• Dace Keidane Latvia University of Life Sciences and Technologies
  • Gita Ozola Latvia University of Life Sciences and Technologies
  • Aija Ilgaza Latvia University of Life Sciences and Technologies
Keywords: horses, ivermectin, resistance, strongyles, digestive.


Lately, much has been said about ivermectin resistance to digestive horse strongilide infections. Often, the owners of the horses choose the animal to do deworming, without sending first the coprogram to the laboratory for the test. Misidentifying antihelmetic and inappropriate doses result in the strongilide ivermectin resistance.

Our goal was to investigate whether the ivermectin resistance was observed in horses in Latvia. The tasks were as follows: collecting faecal samples, examining them, calculating the quantity of an invasion, identifying resistance. The study was launched in March 2018.

In the study, we used 23 horses from the age of five, different sexes and types of use (sport, hobby etc). Horses were from different districts of Latvia (Jelgava, Riga, Jekabpils, Aizkraukle region). All animals were clinically healthy – rectal temperature, respiration rate, heart rate, condition of  the animal were determined. 23 horses were examined for coprology specimens. Samples were obtained from each horse rectal, faeces put into sterile plastic bags, each individually identified (animal identification number, age, gender), and transported in a cold box at plus 40 C to the laboratory for investigation. Samples were examined at the Laboratory of Veterinary Medicine at the Parasitology Laboratory using the flotation method. The egg number is set per gram of faeces after McMaster. (P. Keidans, 2008).

Depending on the results obtained and the volume of the invasion, all positive horses were given an ivermectin-containing paste. The dose is adapted to the individual weight of each horse. Repeated faecal samples were taken after 14 days. Samples were examined by flotation method, and the number of eggs re-diagnosed per gram of faeces after McMaster.

We can conclude that in the samples, before deworming with ivermectin-containing paste, the number of strongilidae eggs varied from 100 to 800 eggs per gram of faeces.

Collection and investigation of faecal samples are still going on.