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Prairie Swine Centre is an affiliate of the University of Saskatchewan
Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.
Financial support for the Enterprise Model Project and Pork Insight has been provided by:
Comparison of Agar Dilution and E-test for antimicrobial susceptibility testing of Campylobacter coli isolates recovered from 80 Ontario swine farms
Posted in: Ontario Pork, Pork Insight Articles by admin on January 1, 2005 | No Comments
The primary aim of this study was to evaluate the level of agreement of the E-test for in vitro antimicrobial susceptibility testing of Campylobacter coli using the agar dilution technique, which is the approved method. A convenience sample of 80 Ontario swine farms was chosen for this study; each farm was visited from January to June 2004. A total of 233 isolates of C. coli were tested for susceptibility to 10 antimicrobials by agar dilution and the E-test. Performance of the tests was evaluated using 7 quality control strains: Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 29213, Campylobacter jejuni ATCC 33560, and Campylobacter coli ATCC 33559 for the E-test and E. coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, and C. jejuni ATCC 33560 for the agar dilution test. Weighted Cohen’s kappa and prevalence-adjusted bias-adjusted kappa (PABAK) tests were used for statistical analysis. The E-test and agar dilution test results had a strong agreement when resistance to streptomycin and tetracycline were evaluated (weighted kappa: 0.68 and 0.66, respectively). However, marked disagreement was detected when testing susceptibility to nalidixic acid and ampicillin (0.15 and 0.22, respectively). Almost perfect agreement was detected by PABAK when testing susceptibility to gentamicin (0.99). Agreement was found to be moderate for ciprofloxacin, azithromycin, clindamycin, erythromycin, and chloramphenicol. Although the level of agreement between the E-test and agar dilution depended on the antimicrobial being tested, the E-test always detected a lower proportion of resistant isolates compared to agar dilution.
Evaluation of potential sources of PRRS virus infection in negative herds
Posted in: Air Filtration, Pork Insight Articles by admin on August 29, 2004 | No Comments
Traditionally PRRS outbreaks were thought to be from replacement animals and tainted semen. New research has shown that the spreading of PRRS and other viruses can also be transmitted by area spread, in transport, by insects and by fomites. This study tries to evaluate some of the other sources of PRRS outbreaks where semen and replacement animals were negative. Over four years 35 PRRS outbreaks were looked at. Of the sites that had outbreaks one was in a sow herd, six in finishing sites and eight in boar studs. When an outbreak was detected blood samples were taken and tested by serology and PCR. The researchers then tried to find the source of the virus. Area spread was considered as a potential cause in pig dense areas and where pigs were transported near other sites. External transport was also evaluated, with special attention to removal of cull sows and slaughter pigs. Other potential sources of infection included mechanical vectors, insects, people, and suspected biosecurity breaches. Reviewing the data found that 83% of the PRRS outbreaks were a result of lateral transfer and 17% were from semen or replacement pigs. For the lateral transmissions, over half were from area spread. Transport due to the removal of cull sows, boars or slaughter and feeder pigs, was strongly suspected in 17% of the lateral infections. Insects were only suspected in one case while biosecurity breaches were suspected in two cases. Seven cases could not be determined and infections had a tendency to happen in colder months. Location of the barns was considered the most likely causes of lateral infection. This study provides insight into sources of PRRS infections other than by replacement animals and semen.
La science au service de l’insémination porcine
Posted in: Air Filtration, Pork Insight Articles by admin on August 28, 2004 | No Comments
Partout à travers le monde, l’insémination porcine a connu un très fort développement au cours des quinze (15) dernières années. Ce développement est dû, entre autres, à la recherche qui a permis des améliorations notables au niveau de cette technique de reproduction. Afin de mieux faire connaître leurs travaux et permettre des échanges utiles, les principaux acteurs ont mis sur pied, il y a plusieurs années, un événement à caractère international : « International Conference on Boar Semen Preservation (ICBSP) », soit Conférence internationale sur la conservation de la semence porcine.
EVALUATION OF PRRSV OUTBREAKS IN NEGATIVE HERDS
Posted in: Air Filtration, Pork Insight Articles by admin on August 23, 2004 | No Comments
PPRS is a detrimental disease to swine producers. To combat PRRS, systems are stocked with PRRS negative animals and semen. Despite this being a measure to prevent PRRS the introducti0n of these animals has been considered the most important source for virus introduction. Although new research has shown that fomites, insects and transport all can help transmit the PRRS virus. The objective of this study is to provide information on the epidemiology of PRRSV breaks in negative systems where the source of replacement animals and semen is negative and to illustrate the ease with which lateral infections occur. Thirty-five PRRS outbreaks were tested during a four year period. They broke down as such: 21 in sow herds, 6 in finishing sites, and 8 in boar studs. Herds were routinely monitored through the observation of clinical signs, blood sample collection and semen testing in the case of boar studs. The samples were compared to samples taken from neighboring sites, and in a lab tests were done to see if the strains were from the same source. Attempts were made to determine the origin of the disease that were considered lateral, not being caused by introduction of new animals or semen. These infections were tested to see if they were because of area movement of the disease, pig movement with in the barn, transport, insect carriers, or human carriers. In this study 83% of infections were considered lateral, the remaining 17% were caused by introduction of infected animal or semen. Area spreading was considered to be the cause of 52% of the lateral cases. Transport due to the removal of cull sows, boars or slaughter and feeder pigs, was strongly suspected to be the causes of 17% of the lateral infections. Insects were suspected in one case, while bio-security breaches were suspected in two cases. This study provides insight into systems that have PRRS negative pigs brought into them. PRRS is then caused mostly by area, meaning vicinity to other operations and transport of dead animals.
Single-component Modelling of Pig Farm Odour with Statistical Methods and Neural Networks
Posted in: Ontario Pork, Pork Insight Articles by admin on August 20, 2004 | No Comments
In this paper, a neural network approach to the pork farm odour using single-component analysis with the consideration of other relevant factors, such as measurement location is proposed. Neural network models and statistical models for pork farm odour have been developed and compared for single-component models to determine which method produces superior results. Non-linear statistical and neural network models were developed and compared for single-component pork farm odour analysis using NH3 and H2S as odour indicators. The first set of models considered only a single-odour indicator and no other factors. In this case, the odour intensity predictions from the neural networks were generally better than the predictions produced by the non-linear statistical models. The second set of models considered asingl e-odour indicator (NH3 or H2S) and the odour source (pig building or pig manure storage). In this case, both of the developed neural network models N5 and N6 performed better than their corresponding neural network models (N1–N4) for every performance measure considered in this paper. In general, the use of neural networks to model the pork farm odour yields more accurate and precise odour intensity predictions than the statistical models. The measurement location for the pork farm odour was considered in several model comparisons. The neural network models significantly outperformed the statistical models in this comparison because the statistical models are not able to consider the measurement location. This indicates that measurement location is a relevant factor for modelling pork farm odour. This also demonstrates that factors other than odour components should be considered during modelling.
Transmission Of Pathogens: We Veterinarians Should Change OurTune!
Posted in: Air Filtration, Pork Insight Articles by admin on March 31, 2004 | No Comments
It has been commonly assumed that the leading cause of disease transmission among animal herds is by contact of infected animals with non infected animals. But since this theory has been so accepted there is little attention payed to other possible causes of disease transmission such as airborne spreading. This article describes instances where diseases have been transferred not by the introduction of infected animals but by aerial transmission. Foot and mouth disease in the UK was found to be caused by the introduction of infected animals in 5% of cases and 79% because of local spreading. In 1997 the epidemic of hog cholera was only found to be spread because of introduction of infected animals in 3% of the cases. Local spreading was the cause of the disease spreading in 36% of the cases. Porcine reproductive and respiratory syndrome is another common disease among swine herds. In an outbreak in Quebec, 44 cases of PRRS were detected, but the multiplier herd had never tested positive for PRRS meaning that none of these cases were because of the introduction of an infected animal. Enzootic pneumonia is another common disease worldwide in the pig industry. A outbreak in Quebec was from a completely negative herd source leading to the belief that the herds were infected by area spread, or neighborhood infection. These events suggest that aerosol transmission should be considered as a likely source of disease spreading along with infected semen and introduction of infected animals.
PRRS in Review: What do we know and where do we go?
Posted in: Air Filtration, Pork Insight Articles by admin on March 29, 2004 | No Comments
Since the discovery of the PRRS virus there have been large strides in further understanding it and how it moves within a swine herd, from one herd to another and how it is diagnosed. This article by Scott Dee summarizes the facts that we currently know about the PRRS virus. Most pigs are infected with the PRRS virus from an infected sow. As sows give birth to piglets they become infected while lactating and run the risk of transferring the virus to older pigs who were not born with PRRS but grouped together with these PRRS positive pigs. Understanding this transmission sequence is crucial in achieving a stabilized herd, meaning there is no chance of transmitting the virus from sow to sow or sow to pig. The work to eliminate PRRS from swine herds has been well documented, despite this completely PRRS negative herds still become infected with the virus. This was originally blamed on introducing PRRS positive pigs into a PRRS negative population and the use of semen that my contain the PRRS virus. But further research has proven that PRRS can also be transmitted by fomites, insects, in transport trailers and aerosols. Many new forms of diagnosing PRRS have become available since the discovery of the virus including the IDEXX ELISA, polymerase chain reaction and nucleic acid sequencing. Although each method still has drawbacks such as it can be difficult to interpret data for an individual pig.
Cost-effectiveness of controlling Salmonella in the pork chain
Posted in: Economics by admin on January 1, 2004 | No Comments
The objective of this paper is to explore the cost effectiveness of different control scenarios against Salmonella
in the Dutch pork chain to determine the most promising scenarios. Multiple scenarios were analysed, whereas each scenario included the epidemiological and economic consequences of interventions in the pork chain on the separate stages and on the pork chain as a whole. The first conclusion is that with respect to the prevalence reduction in the stages, the lairage stage seems to be most cost-effective. The second conclusion is that the most cost-effective strategy for the pork supply chain is to implement interventions in the first place in the slaughterhouses and also in the finishing farms. The third conclusion is that the cost-effectiveness is reduced in case not all farms or firms within a particular stage participate in reducing the prevalence of Salmonella. The most effective strategy with respect to the reduction of Salmonella will be to include the transportation and lairage in the Salmonella control
program, since these stages may become more important when the largest problems are solved in the finishing and
slaughter stage. The results of this paper give the first insight in the promising scenarios. In further research,
these scenarios have to be examined in more detail and can subsequently put into practice.
The effect of ACTH on pigs' attraction to salt or blood-flavored tail-models.
Posted in: Welfare by admin on | No Comments
As part of the stress response adrenocorticotrophic hormone (ACTH) is released. In other species, an increase in ACTH has been shown to result in an increase in salt appetite. The hypothesis of this study was that stressful situations increase salt appetite and therefore the pig’s attraction to blood. ACTH was injected for five days to mimic a stress response. The chewing behaviour of, and attraction to, salt- or blood-flavored tail models was studied in growing pigs following an injection of ACTH. Sixteen pigs were housed individually during the study. Half of the pigs were treated with ACTH, the other half were not. Tail models were made from sash cord, which was attached to plywood and mounted in each pen. There were three ‘tails’ per mounting: one soaked in pig blood, one soaked in salt solution (both with the same salt concentration) and one soaked in tap water. Attraction to blood does not appear to be due to the salt content in the blood. Regardless of treatment, pigs preferred to chew blood-soaked tail-models. Chewing of salt- and blood-soaked tail-models decreased for the ACTH-injected pigs. Injecting ACTH did not result in an increased salt appetite. Using ACTH to mimic a stress response needs further research. However, based on these results, the underlying cause of tail biting does not appear to be due to a stress induced salt appetite.
Effect of driver behaviour, driving events and road type on the stability and resting behaviour of sheep in transit
Posted in: Welfare by admin on | No Comments
The behavioural responses of sheep to driving events, and the relationship between driver behaviour and driving events were examined, since driving style can have a large impact on the welfare of animals by affecting risk of injury and disturbing their ability to rest. Two drivers drove groups of 10 sheep on a variety of roads, as the driver, the driver’s view of the road, the speedometer, and the sheep were video recorded. Differences in driving style affected the frequency of losses of balance by the sheep slightly, and affected the degree of disturbance to the sheep’s ability to rest during the journey more significantly. Falls were rare, although losses of balance were common. Driving events such as acceleration, braking, stopping, cornering, gear changes, or uneven road surfaces may have caused about 80 % of losses of balance. Only about 22 % of driving events preceded a loss of balance. Driving events may also have been responsible for many interruptions to lying behaviour and rumination. There were fewer losses of balance, more lying down, more rumination and fewer disturbances to the sheep when the driver was travelling on a motorway compared with a single carriageway. The results of this study provide evidence that would promote careful driving as a means of ensuring animal welfare in-transit for future driver training and education. A number of factors influenced by the driver of the vehicle may affect the quality of the journey experienced by sheep during transport.