Comparison of individual and pooled faecal samples in sheep for the assessment of gastrointestinal strongyle infection intensity and anthelmintic drug efficacy using McMaster and Mini-FLOTAC.

tA field study was conducted to validate pooled faecal samples in sheep for the assessment ofgastrointestinal (GI) strongyle infection intensity (faecal egg count – FEC) and anthelminticdrug efficacy (FEC reduction – FECR). Ten sheep farms located in the Campania region ofsouthern Italy were selected for the study. In each farm, individual faecal samples from 20adult sheep (when possible) were collected, before (D0) and after (D14) an anthelmintictreatment with albendazole. For each farm and at each time point (D0 and D14) the faecalsamples were examined individually and as pools. Specifically, three different pool sizes (5,10 and 20 individual sheep samples) and three different analytic sensitivities (namely 10using Mini-FLOTAC; 15 and 50 using the two variants of McMaster – McM15 and McM50)were compared for FEC and FECR using individual and pooled faecal samples. GI strongyleintensity (eggs per gram of faeces – EPG) of pooled samples correlated positively with meanEPG of individual samples, with very high correlation coefficients (ranging from 0.94 to 0.99)across the 3 different pool sizes and analytic sensitivities. Mini-FLOTAC was more sensitivecompared to the two variants of McMaster (McM15 and McM50) for the diagnosis of GIstrongyles in sheep (100% vs 88.5% vs 75.9%) and resulted in significant higher FEC comparedto both McM15 and McM50, with a mean difference in egg counts of approximately 90 EPG(p < 0.001). The drug efficacy results showed that FECR was higher than 98% at most farmsindependently of the pool size and analytic sensitivity. With the exception of two farms,FECR was 100% when calculated for individual animals and across the different pool sizeand analytic sensitivities. In conclusion, the present study highlighted that pooling ovinefaecal samples is a rapid procedure that holds promise as a valid strategy for assessing GIstrongyles FEC and FECR in sheep.