Distribution of Oxacillin in Serum and Milk of Treated and Untreated Quarters in Cows Following Intramammary Infusion*

Abstract

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

Pharmacokinetic Profile of Erythromycin after Intramammary Administration in Lactating Dairy Cows with Specific Mastitis

“…For example, oxacillin is absorbed twice as rapidly as benzylpenicillin (Ziv and Sulman, 1974). Oxacillin is absorbed quickly and appears in blood serum as early as 10 min post administration (Bansal et al, 2003). On the other hand, cefacetrile sodium cannot be detected in blood plasma even after 10 h following single intramammary infusion of 235 mg of cefacetrile sodium per quarter in lactating dairy cows (Carli et al, 1983).…”

Elimination of erythromycin in milk after intramammary administration in cows with specific mastitis: relation to dose, milking frequency and udder health

“…For example, the drug concentration in milk from the treated quarters at first milking PLI ranged 8.25 to 12.0 μg/ml in G2 and 26.83 to 37.61 μg/ml in G3. This marked variability is a typical phenomenon frequently observed with other antibiotics too, such as oxacillin (Bansal et al 2003) and ceftiofur (Smith et al 2004). The reasons for this are multiple and include udder health (pH affecting ionization and therefore passage via the bloodmilk barrier), the amount of connective tissue present in udder that hampers proper distribution, lactation stage, milk production levels, the milking frequency/milking interval and the udder tissue binding that lead to uneven distribution (Gehring and Smith 2006;Knappstein et al 2006).…”

“…A similar observation was recorded by Nouws and Ziv (1979) who found that following single intramammary administration of 1,200 mg of erythromycin in lactating cows, drug was well distributed in the various body tissues such as liver, kidney and muscles. Further, the passage rates to systemic circulation seem to vary with the antibiotic, e.g., oxacillin: 64% to 82% (Bansal et al 2003) and cephapirin: 30% to 40% (Stockler et al 2009). Knappstein et al (2006) expressed this drug disposition pattern in terms of the milk to serum concentration ratios; great differences were shown to occur between antibiotics and in relation to the udder health.…”