Comparison of two control systems for cyathostome infections in the horse and further aspects of the epidemiology of these infections.

The research article compares two control systems for managing Cyathostome infections in horses, with focus on the effectiveness of treatments and the epidemiology of the infections.

Study Setup

• Small strongylid infections were studied among two groups of three-year-old female Shetland ponies and one yearling Shetland tracer pony.
• One group was set stocked from April to November and received monthly treatments of 5 mg kg-1 albendazole from two days before turnout until July.
• The other group grazed similar pasture until July, was treated with 5 mg kg-1 albendazole, and was then moved to pasture grazed by sheep from April to July.
• The tracer ponies were added to both groups in September.

Effectiveness of Control Methods

• Neither of the methods demonstrated satisfactory efficacy, a likely reason for this could be the low efficacy of anthelmintic treatment.
• No significant differences were observed in the cyathostome burdens between the two groups.

Observations on Infection Spread

• A substantial proportion of the cyathostome populations in all ponies consisted of inhibited early third stage larvae (L3).
• Low numbers of immature fifth-stage worms found in the tracer ponies indicate that the significant adult burdens in the permanent ponies likely originated from infection acquired before the addition of the tracer ponies.
• In the group that moved to sheep pasture after treatment in July, it was hypothesized that the majority of the adult worm burden had likely been ingested as infective larvae prior to the treatment.