The number of Oesophagostomum spp. larvae recovered in coprocultures varies with media used.

Nodular roundworms (Oesophagostomum spp.) are frequent parasites of the large intestine in several mammal species including humans and pigs, and their study often requires the use of infective larvae produced using several coproculture techniques. However, there is no published comparison of techniques to determine which yields the highest number of larvae. This study compares the number of larvae recovered from coprocultures made with charcoal, sawdust, vermiculite, and water in an experiment repeated twice using feces from a sow naturally infected with Oesophagostomum spp. at an organic farm. A higher number of larvae were recovered from coprocultures using sawdust relative to other types of media used, and this was consistent across the two trials. The use of sawdust to culture Oesophagostomum spp. larvae is rarely reported and our study suggests it can yield higher numbers relative to other media.

Intestinal roundworm infection in organic and alternative swine farms in the USA.

Swine parasites are a challenge for organic and alternative pig farmers and represent suboptimal animal health because use of chemical prophylaxis is not recommended. There is no comprehensive study of how prevalent gastrointestinal parasites are in organic or alternative pig farms across the USA. This study investigates prevalence, abundance, and intensity measures for three intestinal roundworm parasites (Ascaris suum, Oesophagostomum spp. and Trichuris suis) on organic and alternative swine farms by quantifying their eggs in pig feces, pastured soil, and bedding. Nine farms raising pigs in bedded facilities across four states (Iowa, Minnesota, Pennsylvania, and Wisconsin) were sampled, and analysis of parasite egg counts from feces indicate that 88.9%, 55.5%, and 44.4% of farms were infected with A. suum, Oesophagostomum spp. and T. suis, respectively. Prevalence, mean abundance, and mean intensity of eggs per gram (EPG) in feces for A. suum and T. suis were higher in growing and finishing pigs, whereas they were higher for Oesophagostomum spp. in finishing pigs and sows. Prevalence and abundance with A. suum eggs in feces were higher in organic certified farms, whereas abundance of Oesophagostomum spp. and T. suis was lower than those in alternative farms. Fewer eggs were recovered from soils than bedding samples, but their presence in both substrates confirmed that dispersal stages occur in farms. Overall, our results indicate that intestinal parasite infection across organic and alternative swine farms in the USA is common, and not surprising given that few options to control infection within organic regulations are available.

Occurrence of Intestinal Parasites and Its Impact on Growth Performance and Carcass Traits of Pigs Raised Under Near-Organic Conditions.

Parasite infection is a common problem in organic pig production, which can compromise health and growth of pigs, threaten food safety of pork products, and cause economic losses to organic farmers. To develop management strategies for controlling parasites, we evaluated intestinal parasite infection in pigs at different ages and of different sexes, and investigated whether parasite infection influences growth performance and carcass traits in a cross-sectional study. Fecal samples were collected from pigs (n = 298) raised under near-organic standards during nursery, growing, finishing, and gestating phases for analysis of fecal egg counts (FEC) of Ascaris suum, Trichuris suis, and Oesophagostomum spp. Ascaris suum eggs were not detected in the feces of nursery pigs. Eggs of Ascaris suum were found in 45%, 74%, and 0% of fecal samples of growing pigs, finishing pigs, and gestating sows, respectively, after false-positive adjustment (P < 0.001). Mean FEC of Ascaris suum was higher in infected finishing pigs than in infected growing pigs [2,502 vs. 724 eggs per gram (epg), P < 0.001]. No differences in percent of Ascaris suum positive samples or FEC of Ascaris suum were detected between sexes. Growth performance and carcass traits were not different between non-infected pigs and those infected with Ascaris suum. All pigs (n = 32) examined at slaughter had white spots on the liver, and 78% harbored Ascaris suum worms. Trichuris suis eggs were not detected in any fecal samples. Eggs of Oesophagostomum spp. were found in 7%, 0%, 1%, and 9% of fecal samples of nursery pigs, growing pigs, finishing pigs, and gestating sows, respectively, with a maximum FEC of 40 epg in all age groups. These results indicate Ascaris suum was the predominant parasite infecting growing and finishing pigs in the herds studied. To control A. suum infection, future research should investigate the efficacy of treating pigs with organically approved anthelmintics during the growing phase of production.