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Objective—

To determine the efficacy of intramuscular administration of ceftiofur sodium as treatment for intra-mammary infections attributable to Streptococcus agalac-tiae, compared with that for a standard treatment of intramammary infusion of penicillin/novobiocin.

Design—

Prospective, randomized, controlled trial.

Animals—

72 lactating Holstein cows with intramammary infections caused by S agalactiae from 5 commercial dairies in Michigan.

Procedure—

In 36 of 72 infected cows, ceftiofur was administered (2.2 mg/kg of body weight, IM, q 24 h) for 5 days; 150 mg of novobiocin and 100,000 U of procaine penicillin G was infused daily into each mammary gland of the other 36 cows for 2 days. Milk samples were collected aseptically at approximately 4 and 8 weeks after initial treatment. If cows were determined to be infected at 4 weeks after initial treatment, the treatment was repeated.

Results—

The cure rate at 4 weeks (91.7%) and at 8 weeks (96.8%) after initial treatment for the penicillin/ novobiocin-treated cows was significantly (P < 0.0001) higher, compared with that of the ceftiofur-treated cows (2.8 and 9.1%, respectively). Somatic cell counts were significantly (P < 0.0001) lower in the penicillin/novobio-cin-treated group after treatment.

Clinical Implications—

Intramuscular administration of ceftiofur is not efficacious as a treatment to eliminate intramammary infections caused by S agalactiae and should not be used to reduce the prevalence of this organism in dairy herds. (J Am Vet Med Assoc 1996;208: 258-260)

Free access
in Journal of the American Veterinary Medical Association

equivalent generic products that originate from the same pioneer product. For example, Norocillin and Penicillin G Procaine have equivalent generic products with meat WDTs that range from 10 to 14 days, depending on the product label referenced. Reasons for

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To evaluate effects of IV administration of penicillin G potassium (KPEN) or potassium chloride (KCl) on defecation and myoelectric activity of the cecum and pelvic flexure of horses.

Animals—5 healthy horses.

Procedure—Horses with 12 bipolar electrodes on the cecum and pelvic flexure received KPEN or KCl solution by IV bolus 4 hours apart. Each horse received the following: 2 × 107 U of KPEN (high-dose KPEN) followed by 34 mEq of KCl (high-dose KCl), 1 × 107 U of KPEN (low-dose KPEN) followed by 17 mEq of KCl (low-dose KCl), high-dose KCl followed by high-dose KPEN, and low-dose KCl followed by low-dose KPEN. Number of defecations and myoelectric activity were recorded for 60 minutes. The first three 5-minute segments and first four 15-minute segments of myoelectric activity were analyzed.

Results—Number of defecations during the first 15- minute segment was greater after high-dose KPEN treatment than after high-dose or low-dose KCl treatment. Compared with reference indexes, myoelectric activity was greater in the pelvic flexure for the first 5- minute segment after high-dose KCl treatment, in the cecum and pelvic flexure for the first 5-minute segment and in the pelvic flexure for the first 15-minute segment after low-dose KPEN treatment, and in the pelvic flexure for the first and second 5-minute segments and the first three 15-minute segments after high-dose KPEN treatment.

Conclusions and Clinical Relevance—IV administration of KPEN stimulates defecation and myoelectric activity of the cecum and pelvic flexure in horses. Effects of KPEN may be beneficial during episodes of ileus. (Am J Vet Res 2003;64:1360–1363)

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in American Journal of Veterinary Research

Abstract

Objective

To compare results of 6 commercially available milk antimicrobial screening tests with results of liquid chromatography (LC) when testing milk samples from individual cows treated for mild clinical mastitis by intramammary (IMM) infusion with amoxicillin or penicillin G.

Animals

6 cows with noninduced clinical mastitis: 3 treated by IMM infusion with amoxicillin and 3 treated by IMM infusion with penicillin G.

Procedure

Composite milk samples were collected before, during, and after treatment. Samples were assayed by use of the screening tests and their results and those of LC were compared. The LC results were assumed to represent the true result.

Results

Results of screening tests compared well with results of LC, with agreement of 94%. Positive screening test results for samples containing drug values below the established tolerance or safe level, as evaluated by LC, were obtained from 2 cows in which abnormal milk, as well as marked increases in composite milk somatic cell count, were observed. With the exception of 1 test in 1 cow, all screening tests had negative results at the end of the labeled milk-withholding time.

Conclusions and Clinical Implications

On the basis of results of the limited sample reported, the screening tests appeared to provide good agreement overall, compared with LC results, when testing milk of individual cows treated by IMM infusion with amoxicillin or penicillin G. Positive screening test results for milk samples containing amoxicillin or penicillin G at values below the established tolerance or safe level, as evaluated by LC, may occasionally be obtained. (Am J Vet Res 1998;59:1096-1100)

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in American Journal of Veterinary Research

In the JAVMA article, “Acute pyelonephritis in cats is frequently caused by Escherichia coli resistant to potentiated penicillins but has a better prognosis than other causes of acute kidney injury,” published in the February issue ( J Am Vet

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in Journal of the American Veterinary Medical Association

susceptibility testing, and the use of plasma versus urinary breakpoints in reporting antibiotic in vitro susceptibility results for the penicillins and potentiated penicillins (eg, ampicillin, amoxicillin-clavulanate) of urinary isolates. Due to these noted

Open access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

mastitis. In general, the consensus from these reports is that among S aureus isolates from mastitis-affected cows, there is little to moderate resistance to most commonly used antimicrobials, with the exception of penicillin and ampicillin and, to a much

Full access
in American Journal of Veterinary Research