Background : Anthelmintic resistance in equine parasites is increasing. Frequent anthelmintic use accelerates selection for resistance. Objectives : Investigate how horse owners currently use anthelmintics to control intestinal parasites. Study design : Online survey. Methods: Questionnaire distributed via practices, equestrian organisations, etc., December 2021 to October 2022. Combination of multiple choice, Likert scale and free text questions. Descriptive / inferential statistics performed (Microsoft Excel and IBM SPSS). Results : 4232 useable responses. Owners of horses on livery yards less likely to make worming decisions compared to those on private properties (p<0.001); managers made decisions in 39.6% of horses on livery yards; 60.7% of owners sought worming advice from their veterinarian; 52.0% administered anthelmintics based on routine faecal egg counts (FECs) / tapeworm serology result; 30.0% routinely tested, but wormed at least once a year regardless of the results; 16.1% did not test, but wormed at least once a year. Owners were more likely to administer anthelmintics based on test results if they sought veterinary advice or were on a health programme (both p<0.001). Of those who routinely wormed, 54.9% wormed once a year; 45.1% wormed twice or more a year. Frequency of routine worming was higher if they didn’t routinely test (p<0.001); 88.9% simultaneously wormed all horses on the pasture. Moxidectin was the first choice for 82.2% of owners who routinely wormed at least once yearly. Routine FECs were performed by 84.7%, higher for those who sought veterinary advice (89.3%, p<0.001). Tapeworm ELISAs were utilised by 40.8%, higher for those on a health programme (68.1%; p<0.001); 58.5% routinely treated for tapeworms regardless of test results. Main Limitations : Selection bias. Conclusions : Owners apply moderately good diagnostic-led parasite control practices, but still common to regularly treat with anthelmintics (30.0% worming at least once a year regardless of the FEC results).

Background : Anthelmintic resistance in equine parasites is increasing. Pasture management is a vital component of parasite control, and is important to limit the development of resistance. Objectives : Investigate how horse owners use management procedures to control common intestinal parasites in horses. Study design : Online survey. Methods : Questionnaire distributed via practices, equestrian organisations, etc., December 2021 - October 2022. Combination of multiple choice, Likert scale and free text questions. Descriptive and inferential statistics performed in Microsoft Excel and IBM SPSS. Results : 4232 useable responses from the UK, predominantly England (85.4%). Premises included livery yards (45.7%) and private properties (51.1%). Most horses (70.4%) were aged 6-20 years. Over half (55.9%) were used for general riding/pleasure; 58.9% grazed with 1-3 other horses, while 20.7% grazed alone; 21.5% alternated or co-grazed with ruminants (significantly higher for horses grazing on private properties compared to horses grazing on livery yards; 73.3% of owners removed faeces from pastures (poo-picking), of which 86.4% removed faeces twice a week or more. Owners of horses pastured individually were significantly more likely to poo-pick (89.8%) than horses pastured in groups (68.9%); 77.1% of respondents rested pastures, but less than 5% for over 6 months. Only 5.1% of owners reported they had experienced illnesses related to worms in any horse (commonest clinical signs were colic and weight loss). Limitations : Selection bias. Conclusions : Results suggest a lack of understanding of the principles of non-chemical parasite control among many horse owners. Many owners (>25%) are not routinely poo-picking. Horses pastured alone or kept on a private property were significantly more likely to have their faeces regularly removed than thoses pastured in groups or kept on livery yards.