Prevalencia, carga parasitaria y susceptibilidad a antiparasitarios de helmintos gastrointestinales en ovinos tropicales de la Estación Experimental Pastaza

Abstract

The objetive of the study was to evaluate a cycle of parasite prevalence, parasite load and susceptibility to benzimidazoles (BZs) and macrocyclic lactones (LMs) in tropical sheep at Estación Experimental Pastaza. The diagnosis was made with 89 sheep of the Pelibuey and Black Belly breeds. Prevalence was determined by statistical analysis, taking into account the main risk factors for parasitic infection. Descriptive statistics were used to evaluate the parasite load in eggs per gram of feces (hpg) in age groups, productive stages, sex and breed. Susceptibility was calculated using the egg reduction test (ERT). For prevalence results, a total of 74% of animals showed gastrointestinal nematode infection (GIN) and 26% showed no evidence. For the parasite load in the categories studied we found the following values: maltons 819 hpg, maltons 358 hpg and ewes 154 hpg. In the productive stages, the replacement maltons obtained an average of 358 hpg higher than the breeding ewes with 154 hpg. In the sexes, it was found that males outperform females with a mean of 819 hpg and 245 hpg respectively. Finally, it was determined that the Black Belly breed outperforms the Pelibuey with a mean of 531 hpg and 350 hpg. Haemonchus contortus was found to be the NGIs with the highest presence, and the Fasciola hepatica test indicated that 100% of the sheep showed no evidence of this parasite. In conclusion, the HRT indicates that there is resistance to BZs and LMS, associating it with the continuous parasitic infections. New management plans, sanitary control and animal selection are recommended.