The aim of this study was to determine the survival of pre-parasitic stages (eggs and larvae) of gastrointestinal nematodes (GN) in Bocashi made from cattle manure. The study was conducted at the facilities of the National University of Costa Rica (UNA) during 2010. Bocashi was made from cattle manure collected from a dairy farm located in Poasito de Alajuela, Costa Rica. Cattle manure contained 600 eggs from the Strongolyda suborder per gram (epg), specifically < 50 epg from Strongyloides papillosus, and < 50 epg from Trichuris spp. Approximately 20 random samples were taken from finished Bocashi and processed using the qualitative method of Sheater and the quantitative method of McMaster in order to identify and quantify eggs from GNs. Additionally, coprocultures were performed and total nematodes were extracted from Bocashi samples to determine the presence of GN larvae. Eggs from GNs were observed in Bocashi samples at very low concentrations, so quantification by the standard parasitological method was not possible. In all cases the eggs showed signs of degradation. No larvae from GNs were observed in coprocultures or in the total nematode extraction. In contrast, large numbers of bacterial-feeding nematodes were observed in Bocashi samples, whose presence is considered positive. We conclude that the conditions present during the preparation process of Bocashi substantially reduce the number of GNs at pre-parasitic stages and promote an increase in the number of beneficial organisms.

Keywords: animal parasites, bacterial-feeding nematodes, food safety, organic fertilizers, Strongylids