Effect of milk fraction on concentrations of cephapirin and desacetylcephapirin in bovine milk after intramammary infusion of cephapirin sodium

Abstract

Clinical mastitis in dairy cows is commonly treated with intramammary (IMM) antimicrobial agents. Pharmacokinetic data are used to design treatment regimens and determine withholding times. In some pharmacokinetic studies, investigators measure antimicrobial concentrations in foremilk, whereas in others, they use bucket milk or do not specify the milk fraction sampled. Our objective was to compare antimicrobial concentrations in foremilk, bucket milk, and strippings after IMM treatment of six healthy Holsteins. One mammary gland/cow was infused with 200 mg of cephapirin (CEPH) after each of the two milkings, using different milking frequencies and treatment intervals in a randomized crossover design. Treated glands were sampled at the first milking following each infusion. Antimicrobial concentrations in milk were measured using HPLC/MS/MS. CEPH concentration was higher in foremilk (geometric mean 44.2 microg/mL) than in bucket milk (15.7 microg/mL) or strippings (18.5 microg/mL), as it was true for desacetylcephapirin (DAC) (59.5, 23.0, and 30.2 microg/mL, respectively). This finding, which was based on milk samples collected at the first milking after IMM infusion, suggests that pharmacokinetic data based on drug concentrations in foremilk may be misleading. Strippings were more representative of bucket milk than foremilk. The relationship between milk fraction and antimicrobial concentration should be investigated for other IMM antimicrobial agents. Meanwhile, it is essential that pharmacokinetic and residue studies report the fraction of milk that was analyzed.

Pharmacokinetics in foremilk and antimicrobial activity of cephapirin following intramammary administration in healthy andStaphylococcus aureus-infected cows

“…The collection of foremilk at frequent intervals after infusion might have removed a substantial proportion of the infused dose. Conversely, desacetyl-cephapirin was scarcely recovered and its concentrations were lower than in other studies results (Stockler et al 2009a(Stockler et al , 2009b. These discrepancies could be attributable to the different analytical techniques and to the lower sensitivity of our method, and the low purity grade of desacetyl-cephapirin analytical standard.…”

“…hand-collected milk before the application of the milking device) and this could have influenced the results. In the present study, cephapirin concentrations in milk samples were markedly higher than those reported by Stockler et al (2009aStockler et al ( , 2009b. In foremilk antimicrobial concentrations could be twice as high as in other milk fractions.…”

“…As reported by Stockler et al (2009a), milk fraction influences the pharmacokinetics and residue depletion of cephapirin, and bucket milk seems to be the best sample because it reflects the whole Cagnardi et al New Zealand Veterinary Journal, 2014 149 condition of the mammary gland. In the present study, samples were collected manually from single quarters after discarding about 10 mL of milk and thus teat cistern and cisternal milk was collected.…”

Selective degradation of tetracycline antibiotics present in raw milk by electrochemical method

“…Clinical mastitis in dairy cows is commonly treated with antibiotics directly via intramammary infusions and injections, which produces waste milk with antibiotic residues. It was reported that cows infused with 200 mg of antibiotic produced milk containing the antibiotic at 44.2 g/ml [4]. During the withdrawal period, the milk from cows that have been treated with an antibiotic must be withheld from sale.…”

Antibiotic removal from waste milk by electrochemical process: degradation characteristics in concentrated organic solution

“…Using antibiotics to treat infection in dairy cows results in producing waste milk because of the antibiotic residues [1]. Stockler et al [2] reported that cows infused with 200 mg of antibiotic produced milk containing the antibiotic at 44.2 lg/mL. During the withdrawal period, the milk from cows that have been treated with an antibiotic must be withheld from sale.…”