Assessment of the economic impact of porcine reproductive and respiratory syndrome virus on United States pork producers

Objective: To estimate the current annual economic impact of porcine reproductive and respiratory syndrome virus (PRRSV) on the US swine industry

Occupational Exposure to Streptococcus suis among US Swine Workers

Despite numerous cases of human infection with Streptococcus suis worldwide, human disease is rarely diagnosed in North America. We studied 73 swine-exposed and 67 non–swine-exposed US adults for antibodies to S. suis serotype 2. Serologic data suggest that human infection with S. suis occurs more frequently than currently documented

Using Machine Learning to Predict Swine Movements within a Regional Program to Improve Control of Infectious Diseases in the US.

Between-farm animal movement is one of the most important factors influencing the spread of infectious diseases in food animals, including in the US swine industry. Understanding the structural network of contacts in a food animal industry is prerequisite to planning for efficient production strategies and for effective disease control measures. Unfortunately, data regarding between-farm animal movements in the US are not systematically collected and thus, such information is often unavailable. In this paper, we develop a procedure to replicate the structure of a network, making use of partial data available, and subsequently use the model developed to predict animal movements among sites in 34 Minnesota counties. First, we summarized two networks of swine producing facilities in Minnesota, then we used a machine learning technique referred to as random forest, an ensemble of independent classification trees, to estimate the probability of pig movements between farms and/or markets sites located in two counties in Minnesota. The model was calibrated and tested by comparing predicted data and observed data in those two counties for which data were available. Finally, the model was used to predict animal movements in sites located across 34 Minnesota counties. Variables that were important in predicting pig movements included between-site distance, ownership, and production type of the sending and receiving farms and/or markets. Using a weighted-kernel approach to describe spatial variation in the centrality measures of the predicted network, we showed that the south-central region of the study area exhibited high aggregation of predicted pig movements. Our results show an overlap with the distribution of outbreaks of porcine reproductive and respiratory syndrome, which is believed to be transmitted, at least in part, though animal movements. While the correspondence of movements and disease is not a causal test, it suggests that the predicted network may approximate actual movements. Accordingly, the predictions provided here might help to design and implement control strategies in the region. Additionally, the methodology here may be used to estimate contact networks for other livestock systems when only incomplete information regarding animal movements is available

Measuring Progress on the Control of Porcine Reproductive and Respiratory Syndrome (PRRS) at a Regional Level: The Minnesota N212 Regional Control Project (Rcp) as a Working Example.

Due to the highly transmissible nature of porcine reproductive and respiratory syndrome (PRRS), implementation of regional programs to control the disease may be critical. Because PRRS is not reported in the US, numerous voluntary regional control projects (RCPs) have been established. However, the effect of RCPs on PRRS control has not been assessed yet. This study aims to quantify the extent to which RCPs contribute to PRRS control by proposing a methodological framework to evaluate the progress of RCPs. Information collected between July 2012 and June 2015 from the Minnesota Voluntary Regional PRRS Elimination Project (RCP-N212) was used. Demography of premises (e.g. composition of farms with sows = SS and without sows = NSS) was assessed by a repeated analysis of variance. By using general linear mixed-effects models, active participation of farms enrolled in the RCP-N212, defined as the decision to share (or not to share) PRRS status, was evaluated and used as a predictor, along with other variables, to assess the PRRS trend over time. Additionally, spatial and temporal patterns of farmers' participation and the disease dynamics were investigated. The number of farms enrolled in RCP-N212 and its geographical coverage increased, but the proportion of SS and NSS did not vary significantly over time. A significant increasing (p<0.001) trend in farmers' decision to share PRRS status was observed, but with NSS producers less willing to report and a large variability between counties. The incidence of PRRS significantly (p<0.001) decreased, showing a negative correlation between degree of participation and occurrence of PRRS (p<0.001) and a positive correlation with farm density at the county level (p = 0.02). Despite a noted decrease in PRRS, significant spatio-temporal patterns of incidence of the disease over 3-weeks and 3-kms during the entire study period were identified. This study established a systematic approach to quantify the effect of RCPs on PRRS control. Despite an increase in number of farms enrolled in the RCP-N212, active participation is not ensured. By evaluating the effect of participation on the occurrence of PRRS, the value of sharing information among producers may be demonstrated, in turn justifying the existence of RCPs

Longitudinal study of Staphylococcus aureus and MRSA colonization of US swine veterinarians

Patterns of detection of S. aureus are being evaluated in a longitudinal study of a cohort of 67 swine veterinarians in the USA. This report presents interim data from the initial period of the study. Overall, approximately 70% of sampling events yielded S. aureus in nasal swabs from veterinarians, and 8% yielded MRSA isolates

Management factors associated with seropositivity to Lawsonia intracellularis in US swine herds.

abstract: This study was conducted to determine risk factors for Lawsonia intracellularis seropositivity in the breeding and grower-finisher units of US farrowing-to-finishing swine herds. Serum was collected from 15 breeding females and 15 grower-finisher pigs per herd in 184 farrow-to-finish herds, a subset of 405 herds in the National Animal Health Monitoring System (NAHMS) Swine 1995 Study that examined management, health and productivity in herds with at least 300 finisher pigs. Sera were tested by indirect fluorescent antibody test for L. intracellularis. Test results were linked with NAHMS questionnaire data and a logistic regression model of management factors associated with L. intracellularis serological status was developed. Separate models were used for breeding and grower-finisher units. Risk factors for seropositive breeding units were L intracellularis-seropositive status of the grower-finisher unit, use of a continuous system of management for the farrowing unit and a young parity structure (<75% multiparous sows). Risk factors for seropositive grower-finisher units were L. intracellularis-seropositive status of the breeding unit, the number of pigs entering the grower-finisher stage, raising pigs on concrete slats, and intensive management compared with raising pigs on outdoor lots. Use of all in-all out management in the farrowing house and an older parity structure in the sow herd were associated with a lower risk of L. intracellularis seropositivity in the breeding unit, and slatted concrete flooring in grower-finisher houses was associated with a greater risk. Alteration of these management factors might improve control of L. intracellularis infection in farrowing-to-finishing herds

Pre-sorting and pen size effects on the stress responses at loading and unloading and transport losses in market weight pigs

Transport losses represent three challenges for the US swine industry and these are: 1) pig well-being, 2) increased rules and regulations, and 3) direct financial losses to producers and packers. Therefore; improving the well-being of pigs during transport and reducing the incidence of dead and non-ambulatory pigs is a priority for the US swine industry (NPB, 2007). Johnson et al. (2010) studied the effects of grow-finish pen size and manually pre-sorting pigs the day before loading on the stress responses at loading and unloading and transport losses in market weight pigs. The authors reported that pigs loaded from large pens (192 pigs/pen) that were pre-sorted from pen mates had 66% fewer dead and non-ambulatory pigs at the harvest facility compared to pigs loaded from small pens (32 pigs/pen) that were sorted from pen mates during loading. However, it is unclear if the reduction in transport losses was due to pen size and/or pre-sorting before marketing. Therefore, the objectives of the current two research trials were to 1) determine the effects of pre-sorting prior to loading on stress responses and transport losses at the harvest facility in the market weight pig; and 2) determine the effects of grow-finish pen size on stress responses and transport losses at the harvest facility in the market weight pig

Review of \u3ci\u3e Pigs, Profits, and Rural Communities\u3c/i\u3e Edited by Kendall M. Thu and E. Paul Durrenberger

These are historic times of rapid change in US agriculture, particularly the swine production industry. Rapid change creates controversy. Controversy surrounding the industrialization of the US swine industry is often over-simplified as a two-sided debate. In Pigs, Profits, and Rural Communities, editors Kendall Thu and Paul Durrenberger-anthropologists-effectively gather and present the multi-dimensional depth and breadth of the profoundly rapid change in the swine industry with a collection of eleven perspectives plus their own introductory comments