Characterization and Description of Alternative Pig Farms in Minnesota

View the project final report

Commodities

• Animals: swine

Practices

• Animal Production: animal protection and health

Practices for managing pig health within the United States (US) swine industry have evolved from backyard pig production circa World War II; pig production is now characterized by raising age-segregated pigs indoors in large premises. Despite this shift, there are still farmers who have chosen to raise their pigs in alternative settings, most notably, with outdoor access. Alternative pig farms (APFs) include, but are not limited to, those labeled as niche, pasture-raised, US Department of Agriculture (USDA) organic-certified, heritage breed, purebred, regenerative, and humane-certified ¹. The demand for pork produced by APFs is increasing as consumers are continuing to seek pork that has been with produced with alternative productive production to those of conventional production practices².

Unfortunately, despite the perceived benefits of alternative production practices, APF pigs may be at a higher risk of a variety of disease-causing pathogens due to their exposure to the natural environment. Pigs on APFs do have a higher likelihood of encountering wild animals who could potentially transmit infectious diseases or parasites to the pigs. Additionally, these risks may continue even after the life of the pig because contaminated meat products could potentially infect both humans and other animals including pigs. Although pigs raised conventionally may face these same risks, they can better mitigate them through the mechanical, chemical, and physical barriers of their confinement. However, these barriers may not apply to APFs due to the unique and diverse production/management, veterinary use, biosecurity, and marketing methods.

Therefore, effort needs to be made to better understand these practices so that appropriate preventative health practice recommendations can be made that are specific to this population. Especially as these farms may exist not only to serve for pork production, but also aid in creating a more robust local food system or utilize their pigs for regeneration of the environment. The objectives of this project include 1) characterize and describe Minnesota (MN) APFs, 2) estimate disease prevalence in APFs, and 3) identify farming practices that increase odds of disease.

To characterize and describe APFs in MN, over 200 farms that raise pigs with outdoor access were identified and subsequently emailed an online Qualtrics® (Provo, UT) survey in December 2022-Decembe 2023 that included questions regarding their farming and management, biosecurity, and marketing practices of their pig herd. A prevalence study was performed for the presence and previous infection with Porcine Reproductive and Respiratory Syndrome Virus (PRRS), the presence of three enteric porcine enteric coronaviruses: Porcine Epidemic Diarrhea Virus (PEDV), Transmissible Gastroenteritis Virus (TGEV) and Porcine Deltacoronavirus (PDCoV), and for previous infection with Pseudorabies Virus (PRV) which is the causative agent of Aujesky’s disease.

Both PRRSV and the porcine enteric coronaviruses (PECs) are endemic diseases in conventional pig farms. PRRSV can cause high abortion rates in breeding herds and morbidity in grow-to-finish herds due to respiratory disease, whereas the PECs can cause high morbidity in all ages due to gastroenteritis. In addition to the welfare implication this has for pigs, it can also cause severe economic losses in CPFs but are of unknown prevalence in APFs. PRV has been eradicated from domestic swine in the US, but does exist in feral populations, for which pigs with outdoor access are at higher risk of infection. Logistic regression was performed using variables from the survey and the outcome of disease from the prevalence study to identify any farming practices that increase odds of these diseases, for which mitigation could then be pursued on the farm.

The results of this survey provide information on the different production, management, veterinary medicine usage, biosecurity, and marketing practices of farms in MN that raise pigs with outdoor access and/or are considered “alternative”. Due to the increasing demand for pork produced by APFs, the information gathered from the survey has identified a few practices that should be further explored, to evaluate their role in the spread of disease, and how they may be improved to decrease the spread of disease.

Researchers were able to better understand the barriers APF farmers may face against the utilization of veterinarians and on-farm veterinary care. Over 1/3 of survey respondents have never consulted with a veterinarian, either because their pigs were healthy or because they didn’t have access to a veterinarian who is knowledgeable in swine medicine. Therefore, education thus far has focused on the veterinary industry, as we believe this will have the greatest impact on changing the attitudes for all those involved in the care of pigs raised on APFs. A presentation focusing on areas of improvement for the veterinary industry from the survey results was presented to the American Association of Extension of Veterinarians and a poster presentation was given at the American Association of Swine Veterinarians that highlighted the farm demographics and farming, management, and biosecurity practices of survey participants.

All prevalence study participants were compensated with $150 which they were encouraged to use towards any existing or future veterinary care. Sampling and diagnostic testing was provided free of charge, and we worked to connect the farms with veterinarians if they wanted. We hope to disseminate the key findings of the survey along with recommendations for on-farm practices to improve pig health emailed directly to participants and other APF farmers via association newsletters, extension publications, and peer-reviewed publications.

From the prevalence study, there were no farms that tested positive for PRV or any of the PECs. It is possible that PECs were not found in this population because the housing environment of APFs may limit its spread and/or the survivability of the virus. Regardless, PECs do not seem to be a disease of concern in this population. Of the 25 farms that were tested for PRRSV, 36% of farms showed evidence of previous infection and 20% tested positive for the presence of the virus at the time of testing. Although this prevalence is comparable to conventional pig farms, risk factor analysis suggests that APFs with hoop barns may have a higher odd of being infected with PRRSV. In addition to on-farm practices, how these APFs interact with each other, such as pig movement or location of their farm in relation to another, can also play a role in disease spread. Therefore, additional research should be performed to evaluate the extent to which this population interacts with each other, the broader swine industry, and the impact this could have on disease spread.

1. Certified Humane - A Project of Humane Farm Animal Care. Accessed July 4, 2022. https://certifiedhumane.org/
2. Sato P, Hötzel MJ, Von Keyserlingk MAG. American citizens’ views of an ideal pig farm. Animals. 2017;7(8). doi:10.3390/ani7080064

Objective 1: Characterize and describe Minnesota (MN) APFs.

Results from the survey will provide information for four farm practice areas in: 1) Production/Management, 2) Veterinary Use, 3) Biosecurity, and 4) Marketing. The information gathered in this study can be used to better understand the APFs’ role in the ecology of infectious disease and identify specific practices for which established disease prevention and control measures can be adapted for this population, ultimately improving pig health.

Objective 2: Estimate PRRS, PECs, and PRV pathogen prevalence in APFs.

Establishing the baseline for which disease prevalence exists in APFs will not only allow us to assess the degree to which the disease exists in the population but will allow us to have a metric when comparing this population to others (such as convention pig farms), and to future prevalence studies following intervention applications. Pathogens that are pig specific and are endemic in conventional pig farms will be tested for, along with one disease that has been eradicated from domestic pigs in the US but can be found in the feral pig population.

Objective 3: Identify farming practices that increase disease risk.

It is expected that general farming practices will differ on APFs from conventional pig farms, therefore, it may be that the practices that may lead to increased risk to disease on conventional farms may not be the same practices that lead to increased risk to disease on APFs. Therefore, the last objective of the project is to identify any practices that lead to an increased risk, or increased odds, of disease. This is turn, will identify practices that can be improved and mitigated to decrease disease in the future. Using the survey results and the prevalence study diagnostic test results, logistic regression can be performed to calculated Odds Risk Ratio for variables that are identified to have an association with the outcome of a positive test and are statistically significant.

Introduction:

The aim of this study was to describe and characterize four areas of practice of APFs in MN: 1) Production/Management, 2) Veterinary Use, 3) Biosecurity, and 4) Marketing, calculate disease prevalence, and identify any practices that may lead to an increase in the odds of disease infection. The information gathered in this study can be used to better understand the APFs’ role in the ecology of infectious disease and identify specific practices for which established disease prevention and control measures can be adapted for this population, ultimately improving pig health and ensure the longevity of this type of pig production.

Problem 1: Current knowledge of APF practices in US is lacking.

Unfortunately, there is little published information about APF practices in the US within the context of veterinary medicine or swine health and production. The literature that does exist is outdated, non-specific, or only captures information on one type of APF. Additionally, niche and organic pig production is much more common in Europe with a variety of research reports available regarding this type of pig production. Yet, the information on their practices seems to be country specific and may not be as applicable to US APF production, especially within the context of the respective country’s laws, regulations, or culture. As the demand for pork produced by APFs is increasing in the US², knowledge on the current practices of these farms will be important to have, especially for the veterinary and swine industry.

Problem 2: Unknown Disease Prevalence for PRRS, PECs, and PRV.

There is a published report on the health challenges in midwestern niche pork ³, and a survey of disease pressures in twenty-six niche herds ⁴, but these were limited in scope to niche pork producers under contract with three midwestern marketing companies. Additionally, there was a survey of disease prevalence for pigs in Hawai’i, but this population itself differs from that of APF production found in MN and the Midwest. An updated disease prevalence for PRRS (20%), PECs (0%), and PRV (0%), was able to be estimated from this project that is specific to the APF population in MN.

Problem 3: Factors that increase disease risk for APFs are unknown.

Due to the generally different practices employed by APFs, the factors that may lead to increased disease risk for these farms may be different than what has been historically established for conventional pig farms. Differences in practices that were identified included housing, genetics, farm type, herd size, biosecurity, veterinary use, and marketing. Using the results from the survey and prevalence study factors were identified that may lead to an increase in disease risk for APFs. Specifically, the use of hoop barns may lead to an increase in disease risk for PRRSV, and the use of a farm specific vehicle may lead to a decrease in disease risk for PRRSV. The project also identified variables for which can be further researched for association of risk such as location.

2. Sato P, Hötzel MJ, Von Keyserlingk MAG. American citizens’ views of an ideal pig farm. Animals. 2017;7(8). doi:10.3390/ani7080064
3. Layman L, Yaeger M, Karriker LA. Health Challenges in Midwestern “Niche” Pork Production Systems. Iowa State Univ Anim Ind Rep. 2008;5. doi:10.31274/ans_air-180814-732
4. Yaeger MJ, Karriker LA, Layman L, Halbur PG, Huber GH, Hulzen KV. Survey of disease pressures in twenty-six niche herds in the midwestern United States. J Swine Health Prod. 2009;17(5):8.