Agronomic and Seed Traits of Soybean Lines with Low–Phytate Phosphorus

Posted in: Environment by admin on January 1, 2005 | No Comments

Engineering controls to reduce hydrogen sulfide exposure of workers in swine buildings

Posted in: Environment by admin on | No Comments

Three engineering control measures were developed and tested for effectiveness in protecting swine barn workers from exposure to hydrogen sulfide (H2S) gas during manure handling. A remote manure pit plug pulling system allowed the worker to pull the manure pit plug from outside the room, thereby significantly reducing risk of worker exposure to H2S. A water sprinkling apparatus was also devised, which resulted in 79% reduction of H2S gas concentration under optimal laboratory conditions. However, the use of a similar system on agitated manure showed the opposite effect. A manure scraper system was installed to remove manure daily from the manure pit of a grower-finisher room. Preliminary measurements showed that H2S levels were 80 to 96% lower in the scraper room than in a similar room with a conventional pull-plug system. However higher ammonia emissions were observed in the scraper room compared to the conventional grower-finisher room.

Engineering controls to reduce hydrogen sulfide exposure to workers in swine buildings

Posted in: Prairie Swine Centre by admin on | No Comments

Engineering controls to reduce hydrogen sulfide exposure
of workers in swine buildings

Bernardo Predicala1, Stéphane Lemay2, Claude Laguë3, Shala Christianson1

Summary

Three engineering control measures were developed and tested for effectiveness in protecting swine barn workers from exposure to hydrogen sulfide (H2S) gas during manure handling events. A remote manure pit plug pulling system allowed the worker to pull the manure pit plug from outside the room, thereby significantly reducing risk of worker exposure to H2S. A water sprinkling apparatus was also devised, which resulted in 79% reduction of H2S gas concentration under optimal laboratory conditions. However, the use of a similar system on agitated manure showed the opposite effect. A manure scraper system was installed to remove manure daily from the manure pit of a grower-finisher room. Preliminary measurements showed that H2S levels were 80 to 96% lower in the scraper room than in a similar room with a conventional pull-plug system. However, higher ammonia emissions were observed in the scraper room compared to the conventional grower-finisher room.

Introduction

High levels of H2S can have detrimental effects on both workers and swine. Previous research by the Prairie Swine Centre Inc. (PSCI) indicated that workers are at risk of exposure to potentially hazardous H2S levels when performing manure management tasks, such as pulling manure pit plugs. The main goal of this project is to develop practical measures that can prevent or reduce worker exposure to high H2S concentration in swine buildings. Three different systems were investigated in separate modules.

Module 1 – Improved Design for Pit Plugs

In this module, an improved pit plug concept that allowed for pulling the plugs from a remote location was designed and evaluated. Two undergraduate students, assisted by technical staff at University of Saskatchewan and PSCI, designed and built a prototype system (Fig. 1). The system was installed in two grower-finisher rooms at PSCI and tested by measuring H2S concentrations using a H2S monitor (Draeger Pac III monitor with a H2S sensor, Draeger, Lübeck, Germany) during the plug-pulling operations.

After examining several plug designs, the extended cone plug was selected and installed. Monitoring of H2S levels during nine plug-pulling events showed that the maximum H2S concentration in the room over the plug area was 68 ppm, while corresponding concentrations at the alleyway near the winch was 0 ppm. Hence, the system was very effective in protecting the worker from being exposed to H2S by allowing the worker to perform the task away from the plug area.

Module 2 – H2S Abatement by Water-based Liquid Spray

Because H2S is water soluble, it was hypothesized that spraying a water-based liquid over agitated manure would reduce emissions into the air. In this module, a laboratory spray chamber was set up to determine the impact of a water-based spray on H2S levels in the chamber (Fig. 2). Preliminary tests were done to investigate the reduction in H2S levels as affected by various parameters such as type of spray nozzle, water pressure, temperature and pH, as well as the use of various chemical additives.

Laboratory tests with various combinations of test parameters consistently reduced the concentration of pure H2S gas released into the chamber (Fig. 3). Using a hollow cone nozzle at 200 kPa with water at pH = 9 resulted in a 79% reduction of the peak H2S levels. The treatment was applied to a set of barrels filled with swine manure. In four control barrels where no spray was applied, manure agitation produced an average of 148 ppm, with a peak reading of 520 ppm measured from the exhaust air. However, application of the water-spray treatment increased the average and maximum H2S concentrations to 273 and 690 ppm, respectively. Because these were not consistent with the observations in the laboratory study, it was suspected that other gases generated in the manure barrel affected the Draeger Pac III monitor. Additional tests are on-going to investigate the water-spray treatment further.

Module 3 – Manure Scraper System to Reduce H2S Levels

In this module, a manure pit scraper system (Fig. 4) was installed in a grower-finisher room to remove swine manure on a daily basis. Its effectiveness was evaluated by comparing the air quality in the scraper room and a similar room (Control) with conventional manure pit-plug system.

The scraper system was evaluated over two production cycles; during each trial both rooms were monitored closely over four one-week periods. Table 1 summarises the maximum H2S concentrations measured at two locations in the rooms. Compared to the control room, the maximum H2S concentrations were lower in the scraper room by an average of 80% over the plug area and by an average of 96% over the middle pen. Additionally, the maximum H2S levels in the control room exceeded the 15-ppm ceiling occupational exposure limit (OEL) value on three occasions during the two trials, while no peak H2S readings were higher than this limit value in the scraper room. The ceiling OEL is the maximum concentration of a biological or chemical agent to which a worker may be exposed, i.e., no worker should be exposed to any levels above this limit at any time.

During the two trials, significant levels of ammonia were measured in the incoming inlet air for both rooms, possibly due to recirculation of air exhausted from the fans into the supply air as well as from possible back draft of ammonia from adjacent rooms into the barn attic. The weekly average ammonia concentrations measured at the exhaust was significantly (p<0.05) higher in the scraper room (11.3 ppm, SD = 2.3 ppm) than in the control room (9.8 ppm, SD = 2.1 ppm), although the mean difference was smaller than the indicated accuracy of the ammonia analyzer. The calculated ammonia emissions were about 44% higher in the scraper room, which was attributed to the formation of a film of excreta on the pit bottom surface after scraping; this has been previously reported as possibly causing increased ammonia emissions in scraper systems. However, the observed ammonia levels were still lower than the 25-ppm OEL for ammonia, despite the presence of ammonia in the incoming air. Additional tests are on-going to determine the effectiveness of maintaining a layer of standing water at the bottom of the manure channel to control ammonia emissions. Conclusions A remote manure plug pulling system was successfully developed. Results showed that the system was effective in preventing worker exposure to H2S by allowing the pulling of the plugs from the alleyway. A water-spray treatment showed consistent reduction in H2S levels in a laboratory study. However, application of the treatment on agitated manure showed opposite effect on H2S. A manure scraper system used for daily manure removal from a swine room was effective in reducing H2S to levels below the maximum exposure limit for worker's safety. The system generated higher ammonia levels, although peak readings did not exceed the ammonia exposure limit value. Additional tests are being conducted to further investigate both the scraper and the water-spray systems. Acknowledgment Strategic funding provided by Sask Pork, Alberta Pork, Manitoba Pork, and Saskatchewan Agriculture and Food Development Fund. Project funding provided by Sask Pork, Agriculture Development Fund, and PIC Canada. (a) (b) (c) Figure 1. Improved pit-plug design showing the (a) extended cone plug, (b) with cable attached and plug-height stop, and (c) the cable-winch system for remotely pulling the plug from outside the room. Figure 2. Schematic diagram of laboratory set-up used to determine the effect of water-based spray on H2S levels in the chamber. Figure 3. Summary of laboratory test results (Nozzle Types: H (hollow cone) and F (full cone); Water Type: pH (water at pH 9), HP (water with hydrogen peroxide added), and N (normal water); Pressures: 70, 140 and 200 kPa). Figure 4. Scraper blade used for daily removal of manure from the pit. The manure pit has drains at both ends, through which the scraped manure was emptied to the sewer line. Table 1. Summary of maximum H2S concentration (ppm) measured in the scraper and control rooms. Control Scraper Date Over plug Middle pen Over plug Middle pen Trial 1 10-Mar-04 4.0 2.0 0.0 0.0 24-Mar-04 0.0 0.0 0.0 0.0 7-Apr-04 9.0 0.0 11.0 7.0 21-Apr-04 12.0 4.0 0.0 0.0 Trial 2 30-Jun-04 12.0 2.0 0.0 0.0 21-Jul-04 95.0 N/A 6.0 N/A 11-Aug-04 40.0 30.0 2.0 0.0 25-Aug-04 30.0 10.0 1.0 2.0 Average 25.3 6.9 2.5 1.3 SD 31.2 10.8 4.0 2.6 N/A – data not available, instrument malfunction

Larger Groups for Grower-Finisher Pigs: Feeding and Social Behaviours and Impacts on Social Stress.

Posted in: Prairie Swine Centre by admin on | No Comments

The dynamics of feeding and other behavioural activities of pigs in large social groups are not well understood. Therefore, the objective of this study was to gain a better understanding of feeding and other behavioural activities and the impacts of larger social groups on social stress in grower finisher pigs. One main concern of large group sizes for pigs is the potential for increased social stressors. Results from this experiment do not support this concern as no short or long-term responses of social stress were observed. Overall it was found that feeding behaviour was disturbed immediately following regrouping into large group sizes. Larger groups also seemed to take additional time to adapt feeding behaviours. Other behaviours such as eating/drinking, standing/walking and resting as well as diurnal patterns of these activities were not affected by large group housing. It is suggested that management of feeding behaviour in terms of accessing feeders may be critical immediately following formation of pigs into larger groups.

Energy Efficiencies Strategies for Reducing Utility Cost in the Barn

Posted in: Energy by admin on | No Comments

Energy resources should be efficiently managed to reduce expenses, pollution, and improve barn air quality. New lighting systems in barns allow for customizable lighting intensity and duration to be barn specific (for example, dimmer switches). $600.00 per year can be saved by using T-8 4’ vapour proof fluorescent lights as opposed to incandescent. Incandescent lights are obsolete, as they waste energy and have a short life. Convective heat systems are used to heat air itself. The drawback from the combustion is the CO2, carbon monoxide, and oxygen consumption. This is why ventilation is required, but with proper settings this can be minimized, or alternatively using a hot water heating system. Radiant heaters work much like microwaves because they heat the objects in the barn (i.e. – the pigs) directly. Of the gas tube heaters, catalytic/open flame brooders, and in-floor radiant heaters the in-floor has the best attributes. CFM/W (cubic feet of air per minute per watt) should be looked at when purchasing fans. The higher the CFM/W, the more efficient the fan is. This indicates how much air is moved throughout the day and how much it cost to move that air. Fans should be sized to match the stage requirements and they should have adequate hoods for optimum airflow. Monitoring equipment is used to monitor the quality of the environment. Some of this equipment can be used to measure general airflow, temperature and relative humidity, static pressure, inlet management, and gas detection. Gases of particular importance include ammonia, hydrogen sulphide (H2S), carbon monoxide, and carbon dioxide.

Lying down and rolling behaviour is sows in relation to piglet crushing (review).

Posted in: Welfare by admin on | No Comments

The crushing of piglets by the sow has always been a problem, but it has become increasingly prevalent in farrowing systems that loose house the sows. This article, reviewed papers pertaining to piglets crushing related to sows’ lying down and rolling behaviours. Very little research has been conducted on the rolling behaviours in sows. It is known that sows will roll more frequently when they are housed on concrete versus plasticized floors. Also the more quickly a sow rolls over, the higher the risk of piglets being crushed. Considerably more work has been done on the lying behaviour of sows; for example, the sequence of movements made during the process of lying down has been clearly broken down into five stages. Once again the speed of the movements, especially when the sow lowers her hindquarters, could possibly be related to piglet crushing. However, if a sow leans against a surface or if performs pre-lying behaviours (moves around, paws, roots, and gathers the piglets to in an area opposite of where she will lie) the risk of piglet crushing is reduced. As well, how responsive the sow is to a piglet that has become trapped underneath her affect the incidence of crushing, which may be influenced by the piglets’ responses to crushing (vocalizations), how long after parturition the incident occurs, the amount of space provided to the sow and bedding. Various factors such as domestication, breed, muscle control, previous and current housing may impact the methodology and how quickly a sow lies down. Piglets’ responses to crushing and space allocated to the sow may impact the exhibition of pre-lying behaviours. The authors believe all these factors should be taken into consideration when designing and managing the farrowing environment of the sow to help reduce the incidence of piglet crushing. However, the authors also call for more research in this area, as they believe a better understanding of these behaviours is needed.

Effects of specific noise and music stimuli on stress and fear levels of laying hens of several breeds.

Posted in: Welfare by admin on | No Comments

The tonic immobility duration and heterophil to lymphocyte ratio were measured in laying hens that were exposed to specific sound stimuli. In the first experiment, 36-week-old hens of four different breeds were studied. The treatments consisted of a control: 65 dB (background chicken vocalizations and fans) and 90 dB (background noises plus truck, train, and aircraft noises), which they were exposed to once for one hour. There was a significant difference between the noise treatments for the heterophil to lymphocyte ratio. Hens that were exposed to the excessive noise had significant heterophilia and had longer durations of tonic immobility. The results did not differ among the breeds. These results suggest that hens exposed to excessive noise were more stressed and fearful than the control hens. In the second experiment, 36-week-old birds from two different breeds were either maintained as the control (exposed to 65 dB of background noise) or were exposed to classical music and background noises at 75 dB for five hours per day for three days. There were no differences in heterophil to lymphocyte ratio between the control and treated hens. However, there was a difference in tonic immobility. The hens treated with music had longer durations of tonic immobility than the control hens. This suggests that treated hens were more fearful than control hens. The authors concluded that excessive noise is stressful and causes fearfulness in laying hens, and that the addition of classical music to the background noise also induces fear.

The effect of reward duration on demand functions for rest in dairy heifers and lying requirements as measure by demand functions

Posted in: Welfare by admin on | No Comments

The strength underlying a heifer’s motivation to lie down during a 24h period was examined in two experiments. In the first, eight heifers housed in tether-stalls were provided the freedom to lie down for 9 hours a day, and had to work to lie down for 6 per day. To earn the ability to lie down, a heifer had to press a panel 10 to 50 times and were rewarded with the ability to lie down for 20, 30, 50 or 80 minutes. The heifer were prevented from lying down by a strap around her midsection that was hooked up to a release mechanism. The amount of time offered as the reward affected how hard the cow was willing to work for the ability to lie down. When the reward duration was 20 minutes, the harder the cow had to work, the less likely she was to press the panel. During reward period that were longer in duration, the heifer would not lying down the entire time. When the reward was 50 minutes access to lying time, the cows tended to work for 4 extra hours of lying time. In total this provided the cow with 13 hours of lying time per day. In the second experiment the cow was only given 6 hours of free lying time and had to work to be able to lie down for 12 hours a day. The reward duration was kept constant at 50 minutes. Cows were observed to lie down for 5.5 hours of the 6 hours of free lying time. During the test period, cows would work for another 7 hours of lying time. In total cows spent 12.5 hour lying per day. The consistency of working towards the ability to lie down for approximately 13 hours/day illustrates that cows have an inelastic demand (willing to achieve that level regardless of cost) to rest lying down for that amount of time.

Behavior, physiology, and performance of bulls mixed at the onset of finishing to form uniform body weight groups.

Posted in: Welfare by admin on | No Comments

Young bulls were finished over a period of 8 months. They were either mixed or unmixed and were grouped with similar or non-similar BW at the beginning of the finishing period. Social behavior following mixing and throughout the finishing period, stress measurements (cortisol concentration, adrenal weight, catecholamines-synthesizing enzyme activity, and pain sensitivity), and production traits such as growth rate, homogeneity, feed efficiency, and carcass measurements were analyzed. Frequency of social interactions among the bulls increased after mixing. These included agonistic and nonagonistic interactions as well as sexual interactions. Agonistic and sexual interactions were more frequent among bulls in the similar BW groups. During the finishing period, synchronization of activity tended to be lower among mixed bulls. At slaughter, the activity of the catecholamines-synthesizing enzyme, tyrosine hydroxylase, was increased in mixed bulls, possibly indicating chronic stress. There were no differences noted in ADG or carcass traits among treatments. Body weight variability within groups increased in groups that initially had similar BW, but decreased in groups that initially had nonsimilar BW. Conclusions stated that mixing young beef bulls at the beginning of the finishing period did not have detrimental effects on health and production but mixing did increase stress levels, possibly due to decreased cohesion within the groups. The authors did not confirm that there was any benefit to mixing bulls at the onset of finishing in order to create groups of similar BW. This was because BW similarities within groups were not maintained throughout the finishing period.

Socio-spatial criteria are important for the establishement of maternal preference in lambs

Posted in: Welfare by admin on | No Comments

To enhance the relationship development between the ewe and the dam at lambing, it is believed that the ewe will isolate herself from the herd. After lambing, the ewe and her lamb return to the flock and the lamb begins to interact with other lambs. This study examined the importance of the social isolation at birth and other social and spatial factors that affect the maternal recognition of lambs. The ewes lambed in individual 2 m2 pens, which allowed the lambs to freely interact with the dam. The role of isolation was examined in the first experiment. The control treatment left the ewe and her lamb were left isolated in the birthing pen for the first 24 hours following birth. The experimental treatment progressively provided the pair with more space and increased contact with other pairs during the first 24 hours after birth (0-6h 1 ewe, 1 litter, 2 m2; 6-12h 2 ewes, 2 litters, 4 m2; 12-24h: 4 ewes, 4 litters, 8 m2). The lambs also underwent a choice test, in which they had to choose between their mother and an unfamiliar lamb. Twelve hours after birth, the lambs allowed social interaction displayed a preference for their mother, while the isolated lambs did not display this same preference. Even after 24 hour, the isolated lambs did not display any maternal preference. A second experiment investigated the importance of social interactions within each of the two groups previously studied. The isolated treatment received an increasing amount of space during the first 24 hours after lambing, similar to what the social treatment underwent. Twelve hours after lambing, lambs from both treatments displayed a preference for the dam, but was seen much sooner in the isolated mother-lamb pair. Data from both experiments suggests that lambs that were remained only with the dam during the first 24 hours after birth, also displayed a preference for their dam from a distance. The results from this study demonstrated that increasing the exposure to other flock members following birth, encourages the lamb to develop an attachment to the dam, and this bond is even stronger when they are provided increased space. Therefore, the development of the mother-lamb bond is socially and environmentally complex.