Relationship between racial predominance and ectoparasites in crossbreed cattle herds in a dry tropical weather. Technical note

To estimate the ectoparasites prevalence and assess the impact of the racial predominance of Bos taurus taurus, Bos taurus indicus, and their crossbreeds on this prevalence in dual- purpose cattle herds in a tropical dry weather in Venezuela, a cluster sampling was conducted. 564 animals from twenty- two cattle production systems were sampled, proportionally distributed across six age groups (<3, 3-6, 6-12, 12-18, 18-32, and >32 months, respectively). The animals were evaluated for the presence of ectoparasites, with specimens collected for identification using dichotomous keys. Additionally, the variables of age and racial predominance were analyzed. The overall prevalence of ectoparasites was 57.54%, with specific prevalences of 51.5% for Haematobia irritans, 20.6% for Rhipicephalus (Boophilus) microplus, and 1.06% for Stomoxys calcitrans. There was a significant effect of age and racial predominance on the prevalence of ectoparasites overall, particularly for H. irritans and R. (B.) microplus, with a higher probability of infestation observed in adult animals and those predominantly B.t. taurus. The predominance of B.t. indicus and their crossbreeds was found to be a protective factor against ectoparasitosis. The relationship between ectoparasite prevalence and cattle racial predominance is clear, with B.t. indicus showing the highest resistance.