Oral and Poster Abstracts

same protocol. Cattle having a combination of predetermined
lameness, swelling and lesion scores on one foot for two
consecutive days were enrolled. Day 0 was the day the cattle met
the enrollment criteria, were allotted to treatment and administered
either tulathromycin or saline control according to a generalized
block design.Treatment success was analyzed using a mixed model
which included the fixed effect of treatment and the random effects
of block and residual. Samples were obtained from the lesions prior
to treatment for anaerobic culture and sensitivity testing.
Presumptive identification of isolates obtained from the samples
was based on classical biochemical methods. Final identification of
the isolates was based on PCR amplification of the 16S ribosomal
gene. The agar dilution method described by the Clinical and
Laboratory Standards Institute was employed for determination of
tulathromycin MICs. Cattle were clinically evaluated on day 7 and
treatment success was determined based on defined decreases in
lesion, swelling and lameness scores. The number of animals
classified as a treatment success for the Nebraska site was
significantly greater, P