Electricity generation from swine wastewater using microbial fuel cells

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

Microbial fuel cells (MFCs) represent a new method for treating animal wastewaters and simultaneously producing electricity. Preliminary tests using a two-chambered MFC with an aqueous cathode indicated that electricity could be generated from swine wastewater containing 83207190 mg/L of soluble chemical oxygen demand (SCOD) (maximum power density of 45mW/m2). More extensive tests with a single-chambered air cathode MFC produced a maximum power density with the animal wastewater of 261mW/m2 (200O resistor), which was 79% larger than that previously obtained with the same system using domestic wastewater (14678mW/m2) due to the higher concentration of organic matter in the swine wastewater. Power generation as a function of substrate concentration was modeled according to
saturation kinetics, with a maximum power density of Pmax ¼ 225mW=m2 (fixed 1000O resistor) and half-saturation concentration of Ks ¼ 1512mg=L (total COD). Ammonia was removed from 19871 to 3471 mg/L (83% removal). In order to try to increase power output and overall treatment efficiency, diluted (1:10) wastewater was sonicated and autoclaved. This pretreated wastewater generated 16% more power after treatment (11074mW/m2) than before treatment (9674mW/m2). SCOD removal was increased from 88% to 92% by stirring diluted wastewater, although power output slightly decreased. These results demonstrate that animal wastewaters such as this swine wastewater can be used for power generation in MFCs while at the same time achieving wastewater treatment.

The effect of two piglet teeth resection procedures on the welfare of sows in farrowing crates. Part 2.

Posted in: Welfare by admin on | No Comments

A sow’s welfare may be in jeopardy if her piglets’ needle teeth are left intact during the lactation period. The current study was designed to determine the effects of clipping needle teeth or grinding needle teeth compared to leaving needle teeth intact, on the welfare of sows housed in farrowing crates. The sows’ teats were inspected for injuries at set intervals. Sow postural and lactational behaviours were also monitored. Findings indicated that intact teeth caused a greater number of udder injuries on days 11 and 18. Teeth that were ground also caused some injury, but not to the same extent as intact teeth. Sows housed with litters with intact teeth spent more time dog-sitting than sows in the other two treatments. On day 4, sows housed with litters with intact teeth allowed piglet suckling sooner after a 60 minute bout of separation than sows in the other two treatments, but terminated post-suckling udder massage sooner than sows in the other two treatments. Sows housed with litters with clipped or ground teeth spent more time lying on their chest (without their udder exposed) than sows in the clipped teeth treatment. Leaving needle teeth intact caused injury and disturbance to the sow, as did the grinding of needle teeth, but to a lesser extent. While in farrowing crates, leaving the piglets’ needle teeth intact was not recommended.

Effect of group size on aggressive reactions to an introduced conspecific in groups of domestic turkeys (Meleagris gallopavo).

Posted in: Welfare by admin on | No Comments

Aggressive encounters and injuries due to head pecking seriously threaten the welfare of domestic turkeys and also result in economic losses for the turkey industry. Animals of different species show an increase in aggression when unfamiliar conspecifics are mixed but a marked drop in aggression occurs as they become familiar with each other. This experiment was conducted to investigate the effect of group size on the frequencies of different types of aggressive interactions performed by 12-week-old broad-breasted turkey toms. Non-group members were introduced for 30 min into 12 small (6 bird) and 12 large groups (30 birds) and the subsequent aggressive behaviour was observed. The members of small groups initiated more fights and delivered more aggressive pecks to the introduced bird than members of larger groups. Also birds originating from small groups initiated more fights and delivered more aggressive pecks than birds from large groups. This study demonstrates that groups of turkey toms react differently to an introduced conspecifics depending on their group size.

Dominance relationships between sows dependent on the time interval between separation and reunion.

Posted in: Welfare by admin on | No Comments

Regrouping of sows after weaning can be a very stressful event and this study examined the practice of introducing these sows to each other prior to breeding so that the stress during pregnancy is reduced. Sows were weaned into groups of 8 sows immediately on removal from the farrowing crate. After 4 days the sows were stalled for breeding. Eight groups were reunited into their original groups after 7 days in the stalls, while 9 groups were reunited after 28 days. The aggression that followed the initial introduction was more extensive than either of the reunions, after either 7 or 28 days. Those kept apart for 28 days fought more upon being reunited than those separated for only 7 days. So, it is possible to reduce post-breeding aggression by familiarizing pigs to each other prior to breeding, and by reuniting them after a shorter period of separation for breeding.

On-farm assessment of laying hen welfare: a comparison of one environment-based and two animal-based methods.

Posted in: Welfare by admin on | No Comments

Methods for assessing animal welfare at farm level are based on a range of welfare parameters which can be divided into two categories: environment-based and animal-based. Environment-based parameters describe features of the environment and management, which can be considered prerequisites for animal welfare. Animal-based parameters records animals’ responses to particular environment and management factors. The current study was designed to assess the animal needs index (ANI), which is and environment-based method, with animal-based methods such as behavioural observations and feather condition scores (FCS). All measurements were taken during a one-day visit to each of 20 commercial laying hen farms. Positive correlations were found between ANI. Positive correlations were also found between ‘movement’ and ‘comfort’ behavioural factors. A negative correlation was found between ANI and ‘wing damage (from FCS). Conclusions stated that ANI was valid and sensitive enough to show differences in animal welfare between housing systems. Differences in welfare within housing systems, however, could not be shown. Thus, ANI was an appropriate method for assessment of laying hen welfare on a large number of farms with different housing systems.

Effects of age of Holstein-Friesian calves on plasma cortisol, acute-phase proteins, immunological function, scrotal measurements and growth in response to Burdizzo castration

Posted in: Welfare by admin on | No Comments

Bull calves were castrated using a Burdizzo to determine the effect of age at castration on physiological and immunological stress indices. Five age groups were studied: 1.5, 2.5, 3.5, 4.5, and 5.5 months of age, or the calves were sham castrated at 5.5 months of age to serve as a control. The results indicated that calves that were castrated at 5.5 months of age had significantly higher peak plasma cortisol responses than intact calves. All calves castrated at a younger age had lower peak responses, with bulls castrated at 1.5 months having the lowest. For the first 3 hours after castration, the integrated cortisol responses were three-fold greater in the 5.5 month old than intact calves. For the following 9 hours after castration there were no significant differences in integrated cortisol responses among the treatments. The calves castrated at 5.5 months of age had significantly greater concentrations of plasma haptoglobin and fibrinogen than intact calves. These concentrations were significantly reduced in calves castrated at 1.5 and 2.5 months of age compared to the 5.5-month castrates. On the first day following castration, there was a suppression of phythohaemagglutinin-induced in vitro interferon- production in calves castrated at 5.5 months of age compared to intact calves. All castrates had increased scrotal circumferences on days 1 and 7. There was a reduction in swelling in the 1.5 month olds compared to the 5.5 month old castrates. Castration did not affect growth rate among the calves. The authors concluded that castrating calves at 1.5 months of age causes less physiological stress and inflammation than castrating at 5.5 months of age.

Identification of Pig Circovirus Type 2 in New Zealand Pigs

Posted in: Welfare by admin on | No Comments

Organic Farming Scenarios: Operational Analysis and Costs of implementing Innovative Technologies

Posted in: Production by admin on | No Comments

The objective of this study has been to design a number of farm scenarios representing future plausible and internally consistent organic farming enterprises based on milk, pig, and plant production and use these farm scenarios as the basis for the generation of generalised knowledge on labour and machinery input and costs. Also, an impact analysis and feasibility study of introducing innovative technologies into the organic production system has been invoked. The labour demand for the production farms ranged from 6
1 to 25
3hha1 and from 19
4 to 39
6hLU1 (LU is livestock units) for work in the animal houses. Model validation results showed that farm managerial tasks amount to 14–19% of the total labour requirement. The impact of introducing new technologies and work methods related to organic farming was evaluated using two innovative examples of weed control: a
weeding robot and an integrated system for band steaming. While these technologies increased the capital investment required, the labour demand was reduced by 83–85% in sugar beet and 60% in carrots, which would improve profitability by 72–85% if fully utilised. Profitability is reduced, if automation efforts result in insufficient weed removal compared to manual weeding. Specifically, the benefit gained by robotic weeding was sensitive to the weed intensity and the initial price of the equipment, but a weeding efficiency of under 25% is required to make it unprofitable. This approach demonstrates the feasibility of applying and testing operational models in organic farming systems in the continued evaluation and documentation of labour and machinery inputs.

Biosecurity & You

Posted in: Production by admin on | No Comments

Dr. Shawn Davidson offers key components of biosecurity and attempts to identify specific pathogens that are biosecurity risks. There should be a 30 to 60 day quarantine period for any new stock entering the herd to protect from organisms such as Strep suis and Haemophilus parasuis. The quarantine facility should ideally have its own staff. There should only be one source of breeding stock rather than multiple. 3.2 km between farms appears to be adequate to prevent area spread of diseases such as PRRS and Mycoplasma hypopneumoniae. The ability to put large distances between barns makes building an operation in Saskatchewan and Western Canada optimal. In regards to transportation, trucks should be thoroughly washed and dried to tackle possible PRRS, and load-out chutes should have a “point of no return” so that workers do not enter the trucks and vice versa. Personnel who do enter the barn should shower through and change into clothing supplied in order to prevent PRRS, TGE, and zoonotic diseases such as Salmonella and influenza. Semen brought in from external sources should be free of PRRS or PCV2, or at the minimum have a sufficient semen-monitoring program. Rodents (e.g. – rats, mice, birds, etc.) should be minimized, and any barn supplies that may pose a risk should be disinfected.

Compensation Measures – A Necessary Condition for a Successful Foreign Animal Disease Effort

Posted in: Production by admin on | No Comments

The Canadian swine and pork industries have a huge interest in preventing foreign animal diseases from entering Canada. Today, Canadian producers sell their products to more than 90 different countries worldwide. An outbreak of a foreign animal disease such as foot-and-mouth disease would cause a negative economic impact of over $45 billion! In Canada it has been more than 40 years since an outbreak, with hog cholera in the 60s being the most recent. The key concern for producers is what is the compensation for destruction of infected animals, preventative stamping out in control zones, and loss of income during the interval before restocking is permitted. An adequate compensation program must compensate maximums per animal, compensate provisions must be equitable across species, differences in values between commercial and breeding values must be recognized, must be based on market intelligence and data, and allowances must be provided to account for the length of time before the affected farms are able to once again generate revenue.