No one wants to think about what would happen if an outbreak of African swine fever (ASF) would take place in the U.S. Fortunately, in addition to experts working to keep it out, many experts are working in the background developing plans for what would happen if it does.
One group of experts – the USDA’s National Animal Health Monitoring System (NAHMS) – is getting ready to conduct its next swine study in an effort to obtain a more accurate picture of the U.S. swine herd. If a foreign animal disease outbreak were to occur, the survey results would allow for more accurate federal and state resource planning.
Since 1990, NAHMS has conducted studies on swine production in the U.S. approximately every five years. Swine were the first livestock commodity to be studied in 1990 because of the industry’s need for a national snapshot of U.S. swine health, says Charles Haley, swine study lead for NAHMS.
“Study questions are designed to produce national estimates on business demographics (e.g., number of production sites per operation), site demographics (e.g., growing pig barns per site), housing types and farm inputs and outputs (e.g., where feed and pigs come from and where pigs go),” Haley says. “Other study questions, such as those that ask about medications used by swine farmers to contribute to the wellbeing of pigs, produce national estimates that rebut claims of misuse of medications made by groups that are hostile to livestock agriculture.”
In short, the information obtained for these studies provides stakeholders in the private and public sectors with valuable information on disease prevalence, management practices, productivity and disease preparedness strategies.
NAHMS, in collaboration with the USDA’s National Agricultural Statistics Service (NASS), will conduct its sixth national study of U.S. large enterprise swine operations starting this summer. The study was originally scheduled to start in June 2020, but was put on hold due to the economic hardships pork producers faced during the pandemic.
The Swine 2021 study distinguishes swine producers with less than 1,000 hogs (smaller producer component) and swine producers with 1,000 or more hogs (larger producer component). For the larger producers that agree to participate in the study, USDA NASS personnel will conduct the first interview in July 2021. For the larger producers that are willing to continue, Veterinary Services (VS) personnel will follow up with a second interview and collect biologic samples (e.g., oral fluids and feces) in fall 2021.
For the smaller producer component, NASS will mail a questionnaire with a pre-addressed and stamped return envelope to selected producers in July 2021. NASS will also provide a website for those producers who prefer to complete the questionnaire online. Producers that do not complete the questionnaire via mail or online will receive a phone call from NASS requesting an interview approximately a month after the initial mailing.
This study has four main objectives. They include describing current U.S. swine production practices related to housing, productivity, biosecurity and morbidity and mortality prevention; determining the producer-reported prevalence of select pathogens in weaned market pigs; describing antimicrobial stewardship and use patterns; and evaluating the presence of select economically important pathogens and characterize isolated organisms from biological specimens.
Here are eight ways NAHMS swine studies have already made an impact in the swine industry.
1. Documented the decline and virtual elimination of trichinae in commercial swine.
From trend data collected between 1990 and 2006, NAHMS documented the decline and virtual elimination of trichinae in commercial market swine and showed a corresponding decrease in the use of production practices that contribute to trichinae infection. NAHMS developed information sheets on toxoplasma and trichinae to share with trading partners to provide objective national data on the low prevalence of these parasites in swine.
2. Developed ASF and CSF disease spread models.
NAHMS studies helped develop national African swine fever (ASF) and classical swine fever (CSF) disease spread models for the Centers for Epidemiology and Animal Health (CEAH). NAHMS studies inform the structure of the models’ swine population estimates which describe both the sourcing of pigs and where they go when they leave a farm, both of which are the basis of live animal movement parameters that influence the rate of disease spread.
3. Evaluated the economic impacts of swine dysentery.
Data from 1995 to 2012 helped predict the change in pork production due to a decrease in the prevalence of swine dysentery. Results from an economic model showed the change in pork production had a negligible impact on national level prices. However, if producers who had more animals experience swine dysentery on their sites were able to eradicate the disease, they could realize larger profits (or less loss) if eradication investments did not exceed $7.80 per hog.
4. Assisted with initial epidemiologic investigations for PED and PDCoV.
During the initial U.S. outbreaks involving Porcine Epidemic Diarrhea (PED) in 2013 and Porcine Deltacoronavirus (PDCoV) in 2014, NAHMS assisted with the initial epidemiologic investigations. NAHMS provided a support role in PED efforts by providing industry and academia with quick analytic turnaround of data they collected. With the VS Chief Epidemiologist, NAHMS collected field data and conducted a case series investigation of PDCoV.
5. Provided an estimate of the economic cost of PRRS.
Utilizing data from two NAHMS national swine studies, academia provided the swine industry with an estimate of the economic cost of porcine reproductive and respiratory syndrome (PRRS). This information gave the industry baseline data to use in efforts to regionalize and/or eradicate this costly disease.
6. Helped spread correct information on antimicrobial use in the swine industry.
NAHMS 2006 and 2012 studies, along with the 2017 study on Antimicrobial Use and Stewardship on U.S. Swine Operations, provided insight into the use of antimicrobials in feed and water before and after the FDA Veterinary Feed Directive regulations went into effect in 2017. Providing baseline and objective data regarding antimicrobial use and stewardship is an important and increasingly requested service for a variety of stakeholders, which helps combat the spread of misinformation on antimicrobial use in the swine industry.
7. Collected samples help isolate potential animal and food-borne pathogens.
Fecal specimen samples collected from NAHMS studies are examined to isolate bacteria considered to be animal and food-borne pathogens. Not only does NAHMS generate information on the prevalence of these pathogens on-farm, but assessment of antibiotic resistance profiles is also conducted. Biologic sampling such as this generates aggregate and trend data important to an increasingly active research agenda on antimicrobial use and resistance.
8. Examined the prevalence of circovirus strains.
NAHMS 2006 and 2012 national swine studies also examined the prevalence and profiles of circovirus strains before and after Porcine Circovirus 2 vaccine development. This helps identify potential factors to the manifestation of Porcine Circovirus Associated Disease (PCVAD).
“NAHMS provides up-to-date, comprehensive snapshots of swine health and production practices of the U.S. swine industry. The valuable information gleaned from this study is only made possible and credible by industry-wide cooperation of pork producers and their veterinarians. I fully support this effort and strongly encourage everyone’s cooperation, if selected to participate,” said John Waddell DVM, in a NAHMS 2020 Study Launch.
Participation in NAHMS studies is voluntary. For more information, contact NAHMS.
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