A survey of the level of horse owner uptake of evidence-based anthelmintic treatment protocols for equine helminth control in the UK

Abstract

Interval treatment control programmes used widely in equine helminth control have favoured the development of anthelmintic resistance worldwide. Best practice guidelines have been designed to address resistance and include the requirement for improved pasture hygiene to break helminth transmission cycles, along with anthelmintic application informed by the results of diagnostic tests to reduce selection pressure for resistance. Using an online questionnaire, this study examined uptake of measures recommended in these guidelines by UK horse owners. The survey comprised 58 questions spanning grazing management, anthelmintic use and use of faecal egg count (FEC) testing to inform treatment decisions. Analysis was carried out using a combination of Chi-square and Mann-Whitney tests. In total, 705 owners responded and, following specific exclusion criteria, the responses of 652 individuals were analysed. The majority of the respondents owned <20 horses on private premises or livery yards in England. The main outputs of the survey were as follows. Overall, 60.9% of respondents used FEC tests to inform the requirement to administer anthelmintics, with macrocyclic lactones the most frequently-used anthelmintics. Of the respondents, 38% obtained advice on anthelmintic choice from their veterinarians; however, many respondents (43.8%) purchased anthelmintics via the internet. Encouragingly, 74.4% of respondents stated that they practiced good pasture hygiene by removing dung from pasture. Generally, there were differences between the responses of participants who based anthelmintic treatments on FEC testing (targeted treatments; TT) and those who practiced calendar-based anthelmintic treatments (interval treatments; IT). Briefly, the "key" findings from the Chi-square analysis included higher levels of satisfaction with the level of knowledge about equine parasites/parasitic diseases and higher levels of concern about anthelmintic resistance from TT-respondents compared to IT-participants. Confusion on the interpretation of quarantine recommendations was identified in this study group and there was poor uptake of testing for anthelmintic effectiveness. Overall, compared to previous reports, this study indicated improved engagement of UK horse owners with some helminth control practices recommended to reduce the spread of anthelmintic resistance. However, a proportion of respondents did not utilise these practices and there were still important gaps in the use of appropriate quarantine and efficacy testing. These identified gaps must be taken into consideration in knowledge dissemination activities in the future.

Keywords: Anthelmintic resistance; Anthelmintics; Equine; Faecal egg count tests; Helminths; Questionnaire.