Risk factors associated the occurrence of respiratory diseases they were evaluated between 349 Thoroughbred foals, monitored of the birth to the sixth month of life in the region of Bagé-RS-Brazil. From the laboratory and clinical evaluation, the frequency of 9.5% (33) of respiratory cases with mortality of 0.57% (2) was recorded. The occurrence of cases was higher in months of summer and foals with age between four and six months were more susceptible (P<0.001). The development of the diseases was influenced (P<0.001) by the breeding system of and management practices that increased the environmental contamination potential. In the evaluation microbiological, , the highest frequency of isolated was of Streptococcus equi (57%), followed by the Rhodococcus equi (17%), lethal in 50% of the cases. No clinic case was associated to the equine influenza virus (EIV) and to the equine herpesvirus (EHV-1-4). The results suggest that connected factors to the management in the breeding of thoroughbred equine are going to contribute decisively for the manifestation of the respiratory disease and alert for the morbidity caused by the equine adenitis and the lethality related to rodococosis.
foals; respiratory diseases; Streptococcus equi; Rhodococcus equi
