Selective Anthelmintic Treatment in Horses in Sweden Based on Coprological Analyses: Ten-Year Results.

In Sweden, routine deworming has been used for several decades; however, to slow down the development of anthelmintic resistance, selective treatment is currently recommended. As part of a monitoring programme, equestrian premises submitted faecal samples to the National Veterinary Institute (SVA) twice per year between 2008 and 2017. Analyses for strongyles (small and large), tapeworms and ascarids, followed by premise-specific advice regarding deworming and parasite control strategies, were provided. In total, 43,330 faecal samples, collected from 26,625 horses on 935 premises in springtime (March to June), were analysed by quantitative or semi-quantitative flotation. Moreover, was detected by larval culture or PCR. Between 4 and 11% of individual horses tested positive for and 3-10% were shedding tapeworm eggs. There were recurrent high and low egg shedders; 75% of horses with appeared to have been recently introduced into the herd; the proportion of -positive premises increased when individual samples rather than pooled samples were used. Based on the results of diagnostics and strongyle egg-shedding level, 59% of the horses did not need to be dewormed.