Methicillin-resistant Staphylococcus aureus (MRSA) contamination of retail pork

Posted in: Meat Quality, Production by admin on August 22, 2011 | No Comments

Recent reports of isolation of methicillin-resistant Staphylococcus aureus (MRSA) from food animals have raised concern about the potential for foodborne transmission. This study evaluated the prevalence of MRSA contamination of retail pork from 4 Canadian provinces. Methicillin-resistant Staphylococcus aureus was isolated from 31/402 [7.7%] of samples. Adjusted for clustering at the provincial level, the prevalence was 5.8%. The most common clone was Canadian epidemic MRSA (CMRSA)-5 (12/31, 39%), which has been widely identified in horses and horse personnel, but not in pigs. Ten of the 31 (32%) isolates were nontypable by pulsed-field gel electrophoresis (PFGE) and belonged to spa 539/t034, a clone that is associated with food animals internationally. Nine (29%) isolates were CMRSA-2, a common human epidemic clone that has been found in pigs in Canada. While the relevance of contamination of retail meat is currently unclear, further study is required to determine if food may be a source of infection.

Granulomatous lymphadenitis associated with Actinobacillus pleuropneumoniae serotype 2 in slaughter barrows

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This study evaluated the occurrence of granulomatous lymphadenitis and its association with Actinobacillus spp. in 151 653 slaughtered pigs. Markedly enlarged pulmonary hilar, mediastinal, mandibular or hepatic lymph nodes were detected in 6 castrated males. The cut surfaces showed multifocal yellow-white lesions. Histologically, gram-negative bacilli were visible in the centers of the lesions with asteroid bodies, epithelioid cells, and multinucleated giant cells. Dense fibrous connective tissue surrounded these granulomatous lesions. Immunohistochemically, the organisms reacted with polyclonal antibodies against Actinobacillus pleuropneumoniae serotype 2 in all 6 barrows. The organism was isolated from the lymph nodes of all 6 animals. The results indicate that the granulomatous lymphadenitis was associated with A. pleuropneumoniae serotype 2 and the disorder had a tendency to occur in slaughter barrows.

Peracute selenium toxicosis followed by sudden death in growing and finishing pigs

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Fattening pigs (n = 751) showed progressive apathy, paralysis, and sudden death after accidental ingestion of excessive concentrations of selenium in mineral feed. Selenium concentrations of 1.09 to 1.32 mg/L in the serum confirmed the diagnosis. Within 3 d all pigs had died spontaneously or were euthanized due to the grave prognosis and on welfare grounds.

Prevalence of Clostridium difficile in retail pork

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Clostridium difficile was isolated from 1.8% (7/393) of retail pork samples obtained from 4 Canadian provinces. Five ribotypes and 3 toxinotypes were identified. Three isolates were indistinguishable from the international outbreak strain ribotype 027 and were toxinotype III. Although the implications for food safety practices remain elusive, the frequency of toxigenic isolates and isolates indistinguishable from known human pathogenic strains suggests contaminated pork may be a source of C. difficile in humans

An investigation into human pandemic influenza virus (H1N1) 2009 on an Alberta swine farm

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On May 2, 2009 the Canadian Food Inspection Agency notified the World Organization for Animal Health that an emerging novel influenza A virus (pandemic H1N1 2009) had been confirmed on a swine farm in Alberta. Over a 4-week period pigs in this farrow-to-finish operation were clinically affected by respiratory disease consistent with an influenza A virus infection and the presence of active viral infection was confirmed in all production areas by real-time polymerase chain reaction (RT-PCR). Despite clinical recovery of animals, there was reluctance by purchasers to receive animals from this operation due to concerns about the effect on both domestic and international markets. The owner decided to depopulate the entire herd due to impending welfare issues associated with overcrowding and economic concerns resulting from the inability to market these animals. Carcasses were rendered or composted and did not enter the human food or animal feed chain. The source of virus in this herd was determined to be an infected human. Zoonotic transmission to 2 individuals responding to the outbreak was suspected and recommendations to prevent occupational exposure are discussed.

Full text is available by subscribing to the Canadian Veterinary Journal

Epidemiological investigation of femoral fractures in market pigs and the associated economic implications

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The cause of an increased number of femoral fractures in market pigs from a single producer is described. Blood chemical, bone ash, radiographic, and feed analyses revealed that the fractures were caused by insufficient calcium in the diet. Associated economic and welfare implications are discussed.

Decreased mortality of weaned pigs with Streptococcus suis with the use of in-water potassium penicillin G

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This study evaluated the efficacy of potassium penicillin G in drinking water of weaned pigs to reduce mortality and spread of infection caused by Streptococcus suis. A total of 896 18-day-old weaned pigs were randomly assigned to either treatment with potassium penicillin G in-water (Treated), or no treatment (Control). The outcomes analyzed were total mortality, mortality due to S. suis, and overall counts of S. suis colonies. The risk of mortality due to S. suis and total mortality were significantly increased in the Control group compared with Treated pigs. Bacterial culture of posterior pharyngeal swabs indicated that Control pigs were significantly more likely to have $ 1000 colonies of S. suis per plate than were Treated pigs. This study demonstrates that potassium penicillin G administered in drinking water is effective in reducing mortality associated with S. suis infection and reducing tonsillar carriage of S. suis.

Crop Nitrogen and Phosphorus Utilization following Application of Slurry from Swine Fed Traditional or Low Phytate Corn Diets

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Field application of swine (Sus scrofa) slurry provides essential nutrients for crop production. The N to P ratio for slurry is lower than needed by most crops resulting in P accumulation when applied at N rates required for crop growth. Low phytate corn (Zea mays L.) (LPC) contains similar amounts of total P but less phytate P than traditional corn (TC) resulting in improved P bioavailability and reduced P excretion by monogastric animals. While manure from swine-fed LPC diets has a higher N to P ratio than that from TC diets, field studies comparing crop utilization of nutrients from LPC manure have not been conducted. A field study was conducted to compare N and P utilization by no-tillage rainfed sorghum [Sorghum bicolor (L.) Moench.] receiving three annual surface applications of nutrients (inorganic fertilizer, LPC slurry, and TC slurry) and by irrigated corn receiving one incorporated application of nutrients. Sorghum grain and total dry matter N utilization exhibited a year by treatment interaction but total dry matter N utilization was similar for both manure types in all years (61.2 % for TC and 53.8 % for LPC). Grain P utilization was similar for inorganic fertilizer and manure but differed among years (44.4% in 1999, 25.1% in 2000, and 57.0% in 2001). Corn grain N and P utilization did not differ among nutrient sources in the year of application (50.7% for N and 40.4 for P) and increased little in the year following application (62.2 % for N and 50.2 % for P). Crop N and P utilization from LPC manure and TC manure was similar and nutrient guidelines developed for TC swine slurry should also apply for LPC slurry.

PDF provided from Agron. J. 100:4 pp: 997-1004 (2008), with permission, copyright American Society of Agronomy.

Stillbirth and Preweaning Mortality in Litters of Sows Induced to Farrow with Supervision Compared to Litters of Naturally Farrowing Sows with Minimal Supervision

Posted in: Ontario Pork, Pork Insight Articles by admin on August 19, 2011 | No Comments

The objective of this study was to evaluate the benefits of induced farrowing with supervision on rates of stillbirths and preweaning mortality.  A total of 159 multiparous sows were assigned in approximately equal numbers to two groups.  Group One sows (n = 75) were induced to farrow using two intravulvar injections of 5 mg prostaglandin F2α administered 6 hours apart on day 114 of gestation (Day 0). Farrowing was supervised, with assistance given as required. Group Two sows (n = 84) were allowed to farrow naturally, with supervision and neonatal care standard for the production facility. All live piglets were weighed at 3 days and 21 days of lactation. Of the Group One sows, 56 farrowed during working hours on Day 1. There were fewer stillbirths per litter in Group One than in Group Two sows (0.4 ± 0.09 versus 1.0 ± 0.17, respectively). There was no effect of treatment on overall preweaning mortality. Weights were greater for Group One than for Group Two piglets at both 3 days of age (1.9 ± 0.04 kg versus 1.7 ± 0.02 kg, respectively; P < .01) and 21 days of age (5.7 ± 0.06 kg versus 5.5 ± 0.05 kg, respectively;P <.01). Inducing farrowing and providing supervision on the day of farrowing can reduce stillbirths. However, reducing overall preweaning mortality requires more than 1 day of supervision.

The Metabolic Availability of Threonine in Common Feedstuffs Fed to Adult Sows Is Higher Than Published Ileal Digestibility Estimates

Posted in: Ontario Pork, Pork Insight Articles by admin on August 15, 2011 | No Comments

Amino acid (AA) requirements for sows during pregnancy are currently under review. However, requirement recommendations must be accompanied by an estimate of the bioavailability of AA from feeds to ensure adequate supply of AA and to minimize excess nitrogen excretion. Current ileal AA digestibility estimates are based on growing pig data; however, availability of AA in adult pigs may be different from that in growing pigs. The metabolic availability (MA) of threonine (Thr) in corn and barley was determined in 6 pregnant sows using the indicator AA oxidation method and L-[1-13C]phenylalanine as the tracer AA. Sows were fed reference diets formulated from 30 to 75% of the breakpoint derived in Expt. 1; all other nutrients were set at 120% of requirement. Test ingredients diets were formulated to supply Thr at 75% of the determined requirement. Tracer phenylalanine was given orally in 8 one-half–hourly meals and expired 13CO2 was quantified. The determined MA of Thr from corn and barley fed to pregnant sows was 88.0 and 89.3%, respectively. The determined MA was 7 and 9% greater than the published standard ileal digestibility estimates of Thr in corn (82%) and barley (81%), respectively. Mature animals have a greater capacity to digest and absorb nutrients from feed ingredients than previously assumed based on ileal digestibility studies. Sow diets formulated based on published ileal digestibility estimates are overformulated with respect to available protein and AA and thus increase excess nitrogen excretion and potential environmental concerns