Dataset Information

Financial Analysis of Herd Status and Vaccination Practices for Porcine Reproductive and Respiratory Syndrome Virus, Swine Influenza Virus, and Mycoplasma hyopneumoniae in Farrow-to-Finish Pig Farms Using a Bio-Economic Simulation Model.

ABSTRACT: This study aimed (1) to quantify the effects of positive status and vaccination practices for porcine reproductive and respiratory syndrome virus (PRRSv), swine influenza virus (SIV) and Mycoplasma hyopneumoniae (MHYO) on the profitability of farrow-to-finish pig farms and (2) to examine the financial impact of vaccination status in PRRSv and SIV positive farms. Data from 56 Irish farrow-to-finish pig farms were used for this study. Production effects associated with herd status for the three pathogens were incorporated into the Teagasc Pig Production Model (TPPM), a bio-economic stochastic simulation model for farrow-to-finish pig farms. In the analysis, farms negative (-) for either PRRSv, SIV or MHYO were assumed as baseline when presenting results for farms positive (+) for each pathogen. While all MHYO(+) farms used vaccination against the pathogen, not all PRRSv(+) or SIV(+) farms vaccinated against the disease. For all scenarios, a 728-sow farrow-to-finish farm with weekly farrowing batches was simulated. Financial risk analysis was conducted by Monte Carlo simulation within the TPPM using the Microsoft Excel add-in @Risk. Mortality rates, feedstuff costs and price per kg of meat produced were included as input stochastic variables and annual net profit was set as stochastic output variable. Positive farms sold fewer pigs and produced less kg of meat than negative farms and had increased feed usage during the weaner and finisher stages. Variable costs increased in positive farms due to increased feed costs, more dead animals for disposal and healthcare costs. Annual mean profit was lower by 24% in vaccinated PRRSv(+), 14.6% in unvaccinated PRRSv(+), 36.7% in vaccinating SIV(+), 12.8% in unvaccinated SIV(+), and 41% in MHYO(+) farms. Negative farms were first order stochastically dominant over positive farms, indicating that for a given level of profit, the financial risk is lower by avoiding respiratory pathogens. Similarly, unvaccinated farms were second order stochastically dominant over vaccinating farms suggesting that farms that do not vaccinate are less affected by the disease. Results from this study provide further evidence to encourage farmers to undertake improved disease control measures and/or to implement eradication programs.

SUBMITTER: Calderon Diaz JA

PROVIDER: S-EPMC7680737 | biostudies-literature | 2020

REPOSITORIES: biostudies-literature

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Financial Analysis of Herd Status and Vaccination Practices for Porcine Reproductive and Respiratory Syndrome Virus, Swine Influenza Virus, and <i>Mycoplasma hyopneumoniae</i> in Farrow-to-Finish Pig Farms Using a Bio-Economic Simulation Model.

Calderón Díaz Julia Adriana JA Fitzgerald Rose Mary RM Shalloo Laurence L Rodrigues da Costa Maria M Niemi Jarkko J Leonard Finola C FC Kyriazakis Ilias I García Manzanilla Edgar E

Frontiers in veterinary science 20201109

This study aimed (1) to quantify the effects of positive status and vaccination practices for porcine reproductive and respiratory syndrome virus (PRRSv), swine influenza virus (SIV) and <i>Mycoplasma hyopneumoniae</i> (MHYO) on the profitability of farrow-to-finish pig farms and (2) to examine the financial impact of vaccination status in PRRSv and SIV positive farms. Data from 56 Irish farrow-to-finish pig farms were used for this study. Production effects associated with herd status for the t ...[more]

PMID: 33240946

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Project description:BackgroundDam-to-piglet transmission plays an important role in the epidemiology of enzootic pneumonia on farms. Although Mycoplasma hyopneumoniae (M. hyopneumoniae) infections in breeding animals are often subclinical, their control could have a positive effect on M. hyopneumoniae infection levels in fattening pigs. This study investigated the presence of M. hyopneumoniae in the breeding population of ten Belgian farrow-to-finish farms suspected by the herd veterinarian to be M. hyopneumoniae infected. Gilt vaccination against M. hyopneumoniae prior to first insemination was practiced on nine of the ten farms. At four different time points in the reproductive cycle 20 animals were sampled on each farm, namely 30-40 days of gestation, 75-85 days of gestation, 3-5 days after farrowing, and 1-3 days after weaning. In total, tracheobronchial swabs and blood samples were collected from 344 gilts and 456 sows (n = 80/farm). Swabs were analysed for the presence of M. hyopneumoniae DNA using nested PCR and M. hyopneumoniae-specific antibodies were detected in serum with a commercial ELISA. Generalized linear mixed models with farm as random factor were used to test the effect of time point in the reproductive cycle and parity on M. hyopneumoniae PCR prevalence and seroprevalence.ResultsM. hyopneumoniae PCR prevalence ranged between 0% and 43.8% at the farm level and the seroprevalence between 32.5% and 93.8%. Gilts were significantly more M. hyopneumoniae PCR positive than sows at the 2-4th parity (P = 0.02) and > 4th parity (P = 0.02). At 30-40 days of gestation, significantly more breeding animals were PCR positive as compared to 75-85 days of gestation (P = 0.04), 3-5 days after farrowing (P = 0.02) and 1-3 days after weaning (P = 0.02). Gilts had significantly more often M. hyopneumoniae-specific antibodies than sows (P = 0.03).ConclusionsM. hyopneumoniae PCR prevalence varied a lot between farms and due to gilt vaccination the number of animals with M. hyopneumoniae-specific antibodies was high on most farms. Gilts were more often M. hyopneumoniae PCR positive than sows and positive animals were mostly found at 30-40 days of gestation. This emphasizes the importance of a sufficiently long quarantine period and proper gilt acclimation practices before introducing gilts to the sow herd.

Project description:BackgroundA discrete time, stochastic, compartmental model simulating the spread of Mycoplasma hyopneumoniae within a batch of industrially raised pigs was developed to understand infection dynamics and to assess the impact of a range of husbandry practices. A 'disease severity' index was calculated based on the ratio between the cumulative numbers of acutely and chronically diseased and infectious pigs per day in each age category, divided by the length of time that pigs spent in this age category. This is equal to the number of pigs per day, either acutely or chronically infectious and diseased, divided by the number of all pigs per all days in the model. The impact of risk and protective factors at batch level was examined by adjusting 'acclimatisation of gilts', 'length of suckling period', 'vaccination of suckling pigs against M. hyopneumoniae', 'contact between fattening pigs of different age during restocking of compartments' and 'co-infections in fattening pigs'.ResultsThe highest 'disease severity' was predicted, when gilts do not have contact with live animals during their acclimatisation, suckling period is 28 days, no vaccine is applied, fatteners have contact with pigs of other ages and are suffering from co-infections. Pigs in this scenario become diseased/infectious for 26.1 % of their lifetime. Logistic regression showed that vaccination of suckling pigs was influential for 'disease severity' in growers and finishers, but not in suckling and nursery pigs. Lack of contact between gilts and other live pigs during the acclimatisation significantly influenced the 'disease severity' in suckling pigs but had less impact in growing and finishing pigs. The length of the suckling period equally affected the severity of the disease in all age groups with the strongest association in nursery pigs. The contact between fatteners of different groups influenced the course of infection among finishers, but not among other pigs. Finally, presence of co-infections was relevant in growers and finishers, but not in younger pigs.ConclusionThe developed model allows comparison of different prevention programmes and strategies for controlling transmission of M. hyopneumoniae.

Project description:Knowledge on successful interventions against livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) within pig herds is sparse. In situations like this, a mechanistic simulation model can be a valuable tool for assessing the effect of potential intervention strategies, and prioritising which should be tested in the field. We have simulated on-farm interventions in a farrow-to-finish pig herd, with a previously published LA-MRSA spread model, within four different areas: 1) Reduced antimicrobial consumption, 2) Reduced number of pigs within each section, 3) Reduced mixing of pigs, and 4) Improved internal biosecurity. To model a decrease in the selective pressure, the transmission rates were reduced after LA-MRSA had become fully established within a herd, which resulted in a marked decrease in the prevalence within all stable units. However, LA-MRSA rarely disappeared completely from the herd; this was only observed in scenarios where the transmission rates were reduced to ? 30% of the original level. While changes in antimicrobial consumption patterns might be a very important step towards reducing the spread of LA-MRSA, the simulation results indicate that it may need to be paired with other preventive or intervention measures. Reducing the number of pigs within each section, reducing mixing of pigs, or improving internal biosecurity after LA-MRSA had become established within the herd only resulted in marginal changes in the median prevalence within the herd. However, these factors might be important in relation to being able to achieve or maintain a low level of antimicrobial consumption, and thus still indirectly influence the LA-MRSA prevalence within the herd. The results of a sensitivity analysis indicated the assumptions regarding the existence of pigs persistently shedding MRSA have a noticeable influence on the model results. The assumptions regarding transmission from sow to offspring at the day of birth also had a considerable influence on the MRSA prevalence within the farrowing unit but did not cause any marked changes in the simulated effect of interventions. Effects might differ between different farm types contaminated in different levels and this simulation study highlights a strong need for more knowledge from on-farm trials.

Project description:Among the zoonotic pathogens affecting pigs, Salmonella stands out due to the high number of human cases linked to pork consumption. In the last two decades many countries have put considerable effort into the control of the infection by surveillance and control strategies on farm. Despite this effort, many herds still have a high Salmonella prevalence and they require guidance to address this problem. The present study, using the serological surveillance data of finishing pigs from the Irish National pig Salmonella Control Programme, aimed to highlight factors associated with increased risk or that might mitigate Salmonella occurrence on farm. A questionnaire with 33 questions regarding herd characteristics, management, feeding, biosecurity, and health was completed for 61 individual herds. After the multivariate analysis by linear regression, nine variables were retained in the final model and linked to herd seroprevalence. Home produced-feed linked to the use of meal showed an eight points reduction in Salmonella prevalence compared to purchased feed (p = 0.042). Different biosecurity measures were associated to lower seroprevalence. Changing of footwear from outside to inside the farm decreased seroprevalence nearly 20 units (p = 0.014) and policies not permitting access to the farmyard to feed trucks (p = 0.048) or avoiding the presence of cats on the farm (p = 0.05) were estimated in 10 units less of seroprevalence. In contrast, the lack of perimeter fence increased the chance to have higher seroprevalence in five units (p = 0.05). Finally, intestinal diseases such as swine dysentery (p = 0.044) and E. coli diarrhea (p = 0.1) were estimated to increase Salmonella prevalence in ~20 and 10 units, respectively, demonstrating the importance of controlling other enteric pathogens in an on-farm Salmonella control programme. These results show the usefulness of surveillance data to improve on-farm control and confirm that Salmonella infection in pigs is multi-factorial and the approach to its control should be multifaceted.

Project description:BackgroundGenotypic variability in M. hyopneumoniae has been reported within and among herds. However, information regarding VNTR types within single lung lobes is lacking. The objective of his study was to analyse M. hyopneumoniae infections and their association with VNTR types and lung lesions at the lobe level. Lungs from 300 pigs from 10 farms experiencing an enzootic pneumonia outbreak were collected and scored. M. hyopneumoniae was detected by real-time PCR and genotyped by MLVA assay in all samples.ResultsThe results showed genotypic variability within single pigs and among lung lobes. At the lobe level, infection with one VNTR type (SN infection) was dominant. Lobes with lesion scores > 0 were associated with positive results for real-time PCR. At the lobe level, no relationship was observed between infections with more than one genotype (MX infections) and the proportion of Mycoplasma-like lesions. Lesion-free lobes presented a higher proportion of MX infections than lobes scored > 0. M. hyopneumoniae was detected more frequently in the right lobe of the lung (p < 0.05), with a similar distribution within lobes for SN and MX infections. The anatomic conformation of swine lungs led to a higher prevalence of infections in the right lobe. However, this study showed that this condition did not affect the distribution of infections with multiple VNTR types. Nevertheless, careful consideration of sample selection should be practised for M. hyopneumoniae genotype analyses, including lung lobes with no visible lesions.ConclusionThe results did not show a significant association between the number of detected genotypes and the severity of the lesions at the lung lobe level, but revealed the unexpected detection of M. hyopneumoniae genotypes in lesion-free lobes. These results imply that a representative sampling of all lobes may lead to an accurate identification of the VNTR-type distribution. Further studies including factors that can affect pathogenetic evolution of this bacterium could shed light on the complexity of the relationship between genotypes and the lung lesions magnitude.

Dataset Information

Financial Analysis of Herd Status and Vaccination Practices for Porcine Reproductive and Respiratory Syndrome Virus, Swine Influenza Virus, and Mycoplasma hyopneumoniae in Farrow-to-Finish Pig Farms Using a Bio-Economic Simulation Model.

Publications

Financial Analysis of Herd Status and Vaccination Practices for Porcine Reproductive and Respiratory Syndrome Virus, Swine Influenza Virus, and <i>Mycoplasma hyopneumoniae</i> in Farrow-to-Finish Pig Farms Using a Bio-Economic Simulation Model.

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