Parasite control strategies on Australian stud farms are over‐reliant on dewormers, according to researchers.
The study team from Charles Sturt University in Wagga Wagga based its conclusion on the results of a questionnaire targeting Thoroughbred and Standardbred studs.
Edwina Wilkes and her colleagues set out to identify parasite control practices used on Australian studs and investigate their use of strategies with the potential to promote or delay anthelminitic resistance.
They invited 300 studs to fill in an online questionnaire, which explored property details, grazing management, the use of dewormers, other parasite control practices, their use of faecal egg counts, and perceptions of parasite resistance to available drugs.
The researchers, writing in the Equine Veterinary Journal, reported receiving 75 completed questionnaires, representing a 25% response rate.
Macrocyclic lactones — the family of deworming drugs that includes ivermectin — were the most commonly given dewormer in mares and foals.
Less than 5% of respondents used targeted treatment regimens, they found.
The researchers said the use of pasture hygiene practices was variable.
Nearly all of the respondents — 97% — considered parasite resistance to dewormers to be important. However, few were aware of the use of faecal egg count reduction tests for monitoring the effectiveness of drugs.
“Parasite control strategies on Australian stud farms remain over‐reliant on anthelmintic use,” they concluded.
The study team said the frequent use of macrocyclic lactones was of concern for the increased selection pressure for anthelmintic resistance.
“There is a lack of awareness of the importance of non‐chemotherapeutic strategies in integrated approaches to parasite control aimed at delaying the development of anthelmintic resistance.”
They said their study highlighted the need for greater veterinary involvement in implementing more sustainable parasite control practices, with greater emphasis on surveillance through egg counts.
The study team comprised Wilkes, Jane Heller, Sharanne Raidal, Robert Woodgate and Kristopher Hughes, all with Charles Sturt University.
A questionnaire study of parasite control in Thoroughbred and Standardbred horses in Australia
Edwina J. A. Wilkes Jane Heller Sharanne L. Raidal Robert G. Woodgate Kristopher J. Hughes
First published: 14 November 2019 https://doi.org/10.1111/evj.13207
The abstract can be read here.