N. Schembri

Evaluation of post-farm-gate passive surveillance in swine for the detection of foot and mouth disease in Australia.

Pigs are considered high risk for the introduction and spread of foot and mouth disease (FMD) in Australia. One of the most likely pathways of introduction of FMD into Australia would be through the illegal importation of FMD-contaminated meat, which is then fed to feral or domestic pigs. Locations where animals from different origins are commingled, such as livestock markets and abattoirs, pose a risk for disease spread. Early detection of exotic diseases at these locations is crucial in limiting the spread of an outbreak. The aims of this study were to evaluate the likelihood of exotic disease detection with current passive disease surveillance activities for pigs at saleyards and abattoirs in eastern Australia, and make recommendations for improving surveillance. Sensitivity (Se) of the current post-farm-gate passive surveillance for detection of exotic diseases was estimated using the scenario tree modelling methodology (Martin et al., 2007a). Four surveillance system components were identified: (i) domestic saleyard, (ii) export saleyard, (iii) domestic abattoir, and (iv) export abattoir. Pig farms were classified according to herd size (Small vs. Large) and subsequently into two risk categories depending on the probability of swill feeding (Swill feeding vs. Not swill feeding). A scenario tree representing the pathways by which infected animals could be detected was developed and the Se of detection in each surveillance system component was estimated. Industry statistics, information on previous exotic disease outbreaks, and interviews with pig producers were used to estimate herd category proportions and the relative risk of swill feeding. Quantitative estimates for probabilities of detection were sourced from State legislation and policies, stakeholder consultation and observational studies at saleyards and abattoirs. Results of a FMD case study showed a Se of detection at a representative location for each surveillance system component during a 2-week period of 0.19 at domestic saleyards, 0.40 at export saleyards, 0.32 at domestic abattoirs and, 0.53 at export abattoirs. This output assumed the country was infected with herd and unit design prevalences of 1% and 30%, respectively. Improving disease awareness of saleyard and abattoir stockmen, increasing the presence of inspectors at these venues and identifying those herds posing a higher risk for FMD introduction, could improve the capacity of the country for early detection of emerging animal diseases.

Biosecurity risks associated with current identification practices of producers trading live pigs at livestock sales.

Approximately 5% of pigs produced in Australia is believed to be traded at livestock sales. Interviews and focus group discussions were conducted with producers (106 and 30 producers, respectively), who traded pigs at livestock sales. The purpose of the study was to gather information on how producers identified their pigs in order to evaluate how these practices may impact the ability to trace pig movements in the event of an emergency animal disease outbreak or food safety hazard. Results were analyzed according to herd size (0 to 150 sows, 150+ sows) and location (peri-urban, regional) as prior studies suggested a higher biosecurity risk among smaller farms and due to perceptions that peri-urban farms pose additional risk. Most producers (91.5%) had less than 150 sows and a high proportion (70.8%) resided in regional areas compared with only 29.2% residing in peri-urban areas. A higher proportion of large-scale producers identified their pigs than small-scale producers. A third of small-scale producers reported not identifying breeding stock and most did not identify progeny. The most common forms of on-farm identification used were ear tags for breeding stock and ear notches for progeny. Producers identified breeding stock to assist with mating management and genetic improvement. Ear notches were used to determine the litter of origin of progeny. All large-scale producers owned a registered swine brand and used the official body tattoo for post-farm-gate identification. However, approximately 15% of small-scale producers did not own a registered swine brand, and an additional 8% did not identify their pigs post-farm-gate. Producers were satisfied with tattoos as a methodology for post-farm-gate identification of pigs and considered other methodologies cost-prohibitive. However, variations in the maintenance of the branding equipment, the type of ink used and the time of tattoo application in relation to the animal sale were highlighted during focus group discussions. These results suggest that there is a need for education and extension activities, especially among small-scale pig producers, regarding the benefits of identifying animals on-farm. In addition, increased awareness of the traceability legislation that exists in Australia to meet the National Performance Standards for Livestock Traceability in this country is required.

On-farm characteristics and biosecurity protocols for small-scale swine producers in eastern Australia.

Pigs are considered high risk for the introduction and spread of foot and mouth disease (FMD) in Australia. Facilities where animals from different origins are commingled, such as saleyards, pose a high risk for disease spread. Sound on-farm management practices and biosecurity protocols are the first line of defence against a potential on-farm disease outbreak. This study evaluated the practices of 104 producers (vendors who sold pigs and purchasers of live pigs for grow-out) who traded pigs at 6 peri-urban and rural saleyards in eastern Australia. Specifically, management and on-farm biosecurity practices were assessed using an in-depth questionnaire. Univariable and multivariable logistic regression analyses were used to investigate (1) producer associations: producer type, State, motivation to keep pigs, farm type, gender, years having owned pigs, and the acquisition of formal livestock qualifications; and (2) pig associations: herd size, housing, management (husbandry and feeding) practices and biosecurity (including pig movement) practices. Backyard operations (<20 sows) were undertaken by 60.6% of participants, followed by small-scale pig operations (28.8%; 21-100 sows). Few producers (16.3%) reported residing in close proximity (<5 km) to commercial operations; however, less rural producers had neighbouring hobby pig operations within 5 km of their property (P=0.033). Motivation for keeping pigs was significantly associated with a number of biosecurity practices. Producers who kept pigs for primary income were more likely to provide footwear precautions (P=0.007) and ask visitors about prior pig contacts (P=0.004). Approximately 40% of backyard and small-scale producers reported not having any quarantine practices in place for incoming pigs, compared to only 9.1% among larger producers. The main reasons cited for not adopting on-farm biosecurity practices in this study included having no need on their property (43.1%) and a lack of information and support (by the industry and/or authorities; 18.5%). Up to three-quarters of all producers maintained an open breeding herd, regularly introducing new pigs to the main herd. Saleyards are an important source of income for backyard and small-scale producers as well as an important risk factor for the introduction and dissemination of endemic and emerging animal diseases. Differing management and biosecurity practices as well as the motivations of these producers keeping pigs in small numbers and trading pigs at saleyards need to be taken into account in the development of successful biosecurity extension programmes for this sector of the Australian pork industry.

A qualitative study of the management and biosecurity practices of 13 interviewed pig owners selling via informal means in New South Wales, Australia

ThereisincreasinginterestinthetradingpracticesofproducerswhomarketpigsatliveauctioninAustraliaand the potential for infectious disease establishment and spread. The practices that underpin the commercial pork industry in Australiaarewellknown.However,littleisknownaboutinformalmovementsofpigsinAustralia,andthebiosecurityrisks associated with pig production enterprises that utilise these methods of trade. The aim of this study was to qualitatively evaluate the biosecurity and pig-keeping practices of owners who trade pigs informally for Foot and Mouth Disease and Classical Swine Fever exposure and spread. Interviews were conducted with 13 pig owners who trade via informal means between April and June 2009. Information provided by producers was able to be validated for the six interviews conducted on-farm.Therewaslimitedapplicationofrecommendedbiosecuritypracticeson-farmandfewkepthealthandmanagement records.All interviewees rearedother livestockspecies,such asruminants and/or poultry,as wellas pigs.Mostinterviewed owners claimed toquarantine introduced pigs fromthe main herd; however,few complied with industry recommendations. The results of this study suggest that pig owners (n = 13 interviewed) who currently trade their pigs informally pose few threats for the introduction of emergency animal disease. Pig keepers largely obtained their pig feed from reputable sources andappeared tohaveasound understandingof swillfeeding.However,thelackofon-farmbiosecurity, variablequarantine practices and the failure to keep health records could play a role in the spread of an emergency animal disease if it was to be introduced. Furtherworkisbeingundertaken todetermine, qualitatively, theriskassociatedwith themanagementpractices undertaken by informal pig traders and Foot and Mouth Disease and Classical Swine Fever introduction and spread.

Challenges posed to the traceability of weaner pigs following live auction

OBJECTIVES To gather demographic data on live pig sales through a peri-urban saleyard in Camden, New South Wales, and to demonstrate the difficulties in tracing the subsequent movements of pigs, particularly weaner pigs. PROCEDURE Records of pig sales held weekly at the Camden saleyards for the 2003/2004 and 2004/2005 financial years were analysed. Saleyard data on a number of variables were entered into a purpose-designed database. Distributions of pig sales according to pig class (weaner/porker/baconer/backfatter), purchaser type (butcher/non-butcher), and transaction type (cash/account) were determined. RESULTS More weaners (3192 in 2003/2004 and 3940 in 2004/2005) were sold than any other class of pig, accounting for 45% of the total pigs sold during this period. During 2003/2004, 3802 pigs were bought by 329 non-butcher purchasers including 1631 weaners (43%) purchased by 153 non-butchers (47%). The majority of these non-butchers during the study period (86%) paid cash for their pigs and did not provide the necessary information to allow the end destination of pigs to be determined. Location data was available for all vendors but only 25% of purchasers. CONCLUSIONS This study highlights the challenges posed in tracing movement of pigs following sale by auction. A high proportion of weaners sold at this peri-urban saleyard would not have been slaughtered immediately. This study highlights the potential difficulties in tracing pig movements after sale, for disease control purposes. We recommend that legislation be amended requiring the identification of weaner pigs sold live at auction in all states of Australia and the recording of the property identification code of all vendors and purchasers of pigs sold live at auction.

a comparative assessment of the risks of introduction and spread of Foot-and-Mouth Disease among Different Pig sectors in australia

Small-scale pig producers are believed to pose higher biosecurity risks for the introduction and spread of exotic diseases than commercial pig producers. However, the magnitude of these risks is poorly understood. This study is a comparative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) through different sectors of the pig industry: (1) large-scale pig producers; (2) small-scale producers (<100 sows) selling at saleyards and abattoirs; and (3) small-scale producers selling through informal means. An exposure and consequence assessments were conducted using the World Organization for Animal Health methodology for risk analysis, assuming FMD virus was introduced into Australia through illegal importation of infected meat. A quantitative assessment, using scenario trees and Monte Carlo stochastic simulation, was used to calculate the probabilities of exposure and spread. Input data for these assessments were obtained from a series of data gathering exercises among pig producers, industry statistics, and literature. Findings of this study suggest there is an Extremely low probability of exposure (8.69 × 10−6 to 3.81 × 10−5) for the three sectors of the pig industry, with exposure through direct swill feeding being 10–100 times more likely to occur than through contact with infected feral pigs. Spread of FMD from the index farm is most likely to occur through movement of contaminated fomites, pigs, and ruminants. The virus is more likely to spread from small-scale piggeries selling at saleyards and abattoirs than from other piggeries. The most influential factors on the spread of FMD from the index farm is the ability of the farmer to detect FMD, the probability of FMD spread through contaminated fomites and the presence of ruminants on the farm. Although small-scale producers selling informally move animals less frequently and do not use external staff, movement of pigs to non-commercial pathways could jeopardize animal traceability in the event of a disease outbreak. This study suggests that producers’ awareness on and engagement with legislative and industry requirements in relation to biosecurity and emergency animal disease management needs to be improved. Results from this study could be used by decision-makers to prioritize resource allocation for improving animal biosecurity in the pig industry.