8Katsande S,Matope G,Ndengu M,et al.Prevalence of mastitis in dairy cows from smallholder farms in Zimbabwe[J].Onderstepoort J Vet Res,2013,80(1):523.
9Aslan V,Maden M,Erganis O,et al.Clinical efficacy of florfenicol in the treatment of calf respiratory tract infections[J].Vet Q,2002,24(1):35-39.
10Boyd E F,Hartl D L.Chromosomal regions specific to pathogenic isolates of Escherichia coli have a phylogenetically clustered distribution[J].J Bacteriol,1998,180(5):1159-1165.
