Determination of Milk and Mammary Tissue Concentrations of Ceftiofur After Intramammary and Intramuscular Therapy

Abstract

Twenty-five Staphylococcus aureus strains isolated from bovine mastitis were tested for their susceptibility to ceftiofur. Zone diameter for 30 micrograms disks averaged 39 mm, and minimum inhibitory concentrations ranged from .5 to 1 microgram/ml. Tissue and milk concentrations were determined from biopsy and quarter milk samples collected from eight cows treated with either intramammary infusion of 100 or 200 mg of ceftiofur, one or two intramuscular injections of 500 mg of ceftiofur, or combination therapy of intramammary infusion coupled with intramuscular injection. Three additional cows received two intramammary infusions of 200 mg of cephapirin at 24-h intervals. Intramuscular injections of ceftiofur resulted in tissue and milk concentrations below detectable limits. Staphylococcus aureus was not eliminated from infected mammary glands by infusion of 100 mg of ceftiofur or by injection of 500 mg of ceftiofur by 48 h after treatment. Combination therapy of 100 mg of ceftiofur infused and 500 mg injected reduced S. aureus numbers in milk and tissue markedly, as did infusion of 200 mg of ceftiofur. Cows receiving intramammary infusion of 200 mg of ceftiofur (two doses at 24-h intervals) had highest concentrations in milk (450 micrograms/ml at 4 and 6 h) and in tissue (.08 microgram/mg at 30 h). These concentrations are similar to those obtained with two 200-mg doses of cephapirin at 24-h intervals. Histologic analysis of mammary parenchymal tissues showed that combination therapy resulted in higher percentages of alveolar luminal area and lower percentages of interalveolar stroma compared with infusion or injection alone. Histology of quarters receiving combination therapy was not different from that of quarters receiving cephapirin infusion alone.

Acute coliform mastitis in buffaloes (Bubalus bubalis): Clinical findings and treatment outcomes

“…This may be attributed to the fact that i.m. ceftiofur does not attain effective concentrations in the normal or inflamed mammary gland (Owens et al 1990;Erskine et al 1995). On contrary, more favorable clinical outcomes for cows with severe clinical coliform mastitis that received i.m.…”

Pharmacokinetics and pharmacodynamics of intramammary cefquinome in lactating goats with and without experimentally induced Staphylococcus aureus mastitis

“…The results of the study reported here clearly demonstrate important differences in the pharmacokinetic values in skimmed milk and plasma between healthy and mastitic goats that associated with changes in residue risk. When taken into consideration with the results of other studies (El Badawy et al, ; Cagnardi et al, , ; Gehring & Smith, ; Goutalier, Combeau, Quillon, & Goby, ; Owens, Xiang, Ray, & Nickerson, ; Zonca et al, ), serious concerns must be raised about the clinical value of pharmacokinetic values such as C max , AUC, and K el determined in healthy animals for drugs that are intended to be administered to diseased animals. This highlights the need for performing pharmacokinetic studies in diseased animals.…”

Decision Making in Mastitis Therapy

“…18 However, three intramuscular doses of cefquinome, a fourth-generation cephalosporin with good tissue distribution, was found to improve clinical outcome of experimentally infected cows as compared with use of cloxacillin or ampicillin. [21][22][23] Parenteral administration of ceftiofur did not affect the outcome of mild clinical mastitis. Further research at Illinois confirmed this concept, as intravenous oxytetracycline was determined to improve clinical outcomes in cows with clinical coliform mastitis (not necessarily severe) compared with cows that did not receive systemic antibacterials.…”