Resumen

MARTINEZ-ORTIZ-DE-MONTELLANO, Cintli; RODRIGUEZ-VIVAS, Roger Ivan; ROSADO-AGUILAR, José Alberto  y  GALICIA-VELAZQUEZ, Guadalupe. Effectiveness of ivermectin and moxidectin against cyathostomins in four horse breeding farms in Mexico. Veterinaria México OA [online]. 2023, vol.10, e1192.  Epub 10-Ene-2025. ISSN 2448-6760.  https://doi.org/10.22201/fmvz.24486760e.2023.1192.

This study aimed to evaluate the effectiveness of oral ivermectin and moxidectin against natural cyathostomin infection in four horse farms located in the central regions of Mexico. Of the 445 horses: Warmblood (145), Thoroughbreds (100), and Quarter Horses (200) breeds, aged between 6 months and 27 years, were used. Data on horses and parasite control methods were collected through interviews with farm owners and veterinarians. Using the McMaster technique, fecal samples were processed from all 445 horses, 180 of which were positive for cyathostomins. On each farm, a selection was made of 45 animals meeting the criteria of a Faecal Egg Count Reduction Test yielding results exceeding 150 eggs per gram of strongylid-type nematodes. Subsequently, three separate experimental groups were formed for each farm, each consisting of 15 horses The first group was treated with oral ivermectin 1.87 %; the second group with oral moxidectin 2 %; and the third was the non-treatment control group. Coprocultures were also performed to identify the presence of nematode species. The data obtained were analyzed with RESO.exe©️. Three of the four farms achieved a 100 % reduction in eggs per gram with both macrocyclic lactones. One farm achieved 93 % reduction with ivermectin and 87 % with moxidectin. This study demonstrates that macrocyclic lactones effectively reduce cyathostomins in three of the four farms studied. The results suggest potential cyathostomin resistance to macrocyclic lactones, particularly moxidectin, on one farm. Given these findings, sustainable parasite management is required on horse breeding farms in Mexico.

Palabras llave : Cyathostomins; Ivermectin; Moxidectin; Anthelmintic resistance; Horses.

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