Management factors and their impact on helminthic fecal egg count in horses

Research concerning factors that influence fecal egg count is of great importance for an effective anthelmintic treatment. This study was designed to provide further insight into the management of horse stocks and its influence on the infection of the horses with parasitic helminths. For this purpose, faeces from 620 patients were sampled over a 2 year period and owners were interviewed regarding their stock management, concerning stabling, pasture hygiene and deworming. The faecal egg counts for roundworms, tapeworms and strongyles were determined by FLOTAC and evaluated for correlations with management factors. In this study, strongyles were the most frequently detected group of helminths. The multifactorial logistic regression model showed that the time of last deworming, access to pasture, fertilizing pasture with horse manure, plowing of pasture and age of horses had a significant impact on the presence of strongyle eggs. Horses of the age of 1 to 5 years revealed highest strongyle egg counts and horses with diarrhea had an increased risk (OR 3,84) of a positive strongyle egg count. Furthermore, the coproscopic findings suggest that the macrocyclic lactones still have a high anthelmintic efficacy against equine gastrointestinal strongyles. Deworming of all horses simultaneously in a stock with the same anthelmintic drug increases the chance of a negative strongyles egg count by a factor of 10. Fertilizing pasture with horse manure increased the risk of a strongyle infection whereas plowing of pasture decreased the risk. The results of this study may improve deworming strategies in horse stocks.