Classification of Potential Sheep Heat-Stress Levels According to the Prevailing Meteorological Conditions

Many researchers have found that physiology, welfare, health, and productivity of ruminants are significantly affected when they are exposed to heat-stress conditions. In such cases, heat-stress may also cause a reduction of farmers’ profit in various ways. Heat-stress levels are significantly affected by the prevailing meteorological conditions. This paper aims to study the potential daily peak heat-stress conditions to which sheep are exposed and to classify them according to the prevailing meteorological conditions. For these purposes, temperature, relative humidity, wind speed and incoming solar radiation data were analyzed. The meteorological data were recorded during the summers of the period 2007 – 2012 by an automated meteorological station that operates in a rural area near the east coast of central Greece. Potential sheep’s heat-stress was assessed using the Temperature Humidity Index (THI). The analysis showed that the daily maximum hourly (DMH) THI value exceeded the extreme severe heat-stress threshold (THI ≥ 25.6) in 82% of the days. The average value of the DMH THI values during August was 29.0, being slightly higher than the corresponding value for July (i.e. 28.6) and 2.7 higher than the corresponding value for June. The classification of the DMH THI values according to the prevailing meteorological conditions was achieved by applying cluster analysis (CA). The 4 meteorological parameters mentioned above were used as variables in the CA. CA was performed by using the values of the meteorological parameters recorded when each DMH THI value was observed. CA is considered as an objective technique to group days with similar weather conditions. CA achieved to group extreme hot days (33.8 – 40.8 oC) and days characterized by high (28.5 – 32.3 oC), moderate (26.1 – 28.9 oC), relatively low (24.3 – 26.0 oC) and very low (20.1 – 20.6 oC) summer temperatures. In brackets, the first number corresponds to the average of DMH THI values calculated for the days included in each cluster. The second number corresponds to the average of temperature values recorded when the DMH THI values were observed, for each cluster of days. The impact of wind speed and incoming solar radiation on peak THI levels was also assessed. It was found that when wind speed and solar radiation increased, peak THI and temperature values also increased. The effect of wind speed to the thermal environment could be mainly attributed to mesoscale circulations that develop in the greater area. This paper showed that CA could be regarded as a useful tool to estimate the range of peak summer THI values, and consequently the magnitude of heat-stress, in relation to the prevailing meteorological conditions.        &nbsp

Cost-Effectiveness Analysis of Seven Measures to Reduce Tail Biting Lesions in Fattening Pigs

Tail biting is an important animal welfare issue in the pig sector. Studies have identified various risk factors which can lead to biting incidents and proposed mitigation measures. This study focused on the following seven key measures which have been identified to affect the risk of tail biting lesions: improvements in straw provision, housing ventilation, genetics, stocking density, herd health, provision of point-source enrichment objects, and adoption of early warning systems. The aim of this study was to examine whether these selected measures to reduce the risk of tail biting lesions in pig fattening are cost-effective. The problem was analyzed by first summarizing the most prospective interventions, their costs and expected impacts on the prevalence of tail biting lesions, second, by using a stochastic bio-economic model to simulate the financial return per pig space unit and per pig at different levels of prevalence of tail biting lesions, and third by looking at how large a reduction in tail biting lesions would be needed at different levels of initial prevalence of lesions to cover the costs of interventions. Tail biting lesions of a severity which would require an action (medication, hospitalization of the pig or other care, or taking preventive measures) by the pig producer were considered in the model. The results provide guidance on the expected benefits and costs of the studied interventions. According to the results, if the average prevalence of tail biting lesions is at a level of 10%, the costs of this damaging behavior can be as high as euro2.3 per slaughtered pig (similar to 1.6% of carcass value). Measures which were considered the least expensive to apply, such as provision of point-source enrichment objects, or provided wider production benefits, such as improvements in ventilation and herd health, became profitable at a lower level of efficacy than measures which were considered the most expensive to apply (e.g., straw provision, increased space allowance, automated early warning systems). Measures which were considered most efficient in reducing the risk of tail biting lesions, such as straw provision, can be cost-effective in preventing tail biting, especially when the risk of tail biting is high. At lower risk levels, the provision of point-source objects and other less costly but relatively effective measures can play an important role. However, selection of measures appropriate to the individual farm problem is essential. For instance, if poor health or barren pens are causing the elevated risk of tail biting lesions, then improving health management or enriching the pens may resolve the tail biting problem cost-effectively.Peer reviewe

Multifrequency Nanomechanical Mass Spectrometer Prototype for Measuring Viral Particles Using Optomechanical Disk Resonators

Nanomechanical mass spectrometry allows characterization of analytes with broad mass range, from small proteins to bacterial cells, and with unprecedented mass sensitivity. In this work, we show a novel multifrequency nanomechanical mass spectrometer prototype designed for focusing, guiding and soft-landing of nanoparticles and viral particles on a nanomechanical resonator surface placed in vacuum. The system is compatible with optomechanical disk resonators, with an integrated optomechanical transduction method, and with the laser beam deflection technique for the measurement of the vibrations of microcantilever resonators. The prototype allows the in-vacuum alignment of resonators thanks to a dedicated visualization system. Finally, in this work, we have demonstrated the detection of gold nanoparticles, polystyrene nanoparticles and phage G viruses with optomechanical disks and microcantilever resonators.Peer reviewe

Environmental conditions, potential heat-stress state and their relations in a sheep barn under hot climate

The aim of this study was to examine climate conditions, air quality, potential heat stress and their relations in a sheep barn under Greek hot weather conditions. Hourly averaged values of temperature, relative humidity, wind speed, and coarse and fine airborne Particulate Matter (PM) concentration recorded inside and outside a naturally ventilated sheep barn during July, August and September of 2015 were used. Indoors potential heat-stress levels were assessed by means of the Temperature Humidity Index (THI). Descriptive statistics were presented and relations between the environmental parameters and the THI values were investigated. The results showed that inside the sheep barn, THI was positively correlated (p < 0.0001) with temperature and wind speed and negatively correlated with relative humidity. Additionally, inside the sheep barn, the concentration of coarse PM was positively and negatively correlated (p < 0.0001) with temperature and relative humidity, respectively, whereas the opposite was observed for the concentration of fine PM. Measures that could be applied to alleviate animals’ heat-stress were proposed

“On-Line” Heating Emissions Based on WRF Meteorology—Application and Evaluation of a Modeling System over Greece

The main objective of the present study is the development of an “on-line” heating emissions modeling system based on simulated meteorological data and its integration with air quality modeling systems in order to improve their accuracy. The WRF-CAMx air quality modeling system is applied over Greece for the cold period of 2015 (January–April, October–December) for two emissions scenarios: using the (a) “on-line” heating emissions based on WRF meteorology and (b) “static” heating emissions based on static temporal profiles. The monthly variation in total “on-line” heating emissions followed the temporal pattern of the air temperature over Greece, leading to the highest heating emissions in January and February, while higher differences in emissions between winter and spring/autumn months were identified in comparison with the static ones. The overall evaluation of the WRF-CAMx modeling system using the “on-line” heating emissions revealed satisfactory model performance for the mean daily air quality levels. The comparison between the simulated and observed mean monthly concentrations revealed an improvement in the pattern of mean monthly concentrations for the “on-line” scenario. Higher values of the index of agreement and correlation for the mean daily values were also identified for the “on-line” scenario in most monitoring sites

Temperature, comfort and pollution levels during heat waves and the role of sea breeze

During the summer of 2007 several Greek regions suffered periods of extreme heat, with midday temperatures of over 40A degrees C on several consecutive days. High temperatures were also recorded on the east coast of central Greece, where a complex sea breeze circulation system frequently develops. The more intense events occurred at the end of June and July. The highest temperatures were observed on 26 June and 25 July, while the sea breeze developed only on 25 July. Meteorological data collected at two sites-a coastal urban location and an inland suburban site that is not reached by the sea breeze flow-as well as pollution data collected at the urban site, were analysed in order to investigate the relationship between sea breeze development and the prevailing environmental conditions during these two heat wave events. The analysis revealed that sea breeze development affects temperature and pollution levels at the shoreline significantly, causing a decrease of similar to 4A degrees C from the maximum temperature value and an increase of similar to 30% in peak PM10 levels. Additionally, several stress indices were calculated in order to assess heat comfort conditions at the two sites. It was found that nocturnal comfort levels are determined mainly by the urban heat island effect, the intensity of which reaches up to 8A degrees C, while the applied indices do not demonstrate any significant daytime thermal stress relief due to sea breeze development

Monitoring particulate matter levels and climate conditions in a Greek sheep and goat livestock building

Atmospheric pollutants from livestock operations influence air quality inside livestock buildings and the air exhausted from them. The climate that prevails inside the building affects human and animal health and welfare, as well as productivity, while emissions from the building contribute to environmental pollution. The aim of this study was to examine the variation of two climatic parameters (namely temperature and relative humidity) and the levels of particulate matter of different sizes (PM10-PM2.5-PM1), as well as the relationships between them, inside a typical Greek naturally ventilated livestock building that hosts mainly sheep. The concentration of particles was recorded during a 45-day period (27/11-10/1), while temperature and relative humidity were observed during an almost 1-year period. The analysis revealed that the variation of outdoor weather conditions significantly influenced the indoor environment, as temperature and relative humidity inside the building varied in accordance to the outside climate conditions. Temperature remained higher indoors than outdoors during the winter and extremely low values were not recorded inside the building. However, the tolerable relative humidity levels recommended by the International Commission of Agricultural Engineering (CIGR) were fulfilled only in 47% of the hours during the almost 1-year period that was examined. This fact indicates that although temperature was satisfactorily controlled, the control of relative humidity was deficient. The concentration of particulate matter was increased during the cold winter days due to poor ventilation. The maximum daily average value of PM10, PM2.5 and PM1 concentration equaled to 363, 61 and 30 mu g/m(3) respectively. The concentration of the coarse particles was strongly influenced by the farming activities that were daily taking place in the building, the dust resuspension being considered as the dominant source. A significant part of the fine particles were secondary, which the production of could be attributed to an increase in relative humidity levels. It is concluded that measures have to be adopted in order to achieve sufficient ventilation and to reduce particulate matter levels