2016 ACVIM Forum Research Abstract Program

From 940 milk samples cultured, 214 yielded growth of CNS of a single colony morphology. Of these 214 isolates, 184 were successfully speciated, of which 157 were identified with rpoB, 26 with tuf, and 1 with 16S. The remaining 30 isolates were unable to be speciated based on the criteria listed above. Overall, 13 different species were identified (Table 1) . Among isolates that could not be assigned an identification, 3 met the criterion for identity but insufficient separation between the species (S. warneri and S. pasteuri) with both rpoB and tuf sequencing. Typeability of CNS isolates from goat milk in this study using gene sequencing was 86%. Typeability with rpoB gene sequencing alone was 73%, which was lower than expected. This may result from underrepresentation of isolates of caprine origin in the reference database. Unsuccessful PCR amplification in a proportion of isolates could reflect imperfect match between the primer and the target sequence. Relative prevalence of different species was similar to that of previous studies using genotyping or phenotyping. The objective of this study was to evaluate the impact of implementing an antimicrobial-use algorithm on antimicrobial (AB) treatment and mortality rates of diarrheic calves.