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.

Laminitis associated with hyperinsulinemia a significant cause of morbidity and mortality in horses with equine metabolic syndrome. The diagnosis and management of insulin dysregulation are therefore critical to prevent the development of hyperinsulinemia-associated laminitis. This review article aims to help primary care clinicians manage patients with insulin dysregulation by providing an overview of diagnostics, management strategies and new therapies that are available.

Whilst there are limited data on the environmental impact of administering parasiticide drugs to horses, evidence from other species treated with identical drugs indicates significant negative ecological effects. Anthelmintic drugs may be excreted unchanged or metabolised to other active and/or toxic metabolites that enter the environment through direct excretion during grazing. These chemicals can have significant toxic effects on non-target insects, such as dung beetles, earthworms and aquatic animals. Of the anthelmintics frequently used in horses, ivermectin appears to be the most ecotoxic; available evidence indicates that moxidectin is less toxic. Fenbendazole appears to have little impact on dung-colonising insects but may be toxic to aquatic organisms and fungi. There is very little data regarding the ecotoxicity of pyrantel and praziquantel, although their ecotoxic effects are thought to be low. Pasture hygiene reduces pharmaceutical contamination and also helps to break the endoparasitic cycle of infectivity, thus reducing reliance on anthelmintics. Judicious use of endoparasiticides, along with pasture hygiene measures, will limit the ecotoxic effects of these drugs and reduce the selection pressure that drives anthelmintic resistance. Anthelmintics may also impact the equine gastrointestinal microbiota.Following topical treatment with ectoparasiticides (such as fipronil, permethrin or cypermethrin), there is a risk of contamination of both the immediate environment and water courses. The half-life of fipronil in the environment is variable, but it degrades into compounds which are more toxic; it is highly toxic to bees, and is reported to bioaccumulate in fish and can be toxic to birds. Of the synthetic pyrethroids, permethrin degrades at a faster rate than cypermethrin and may therefore have a lower ecotoxic effect. The ecotoxic effects of injectable doramectin are likely to be similar to oral ivermectin, although persistence in faeces may be significantly prolonged compared to the oral treatment route.