Repeatability of strongyle egg counts in naturally infected horses.

The research discusses the stability of parasite egg-shedding patterns in horses over time, using faecal egg counts to identify ‘high shedders’ in a bid to reduce the use of anthelmintic treatments.

Objective of the Research

• The study was undertaken to assess if the number of parasite eggs a horse sheds in its faeces remains consistent over time, contributing to strategic and responsible use of anthelmintic treatments.
• The ability to predict which horses will consistently shed a high number of eggs allows veterinarians to focus on treating only this subset of horses, reducing overall anthelmintic treatment use and potential drug resistance development.

Methodology of the Research

• In order to measure the stability of egg-shedding, researchers collected and analysed 2637 faecal egg counts (FEC) from 303 horses.
• Raw egg counts (REC) were also used in the study. These are originally counted eggs without the multiplication factor used in FEC.
• Due to the FEC distribution being more overdispersed than a standard Poisson distribution, a negative-binomial model was utilised for the analysis.

Outcomes of the Research

• The study revealed a within-horse-repeatability of raw egg counts (RECs) at 0.52. This implies a notable level of consistency in individual horses’ egg-shedding over time.
• The findings remained fairly consistent even after excluding horses that had been treated with anthelmintic drugs; the within-horse repeatability was computed at 0.53 in this case.

Significance of the Findings

• The research results indicate that horses who shed a relatively high number of nematode eggs can be accurately identified over a period of time, allowing for targeted and effective treatment strategies.
• With these results, it’s possible to reduce overall usage of anthelmintic treatments, which not only holds economic benefits but could also slow the rise of drug-resistant parasites.