Fecal Egg Counts, Nemabiomes, and Management Practices in Saskatchewan Horses

Saworski, Toni

Fecal Egg Counts, Nemabiomes, and Management Practices in Saskatchewan Horses

dc.contributor.advisor	Jenkins, Emily
dc.contributor.committeeMember	Poissant, Jocelyn
dc.contributor.committeeMember	Gilleard, John
dc.contributor.committeeMember	Clark, Chris
dc.contributor.committeeMember	Hill, Janet E
dc.contributor.committeeMember	de Queiroz, Camila
dc.contributor.committeeMember	Reuben, Joseph
dc.creator	Saworski, Toni
dc.creator.orcid	0009-0001-6869-9028
dc.date.accessioned	2023-08-25T19:35:40Z
dc.date.available	2023-08-25T19:35:40Z
dc.date.copyright	2023
dc.date.created	2023-08
dc.date.issued	2023-08-25
dc.date.submitted	August 2023
dc.date.updated	2023-08-25T19:35:40Z
dc.description.abstract	The purpose of this thesis was to describe intensity (fecal egg counts, FEC) and diversity (using nemabiome ITS2 metabarcoding approaches) of gastrointestinal nematodes in Saskatchewan horses, their relationships with individual horse variables and management practices, and effectiveness of owner-administered treatments. We conducted fecal surveys in horses in fall 2021 (n=107) and spring 2022 (n=123) that had not been dewormed in the previous 6 months, most of which were adults (greater than 3 years old). Parascaris spp. eggs were rare, more commonly present in spring and in horses less than 3 years old. Strongyle prevalence and mean FEC were significantly higher in fall (76% and 964 eggs per gram of feces, EPG) than spring (66% and 593 EPG), and in pastured vs stabled horses. Age was significantly associated with strongyle FEC, with higher counts in young and old horses, especially older mares. Third stage larvae were cultured from 95 fecal samples containing >200 strongyle EPG, and 34 unique species were identified, including 28 small strongyles (dominated by Cylicocyclus nassatus, Cyathostomum catinatum, and Cylicostephanus longibursatus), 2 large migratory strongyles (Strongylus vulgaris and S. edentatus), 3 non-migratory large strongyles (Triodontophorus spp. and Craterostomum acuticaudatum), and the cattle nematode Ostertagia ostertagi. Nemabiome composition was significantly associated with age, sex, collection season, and FEC. In fall, fecal samples from 5 of 29 horses resampled 14 days after anthelmintic treatment administered by owners harboured strongyle eggs (from 11 to 775 EPG) with a mean treatment effectiveness of 96%; on a single property with 15 horses, mean effectiveness was 92%, excluding a horse that likely missed its dose. Three samples contained 18 small strongyle species before treatment, and seven species after, including the 3 dominant small strongyles. Only 23% of horse owners used FEC to determine need for treatment, 41% automatically dewormed twice per year, 26% relied on appearance of the horse to calculate body weight, 55% used a product containing a macrocyclic lactone, and 39% of owners did not know what product they had most recently used. We report high strongyle FEC and diversity of strongyles for managed domestic horses, and evidence of lack of effectiveness of owner-administered treatments which may in part be related to suboptimal deworming practices as well as emerging resistance of small strongyles.
dc.format.mimetype	application/pdf
dc.identifier.uri	https://hdl.handle.net/10388/14926
dc.language.iso	en
dc.subject	equine
dc.subject	veterinary
dc.subject	parasitology
dc.subject	care
dc.subject	anthelmintics
dc.subject	resistance
dc.subject	strongyle
dc.title	Fecal Egg Counts, Nemabiomes, and Management Practices in Saskatchewan Horses
dc.type	Thesis
dc.type.material	text
thesis.degree.department	Western College of Veterinary Medicine
thesis.degree.discipline	Veterinary Microbiology
thesis.degree.grantor	University of Saskatchewan
thesis.degree.level	Masters
thesis.degree.name	Master of Science (M.Sc.)