Ceftiofur distribution in serum and milk from clinically normal cows and cows with experimental Escherichia coli-induced mastitis

R. J. Erskine From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by R. J. Erskine in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Robert C. Wilson From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by Robert C. Wilson in
Current site
Google Scholar
PubMed
Close
 DVM, PhD
,
Jeff W. Tyler From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by Jeff W. Tyler in
Current site
Google Scholar
PubMed
Close
 DVM, MVPM, PhD
,
Kim A. McClure From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by Kim A. McClure in
Current site
Google Scholar
PubMed
Close
 DVM
,
Renee S. Nelson From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by Renee S. Nelson in
Current site
Google Scholar
PubMed
Close
 DVM
, and
Harold J. Spears From the Departments of Large Animal Surgery and Medicine (Erskine, Tyler, McClure, Nelson, Spears) and Physiology and Pharmacology (Wilson), College of Veterinary Medicine, Auburn University, AL 36849.

Search for other papers by Harold J. Spears in
Current site
Google Scholar
PubMed
Close
 MS

Click on author name to view affiliation information

Abstract

Eight Holstein cows, 4 inoculated intracistemally in 1 quarter of the mammary gland with Escherichia coli and 4 noninfected controls, were administered ceftiofur sodium (3 mg/kg of body weight, IV, q 12 hours) for 24 hours, beginning at 14 hours after inoculation of infected cows. All challenge-exposed cows became infected, with mean ± SEM peak log10 bacterial concentration in milk of 5.03 ± 0.69 colonyforming units/ml. The infection resulted in systemic signs (mean peak rectal temperature, 41.5 ± 0.3 C; anorexia; signs of depression) and local inflammation (mean peak albumin concentration in milk, 7.89 ± 1.71 mg/ml). Ceftiofur was detectable in milk from all challenge-exposed cows, compared with only 1 of 4 noninfected cows, and the mean period after inoculation that ceftiofur was detectable in milk was longer (P < 0.05) in infected (147.7 ± 27.5 hours) than noninfected cows (1.3 ± 1.3 hours). However, maximal ceftiofur concentration attained in milk for all cows was 0.28 p.g/ml, and was 0.20 jig/ml or less for all but 2 milk samples collected for 10 days after challenge exposure. Mean serum concentration of ceftiofur peaked at 1.0 ± 0.3 μg/ml and 0.7 ± 0.1 μg/ml for infected and noninfected cows, respectively. After each ceftiofur dose, mean peak and trough concentrations of ceftiofur in serum did not differ between groups; however, concentration of ceftiofur in serum was higher at 7 hours after each dose in noninfected cows, suggesting more rapid clearance of the drug in infected cows. Ceftiofur was not detected in serum (< 0.05 μg/ml) of any cow at or after 120 hours following inoculation of infected cows.

Storage of serum samples at —20 C for 3 weeks resulted in a 98.8% decrease in ceftiofur activity, compared with that in fresh serum samples. Eightyseven percent of this loss occurred 30 minutes after mixing serum and ceftiofur; thus, about 13% of the original activity was lost in storage. Storage of milk samples under similar conditions did not result in loss of ceftiofur activity.

Despite acute inflammation, the dosage of ceftiofur used in this trial would not result in drug concentrations in milk above FDA safe concentrations, or above the reported minimum inhibitory concentration for coliform bacteria.

Abstract

Eight Holstein cows, 4 inoculated intracistemally in 1 quarter of the mammary gland with Escherichia coli and 4 noninfected controls, were administered ceftiofur sodium (3 mg/kg of body weight, IV, q 12 hours) for 24 hours, beginning at 14 hours after inoculation of infected cows. All challenge-exposed cows became infected, with mean ± SEM peak log10 bacterial concentration in milk of 5.03 ± 0.69 colonyforming units/ml. The infection resulted in systemic signs (mean peak rectal temperature, 41.5 ± 0.3 C; anorexia; signs of depression) and local inflammation (mean peak albumin concentration in milk, 7.89 ± 1.71 mg/ml). Ceftiofur was detectable in milk from all challenge-exposed cows, compared with only 1 of 4 noninfected cows, and the mean period after inoculation that ceftiofur was detectable in milk was longer (P < 0.05) in infected (147.7 ± 27.5 hours) than noninfected cows (1.3 ± 1.3 hours). However, maximal ceftiofur concentration attained in milk for all cows was 0.28 p.g/ml, and was 0.20 jig/ml or less for all but 2 milk samples collected for 10 days after challenge exposure. Mean serum concentration of ceftiofur peaked at 1.0 ± 0.3 μg/ml and 0.7 ± 0.1 μg/ml for infected and noninfected cows, respectively. After each ceftiofur dose, mean peak and trough concentrations of ceftiofur in serum did not differ between groups; however, concentration of ceftiofur in serum was higher at 7 hours after each dose in noninfected cows, suggesting more rapid clearance of the drug in infected cows. Ceftiofur was not detected in serum (< 0.05 μg/ml) of any cow at or after 120 hours following inoculation of infected cows.

Storage of serum samples at —20 C for 3 weeks resulted in a 98.8% decrease in ceftiofur activity, compared with that in fresh serum samples. Eightyseven percent of this loss occurred 30 minutes after mixing serum and ceftiofur; thus, about 13% of the original activity was lost in storage. Storage of milk samples under similar conditions did not result in loss of ceftiofur activity.

Despite acute inflammation, the dosage of ceftiofur used in this trial would not result in drug concentrations in milk above FDA safe concentrations, or above the reported minimum inhibitory concentration for coliform bacteria.

All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 71 71 11
PDF Downloads 31 31 5
Advertisement