Contribution to the study of diarrhea etiology in neonate dairy calves in São Paulo state, Brazil

Abstract

Two hundred and three samples of feces of calves aged less than 30 days old from both sexes and from different properties and regions of the state of São Paulo were examined in the period of two years. Bacterial cultures were carried out in bovine 10% bloodagar and Levine mediums, incubated for up to 96 hours in aerobic conditions at 37°C, with the observation of colonies and morphological and biochemical study to characterize isolated microorganisms, or other tests, when pertinent. ELISA was performed for the Rotavirus research. The Cryptosporydium spp was surveyed and its parasitological examination was made. Results revealed the involvement of several enteropathogens alone and associated. Rotavirus was found in 51 (25.1%) samples, being 58.8% alone and 41.7% associated. Cryptosporidium spp was obtained in 43 (21.3%) samples, being the only agent involved in 65.1% of them and associated to other enteropathogens in the remaining 34.9%. The parasitological examination showed strongylids eggs in only 5 (2.5%) of the animals and in little amount, not exceeding more than two eggs by examined field. In the microbiological examination, one or more microorganisms were isolated; Escherichia coli was found in 100% of samples. The thermostable toxin and the adherence antigen K99 researches, made in 73 samples of E.coli, were negative. The serological grouping of the same ones were configured as 34.2%, 17.8% and 47.9% of the samples belonging to serological groups O8, O11 and O101, respectively. Salmonella dublin and Salmonella typhimurium were isolated in 5.4% and 6.1 % of the examined samples, respectively.