Manure and Pasture Management to Reduce Swine Parasites in Western Washington Organic Pastured Pork Production

Final report for FW20-362

Project Type: Farmer/Rancher
Funds awarded in 2020: $19,899.00
Projected End Date: 06/30/2023
Host Institution Award ID: G325-20-W7900
Grant Recipient: Alluvial Farms
Region: Western
State: Washington
Principal Investigator:
Katie Pencke
Alluvial Farms
Expand All

Project Information


Managing swine intestinal parasites continues to be an obstacle for pig farmers seeking to certify their pork as Organic. Since Ivermectin was removed from the National List of Allowed and Prohibited Substances in 2016, there is a lack of organically-approved veterinary options for control, as well as a lack of information on best management practices for control in organic pork production systems for the various regions of the United States (Percy, 2019). Alluvial Farms based our project on research work being done concurrent with our project through a collaboration of the University of Minnesota, Kutztown University and Rodale Institute. This multiyear national study was funded by the US Department of Agriculture National Institute of Food and Agriculture program (USDA NIFA) for 2018-2020. It explored manure and pasture management strategies that would control swine parasites by reducing parasite contamination and transmission in organic pig production (Yuzhi, Hernandez, Carr, 2019).

In the three-year research project we have just concluded, Alluvial Farms followed some of the same protocols of this larger national study to evaluate parasite pressures on our own farm. We have been in business for eight seasons and on our own 45 acre farm for five. Over our five years here we have produced certified organic small grains and other crops, experimented with certifying our pork as Organic, and finally settled on certifying our pork as Animal Welfare Approved, by A Greener World. We established a protocol and a practice for on-farm parasite monitoring, and collected a year's worth of information about baseline parasite presence on farm. We will then taught ourselves to measure parasite presence in soil and bedding, following protocols from our mentors at Rodale. We used this technique to determine effectiveness of thermophilic composting of bedding and manure for eliminating swine parasites. We also determined additional interventions we could test for effectiveness at managing swine parasites on organic farms, such as the Rodale experiment test of biofumigation of pastures with brassica crops.

Our project addressed all three aspects of sustainable agriculture as defined by SARE:

  • environmental stewardship through parasite management on pastured-based hog systems,
  • economic profitability by aiming to increase weight gains and carcass yields through parasite mitigation strategies
  • and the social component of increased quality of life for family farmers through increased income potential if we could develop a management protocol that would allow us mitigate the negative effects on animal welfare created by parasite pressure.  
Project Objectives:
  1. Evaluate parasite prevalence on our Animal Welfare Approved, eleven sow and one board pig farm in Western Washington, with special focus on the presence of three common parasites: Oesophagostomum spp. “nodular worms,” Ascaris suum “large intestinal roundworm,” and Trichuris suis “swine whipworm.”
  2. Establish thermophilic composting facility on-farm. 
  3. Develop skills to test compost inputs and outputs for parasite presence in order to determine the effectiveness of manure composting on eliminating these swine parasites and their underlying reproductive mechanisms.
  4. Develop skills to test pig pasture soils for parasite presence in order to determine the effectiveness of biofumigation of pastures with brassica plants at reducing swine parasite presence in soils. 
  5. Share results with local, regional, and national producer community.
  Q3 2020 Q4 2020  Q1 2021 Q2 2021 Q3 2021 Q4 2021 Q1 2022 Q2 2022 year three
1. Evaluate parasite presence on W. Washington pig farms                  
Compost swine bed pack to completion                  
Trial of biological, pasture-based parasite management                  
Track swine weight gain monthly                   
Education & Outreach                  
Whatcom Conservation District field day                  
Regional Conservation District webinar                  
Present at Tilth Producers                   

Please also see timeline graphic included in supporting documents. 


Click linked name(s) to expand/collapse or show everyone's info
  • Alexander Hernandez - Technical Advisor (Educator and Researcher)
  • Ruth Kulshan
  • Matthew McDermott - Producer
  • Katie Pencke - Producer


Materials and methods:

Organic pork farms are prohibited from using anti-helminthic and other deworming medications in meat pigs (Percy, 2019). Deep bedded hoop barns with earthen floors and rotational grazing on pastures, combined with the rooting nature of the pig, all contribute to a high incidence of parasites on organic pig farms (Yuzhi, Hernandez, Carr, 2019).  Without taking some action a natural or Organic approach to pork production using deep bedded barns and seasonal pastures could quickly threaten economic viability of the enterprise and be a barrier to certification. Our technical advisor's pig parasite study focuses on pig farms in the five largest pig producing states in the US. Those are all in the midwest and eastern states. At the time we began our study we could find very little conclusive research already completed and none with a focus in the Pacific Northwest region.


Our field trials were conducted at the 45 acre Alluvial Farms in Everson, WA. Our family farm business is a product of our career-long work in agriculture and small farm business management. We are a certified Animal Welfare Approved, eleven sow, farrow-to-finish operation, with a focus on direct to consumer pork marketing and some small wholesale accounts. We harvest 120-140 hogs per year. Our trials were conducted in a deep bedded, 4000 square foot centralized housing facility with ten acres of rotational paddocks adjacent, divided into one acre pastures. Our additional 20-acre organic grain field is also used seasonally as pig pasture.


Our on-farm study was inspired by a national study currently funded by the USDA NIFA Organic Transitions grant program (NIFA 2018-2020).  We will use the study design developed by the University of Minnesota, Kutztown University and the Rodale institute throughout this project to help guide our methods and questions. Our primary technical advisor Alexander Hernandez, and our additional collaborator at the Rodale Institute, Rick Carr, will provide assistance with research design, statistical analysis of results and education and outreach. Our local large animal veterinary clinic's laboratory director, Ruth Smith, will advise on parasite testing and swine parasite identification.

  1. Evaluate parasite prevalence on organic pig farms in Western Washington, as measured by the presence of three common parasites: Oesophagostomum spp. “nodular worms,” Ascaris suum “large intestinal roundworm,” and Trichuris suis “swine whipworm.”
  2. Determine the effectiveness of manure composting on eliminating these swine parasites and their underlying reproductive mechanisms.
  3. Determine the effects of pumpkins as a forage crop by organic pigs on reducing swine parasite contamination.
  4. Track swine weight gain monthly to compare weight gain with parasite loading changes.
  5. Share results with local, regional, and national producer community.

Objective 1: Evaluate parasite presence on transitional Organic pig farm in Western Washington.  

Alluvial Farms developed on-farm systems and skills to test pig fecal samples on-farm for parasite presence. Fecal samples were collected quarterly for the three years of the grant period and evaluated for presence of parasites with a focus on the following species: Ascaris suum (large roundworm), Trichuris suis (whipworm), and Oesophagostomum spp. (nodular worms). Fecal samples from numerous individuals of three categories of pigs were compared: feeders (2-4 months old), Finishing pigs (5 months to market weight), and sows.

We measured the following: 

  • Percentage of pigs sampled who are infected with each of the three parasites.
  • Average number of eggs per gram of feces.
  • Comparison of the above for feeders, finishers, and sows.

Alluvial Farms also attempted to train ourselves to measure parasite presence in pig pasture soil and in soiled barn bedding or manured shavings from heavy use area footing. We would use these techniques to measure:

  • Average number of eggs per gram of bedded pack barn bedding or heavy use area footing, before introduction into thermophilic composting system.
  • Average number of eggs per gram of soil in outdoor swine pastures, before biofumigation treatment with brassica crops.

Objective 2: Determine the effectiveness of manure composting on eliminating these swine parasites and their underlying reproductive mechanisms.

In 2021 Alluvial Farms completed construction of a 400 cubic yard thermophilic composting facility. With this we transitioned from aerated windrow composting to static aerated pile composting within the facility. High temperatures generated during composting are predicted to inactivate or destroy parasite eggs, and have been shown to do so within the results of the Rodale research. Samples of bedded pack will be collected and tested for parasite presence before composting and weekly for four weeks during static aerated pile composting. Protocols from Rodale Institute’s compost research program will be followed when undertaking this study, including tracking temperatures in an attempt to show at what temperature the majority of parasite eggs are killed.

Objective 3: Determine the effects of brassica biofumigation in pig paddocks on parasite presence. 

  • This is an adaptation of our original objective to determine the effects of pumpkins as a forage crop by organic pigs on reducing swine parasite contamination. We made this adaptation after starting our SARE project in order to align our study more closely with our model study being undertaken by the Rodale Institute and their land grant university research partners. 
  • In order to accomplish this objective the farmers will learn and practice a technique for detection of parasite eggs in soil from one acre paddocks where pigs have temporary residency. 
  • Test soil for parasite egg presence in paddocks while noting time since pig residency, crop coverage at the time of testing, most recent pig waste-based compost application, and time of year. 

Objective 4: Track swine weight gain monthly to compare weight gain with parasite loading changes.

In our final year of the study we monitored parasite presence and weight gain in our finishing pigs (150-300 pounds) while they are housed in the hoop barn with outdoor yard access. Their residency in the barn will make regular weight checks and fecal testing easier than it would be for the younger field pigs who are in a field with poly-wire fences and much harder to organize. 

Objective 5: Share results with local, regional, and national producer community.

In the final year of our SARE grant we completed the following educational activities:

a. Co-hosted an on-farm workshop on best management practices for pig veterinary care with our local large animal vet: Kulshan Veterinary Services. Workshop took place on Thursday May 25, and ten local non-commercial pig farmers attended.

b. We presented a workshop at the Tilth Alliance regional farm conference in November of 2022 discussing our study and results and SARE supported research. Our workshop was attended by 20 people, roughly half were commercial pig farmers and half were interested service providers or other community members. 

Activities of first research year: 

-Met with three principal investigators of Rodale study. 

-Identified technical guide for our study : Epidemiology, diagnosis and control of helminth parasites of swine, Roepstorff & Nansen, 1998, Food And Agriculture Organization of the United Nations. 

-Implemented RFID ear tagging system on the farm and after a few months realized that this was not a good fit for our farm or our research needs. Made a transition to an non-electronic ear tag system. 

-Taught ourselves how to do fecal sampling with concentrated McMaster technique. Action steps to improve our process is to do the testing on the farm, and not at the Conservation District office as we first tried. We also need to either repair, or troubleshoot the loaned microscope we are using, as it's top magnification is not functioning and hinders identification. 

-Started to teach ourselves identification and interpretation of on-farm fecal sampling with the help of our local veterinarian. We have realized what a skill it is to read these slides and hope that it will become easier if we can repair our microscope. We have found it challenging to find a good resource to teach ourselves these identification skills. Our local veterinarian has been a great resource, as well we had a student of veterinary science volunteer with us for a few days to help with our first large scale monitoring. 

-First trial quarterly data collection from 25 individuals on 2/22/2021.

-Secured financing for construction of 300 cubic yard on-farm aerated composting facility, contracted with designer, began design and permitting process. 

-Conducted aerated windrow composting trials of heavy use area bedding and barn bedding in the meantime. 

Activities of second research year:

-Bridging year two and three of our project we hosted an on-farm internship for one student in partnership with Washington State University in Pullman, Animal Sciences department.  This student helped with data collection during her time here. 

-Quarterly data collection from fecal samples on 5/25/21 of nine individuals from different age groups, on 7/21/21 of five individuals, and on 1/27/22 of eight individuals. 

-implemented analog ear tagging system

Activities of third research year: 

-monitored parasite presence and weight gain in our finishing pigs (150-300 pounds) while they are housed in the hoop barn with outdoor yard access.

-worked with our technical advisor at Kutztown University to determine that testing soil and compost for pig parasite eggs is not feasible at this time due to the constraints of not being in a laboratory setting and not having the correct equipment at our disposal. 

-planted and incorporated three test crops of brassica biofumigation plants within our system of one acre pig paddocks. 

- Created a 30 slide presentation summarizing best management practices for pastured pigs in the Pacific Northwest. Presented this slideshow about our work at the Tilth Producers conference in November 2022 and in an on-farm workshop in May 2023. 

Research results and discussion:

First quarterly on-farm fecal sampling conducted February 22, 2021. 

Samples taken from 25 individuals: nine finishers (150-275 lbs), two breeders, and thirteen growers (35-100 lb.). 

7 out of 25 samples, or 28%, were interpreted by professional veterinarian service, the other 18 samples, or 72% were interpreted by volunteer student veterinarian. 

Parameters measured were presence of three specific kinds of helminths and coccidia. Need to refine ability to report in eggs per gram vs total eggs seen on the slide in order to match national study data, and in order to match data provided by veterinary lab analysis. 


The national study only took place on farms that were either certified Organic, or following most Organic program rules, but especially that they were not using chemical dewormers on any animals other than breeding stock, and then only outside last third of gestation. On our farm, after going through our first round of managing breeding stock on site and farrowing piglets without the use of chemical dewormers, we were faced with serious veterinary issues that caused us to seek to develop a deworming program for our herd. 

Other takeaways from year one are that principle farmer researchers - ourselves -  need more training in slide interpretation. This is a specialized skill but in order for study to be cost effective we need to develop this skill on farm. 

Results by age group

Finishers: 100% of finishers positive for nodular worm, 4 out of nine finishers positive for coccidia, two out of nine finishers positive for roundworm.

Growers: 8 out of thirteen positive for coccidia, 2 out of 13 positive for roundworm, and five out of thirteen positive for whipworm. 

Breeders: of the two individuals samples, no parasitism detected. 

Year two saw three quarterly fecal testing events for different aged members of the pig herd. The two principle farmer researchers gained confidence in our skill at slide interpretation and in the use of our microscope and testing protocol. 

Results of year two monitoring showed that in our first monitoring out of nine animals sampled 4 individuals carried more than one parasite, four individuals carried none, and one individual carried only one parasite. Similar results were found in our second monitoring with whipworm being the most prevalent parasite. In the January 2022 monitoring there were no parasite presence found in any of the age groups. We double checked this by sending a few duplicate samples to our veterinarian and they agreed with our findings. 

Year three monitoring showed continued presence of all three target species of parasite, with small accumulations in just weaned nursery pigs, heavy accumulations in feeder pigs, and then reduced number in finishing pigs, down to almost no parasite presence in our sows. 

Biofumigation and composting trials: 

After research and consultation with our technical advisor we determined that we were not going to be able to test compost and soil here on the farm for the presence of pig parasite eggs. We did however complete construction of our aerated composting facility. Once a bay is filled, and the aeration cycles begin, we reach temperatures of at least 160 degrees F for at least ten days. Compost is allowed to cure for roughly one month after active aeration, and is often turned once into another bay in order to mix and homogenize materials, before application to pig paddocks with our manure spreader. After application, a time period of at least three months elapses before pigs are put on that area. 

Participation Summary
2 Producers participating in research

Research Outcomes

2 New working collaborations

Education and Outreach

1 Minigrants
1 On-farm demonstrations
2 Online trainings
1 Webinars / talks / presentations

Participation Summary:

85 Farmers participated
25 Ag professionals participated
Education and outreach methods and analyses:

Year 1:

January 2021

Established static webpage on our farm website to provide public information about our study:

Gave two webinar presentations viewed by 70 participants in total at the Washington State University Cattleman's Winter School virtual conference: 

Year 2:

  • Formed partnership with the California Coalition of Organic Farmers on their much larger three year SARE grant application, "Bringing home the Organic bacon." Their study is based on our SARE grant application and on their own research.  Our role is one of five independent producers. Primary investigator is Alda Pires University of California Agriculture and Natural Resources, Cooperative Extension, UC Davis, School of Veterinary medicine. 
  • Completed pour for 70' x 40' aerated slab with apron and ecology block bays for thermophilic composting. 
  • attended webinar at February 2022 MOSES conference given by our mentor study - the Rodale Institute and Kutztown University pig parasite management on organic pork farms study. 
  • Continued quarterly monitoring of parasites in Alluvial Farms pig herd. Hoping to connect with CCOF & Rodale to start planning outreach together next year. 

Year 3:

  • Bridging year two and year three we partnered with WSU Animal Sciences program to recruit a pre-veterinary student to complete a summer internship on our farm. She supported parasite monitoring within the pig herd, the compost facility, and from the pastures.  
  • In year three we produced a digital presentation that we wish had been available when we started this project to help equip other pig farmers to monitor parasites on pig farms - a manual for pig parasite monitoring in the herd, in the compost, and in pig pastures, as well as a manual for aerated composting of pig bedding and manures. 
  • W presented our findings at the Washington State Tilth Producers conference. This is an annual gathering for Organic and natural farmers around our state.
  • We also presented at a workshop we hosted here on our own farm with the collaboration of our local large animal vet. 
  • The California Coalition of Organic Farmers contacted us to serve as advisors on a similar study they were seeking funding for, but they were not awarded after multiple attempts, so no further work is anticipated at this time. 

Thank you for this opportunity. 

5 Farmers intend/plan to change their practice(s)
5 Farmers changed or adopted a practice

Education and Outreach Outcomes

Recommendations for education and outreach:

Year two of our SARE grant was primarily taken up with construction of a 400 cubic yard capacity aerated composting structure and quarterly monitoring of parasite loads in our pig herd.   

We were very pleased to become collaborators with the California Coalition of Organic Farmers (CCOF) in support of their SARE application to study this same topic in California on a much larger scale. Our hope is that they will be awarded and be able to move forward with their project. In that case our work in year three would be leveraged by participation in their project in an advisory role. 

In addition to our collaboration with CCOF, over the past few months we developed a partnership with Washington State University (WSU) Department of Animal Sciences. In year three Alluvial Farms will host our first intern from the WSU Animal Sciences student body here on the farm in the summer of 2022. The primary focus of this intern will be to collect parasite monitoring data from the pig herd, the compost facility, and from the pastures. This data will be collected in the manner set out in the CCOF study and will be included in our outreach presentation at the Tilth Alliance conference in November of 2022.

In year three we worked with the 2022 intern to publish digital manuals that we wish had been available when we started this project to help equip other pig farmers to monitor parasites on pig farms - a manual for pig parasite monitoring in the herd, in the compost, and in pig pastures, as well as a manual for aerated composting of pig bedding and manures. 

We made some adjustments to our study from our original proposal during our first year of implementation: 

-In year one we realized that using RFID tags and conducting monthly weight checks would be challenging on our farm with our current infrastructure. There was a significant retention issue with the RFID tags.  We switched to analog ear tags for animal identification with allows us to visually (by color) distinguish litters as well as by number.  Measuring weight in the field turned out to be too time consuming.  Without the ability to coral the pigs, we couldn't efficiently move them through the scale.  We will shift the weight monitoring to the barn area where additional infrastructure allows us to create shoots and gates for efficient movement through a scale.

- In year one we realized that using veterinary lab service for all fecal testing was not affordable, once we realized the large volume of sampling that would need to be done to understand variations within age groups by individual and variations between age groups. We pivoted instead to teaching ourselves to do fecal testing and acquiring the necessary equipment to do so. We purchased a centrifuge, test tubes, mcmaster slides, flotation solution and a microscope.  The microscope might need to be upgraded for increased resolution.  We worked with a veterinary student to take samples and provide analysis.

- In year one we increased the scope and timeline for construction of aerated compost facility so focused in year one on pig fecal testing and monitoring and in year two will complete construction of the composting facility and year three teach ourselves methodology for monitoring parasite presence in soils and composts. 

-In person workshops were put on hold due to COVID, and in year one offered two virtual workshops in partnership with our local Conservation District- one on pastured pork systems and the other on aerated composting. 

70 Producers reported gaining knowledge, attitude, skills and/or awareness as a result of the project

Information Products

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.