Seasonal Variations of Strongyle Egg Excretion in Horses in a Subhumid Area of Algeria

The seasonal evolution of strongyle egg excretion was studied in untreated horses, grazing on pastures in the coastal area of El Tarf, using the fecal egg count method and larval cultures. Strongyle egg excretion occurred mainly in the summer and reached a single peak in September, appearing thus very similar to kinetics observed in England and France. In fecal larval cultures, Strongylus vulgaris prevailed. S. vulgaris and S. edentatus were present throughout the year. Larvae 3 of S. equinus were very numerous in April, suggesting a seasonal return of stage 5 in the digestive tract. Larvae of Oesophagodontus and Triodontophorus were also rather constant in larval cultures. Absent in the winter, the egg excretion of Trichostrongylus axei was thus seasonal. Cyathostominae eggs were excreted all year round, but with a marked minimum between May and October.