Objective—To evaluate the efficacy of ceftiofur
hydrochloride sterile suspension administered parenterally
for treatment of acute postpartum metritis
(APM) in dairy cows.
Design—Multilocation, randomized block, field trial.
Animals—406 cows in the first 14 days postpartum.
Procedure—Cows with rectal temperatures ≥
39.5°C (103.1°F) without clinical signs of respiratory
or gastrointestinal tract disease and with a fetid
vaginal discharge were allocated randomly in
blocks of 3 to 3 treatment groups: sterile saline
(0.9% NaCl) solution administered at a dosage of 2
mL/45.4 kg (2 mL/100 lb), SC or IM, once daily for
5 days (control); or ceftiofur hydrochloride administered
at a dosage of 1.1 or 2.2 mg of ceftiofur
equivalents (CE)/kg (0.5 or 1 mg/lb, respectively),
SC or IM, once daily for 5 days. Cows were evaluated
on days 6, 10, and 14, and clinical cure or failure
to cure was determined. Clinical cure was
defined as no additional antimicrobial treatment
administered, rectal temperature < 39.5°C, and
absence of a fetid vaginal discharge.
Results—On day 14, clinical cure rates were 77%,
65%, and 62% for the 2.2 mg of CE/kg, 1.1 mg of
CE/kg, and control groups, respectively. No significant
differences were detected in clinical cure
rates between control and treatment groups on day
10 or 6.
Conclusions and Clinical Relevance—Ceftiofur
hydrochloride administered at a dosage of 2.2 mg of
CE/kg, SC or IM, once daily for 5 days was efficacious for
treatment of APM in dairy cows. (J Am Vet Med Assoc
Objective—To compare the results of regulatory
screening and confirmation assays with those of highperformance
liquid chromatography (HPLC) in the
detection of ceftiofur metabolites in the tissues of
culled dairy cattle.
Animals—17 lactating Holstein dairy cows.
Procedure—Daily IM injections of ceftiofur sodium
were administered at a dose of 2.2 mg of ceftiofur
equivalents/kg (n = 6) or 1.0 mg of ceftiofur equivalents/kg (10) for 5 days. Following withdrawal times of
12 hours (high-dose ceftiofur) and either 5 or 10 days
(low-dose ceftiofur), cows were slaughtered and liver,
kidney, and diaphragmatic muscle specimens were
harvested and analyzed by HPLC and standard regulatory
methods that included the following assays:
the swab test on premises, the fast antimicrobial
screen test, the calf antibiotic and sulfa test, and the
7-plate bioassay confirmation test.
Results—In all tissue specimens, residues of ceftiofur
and desfuroylceftiofur-related metabolites, as
measured by HPLC, were less than regulatory tolerance,
as defined by the FDA. False-positive screening
assay results were more likely for tissue specimens
that had been frozen for shipment to a federal laboratory,
compared with fresh tissue specimens that
were assayed at the slaughter establishment (23% vs
3% false-positive results, respectively).
Conclusions and Clinical Relevance—The observation
that fresh tissues had negative results on screening
assays, whereas subsets of the same tissue specimens
had false-positive results on screening assays
following freezing, suggests that freezing and thawing
interferes with microbial inhibition-based regulatory
screening assays. (Am J Vet Res 2004;65:1730–1733)