Parasite Infection in Organic Pigs

By Yuzhi Li, Alternative and Organic Swine Production

Managing intestinal parasites in organic pigs continues to be a challenge because there is a lack of organically approved options for controlling parasites. A survey across fives states in the United States indicates that parasite infection is so common that all organic pig farms surveyed were infected with at least one species of intestinal swine parasites (Li et al., 2020). However, research on parasite infection in organic pigs in the United States barely exists.

We investigated three species of intestinal parasites in pigs that were raised in bedded barns at the West Central Research and Outreach Center. All pigs were managed according to the National Organic Standards (NOP, 2000), except without access to outdoors. Fecal samples were collected from 293 pigs, including 29 nursery pigs, 91 growing pigs (15-week old), 133 finishing pigs (23-week old), and 40 gestating sows, for analysis of eggs of Ascaris suum (ASC, large roundworms), Trichuris suis (TRI, whipworms), and esophagostomum spp (OES, nodular worms). We found that 76% of growing pigs and 92% of the finishing pigs shed ASC eggs in their feces. However, we did not detect ASC eggs in the feces of nursery pigs or gestating sows, probably because sows were dewormed 40 days before farrowing according to the National Organic standards.

We recorded growth performance of 103 pigs and evaluated whether ASC infection influenced pig growth.  Pigs that were infected and were not infected with ASC had similar daily weight gain and final weight, suggesting that ASC infection did not affect growth of pigs. Thirty-two pigs were examined for liver white spots (an indicator of ASC infection) and large roundworms in their gut at slaughter. All these pigs had white spots on their liver, and 78% harbored large roundworms. We did not detect TRI eggs and barely detected OES eggs in fecal samples analyzed. 

These results indicate that TRI and OES infections are not a concern for the swine herd managed organically at the WCROC. However, ASC infection in growing and finishing pigs could be a threat to food safety of organic pig products. To control ASC infection in organic pigs, we suggest treating pigs during the growing phase with prophylaxes that are approved for organic production, combined with maintaining good environmental hygiene by thoroughly cleaning, washing, and drying barns between groups of pigs.

This project is supported by Organic Transition Program (Award# 2018-51106-28772) from the USDA National Institute of Food and Agriculture, and conducted in collaboration with Rodale Institute and Kutztown University in Kutztown, PA. 


Li, Y. Z., A. Hernandez, R. Carr, S. Major, and D. DeWitte. 2020. Parasite prevalence and fecal egg counts on organic pig farms. J. Anim. Sci. 98 (Suppl. 3): 463.

NOP (National Organic Program). 2000. A Rule by the Agriculture Department, and the Agricultural Marketing Service. Available at: