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.

Ammonia Emissions from Irrigation of Dilute Pig Slurries

Posted in: Environment by admin on January 1, 2004 | No Comments

Approximately 20% of pig slurry in the UK is applied to land as dilute slurry (o2% dry matter content) via irrigation systems, which may result in larger emissions of ammonia (NH3) to the atmosphere than conventional application techniques. This study aimed to quantify this source under UK conditions and to assess the possibilities foremission abatement using alternative application techniques. Methodology was developed to measure emissions during irrigation, from both raingun- and boom-mounted splashplate systems. Measurements were also made following irrigation at both field- and small-plot scales. Emissions during irrigation of pig slurry to land were small, representing o0
1–2
5% of the total ammoniacal N (TAN) applied. Emissions from the land surface following irrigation were also small, typically amounting to only 10% of the TAN applied. Application via trailing hoses (band spreading) gave some reductions in emission for applications to growing crops, but no reduction when used on cereal stubble. Irrigation of dilute pig slurries does not therefore represent a major source of NH3 emission in the UK and, based on the results of this study, replacement of raingun or splashplate irrigation systems with trailing hose booms cannot be recommended as a worthwhile mitigation option.

Manitoba Revises Manure Rules

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Amendments to the Livestock Manure and Mortalities Management Regulation in Manitoba :
– Livestock operations of 300+ animal units will be required to submit test results for samples of water from the source used for livestock
– Existing operations of between 300 and 400 animal units have until 2010 to develop sufficient storage capacity and will not be allowed to winter spread after this date
– Older manure storage facilities built without a permit must now be registered. An application for registration must be submitted to government by July 10, 2004. Non-registered storage facilities cannot be used after July 10, 2010.
– Commercial applicators hired to spread manure must be certified and consultants retained to prepare manure management plans must be professional agrologists or Certified Crop Advisors registered in Manitoba
– Reduced rates of manure application to environmentally sensitive soils.

Other actions taken to date in the overall strategy to enhance land use planning and protection of water quality are:
– The Water Protection Act in March 2004 to protect and conserve Manitoba’s water
– Amendments to the Planning Act in 2004 to improve the process by which municipalities evaluate proposed livestock operations
– The establishment of a Department of Water Stewardship in the fall of 2003
– The Safe Drinking Water Act in August 2002
– The release of Manitoba’s Water Strategy in April 2003
– The establishment of the Office of Drinking Water
– The hiring of 12 new drinking water officers
– Enhanced training programs for operators of water and waste water systems
– The establishment of the Lake Winnipeg Stewardship Board

Suitability of Using “End of Pipe” Systems to Treat Farm Tile Drainage Water

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