Bart Sonck

The Influence of Operator-Controlled Variables on Spray Drift from Field Crop Sprayers

Spray drift can be defined as the quantity of plant protection product that is carried out of the sprayed area by the action of air currents during the application process. This continues to be a major problem in applying agricultural pesticides. The purpose of this research is to measure the amount of sedimenting drift from a horizontal boom sprayer for different (drift reducing) spray application techniques under field conditions and to compare the results with the results from a reference spray, taking into account variations in meteorological conditions during the field drift experiments. Field drift measurements were performed for several combinations of nozzle type (standard flat-fan, low-drift, air inclusion) and size (ISO 02, 03, 04, and 06), spray pressure (2.0, 3.0, and 4.0 bar), driving speed (4, 6, 8, and 10 km h-1), and spray boom height (0.3, 0.5, and 0.75 m ) according to ISO 22866 by sampling in a defined downwind area at 24 different positions using horizontal drift collectors. The reference spray was defined as a standard horizontal spray boom without air support, a spray boom height of 0.50 m, a nozzle distance of 0.50 m, ISO 110 03 standard flat-fan nozzles at 3.0 bar (1.2 L min-1), and a driving speed of 8 km h-1, resulting in an application rate of approximately 180 L ha-1. Nozzle type as well as spray pressure, driving speed, and spray boom height, have an important effect on the amount of spray drift. Larger nozzle sizes, lower spray pressures and driving speeds, and lower spray boom heights generally reduce spray drift. Concerning nozzle types, air inclusion nozzles have the highest drift reduction potential, followed by the low-drift nozzles and the standard flat-fan nozzles. Drift results are closely linked with droplet size characteristics of the sprays.

Potential dermal pesticide exposure affected by greenhouse spray application technique.

BACKGROUND Operator safety is still one of the main problems concerning greenhouse spray applications in South European horticulture. The main objective of this study was to compare potential dermal exposure (PDE) between traditional handheld spray application techniques (i.e. a standard spray gun walking forwards, a spray lance walking forwards and backwards) and novel spray application techniques with spray booms (i.e. a trolley, the Fumimatic and the Fumicar). RESULTS PDE varied from 19.7 mL h(-1) for the Fumimatic to 460 mL h(-1) for the spray lance walking forwards. Walking backwards reduced PDE by a factor 7. With the trolley, Fumimatic and Fumicar, PDE was respectively 20, 60 and 8 times lower than with the standard spray gun. With the spray lance, PDE was about 2.5 times higher than with the spray gun. Pesticide distribution over the operators body was non-uniform and correlated strongly with the application technique. With the traditional techniques, exposure to the legs and feet represents 60-80% of the total exposure. CONCLUSIONS Novel spray application techniques using spray booms greatly decrease operator exposure because the operator is not walking directly into the spray cloud and the sprayed crop, and because of their higher capacity. Depending on the type of spray application, different parts of the body need to be protected most.

Welfare, Health, and Hygiene of Laying Hens Housed in Furnished Cages and in Alternative Housing Systems

The aim of this review was to compare welfare, health, and hygienic status of laying hens housed in furnished cages and in alternative systems. In alternative systems (floor housing and aviaries), birds have more freedom of movement and a more complex environment than in furnished cages. However, housing birds in much larger flocks in alternative systems leads to an increased risk of feather-pecking. Furthermore, air quality can be poorer in alternative systems than in furnished cages. This can affect health and hygienic status. There are only limited data on a direct comparison between furnished cages and alternative systems. Therefore, there is a need for an on-farm comparison of welfare, health, and hygienic status in these systems.

Bacteriological contamination, dirt, and cracks of eggshells in furnished cages and noncage systems for laying hens: An international on-farm comparison

For laying hens, the effects of housing system on bacterial eggshell contamination and eggshell quality is almost exclusively studied in experimental hen houses. The aim of this study was to compare eggshell hygiene and quality under commercial conditions. Six flocks of laying hens in furnished cages and 7 flocks in noncage systems were visited when hens were about 60 wk of age. Farms from Belgium, the Netherlands, and Germany were included in the study. The following parameters were determined on eggs sampled at the egg belts: 1) bacterial eggshell contamination, as expressed by total count of aerobic bacteria and number of Enterobacteriaceae; 2) proportion of dirty eggs; and 3) proportion of cracked eggs and eggs with microcracks. Considerable within-flock differences were found in eggshell contamination with total count of aerobic bacteria, both for furnished cages (P < or = 0.001, range 4.24 to 5.22 log cfu/eggshell) and noncage systems (P < or = 0.001, range 4.35 to 5.51 log cfu/eggshell). On average, lower levels of contamination with total count of aerobic bacteria (4.75 vs. 4.98 log cfu/eggshell; P < or = 0.001) were found on eggshells from furnished cages compared with noncage systems. Concerning Enterobacteriaceae, no significant difference in average eggshell contamination between both systems could be shown. The total percentage of cracked eggs was higher (P < or = 0.01) in furnished cages (7.8%) compared with noncage systems (4.1%). This was, however, due to the high percentage of cracked eggs (24%) observed on one of the furnished cage farms. We conclude that bacteriological eggshell contamination and percentage of cracked eggs differed substantially between individual farms using the same housing system. This may also explain some discrepancies between the findings of the present study versus some findings of previous experimental studies or studies on a small number of farms. Although statistically significant, the average differences in bacteriological contamination of nest eggs between both housing systems have limited microbiological relevancy.

Survey of egg producers on the introduction of alternative housing systems for laying hens in Flanders, Belgium

In the context of the European Union ban on battery cages by 2012, a survey was conducted among Flemish egg producers (60% response rate, 140 completed questionnaires) about the introduction and opinion of alternative housing systems. Belgium appears to be among the countries in the European Union that are slower to adopt alternative housing. Belgiums egg industry is thus likely to undergo drastic changes to comply with the 2012 deadline. As of 2010, the battery cage was the dominant housing system (56% housing units, 67% hens), followed by floor housing (33% housing units, 15% hens) and aviary (10% housing units, 15% hens), whereas colony cages and furnished cages were extremely rare. Future- and market-oriented production was the most important reason for choosing a certain type of alternative system, although the importance of hen performance and amount of labor seemed to increase. A quarter of the producers with battery cages had detailed plans to convert to an alternative system (most planned to install aviaries, followed by colony cages, furnished cages, and floor housing) by 2012. Many older farmers indicated that they would stop farming, whereas others found it more profitable to delay the conversion as long as possible. Apart from hen welfare, producers expressed a negative opinion (relative to battery cages) about noncage systems and, to a lesser extent, furnished cages. However, users of alternative systems reported being quite satisfied, except for the amount of labor and hen health. The housing system had several effects on user satisfaction: positive effect of flock size, negative effect of experience with battery cages, and negative effect of outdoor area on hen health. Although not all opinions were supported by evidence, such surveys provide feedback about the success of alternative systems in practice. This information is valuable to further improve these systems and to producers who have yet to convert. Moreover, producer attitude may determine the extent to which legally imposed changes in husbandry environment result in the desired improvement of hen welfare in practice.

Gizzerosine-induced histopathological lesions in broiler chicks

1. The aim of this study was to investigate pathomorphological changes in broiler chicks fed with different doses of gizzerosine, a substance produced during the heat treatments of fish meal. 2. The experiment was carried out in Ross broiler chicks which were divided into three groups: group A received 100% of non-medicated commercial mash for broiler chicks. During an experimental 5-d period, 50% of commercial mash was replaced with unheated fish meal (0.65 ppm gizzerosine) in group B and in group C with heated fish meal (1.15 ppm gizzerosine). Fourteen chicks from each group were killed every day. Samples of gastrointestinal and lymphoid organs, lung, pancreas, liver, brain and kidney tissue were sampled for histopathological analysis. Organs were embedded in paraffin and stained with hematoxylin-eosin stain and using periodic acid-Schiff reagent (PAS) and Sudan III (frozen sections). 3. Necropsy did not reveal notable differences between treated groups. There were no significant histopathological changes in immunocompetent organs nor in the lungs, the pancreas, the kidney or the brain. Sharply demarcated multiple vacuoles were observed in the myocardium in group C toward the end of the experiment. In group C, the prevalent changes in the gizzard and the proventriculus were slight to severe cuticle erosions and oedema of the lamina propria with or without multiple vacuoles, respectively, towards the end of the experiment. The most prominent changes toward the end of the experiment were dispersed cell vacuolisation in duodenal, jejunual, ileal and caecal lamina propria in group C. 4. In conclusion, it should be emphasised that extra-gizzard gizzerosine-induced lesions are probably not mediated by H 2 -receptor stimulation, but could be a consequence of cellular hypoxia.

Characterization of the On-Body Path Loss at 2.45 GHz and Energy Efficient WBAN Design for Dairy Cows

Wireless body area networks (WBANs) provide promising applications in the healthcare monitoring of dairy cows. The characterization of the path loss (PL) between on-body nodes constitutes an important step in the deployment of a WBAN. In this paper, the PL between nodes placed on the body of a dairy cow was determined at 2.45 GHz. Finite-difference time domain simulations with two half-wavelength dipoles placed 20 mm above a cow model were performed using a 3-D electromagnetic solver. Measurements were conducted on a live cow to validate the simulation results. Excellent agreement between measurements and simulations was achieved and the obtained PL values as a function of the transmitter-receiver separation were well fitted by a lognormal PL model with a PL exponent of 3.1 and a PL at reference distance (10 cm) of 44 dB. As an application, the packet error rate (PER) and the energy efficiency of different WBAN topologies for dairy cows (i.e., single-hop, multihop, and cooperative networks) were investigated. The analysis results revealed that exploiting multihop and cooperative communication schemes decrease the PER and increase the optimal payload packet size. The analysis results revealed that exploiting multihop and cooperative communication schemes increase the optimal payload packet size and improve the energy efficiency by 30%.

Experimental characterisation of the off-body wireless channel at 2.4GHz for dairy cows in barns and pastures

Off-body path loss in indoor (barn) and outdoor (pasture) environments.Path loss was well fitted by a one-slope log-normal model.Cow body shadowing presented maximum value of 7dB.Temporal fading can be described by a Ricean distribution in the considered environments. Wireless Sensor Networks (WSNs) provide promising applications in healthcare monitoring of dairy cows. After sensors measure the data in or on the cows body (temperature, position, leg movement), this information needs to be transmitted to the farm manager, enabling the evaluation of the health state of the cow. In this work, the off-body wireless channel between a node placed on the cows body and an access point positioned in the surroundings of the cows is characterised at 2.4GHz. This characterisation is of critical importance in the design of reliable WSNs operating in the industrial, scientific and medical (ISM) band (e.g., Wi-Fi, ZigBee, and Bluetooth). Two propagation environments were investigated: indoor (inside three barns) and outdoor (pasture). Large-scale fading, cow body shadowing, and temporal fading measurements were determined using ZigBee motes and spectrum analysis measurement. The path loss was well fitted by a one-slope log-normal model, the cow body shadowing values increased when the height of the transmitter and/or the receiver decreased, with a maximum value of 7dB, and the temporal fading due to the cow movement was well described by a Rician distribution in the considered environments. As an application, a network planning tool was used to optimise the number of access points, their locations, and their power inside the investigated barns based on the obtained off-body wireless channel characteristics. Power consumption analysis of the on-cow node was performed to estimate its battery lifetime, which is a key factor for successful WSN deployment.

Image Based Separation of Dairy Cows for Automatic Lameness Detection with a Real Time Vision System

Automation of lameness detection with vision techniques has a high potential to improve the early recognition of lame cows and would have a positive impact on time efficient herd management. In order to get individual information about gait features from cows passing a corridor in row e. g. after leaving the milking parlour an automatic separation of cows in a sequence is necessary. The presented results are based on video recordings done on farm, where cows walk from the milking parlour after milking through a corridor in row of 10 to 20 animals. To cope with problems such as stopping for a while in front of the camera, overlap of cows, non-uniform time interval between cows, etc. an algorithm for cow separation is proposed based on local image filtering and statistical analysis of binary images frame by frame. Filters to enhance horizontal and vertical edges in an image are utilized for shadow and background reduction. Binarization on filtered images is made by using statistical analysis. The column-based summation of binarized images related to a threshold is used to decide when the next cow in a row is detected after another has passed already. First results show 95% correct cow separation.

Heat stress in cows at pasture and benefit of shade in a temperate climate region

Under temperate climates, cattle are often at pasture in summer and are not necessarily provided with shade. We aimed at evaluating in a temperate region (Belgium) to what extent cattle may suffer from heat stress (measured through body temperature, respiration rate and panting score, cortisol or its metabolites in milk, and feces on hot days) and at assessing the potential benefits of shade. During the summer of 2012, 20 cows were kept on pasture without access to shade. During the summer of 2011, ten cows had access to shade (young trees with shade cloth hung between them), whereas ten cows had no access. Climatic conditions were quantified by the Heat Load Index (HLI). In animals without access to shade respiration rates, panting scores, rectal temperatures, and milk cortisol concentrations increased as HLI increased in both 2011 and 2012. Fecal cortisol metabolites varied with HLI in 2011 only. When cattle had access to shade, their use of shade increased as the HLI increased. This effect was more pronounced during the last part of the summer, possibly due to better acquaintance with the shade construction. In this case, shade use increased to 65% at the highest HLI (79). Shade tempered the effects on respiration, rectal temperature, and fecal cortisol metabolites. Milk cortisol was not influenced by HLI for cows using shade for > 10% of the day. Therefore, even in temperate areas, cattle may suffer from heat when they are at pasture in summer and providing shade can reduce such stress.