The pharmacokinetics of erythromycin was studied in five lactating dairy cows following single intramammary infusion of 300 mg erythromycin in each of two quarters per cow with specific mastitis. Levels of erythromycin in plasma and quarter milk samples were measured by agar plate diffusion assay using Micrococcus luteus (ATCC 9341) as the test organism. Erythromycin level in plasma reached a peak concentration value (C(max)) of 0.07 +/- 0.01 microg/ml at 30 min; thereafter, levels declined gradually to reach 0.05 +/- 0.00 microg/ml 12 h post drug administration. The pharmacokinetic profile of the drug revealed mean absorption half life (t(1/2 ka)) as 0.26 +/- 0.05 h. The drug was eliminated slowly with elimination half-life (t(1/2 beta)) of 13.75 +/- 0.35 h and elimination rate constant (k(el)) of 0.04 +/- 0.00 h(-1). The volume of distribution based on the zero-time plasma concentration intercept of the least-squares regression line of the elimination phase (V(d(B))) was 0.032 L/kg. The drug crossed to untreated quarters also; mean drug levels of 0.20 +/- 0.07, 0.23 +/- 0.07, 0.17 +/- 0.04, and 0.17 +/- 0.04 microg/ml were found at 3, 6, 8 and 12 h, respectively. The mean drug concentration for treated quarters was measured as 22.97 +/- 2.31 microg/ml milk at first milking (12 h) following drug infusion. No apparent adverse reaction was seen in cows administered erythromycin. It is concluded that following intramammary infusion erythromycin diffuses readily and extensively in various body fluids and tissues and adequate concentration is maintained in udder tissues for at least 12 h post intramammary administration. Thus, erythromycin may be recommended for local therapy of acute mastitis caused by Gram-positive bacteria in lactating dairy cows.
Experience in the use of intramammary antibiotic therapy has indicated that antibiotics are absorbed from the treated quarters into systemic circulation; degrees of absorption and hence crossover of drug to untreated quarters being different for different antibiotics. To answer these questions, a study was conducted on the use of oxacillin in three lactating cows of German Black Pied breed. The health status of quarters was assessed as per IDF criteria. Two quarters of each cow were infused each with Injection Oxacillin (1000 mg of water free oxacillin sodium, from Virbac Tierarzeneimittel GmbH, Germany) two times at 24 hours interval. The milk and blood samples were collected and processed in pre-treatment phase to rule out any antibiotic contamination. In post-treatment phase milk samples were collected up to 11 regular milking, and blood samples at different time intervals starting from 10 minutes to 24 hours post-therapy. The estimation of drug in milk and serum was done by Charm II test (From Charm Sciences Inc., USA). The therapy produced a drug concentration in milk from treated quarters, of 53.21 µg/ml to 180.55 µg/ml at first milking post-drug administration. The milk drug levels at 2nd milking ranged between 0.95 and 3.83 µg/ml. In all cases, the concentration fell below the detectable level of 0.01 µg/ml at 6th milking in treated quarters, and at 4th milking in bucket milk, after last infusion. The drug passed to untreated quarters; highest drug concentration being 0.65 µg/ml, and crossover residue persisted for 24 to 36 h post-therapy. The total excretion of oxacillin in milk from treated quarters varied between 18.00 and 35.50% of the administered dose. The drug diffused very rapidly to the general circulation; peak serum drug levels were detected at 10 to 30 minutes post-therapy. The peak serum drug levels in different cows ranged from 0.56 µg/ml to 1.38 µg/ml. The serum drug activity of 0.02 to 0.03 µg/ml was still maintained at 24 h when a second infusion was made. Following second infusion, serum drug concentrations of 0.11 to 0.18 µg/ml at 12 h, and 0.02 to 0.04 µg/ml at 24 h were observed.-------* Part of Ph.D. thesis work done by senior author at School of Veterinary Medicine, Hannover, and thesis submitted to
Summary: Nine cross‐bred cows suffering from mucormycosis of the udder were observed. Histopathological and cultural examination of the lesions revealed the presence of Mucor spec. Zusammenfassung: Euter‐Mucormykose wurde an neun kreuzgezüchteten Rindern beobachtet. Die histopathologische und kulturelle Untersuchung der Läsionen belegte das Vorhandensein von Mucorspec.
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