Expulsion of small strongyle nematodes (cyathostomin spp) following deworming of horses on a stud farm in Sweden.

The research investigates the expulsion of a type of nematode worm, known as cyathostomins, from horses in a stud farm in Sweden after treatment with different anti-worm medications. The research primarily studied the composition of the expelled species, the expulsion pattern after medication, and the most prevalent species, providing insight into the efficiency of the examined deworming preparations.

Methodology and Experimentation

• The researchers selected 27 horses from a stud farm in Sweden, each depositing more than 200 strongyle eggs per gram of faeces.
• The horses were equally divided into three groups and each were treated with a different anti-worm medication: ivermectin, pyrantel pamoate or fenbendazole, at proportionate dosages respective to their body weight.
• From the first day post-treatment till the third day, faeces were collected from the horses and subsamples were collected and preserved in formalin.
• Four days after the initial treatment, all the horses were treated once again with ivermectin and faecal samples were collected on the fifth day.
• Subsamples from the collected faecal matter were examined for presence of cyathostomin nematodes.

Findings

• The majority of the worms were expelled during the first day from horses treated with ivermectin or pyrantel pamoate, and on the second day for those treated with fenbendazole.
• Fifteen species of cyathostomin nematodes were identified. Six species in particular made up 91% of the total worm burden – Cylicocyclus nassatus, Cyathostomum catinatum, Cylicostephanus longibursatus, Cylicocyclus leptostomus, Cylicostephanus minutus, and Cylicostephanus calicatus.
• A range of 6 to 13 species were found per horse, averaging at around 9 species per horse. No significant differences in species composition or distribution were recorded across the three treatment groups.
• One day after the second treatment with ivermectin, 93% of adult worms found in the faecal matter of the horses were from those belonging to the fenbendazole treatment group.

Conclusion of the Research

• This study effectively exhibited the possibility of identifying specific species of cyathostomins, expelled in the faeces of dewormed horses, correlating the species frequency with other autopsy studies conducted in different countries.
• The prevalent species and the higher worm burden in horses despite deworming treatments might suggest the need for improved courses or methods of treatment.