Porcine reproductive and respiratory syndrome virus (PRRSv): Update on Noveko’s Air Filtration System

Posted in: Air Filtration, Pork Insight Articles by admin on August 29, 2010 | No Comments

This power point presentation reviews the research and development carried out with N0veko’s antimicrobial air filters. The presentation explains how Noveko’s antimicrobial filters work. Also discussed is engineering aspects with respect to the installation of air filtration systems in swine buildings. Costs are not discussed in this presentation but potentially in a future presentation.

An update of SDEC-related research efforts on the aerobiology and biosecurity of porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae

Posted in: Air Filtration, Pork Insight Articles by admin on August 28, 2010 | No Comments

PRRS has been found to be transported by fomites such as boots and containers, but it was not believed to be transferred with aerosols. This was proven wrong by tests done by Cho et al as they were able to observe a PRRS virus that traveled one mile by aerosol. Although this was difficult for other researchers to achieve or even repeat by the original team. It was found that a modified version of the virus was able to attach to particles such as dust and water to travel long distances. Hog farms in France were able to apply positive air pressure along with high efficiency filters to limit the movement of PRRS, but this was found to not be practical in the US due to different air pressure systems and the costs would not makes sense economically. So researchers set out to find a cheap alternative to this method applicable to US hog operations. A model was set up to replicate a dense pig population involving 300 head of middle aged pigs. Three barns were involved in the study, one was inoculated with PRRS, one was naive and had a high quality filter, and one was naive and held in a poorly filtered barn. Over a year air and blood samples were taken and analyzed for PRRS. Results showed that there was no sign of PRRS in the well filtered barn, and while no pigs became infected in the poorly ventilated barn, 10% of the air samples taken had evidence of PRRS. No hog operation since the onset of PRRS has been able to consistently produce weaned pigs who are PRRS negative. Air filtration is potentially one step towards sustainable PRRS negative production.

“Periweaning Failure to Thrive Syndrome (PFTS)” – difficulties of investigating an emerging clinical problem

Posted in: Ontario Pork, Pork Insight Articles by admin on August 21, 2010 | No Comments

Some young pigs suffer from a disease that causes them to be anorexic and experience catobolic events that leads to body store depletion. These pigs either die or are euthanized as they cannot grow properly.The condition causes mobilization of lipid stores, loss of muscle mass, failure to grow as well as other symptoms. This condition has been increasing recently so members from the Swine Health Management (SHM) section of the American Board of Veterinary Practitioners want to revisit “failure to thrive syndrome”.  In these conference proceedings from the 2010 Leman conference SHM members discuss the disease in detail. The topics they cover are:  Clinical presentation and progression to outcome, progression of the clinical pathologic process, pathologic changes and assumed metabolic changes, experiences and approaches to investigating an emerging clinical problem, and the difficulties of investigating an emerging clinical problem. The intent of this presentation is to educate stakeholders who are impacted by FTS they are researchers, diagnosticians and practitioners.

Development of a Bench-Scale Air Sparged Continuous Flow Reactor for Struvite Precipitation from Two Different Liquid Swine Manure Storage Systems

Posted in: Environment by admin on August 20, 2010 | No Comments

Forced precipitation of struvite (MgNH ₄ PO ₄ ^. 6H ₂ O) can reduce dissolved reactive phosphorus (DRP) in swine manure slurries. Optimization of this process requires that the swine manure slurry pH be increased, that magnesium be added, and that sufficient reaction time be allowed for struvite precipitation. To gather data that could be used for a full-scale continuous-flow struvite precipitation reactor, a bench-scale (14-L) continuous flow reactor was designed, constructed, and tested. The bench-scale reactor used air sparging for both pH adjustment and mixing, used a peristaltic pump to continuously inject magnesium chloride (MgCl ₂ ^. 6H ₂ O), and was operated at a 10-min hydraulic retention time. The bench-scale system provided a 95% reduction of DRP in swine manure slurry collected from a concrete storage tank with a permeable cover, and a 78% reduction of DRP in swine manure slurry collected from a shallow under floor pit collection system. A bench-scale up-flow clarifier was designed, constructed, and tested for continuous flow separation of the precipitated struvite in order to provide total phosphorus (TP) removal. The up-flow clarifier was unable to continuously settle struvite particles formed in the bench-scale reactor and provided no significant TP removal through the system. The implication of this work for full-scale systems is discussed.

Spread of Porcine Circovirus Associated Disease (PCVAD) in Ontario (Canada) Swine Herds: Part II. Matched Case-control Study

Posted in: Ontario Pork, Pork Insight Articles by admin on | No Comments

The primary objective of this study was to evaluate risk factors for incidence cases of reported PCVAD. A time-matched case-control study was used as a study design approach, and conditional logistic regression as the analytical method. Briefly, 278 herds located in southern Ontario were included in this study initially using two different sampling mechanisms: (i) sampling of herds positive for porcine reproductive and respiratory syndrome virus (PRRSv) using data from a diagnostic laboratory (Animal Health Laboratory, University of Guelph, Guelph, ON, Canada), based on rtPCR-positive diagnostic findings, and (ii) sampling of PRRSv-negative herds, based on assessment of a herd veterinarian. Herds were classified into PCVAD-positive and negative herds on the basis of producers’ assessments, and results obtained during exploratory spatial analysis were used to guide the design of this case-control study. In conclusion, the spread of PCVAD due to high-risk local exposure was primarily driven by herd ownership. It was therefore impossible to distinguish local spread from common direct or indirect sources that contributed to the emergence of disease concurrently in different premises under the same ownership. Surprisingly, frequency of direct or indirect contacts did not differ between case and control herds. This also applies to frequency of feed delivery, which, although statistically significant, was driven by a single highly influential point, which in itself did not align with a biological rationale for spread through feed deliveries. Two risk factors that remained stable were herd PRRSv status and directional spread in a western direction.

Tetracycline use and selection of virulent enterotoxigenic Escherichia coli

Posted in: Ontario Pork, Pork Insight Articles by admin on August 16, 2010 | No Comments

In the last decade in Ontario a new strain of E. coli (ETEC) of the serogroup O149 has been causing severe diarrhea in piglets after weaning. This new strain contains pTENT2 which encodes for tetracycline resistance and virulence factors that were absent from previous O149 ETEC strains. This suggests that the increased virulence of the new ETEC is caused by the pTETN2 plasmid and that the use of tetracycline may select for this strain. The objectives of this project was to develop methods to identify and detect this strain, to generate mutants without the new pTENT2 plasmid, and to compare the behavior of the ETEC strain with and without pTENT2 with and without tetracycline in the feed in an animal model for postweaning diarrhea. E. coli O149 strains with and without the pTENT2 plasmid were generated. They were used to infect weaned piglets fed with and without tetracycline. The severity of the treatments was assessed in the piglets.No statistical difference was detected between groups that received the modified ETEC strains. Some variations were found, but studies with larger numbers need to be carried out to confirm the significance.

Early Weaning Reduces Small Intestinal Alkaline Phosphatase Expression in Pigs

Posted in: Ontario Pork, Pork Insight Articles by admin on August 14, 2010 | No Comments

This study was conducted to determine the effect weaning has on intestinal alkaline

phosphatase (IAP) activity. IAP is important for enteric health of the growing pig, playing roles

in immune health, intestinal health, digestion, and fat absorption. 12 piglets were weaned at ten

days old and put on standard commercial weaning diet and 12 piglets remained suckling with the

sow as the control treatment. Overall, weaning decreased IAP affinity by 26% and maximal enzyme

activity by 22%.  The main effect was seen in the jejunal region becasue the jejunum expresses 84-86%

of the total gut mucosal IAP activity. Weaning decreased the amount of IAP associated with the

proximal jejunal apical membrane by 64% and proximal jejunal IAP mRNA by 58% which was

associated with a decrease in the abundances of cytoplasmic (27%) and nuclear (29%) IAP caudal-

associated homeobox transcription factor 1. In conclusion, weaning decreased the amount of

IAP available in the pigs gut to facilitate gut and immune health. This may, in part, contribute

to the growth check and increased susceptibility to gastro-intestinal disease in early weaned pigs.

Relationship between estimated finishing-pig space allowance and in-transit loss in a retrospective survey of 3 packing plants in Ontario in 2003

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A retrospective survey to determine the effect of space allowance on in-transit losses of  finisher pigs in summer temperatures in June, July and August 2003. Both 2- and 3-tiered  trailers were considered that transported greater than 130 pigs to 3 main Ontario packing plants processing 76% of all Ontario market hogs. Packer data was combined with daily in-transit loss data to determine the number of pigs that were transported on that trailer and space allowance was determined from the trailer’s capacity and the number of pigs transported. Environmental temperature and relative humidity data was provided by 2 local Ontario weather stations and were considered on a hourly basis. As environmental temperature increased, in-transit losses  increased. As space allowance decreased, in-transit losses increased when the temperature was  constantly below 21°C however by a lesser amount than was seen with temperature. Overall, it was found that temperature had a greater affect on piglet in-transit losses than space allowance   however increasing space allowance allows pigs to cool more efficiently and will therefore  decrease pig in-transit losses.

Greater Availability of Amino Acids in Feedstuffs for Sows Compared to Growing Pigs

Posted in: Ontario Pork, Pork Insight Articles by admin on August 13, 2010 | No Comments

Recent data suggests that gestating sows have a greater capacity to digest dietary protein than growing pigs and thus different values for amino acid availability should be used when formulating sow diets. The MA of threonine in corn and barley in six gestating gilts (146 ± 4 kg BW) was determined using the indicator amino acid oxidation technique. A paired study using six growing pigs (146 ± 4 kg BW) and corn was conducted to allow a direct comparison between a) determined MA values and published TID values for growing pigs and b) the determined MA for sows and growing pigs. Pigs were fed reference diets with increasing synthetic THR from 50 – 80 % of requirement; all other nutrients were provided in excess. Test ingredient diets were formulated to 80 % of requirement by inclusion of corn or barley. On collection day, L [1-13C] and L [1-14C] phenylalanine (sows and growers, respectively) was given orally in eight ½-hourly meals and expired 13CO2 and 13CO2 was quantified. The Mixed model in SAS was used to determine the change (slope) in indicator oxidation per gram of total dietary THR from reference and test diets. The MA of THR was calculated as the slope for THR from test diets divided by the slope for THR from reference diets.  The MA method gives results not different from TID. The bioavailability of amino acids in feedstuffs is greater in sows than in growing pigs.

The Requirement for Threonine in Early and Late Gestation in Sows

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This study aims to determine the requirement for Threonine in early and late gestation in sows. The THR requirement in early (25-55d) and late (80-111d) gestation was determined by indicator amino acid oxidation in eight sows fed THR from 20 % to 120 % and from 60 % to 180 % of NRC (1998) estimated requirements in early and late gestation, respectively. L [1-13C]phenylalanine was given orally in eight ½-hourly meals as indicator AA and expired 13CO2 was quantified. The nonlinear Mixed model in SAS was used to determine the THR requirement for each period by breakpoint analysis. Sows responded differently to increasing levels of dietary THR in early and late gestation. Breakpoint analysis resulted in a THR requirement of 4.9 g/d in early gestation (R2=0.71) and 12.3 g/d in late gestation (R2=0.58). The current recommended THR intake during gestation is 10 g/d. These results support previously reported data that there is a greater than 2-fold increase in THR requirement in late gestation. Reducing AA content in sow diets up to 80 d gestation followed by higher AA content in late gestation may substantially reduce feed costs. Phase feeding during gestation may also improve sow reproductive performance by more closely meeting AA demand in late gestation. Current practices of feeding a single AA level during gestation results in negative impacts on sow body condition in late gestation due to deficient AA intake.