Relation between range use and parasitic infection in Italian organic laying hens

Organic laying hens have access to outdoor areas that is regarded as a potential source of helminth infections. Helmintic infections with e.g. Ascaridia Galli (A) have been associated with performance losses. Some studies have found that A. Galli and Heterakis spp (H) are the main species founded in organic and free range systems. The aim of this study was to evaluate: -the relation between parasite eggs in the free range soil and the intensity of use of the range area in terms of distance to the stable and proportion of chickens using the range area; -the level of individual laying hens, between frequency of use of the range area and faecal egg counts. The study was carried out in 8 Italian organic layer farms (45 to 80 weeks of age), that have had range access >5 months and were not dewormed. Twenty samples were taken per farm: 6 soil samples (5-20-50 m from the pop-holes), 7 mixed manure samples from 70 ‘outdoor hens’ at >50 m from the pope-holes and 7 mixed samples from 70 ‘indoor hens’. All samples were analyzed for eggs from A/H and Capillaria (EPG; McMaster method). Paired samples t-tests and Pearson correlations were performed with IBM SPSS version 25. Manure from outdoor hens had significantly less EPG for A/H compared to manure from indoor hens (47% vs 63%; mean 43 vs 172 P>0.05); EPG for A/H outdoor and indoor were correlated (p=0,37). Soil samples had a high prevalence of Capillaria (87%), as well as manure collected indoor and outdoor (33 vs 24). The mean of Capillaria eggs were significantly higher in soil then both the outdoor and indoor manure samplings (112,50vs22.22vs12,96; p<0,000). The mean mortality at 60 weeks was 5%, production at 60 weeks and health parameters did not deviate from hybrid standard. The lower presence of A/H both in the soil and in the outdoor manure may indicate a poor use of the farthest location of the range; when investigated on flock level, infection with parasites did not severely impair the performance. Funding: ERA-net Core Organic Cofund FreeBirds