Elimination kinetics of ceftiofur hydrochloride after intramammary administration in lactating dairy cows

Elimination of Cefquinome Sulfate Residue in Cow’s Milk after Intrauterine Infusion

As set in the maximum residue limit regulations of the European Commission, this study aimed to obtain the residual parameters in milk with optimized UPLC-MS/MS conditions and to determine the conclusive drug withdrawal period to ensure food safety. In this research, an ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to study cefquinome sulfate’s residue elimination in milk and to calculate cefquinome’s withdrawal period. Twelve healthy cows free of endometritis were selected for the experiment. Before using the drug, the vaginal orifice and perineum of each cow was disinfected. One dose of intrauterine perfusion was used for each cow, followed by an additional dose after 72 h. Before administration and 12 h, 18 h, 24 h, 36 h, 42 h, 48 h, 60 h, 66 h, 72 h, 84 h, 90 h, and 96 h after the last dose, milk (10 mL) was gathered from each cow’s teat and pooled. For the measurement of cefquinome concentrations in milk, UPLC-MS/MS was performed. A calibration curve was generated using linear regression as follows: Y = 250.86X − 102.29, with a correlation coefficient of 0.9996; the limits of detection and the limits of quantitation were 0.1 μg·kg−1 and 0.2 μg·kg−1, respectively. The average recovery of cefquinome was 88.60 ± 16.33% at 0.2 μg·kg−1, 100.95 ± 2.54% at 10 μg·kg−1, and 97.29 ± 1.77% at 50 μg·kg−1. For 5 consecutive days at the three spiking levels, the intra and inter-day relative standard deviations (RSD) were 1.28%–13.73% and 1.81%–18.44%, respectively; the residual amount of cefquinome was less than the maximum residue limit of 20 μg·kg−1, 36 h after administration; and the residual amount was less than the limit of detection (0.1 μg·kg−1) 48 h after administration. The withdrawal time of cefquinome in cow’s milk was 39.8 h, as calculated using WTM1.4 software. In terms of clinical practical use, the withdrawal period of milk was temporarily set at 48 h after the administration of the cefquinome sulfate uterus injection to cows, in accordance with the recommended dose and course.

Effects of temporary cessation of milking following intramammary cefazolin sodium infusion on residual antibiotic in lactating dairy cows

The aims of studies were to estimate the withdrawal period of antibiotic from milk after the intramammary infusion of cefazolin sodium (CEZ) in cows with difficulties in frequent milk discharge due to disease such as teat injury. The period was compared among cows milked twice a day after 150 or 450 mg of CEZ were administered to all quarters (Study 1, 2) and the cows in which milking of front-right quarter was ceased for five days after administration of these infusions to only that quarter (Study 3). In Studies 1 and 2, the median of 17.66 µg/ml and 83.18 µg/ml of CEZ were detected in the samples of first milking after intramammary administration, respectively; however, there was no residual antibiotic by 72 hr in all cows. In Study 3, the median of 1.96 µg/ml of CEZ was detected in the sample after the resumption of milking at 120 hr, and the residual was eliminated by 174 hr. The withdrawal period may be prolonged by the cessation of milking after administration, and the period is the total time from cessation to 72 hr after the resumption of milking.

Acute Oral Toxicity and Acute Intraperitoneal Studies of Thermally Treated Ceftiofur

Ceftiofur (CEF) is a third-generation and the first animal-specific cephalosporin that is widely used in animal husbandry. As a heat-labile antibiotic, the cytotoxicity of CEF after thermal treatment has been reported. This study seeks to investigate the potential toxicity of thermally treated CEF (TTC) in vivo based on acute oral toxicity studies and acute intraperitoneal studies in mice. Our data indicated that TTC exhibited significant increased toxicity in mice compared with CEF. TTC resulted in weight gain, hypercholesterolemia, hepatocyte steatosis and hepatocyte mitochondrial damage, and downregulated β-oxidation-related genes in mice in acute oral toxicity studies. In addition, TTC caused acute pulmonary congestion, increased levels of reactive oxygen species (ROS), prolonged coagulation time, and even death in mice in acute intraperitoneal toxicity studies. Our data showed that thermal treatment enhanced the toxicity of CEF in vivo. Lung and liver are the main target organs in the pathological damage process mediated by TTC. These findings suggested that residual CEF in animal-derived food may represent a potential food safety risk and pose a potential threat to human health.

Cytotoxicity and degradation product identification of thermally treated ceftiofur

Ceftiofur (CEF) is a cephalosporin antibiotic and is a commonly used drug in animal food production. As a heat-labile compound, the residual CEF toxicity after thermal treatment has rarely been reported. This study was to investigate the potential toxicity of thermally treated CEF and determine the toxic components. By cytotoxicity tests and liquid chromatography-mass spectrometry (LC-MS) assays, the cytotoxicity of the thermally treated CEF (TTC) and the components of TTC was identified, respectively. Our results showed that TTC exhibited significantly increased toxicity compared with CEF towards LO2 cells by inducing apoptosis. Through LC-MS assays, we identified that the toxic compound of TTC was CEF-aldehyde (CEF-1). The IC₅₀ value of CEF-1 on LO2 cells treated for 24 h was 573.1 μg mL⁻¹, approximately 5.3 times lower than CEF (3052.0 μg mL⁻¹) and 3.4 times lower than TTC (1967.0 μg mL⁻¹). Moreover, we found that CEF-1 was also present in thermally treated desfuroylceftiofur (DFC), the primary metabolite of CEF, indicating that residual CEF or DFC could produce CEF-1 during the heating process. These findings suggest that CEF-1 is a newly identified toxic compound, and CEF-1 may pose a potential threat to food safety or public health.

Ceftiofur (CEF) is a cephalosporin antibiotic and is a commonly used drug in animal food production. This study investigated the cytotoxicity of thermally treated CEF.

Antibiotic residues in milk: Past, present, and future

Now-a-days, various types of antibiotics are being used worldwide in veterinary sector indiscriminately for promotion of growth and treatment of the livestock. Significant portions of antibiotics are released through milk of dairy animals unaltered and exert serious harmful effects on human health. This review evaluates and compare researches on antibiotic residues in milk in published literatures from Pubmed, CrossRef, CAB direct, DOAJ, JournalTOCs, AGRICOLA, ScientificGate, Electronic Journals Library, CAB abstracts, Global Health Databases, Global Impact Factor, Google Scholar, Park Directory of Open Access Journals, BanglaJOL and ISC E-Journals. Antibiotics residue in milk was first detected in 60s and then with an increasing trend with highest after 2,000 (188). The highest no. of works, 49 (21.87%) were accomplished in China, followed by Spain, 30 (13.39%); Germany, 11 (4.91%); and USA, 10 (4.46%). Continent-wise highest researches are published from Europe, 105 (46.88%), followed by Asia, 77 (34.38%); South America, 18 (8.04%); North America, 16 (7.14%); and Africa, 8 (3.57%). For detection, Bovine milk sample is mostly used, 193 (86.16%), followed by ovine, 19 (8.48%); and caprine, 14 (6.25%). Acetonitrile was used in maximum cases (77) for processing the samples. Chromatographic technique was the highest, 115 (51.34%) for detection. Residue of β-lactam group have been detected mostly 133 (36.54%), followed by tetracyclines, 51 (14.01%); fluoroquinolones, 49 (13.46%); sulfonamides, 46 (12.64%); and aminoglycosides, 38 (10.44%). This review observe that antibiotics residues are more common in milk samples that are being manifested in increasing researches on antibiotic detection and measures should adopt to cease this residue.

Elimination kinetics of ceftiofur hydrochloride in milk after an 8-day extended intramammary administration in healthy and infected cows

Ceftiofur hydrochloride (CEF) is occasionally used for the intramammary (IMM) treatment of mastitis. This extralabel manner could result in a drug-residue violation of the milk. The objective of this study was to determine the elimination kinetics of IMM CEF in lactating dairy cattle. The pharmacokinetic profile of CEF after repeated IMM administration in nine healthy cows and nine Staphylococcus aureus infected cows was investigated, alongside determining the MICs of Staph. aureus field strains. The MIC 90 value for CEF in Staph. aureus field strains (n = 31) was 0.25 μg/mL. The t >MIC CEF values for low- production quarters were longer than those for high- and mid- production quarters. The results showed that ceftiofur was detected in milk up to 108 h after the last infusion in both healthy and infected cows. Cows with low milk production eliminate IMM drugs more slowly than cows with higher production. Our findings suggest that this extralabel use is not encouraged and a prudent use is recommended for mastitis therapy. The use of CEF should be reserved for infections where susceptibility tests indicate its efficacy and when alternatives are not available.

Intramammary treatment with gentamicin in lactating cows with clinical and subclinical mastitis

Abstract The study evaluated the microbiological profile of milk samples collected before and after mastitis treatment with gentamicin and investigated biofilms production and antimicrobial susceptibility of Staphylococcus spp. isolated. The presence of gentamicin residues in milk after the recommended withdrawal period was also evaluated. Antimicrobial residues were analyzed by Delvotest® SP NT over a period of 12 days beginning after 24 hours the last gentamicin application. Some of Staphylococcus spp. isolates were biofilm producers (19.05%). Staphylococcus spp. showed high levels of resistance to neomycin (16.95%), penicillin G (10.17%), and ampicillin (10.17%). Multidrug resistance to all antibiotics tested was observed in 1.69% of the Staphylococcus spp. isolates. Among 1440 mammary quarter milk samples 24.95% presented gentamicin residues after the withdrawal period. Gentamicin residues were also detected in 3.8% of samples from calibrated glass recorder jar (n=383) 4.1 days after treatment. The indiscriminate use of antibiotics may lead to the emergence of multidrug-resistant strains as well as increasing the risk of presence of residues of these drugs in milk. These problems affect the milk quality and may become a public health problem.

Comparison of pharmacokinetics and milk elimination of flunixin in healthy cows and cows with mastitis

OBJECTIVE

To determine whether pharmacokinetics and milk elimination of flunixin and 5-hydroxy flunixin differed between healthy and mastitic cows.

DESIGN

Prospective controlled clinical trial.

ANIMALS

20 lactating Holstein cows.

PROCEDURES

Cows with mastitis and matched control cows received flunixin IV, ceftiofur IM, and cephapirin or ceftiofur, intramammary. Blood samples were collected before (time 0) and 0.25, 0.5, 1, 2, 4, 8, 12, 24, and 36 hours after flunixin administration. Composite milk samples were collected at 0, 2, 12, 24, 36, 48, 60, 72, 84, and 96 hours. Plasma and milk samples were analyzed by use of ultra-high-performance liquid chromatography with mass spectrometric detection.

RESULTS

For flunixin in plasma samples, differences in area under the concentration-time curve and clearance were detected between groups. Differences in flunixin and 5-hydroxy flunixin concentrations in milk were detected at various time points. At 36 hours after flunixin administration (milk withdrawal time), 8 cows with mastitis had 5-hydroxy flunixin concentrations higher than the tolerance limit (ie, residues). Flunixin residues persisted in milk up to 60 hours after administration in 3 of 10 mastitic cows.

CONCLUSIONS AND CLINICAL RELEVANCE

Pharmacokinetics and elimination of flunixin and 5-hydroxy flunixin in milk differed between mastitic and healthy cows, resulting in violative residues. This may partially explain the high number of flunixin residues reported in beef and dairy cattle. This study also raised questions as to whether healthy animals should be used when determining withdrawal times for meat and milk.

Development of a physiologically based pharmacokinetic model for flunixin in cattle (Bos taurus)

Frequent violation of flunixin residues in tissues from cattle has been attributed to non-compliance with the USFDA-approved route of administration and withdrawal time. However, the effect of administration route and physiological differences among animals on tissue depletion has not been determined. The objective of this work was to develop a physiologically based pharmacokinetic (PBPK) model to predict plasma, liver and milk concentrations of flunixin in cattle following intravenous (i.v.), intramuscular (i.m.) or subcutaneous (s.c.) administration for use as a tool to determine factors that may affect the withdrawal time. The PBPK model included blood flow-limited distribution in all tissues and elimination in the liver, kidney and milk. Regeneration of parent flunixin due to enterohepatic recirculation and hydrolysis of conjugated metabolites was incorporated in the liver compartment. Values for physiological parameters were obtained from the literature, and partition coefficients for all tissues but liver and kidney were derived empirically. Liver and kidney partition coefficients and elimination parameters were estimated for 14 pharmacokinetic studies (including five crossover studies) from the literature or government sources in which flunixin was administered i.v., i.m. or s.c. Model simulations compared well with data for the matrices following all routes of administration. Influential model parameters included those that may be age or disease-dependent, such as clearance and rate of milk production. Based on the model, route of administration would not affect the estimated days to reach the tolerance concentration (0.125 mg kg(-1)) in the liver of treated cattle. The majority of USDA-reported violative residues in liver were below the upper uncertainty predictions based on estimated parameters, which suggests the need to consider variability due to disease and age in establishing withdrawal intervals for drugs used in food animals. The model predicted that extravascular routes of administration prolonged flunixin concentrations in milk, which could result in violative milk residues in treated cattle.

Elimination kinetics of cephapirin sodium in milk after an 8-day extended therapy program of daily intramammary infusion in healthy lactating Holstein-Friesian cows

The objective of this study was to determine the elimination kinetics of extended therapy with intramammary (IMM) cephapirin in lactating dairy cattle. Eight healthy Holstein-Friesian cows were administered cephapirin (200mg) into all 4 mammary glands every 24 h after milking. Cows were milked 3 times per day and concentrations of cephapirin and desacetyl cephapirin were determined in bucket milk using liquid chromatography-mass spectrometry. Milk concentration-time data after the last of the 8 IMM infusions were fitted using compartment and noncompartmental models. The maximum cephapirin concentration was 128±57 µg/mL (mean ± SD), the elimination rate constant from the central compartment was 0.278±0.046 (h(-1)), clearance was 0.053±0.023 L/h, the half time for elimination was 2.55±0.40 h, and the mean residence time was 2.65±0.79 h. The cephapirin concentration was below the approved tolerance in all cows by 96 h after the last infusion, which is the labeled withholding time for the preparation used. Extended therapy for 8 d provided milk cephapirin concentrations above the minimum inhibitory concentration for common gram-positive mastitis pathogens (0.1 to 1.0 µg/mL) for the duration of therapy and for an additional 16 to 32 h after the end of treatment. Our findings suggest that this IMM cephapirin sodium formulation, which is labeled for 2 doses 12 h apart, could be administered at a 24-h interval for up to 8 d in cows milked 3 times per day, with no significant effect on residue levels by 96 h after the last treatment. Longer withdrawal times would be prudent for cows with low milk production.

Plasma pharmacokinetics and milk residues of flunixin and 5-hydroxy flunixin following different routes of administration in dairy cattle

The objective of this study was to determine if the plasma pharmacokinetics and milk elimination of flunixin (FLU) and 5-hydroxy flunixin (5OH) differ following intramuscular and subcutaneous injection of FLU compared with intravenous injection. Twelve lactating Holstein cows were used in a randomized crossover design study. Cows were organized into 2 groups based on milk production (<20 or >30 kg of milk/d). All cattle were administered 2 doses of 1.1mg of FLU/kg at 12-h intervals by intravenous, intramuscular, and subcutaneous injections. The washout period between routes of administration was 7d. Blood samples were collected from the jugular vein before FLU administration and at various time points up to 36 h after the first dose of FLU. Composite milk samples were collected before FLU administration and twice daily for 5d after the first dose of FLU. Samples were analyzed by ultra-HPLC with mass spectrometric detection. For FLU plasma samples, a difference in terminal half-life was observed among routes of administration. Harmonic mean terminal half-lives for FLU were 3.42, 4.48, and 5.39 h for intravenous, intramuscular, and subcutaneous injection, respectively. The mean bioavailability following intramuscular and subcutaneous dosing was 84.5 and 104.2%, respectively. The decrease in 5OH milk concentration versus time after last dose was analyzed with the nonlinear mixed effects modeling approach and indicated that both the route of administration and rate of milk production were significant covariates. The number of milk samples greater than the tolerance limit for each route of administration was also compared at each time point for statistical significance. Forty-eight hours after the first dose, 5OH milk concentrations were undetectable in all intravenously injected cows; however, one intramuscularly injected and one subcutaneously injected cow had measurable concentrations. These cows had 5OH concentrations above the tolerance limit at the 36-h withdrawal time. The high number of FLU residues identified in cull dairy cows by the United States Department of Agriculture Food Safety Inspection Service is likely related to administration of the drug by an unapproved route. Cattle that received FLU by the approved (intravenous) route consistently eliminated the drug before the approved withdrawal times; however, residues can persist beyond these approved times following intramuscular or subcutaneous administration. Cows producing less than 20 kg of milk/d had altered FLU milk clearance, which may also contribute to violative FLU residues.

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

Elimination of erythromycin in milk following intramammary therapy of specific mastitis in cows was studied. Five cows received therapy in one quarter (G1), and eight in two quarters with five milked twice (G2) and three thrice a day (G3). Dose infused was 300 mg/quarter 12 h × 5 times. The drug concentrations in milk were determined using microbial assay technique with Micrococcus luteus as the test organism. Considerable variations occurred in the excretion of drug; levels for treated quarters being 8.25 to 37.61 μg/ml at first milking that declined rapidly at 24 h and no drug activity was observed beyond 36 h post treatment. In total, about 6-25% of the last infused dose appeared in the milk. Drug crossed to 1/15 quarter (G1), 6/10 quarters (G2) and all the six untreated quarters (G3). Crossover levels were significantly higher in mastitic quarters and for G3 cows, but duration of excretion remained same in all cases. It seems that crossover of erythromycin to untreated quarters is related to the udder health and dose infused.

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

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.

A survey on antibiotic usage in dairy herds in Pennsylvania

A survey was conducted (July 2001 to June 2002) on antibiotic usage of 113 dairy herds from 13 counties in Pennsylvania. Fifty percent of dairy farms surveyed maintained antibiotic treatment records. Only 21% of dairy producers had written plans for treating sick animals. Thirty-two percent of dairy producers sought veterinarian advice before administering antibiotics and on most farms (93%), antibiotics were administered by the owner/manager or designated herdsman. Twenty-four percent of the dairy producers said they always completed the course of antibiotic treatment. Any extra-label use of antibiotics was administered only on the guidelines of a veterinarian on majority of the farms. Comprehensive records from 33 dairy farms indicated that antibiotic usage was largest for calves with enteritis (36%) followed by pneumonia in calves (25%) and foot rot in cattle (16%). Twenty-four antibiotics including beta-lactams, spectinomycin, florfenicol, and tetracyclines were used on these farms. Beta-lactam antibiotics were used mostly for dry cow therapy, clinical mastitis, and on some farms for pneumonia and metritis. On 18% of the dairy herds surveyed, ceftiofur was used in an extra-label manner to treat mastitis in lactating cattle. On 70% of farms, calves were fed medicated milk replacers containing oxytetracycline and neomycin. The results of this study suggest that antibiotics are used extensively on dairy herds for both therapeutic and prophylactic purposes. Beta-lactams and tetracyclines were the most widely used antibiotics. There is considerable variation in the management practices associated with antibiotic use on dairy farms. It is anticipated that the findings of this survey will permit developing new strategies for prudent use of antibiotics on dairy herds.