Abstract
Rio Grande do Sul state, in southern Brazil, is one of the country’s largest cattle producers but reports few cases of genital infections caused by Mollicutes, specially Ureaplasma diversum and Mycoplasma bovis. The clinical signs associated with these bacteria can be easily confused with those caused by bovine herpesvirus (Varicellovirus bovinealpha1), Campylobacter fetus, and Tritrichomonas fetus, which complicates diagnosis. This study aimed to assess the occurrence of Mollicutes in cattle from Rio Grande do Sul between April 2022 and November 2024. Vulvo-vaginal and preputial lavage samples submitted for routine diagnosis at a Bacteriology Laboratory, were tested using PCR. Samples were first tested for U. diversum and M. bovis. Those testing negative were further examined for Mycoplasma bovigenitalium and Mycoplasma spp., and if still negative, for the Mollicutes class to detect other species. In total, 136 samples from 16 beef cattle farms in central, southern, and western regions of the state were analyzed. These included herds with reproductive disorders (n = 11) and asymptomatic animals (n = 5). U. diversum was detected in 44 samples (32%) from nine herds, both with and without reproductive issues. M. bovis was identified in one sample (1%) from a herd with reproductive problems. M. bovigenitalium was found in 11 preputial samples (9%) from three affected herds. PCR also detected Mycoplasma spp. in 25 samples (18%) and Mollicutes class in 31 samples (23%). These results confirm the presence of Mollicutes in reprodutive system in both, symptomatic and asymptomatic animals, highlighting their circulation in herds from Southern Brazil.