Profiles of strongyle EPG values for Thoroughbred mares on 14 farms in Kentucky (2012-2013).

The study aims to confirm whether taking three weekly fecal samples would provide consistent results for low strongyle egg shedders, a condition often associated with older horses. Investigations were carried out on over 661 Thoroughbred mares across 14 farms in Kentucky, over 2012-2013. The findings of this research may be used to inform recommendations for global parasite control in horses.

Methodology

• The research team gathered strongyle egg counts per gram of feces (EPG) from each test subject on a weekly basis, over three consecutive weeks.
• None of the horses involved in the study had been treated with ivermectin or moxidectin within the previous 90 days, nor were they treated with fenbendazole, oxibendazole, or pyrantel pamoate for at least 60 days prior.

Results

• The first and second samplings showed that 38.3% of mares were positive. The third sampling found 37.8% to be positive.
• On each farm, between 5.6% and 63.3% of horses were found to be positive.
• There was a high correlation between EPG count data over the three weeks, indicated by an Rs value of 0.84 (p<0.001).
• Horse infection levels appeared to be dependent on factors such as horse age, farm type and individual characteristics of the horse.

Conclusion and Implications

• The strongyle egg counts (EPGs) from individual horses did not show significant differences between weeks, indicating that a single strongyle EPG count can effectively represent the level of egg shedding in a given horse.
• This supports an existing trend of not universally deworming all adult horses on a farm. By this practice, high shedders can be individually identified and treated, thus cost-effectively managing the condition without excessive and unnecessary treatment.
• This approach also helps reduce the potential development of drug resistance in parasites, as a result of lower overall usage of antiparasitic compounds.
• The data and implications gathered from this study may contribute to the formation of global recommendations for parasite control in horses.