Postmortem examination (2016–2017) of weanling and older horses for the presence of select species of endoparasites: Gasterophilus spp., Anoplocephala spp. and Strongylus spp. in specific anatomical sites

Parasite infections are more quantifiable postmortem than antemortem in horses. Thus a study was carried out examining dead horses for specific parasite species. Most of the weanling and older horses submitted to the University of Kentucky Veterinary Diagnostic Laboratory (UKVDL) for postmortem examination between November 22, 2016 and March 23, 2017 were examined for certain species of internal parasites. The stomach and duodenum from 69 horses were examined for bots (Gasterophilus spp.). Combined data for both Thoroughbred and non-Thoroughbred (16 other than Thoroughbred breeds/mixed breeds) horses revealed that the prevalence of Gasterophilus intestinalis was 19% (n = 12) with 2nd instars (x̄ 8.5) and 39% (n = 27) with 3rd instars (x̄ 90). The prevalence of Gasterophilus nasalis was 1.5% (n = 1) for 2nd instars (x̄ 1) and 7% (n = 5) for 3rd instars (x̄ 25). A few third instar G. intestinalis placed in 10% formalin showed slight movement at over two hundred hours later. The cecum and about 25 cm of the terminal part of the ileum were examined from 139 horses for tapeworms (Anoplocephala spp.) and large strongyles (Strongylus spp.). The prevalence of A. perfoliata was 44% (n = 62) and the average number of specimens per infected horse was 92.5. Strongylus vulgaris and Strongylus edentatus were not found in the gut of any horse.