This study was carried out from October 2012 to end of February 2013 in and around Kombolcha, Amhara regional state, Ethiopia, using a total of 201 neonatal calves aged 1 day to 4 months and suffering from diarrhea. The objectives of the study were to isolate Escherichia coli from diarrheic calves, and to determine E. coli biotypes and risk factors associated with its isolation. The fecal samples were collected, transported, and processed following standard microbiological procedures. Seventy-four isolates of E. coli were identified. Yellowish diarrhea, younger age, and low-colostrum feeding were significantly associated with rate of E. coli isolation (P < 0.05). Then the 74 isolates of E. coli were biotyped using fermentation of 9 sugars and grouped into 12 biotypes; the most dominant was biotype III (36.8 %). Finally, by comparing with studies elsewhere, from the 12 isolated biotypes, 3 of them were suggested to be enteropathogenic E. coli (EPEC), entherotoxigenic E. coli (ETEC), and adhesion and effacing E. coli (AEEC) pathogenic strains. The present study showed that E. coli accounted for 37 % of calf diarrhea, with very diverse biotypes.
Keywords: Biotype; Calf diarrhea; Calves; Escherichia coli; Kombolcha; Risk factors; Sugar fermentation.