was combined with a pen NY (P <0.01). We conclude that the physiologic and behavioral responses and hence productivity of group-housed growing pigs raised under tropical climate conditions benefited from the simple cooling systems tested and were affected by the presence of a yard. A fall in the high respiration rate indicated that cooling with the bath or sprinkling alleviated the pigs' heat stress.
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