Distribución y abundancia de los huevos de estróngilos digestivos en bovinos infectados naturalmente

Abstract

Objective: To quantify the prevalence and parasitic burdens of byles in naturally infected bovine herds in an important western cattle production area in Falcon state, Venezuela. Materials y methods: Four ranches with the "Carora" breed (result of crossing Holstein, Swiss Brown, Zebu) were sampled over a seven month period. Every month cattle were examined by the McMaster coprological technique. In each ranch, sampling was stratified among four age groups (calves: 0-6 mo; "maute": 7-12 mo; heifers: 13-24 mo; adults: >25 mo). Results: A total of 1140 samples were collected. Mean prevalence values were 31.06-50.36%. Statistical differences in prevalence values among ranch and age groups were observed. Infections showed an over-dispersed distribution in each herd, as confirmed by very low K coefficients (0.001-0.01). Conclusions: Abundance values (EPG average) were mostly affected by the number of animals with a high parasitic burden rather than high prevalence values at each of the ranches. Most infections were not clinically relevant; animals with high parasite burdens were 1.75-28.56% of the total number of animals evaluated. © 2009 Universidad de Córdoba, Montería, Colombia.