ceftiofur and florfenicol

Antibiotics are commonly used to prevent and treat poultry microbial infections, but certain antibiotic families depress humoral immunity, such as antibody production. Poultry humoral immunity depends on the normal functioning of the bursa of Fabricius and the B lymphocytes that mature in that gland. In this study, recommended therapeutic doses of enrofloxacin, florfenicol, or ceftiofur were administered to 2-d-old chicks. On d 7 post-hatch, bursae were sampled for histological, immunohistochemical, and flow cytometric determination of Bu-1-positive (Bu-1+) cell number, percentage, and distribution. The bursa of Fabricius from all treatment and control groups had normal morphology. The administration of antibiotics significantly decreased the number of Bu-1+ cells in the bursal medulla, with a simultaneous increase of these cells in the cortex. Flow cytometry revealed a significant decrease in the percentage of bursal Bu-1+ cells from all of the studied antibiotics: enrofloxacin (93.91 ± 3.27), florfenicol (87.84 ± 7.14), and ceftiofur (89.16 ± 5.68) compared with that of the control (96.48 ± 2.60). The combination of reduced percentages of Bu-1+ cells and a decrease in these cells in the medullary region suggests lower B cell maturation.

Topics: Animals; Anti-Bacterial Agents; Antibodies, Monoclonal; B-Lymphocytes; Bursa of Fabricius; Cephalosporins; Chickens; Enrofloxacin; Fluoroquinolones; Male; Thiamphenicol

In this field trial, a new combination product containing florfenicol and flunixin meglumine (FLOR-FM) was compared with commercially available products that contained only tulathromycin (TULA) or ceftiofur crystalline free acid (CCFA) for the treatment of undifferentiated fever (UF; rectal temperature >/=105.0 degrees F) in beef calves that received long-acting oxytetracycline at feedlot arrival. The overall mortality rate of the FLOR FM group (2.0%) was significantly (P less than .050) lower than the rates in the TULA and CCFA groups (10.0% and 20.0%, respectively; 50 animals/group), even though the first UF relapse rate of the FLOR FM group was significantly (P less than .050) higher than that of the TULA group. In the FLOR FM group, this resulted in per-animal economic advantages of Can$46.23 (versus TULA) and Can$108.77 (versus CCFA) based on equal costs for initial UF therapy. These results demonstrate that it is more cost-effective to administer FLOR FM than TULA or CCFA for initial UF therapy in feedlot calves at high risk for bovine respiratory disease that receive metaphylactic long-acting oxytetracycline at feedlot arrival.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Cattle; Cattle Diseases; Cephalosporins; Clonixin; Disaccharides; Drug Combinations; Fever; Heterocyclic Compounds; Housing, Animal; Thiamphenicol

The purpose of the present clinical studies was to determine the clinical efficacy of a combined parenteral and oral treatment with Bisolvon in combination with antibiotics in bovines suffering from acute respiratory disease. To this end four trials were conducted in respiratory diseased bovines; a total of 619 animals were evaluated. The animals were randomly assigned to one of two treatment groups within each study and were treated either with enrofloxacin, cefquinome, ceftiofur or florfenicol. The Bisolvon group was additionally treated with Bisolvon over 5 consecutive days. Daily clinical examinations were carried out over a period of 6 days. The clinical respiratory score, the primary parameter, representing a summation of the scoring points for the parameters respiratory rate, nasal discharge, spontaneous coughing, lung sounds and grade of dyspnoea and the clinical index score, which additionally included the general parameters fever, demeanour and feed intake, were significantly lower in the Bisolvon groups compared to the controls at all examinations after initiation of therapy in all trials with the exception of day 2 in one study. Lower values correspond to a less severe clinical condition. This consistent result as well as the evaluation of the single parameters are indicative of an acceleration of the recovery of the animals additionally treated with Bisolvon.

Topics: Acute Disease; Administration, Oral; Animals; Anti-Infective Agents; Bromhexine; Cattle; Cattle Diseases; Cephalosporins; Drug Therapy, Combination; Enrofloxacin; Fluoroquinolones; Injections; Quinolones; Respiratory Tract Infections; Thiamphenicol

The objective of this cross-sectional study was to investigate the relationship between management practices and antimicrobial use in heifer calves on Canadian dairy farms. Questionnaires on calf management practices, herd characteristics, and calf treatment records were administered on 147 dairy farms in 5 provinces during annual farm visits in a multiyear, nationwide research project (Canadian Dairy Network for Antimicrobial Stewardship and Resistance: CaDNetASR). Questions focused on the calf caregiver, calving pen, colostrum management, milk feeding, grouping, bedding management, and age when male calves were sold. Antimicrobial treatment records were collected on each farm from either an electronic herd management system or paper-based records. Newborn heifers born in the last 12 mo were identified retrospectively and followed to 60 d of age, with antimicrobial treatments and dates of sale or death extracted for further analysis. A multivariable linear regression model was developed with the natural log of the number of antimicrobial treatments per calf-year as the dependent variable, and categorized calf management practices and farm characteristics as the independent variables. A complete data set of records on 7,817 calves was retrieved from 74 farms based on completeness of calf records. A total of 2,310 calves were treated at least once with an antimicrobial, and 7,307 individual antimicrobial treatments were recorded. Among the reasons for antimicrobial use, respiratory disease (54%) was most common, followed by diarrhea (20%), presence of a fever (3%), and umbilical disease (2%). Florfenicol (33% of recorded treatments), penicillin (23%), and trimethoprim-sulfamethoxazole (18%) were commonly used, whereas fluoroquinolones (4%), and ceftiofur (1%) were used less commonly. Farms (31%) commonly had 0-1.0 antimicrobial treatments/calf-year (median: 2.2 treatments/calf-year; interquartile range: 0.64-6.43 treatments/calf-year). Defined daily dose (DDD) per calf-year was calculated based on the Canadian bovine standards. Among the 74 farms, florfenicol (1.35 DDD/calf-year) and macrolides (0.73 DDD/calf-year) were used most, whereas ceftiofur (0.008 DDD/calf-year) was the lowest. The final multivariable linear regression model indicated that farms that fed transition milk had fewer than half the number of antimicrobial treatments per calf-year than those who did not feed transition milk. The number of antimicrobial treatments per calf-year in prewean

Topics: Animals; Anti-Bacterial Agents; Canada; Cattle; Cross-Sectional Studies; Dairying; Female; Fluoroquinolones; Humans; Macrolides; Male; Penicillins; Pregnancy; Retrospective Studies; Trimethoprim, Sulfamethoxazole Drug Combination

Actinobacillus pleuropneumoniae, Pasteurella multocida and Streptococcus suis are prevalent bacterial causes of swine infections. Morbidity, mortality and positively impacting the financial burden of infection occurs with appropriate antimicrobial therapy. Increasing antimicrobial resistance complicates drug therapy and resistance prevention is now a necessity to optimize therapy and prolong drug life. Mutant bacterial cells are said to arise spontaneously in bacterial densities of 107-109 or greater colony forming units/ml. Antibiotic drug concentration inhibiting growth of the least susceptible cell in these high density populations has been termed the mutant prevention concentration (MPC). In this study MPC and minimum inhibitory concentration (MIC) values of ceftiofur, enrofloxacin, florfenicol, tilmicosin and tulathromycin were determined against the swine pathogens A. pleuropneumoniae, P.multocida and S. suis. The following MIC90/MPC90 values (mg/L) for 67 A. pleuropneumoniae and 73 P. multocida strains respectively were as follows: A. pleuropneumoniae 0.031/0.5, ≤0.016/0.5, 0.5/2, 4/32, 2/32; P. multocida 0.004/0.25, 0.016/0.125, 0.5/0.5, 8/16, 0.5/1. For 33 S. suis strains, MIC90 values (mg/L) respectively were as follows: 1, 0.25, 4, ≥8 and ≥8. A total of 16 S. suis strains with MIC values of 0.063-0.5 mg/L to ceftiofur and 0.25-0.5 mg/L to enrofloxacin were tested by MPC; MPC values respectively were 0.5 and 1 mg/L respectively. MPC concentrations provide a dosing target which may serve to reduce amplification of bacterial subpopulations with reduced antimicrobial susceptibility. Drug potency based on MIC90 values was ceftiofur > enrofloxacin >florfenicol = tulathromycin > tilmicosin; based on MPC90 values was enrofloxacin > ceftiofur > tulathromycin > florfenicol ≥ tilmicosin.

Topics: Actinobacillus pleuropneumoniae; Animal Husbandry; Animals; Anti-Bacterial Agents; Cephalosporins; Disaccharides; Drug Resistance, Multiple, Bacterial; Enrofloxacin; Heterocyclic Compounds; Microbial Sensitivity Tests; Pasteurella multocida; Streptococcus suis; Swine; Swine Diseases; Thiamphenicol; Tylosin

We determined if antibiotics residues that are excreted from treated animals can contribute to persistence of resistant bacteria in agricultural environments. Administration of ceftiofur, a third-generation cephalosporin, resulted in a ∼ 3 log increase in ceftiofur-resistant Escherichia coli found in the faeces and pen soils by day 10 (P = 0.005). This resistant population quickly subsided in faeces, but was sustained in the pen soil (∼ 4.5 log bacteria g(-1)) throughout the trial (1 month). Florfenicol treatment resulted in a similar pattern although the loss of florfenicol-resistant E. coli was slower for faeces and remained stable at ∼ 6 log bacteria g(-1) in the soil. Calves were treated in pens where eGFP-labelled E. coli were present in the bedding (∼ 2 log g(-1)) resulting in amplification of the eGFP E. coli population ∼ 2.1 log more than eGFP E. coli populations in pens with untreated calves (day 4; P < 0.005). Excreted residues accounted for > 10-fold greater contribution to the bedding reservoir compared with shedding of resistant bacteria in faeces. Treatment with therapeutic doses of ceftiofur or florfenicol resulted in 2-3 log g(-1) more bacteria than the estimated ID50 (2.83 CFU g(-1)), consistent with a soil-borne reservoir emerging after antibiotic treatment that can contribute to the long-term persistence of antibiotic resistance in animal agriculture.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cephalosporins; Drug Residues; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Infections; Feces; Oxytetracycline; Soil; Soil Microbiology; Thiamphenicol

Bacterial pneumonia is the most common reason for parenteral antimicrobial administration to beef cattle in the United States. Yet there is little information describing the antimicrobial concentrations at the site of action. The objective of this study was to compare the active drug concentrations in the pulmonary epithelial lining fluid and interstitial fluid of four antimicrobials commonly used in cattle. After injection, plasma, interstitial fluid, and pulmonary epithelial lining fluid concentrations and protein binding were measured to determine the plasma pharmacokinetics of each drug. A cross-over design with six calves per drug was used. Following sample collection and drug analysis, pharmacokinetic calculations were performed. For enrofloxacin and metabolite ciprofloxacin, the interstitial fluid concentration was 52% and 78% of the plasma concentration, while pulmonary fluid concentrations was 24% and 40% of the plasma concentration, respectively. The pulmonary concentrations (enrofloxacin + ciprofloxacin combined) exceeded the MIC90 of 0.06 μg/mL at 48 hours after administration. For florfenicol, the interstitial fluid concentration was almost 98% of the plasma concentration, and the pulmonary concentrations were over 200% of the plasma concentrations, exceeding the breakpoint (≤ 2 μg/mL), and the MIC90 for Mannheimia haemolytica (1.0 μg/mL) for the duration of the study. For ceftiofur, penetration to the interstitial fluid was only 5% of the plasma concentration. Pulmonary epithelial lining fluid concentration represented 40% of the plasma concentration. Airway concentrations exceeded the MIC breakpoint for susceptible respiratory pathogens (≤ 2 μg/mL) for a short time at 48 hours after administration. The plasma and interstitial fluid concentrations of tulathromcyin were lower than the concentrations in pulmonary fluid throughout the study. The bronchial concentrations were higher than the plasma or interstitial concentrations, with over 900% penetration to the airways. Despite high diffusion into the bronchi, the tulathromycin concentrations achieved were lower than the MIC of susceptible bacteria at most time points.

Topics: Animals; Anti-Bacterial Agents; Biological Availability; Cattle; Cephalosporins; Cross-Over Studies; Disaccharides; Enrofloxacin; Epithelial Cells; Extracellular Fluid; Fluoroquinolones; Heterocyclic Compounds; Lung; Male; Mannheimia haemolytica; Microbial Sensitivity Tests; Respiratory Mucosa; Thiamphenicol; Veterinary Drugs

Rapidly growing mycobacteria (RGM) infections in cats typically manifest as a panniculitis, requiring long-term antimicrobial therapy for resolution. The search for novel antimicrobial therapies to reduce treatment duration and improve the rate of clinical resolution is imperative. Accordingly, RGM isolates underwent susceptibility testing to some avermectins and other antibacterial drugs currently available.. Five Mycobacterium fortuitum and six Mycobacterium smegmatis isolates obtained from Australian cats underwent susceptibility testing by microbroth dilution to ivermectin, moxidectin, ceftiofur and florfenicol.. All isolates were resistant to the highest concentrations of ivermectin, moxidectin and ceftiofur tested (1024 µg/ml, 256 μg/ml and 32 μg/ml, respectively). All isolates of M fortuitum were resistant to the highest concentration of florfenicol tested (128 µg/ml). The minimum inhibitory concentration range of florfenicol that inhibited growth of M smegmatis isolates was 32-64 µg/ml.. All drugs appear to have no efficacy in vitro for the treatment of RGM infections.

Topics: Animals; Anti-Bacterial Agents; Australia; Cat Diseases; Cats; Cephalosporins; Drug Combinations; Drug Resistance, Bacterial; Ivermectin; Macrolides; Microbial Sensitivity Tests; Mycobacterium; Mycobacterium fortuitum; Mycobacterium Infections; Thiamphenicol

This study aimed to investigate the influence of enrofloxacin, florfenicol, ceftiofur and E. coli LPS interaction on T and B subsets in thymus and spleen of newly-hatched chicks. A 126, 1-day-old chicks were administered enrofloxacin, florfenicol or ceftiofur in recommended doses according to the currently treatment schedule advises. E .coli LPS was given intravenously once at the dose of 200 μg kg(-1) BW on the 2nd day of experiment (d. e.). On the 6th and the 14th d. e. thymus and spleens were subjected to flow cytometry investigation.The most significant changes were demonstrated in spleen. The antibiotics administration decreased the percentage of B and T cells subset. Moreover, this suppressive effect was enhanced by E. coli LPS administration. On the 6th d. e. the percentage of CD3(+)TCRγδ(-), CD3(+)TCRγδ(+), CD4(+)CD8(-), CD4(-)CD8(+) decreased significantly after ceftiofur and LPS treatment. A lower percentage of CD3(+)TCRγδ(-), CD4(-)CD8(+) and CD3(+)TCRγδ(+) was observed in enrofloxacine and LPS treated group. The decrease percentage of CD3(+)TCRγδ(+)cells and Bu-1(+) was found after florfenicol and LPS treatment. On the 14th d. e. a decreased percentage of CD4(+)CD8(-) and increased percentage of CD4(-)CD8(+) cells was shown in ceftiofur or enrofloxacine and LPS treated groups. In addition decreased percentage of CD3(+)TCRγδ(+) was found in all antibiotic and LPS treated groups.In this study, it was shown that enrofloxacine, florfenicol, ceftiofur treatment may change the proportions among lymphocytes subset and might have an impact on the immune response to bacterial endotoxins in chicks.

Topics: Animals; Anti-Bacterial Agents; B-Lymphocytes; Cephalosporins; Enrofloxacin; Escherichia coli; Fluoroquinolones; Lipopolysaccharides; Male; Spleen; T-Lymphocyte Subsets; Thiamphenicol; Thymus Gland

This study investigated the effects of hydrothermal liquefaction (HTL) on the fate of bioactive compounds (BACs) often present with wet biosolids from wastewater, manure, or algae. Tracking radiolabeled (14)C for two BACs showed that 60-79% of the carbon was transferred to the HTL raw oil product, and most of the rest was found in the aqueous product. In the presence of both swine manure and Spirulina biomass feedstocks, HTL provided essentially complete removal of three BACs when operated at 300°C for ≥ 30 min. Experiments with both natural transformation and high-efficiency transformation showed that HTL provided complete deactivation of antibiotic resistant genes for all tested HTL conditions (250-300°C, 15-60 min reaction time). Thus, incorporating HTL into wastewater treatment systems can simultaneously produce valuable bio-crude oil, provide effective removal of BACs and disrupt the natural pathways for antibiotic resistant gene transfer from manure and wastewater biosolids to the environment.

Topics: Animals; Azotobacter; Benzhydryl Compounds; Biotechnology; Carbon Radioisotopes; Cephalosporins; Chromatography, High Pressure Liquid; DNA; Electroporation; Escherichia coli; Estrone; Manure; Phenols; Plasmids; Spirulina; Sus scrofa; Temperature; Thiamphenicol; Transformation, Genetic; Water; Water Pollutants, Chemical

Mannheimia haemolytica is the most prevalent cause of bovine respiratory disease (BRD) and this disease accounts for 75% of morbidity, 50-70% of feedlot deaths and is estimated to cost up to $1 billion dollars annually in the USA. Antimicrobial therapy is essential for reducing morbidity, mortality and impacting on the financial burden of this disease. Due to the concern of increasing antimicrobial resistance, investigation of antibacterial agents for their potential for selecting for resistance is of paramount importance. A novel in vitro measurement called the mutant prevention concentration (MPC) defines the antimicrobial drug concentration necessary to block the growth of the least susceptible cells present in high density (≥10(7) colony forming units/ml) bacterial populations such as those seen in acute infection. We compared the minimum inhibitory concentration (MIC) and MPC values for 5 antimicrobial agents (ceftiofur, enrofloxacin, florfenicol, tilmicosin, tulathromycin) against 285 M. haemolytica clinical isolates. The MIC(90)/MPC(90) values for each agent respectively were as follows: 0.016/2, 0.125/1, 2/≥16, 8/≥32, 2/8. Dosing to achieve MPC concentrations (where possible) may serve to reduce the selection of bacterial subpopulations with reduced antimicrobial susceptibility. The rank order of potency based on MIC(90) values was ceftiofur > enrofloxacin > florfenicol = tulathromycin > tilmicosin. The rank order of potency based on MPC(90) values was enrofloxacin > ceftiofur > tulathromycin > florfenicol ≥ tilmicosin.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cephalosporins; Disaccharides; Drug Resistance, Multiple, Bacterial; Enrofloxacin; Fluoroquinolones; Heterocyclic Compounds; Mannheimia haemolytica; Microbial Sensitivity Tests; Thiamphenicol; Tylosin; United States

Mycoplasma bovis is an important pathogen of cattle, causing mastitis, pneumonia, conjunctivitis, otitis, and arthritis. Currently there are only a few reports of sensitivity levels for M. bovis isolates from the United States. Mycoplasma bovis isolates submitted to the Pennsylvania Animal Diagnostic Laboratory between December 2007 and December 2008 (n = 192) were tested for antimicrobial susceptibility to enrofloxacin, erythromycin, florfenicol, spectinomycin, ceftiofur, tetracycline, and oxytetracycline using a broth microdilution method. The most effective antimicrobials against M. bovis determined by using the broth microdilution method were florfenicol, enrofloxacin, and tetracycline with minimum inhibitory concentration (MIC) ranges of 2-32 µg/ml, 0.1-3.2 µg/ml, and 0.05 to >12.8 µg/ml, respectively. Spectinomycin, oxytetracycline, and tetracycline showed a wide-ranging level of efficacy in isolate inhibition with broth microdilution with MIC ranges of 4 to >256 µg/ml, 0.05 to >12.8 µg/ml, and 0.05 to >12.8 µg/ml, respectively. A significant difference in the susceptibility levels between quarter milk and lung isolates was found for spectinomycin. When MIC values of a subset of the M. bovis isolates (n=12) were tested using a flow cytometric technique, the MIC ranges of enrofloxacin, spectinomycin, ceftiofur, erythromycin, tetracycline, oxytetracycline, and florfenicol ranges were 0.1-0.4 µg/ml, 4 to >256 µg/ml, >125 µg/ml, >3.2 µg/ml, <0.025 to >6.4 µg/ml, 0.8 to >12.8 µg/ml, and <2-4 µg/ml, respectively. Flow cytometry offers potential in clinical applications due to high-throughput capability, quick turnaround time, and the objective nature of interpreting results.

Topics: Animals; Anti-Infective Agents; Cattle; Cattle Diseases; Cephalosporins; Enrofloxacin; Erythromycin; Flow Cytometry; Fluoroquinolones; Microbial Sensitivity Tests; Mycoplasma bovis; Mycoplasma Infections; Oxytetracycline; Spectinomycin; Tetracycline; Thiamphenicol

Enrofloxacin (ER) resistant Actinobacillus pleuropneumoniae strains emerged in Taiwan in 2002. The mechanism of ER resistance in A. pleuropneumoniae has not yet been reported. A total of 48 A. pleuropneumoniae isolates were obtained from the lungs of pigs with pleuropneumonia in Taiwan between September 2007 and April 2008. Twenty-nine isolates were found to be resistant to enrofloxacin. To understand the mechanisms of A. pleuropneumoniae's resistance to ER, enrofloxacin susceptibility of the isolates along with the mutations of the quinolone resistance-determining region (QRDR) of DNA gyrase and topoisomerase IV, qnr genes were analyzed. Enrofloxacin resistant isolates were found to carry at least one mutation in the QRDR of gyrA, leading to amino acid changes at codon 83 or 87. Efflux pump inhibitor (Phe-Arg-beta-naphthylamide) decreased enrofloxacin minimum inhibitory concentration 2-16-fold, suggesting participation of efflux in ER resistance. Plasmid mediated quinolone resistance genes qnr were not detected in these isolates. In conclusion, enrofloxacin resistance of A. pleuropneumoniae may be linked to multiple target gene mutations and active effluxs.

Topics: Actinobacillus pleuropneumoniae; Anti-Bacterial Agents; Arginine; Cephalosporins; DNA Gyrase; DNA Topoisomerase IV; Drug Resistance, Bacterial; Enrofloxacin; Fluoroquinolones; Genes, Bacterial; Microbial Sensitivity Tests; Molecular Sequence Data; Mutation; Serotyping; Taiwan; Thiamphenicol

This study was designed to determine the genetic basis of florfenicol and ceftiofur resistance in Escherichia coli isolates recovered from French cattle. In these isolates, ceftiofur resistance was conferred by bla(CMY-2) located on three distinct conjugative plasmids on a specific DNA fragment, ISEcp1-bla(CMY-2)-blc- sugE. Two of the plasmids also carried the floR gene conferring resistance to florfenicol. The floR gene was shown to be associated with the insertion sequence ISCR2. Mobile elements appear to contribute to the mobilization of floR and bla(CMY-2) genes in E. coli. The presence of bla(CMY-2) and floR on the same plasmid highlights the potential risk for a co-selection of the bla(CMY-2) gene through the use of florfenicol in food animal production.

Topics: Animals; beta-Lactamases; Cattle; Cattle Diseases; Cephalosporins; Conjugation, Genetic; Drug Resistance, Bacterial; Escherichia coli; Escherichia coli Proteins; Humans; Plasmids; Thiamphenicol

Topics: Animals; Anti-Bacterial Agents; Catfishes; Drug Resistance, Bacterial; Drug Resistance, Multiple, Bacterial; Edwardsiella ictaluri; Enterobacteriaceae Infections; Fish Diseases; Molecular Sequence Data; Plasmids; Thiamphenicol

To correlate serum concentrations of fibrinogen (Fib), haptoglobin (Hap), serum amyloid-A (SAA), and alpha-1 acid glycoprotein (AGP) with clinical respiratory tract disease and response to treatment in transport-stressed feedlot cattle fed vitamin E-supplemented diets.. 387 heifer calves (mean initial weight, 197 kg).. Calves purchased from an order buyer were delivered to a feedlot to study the effects of dietary supplementation with 2,000 IU of vitamin E for 0, 7, 14, or 28 days after arrival. Serum or plasma Fib, Hap, SAA, and AGP concentrations were measured on days 0, 7, and 28 after arrival as well as at the time of treatment for respiratory tract disease with antimicrobial drugs and after completion of treatment.. Vitamin E supplementation was associated with decreased treatment costs. In cattle that were not recognized as sick or responded positively to 1 antimicrobial treatment, serum Hap concentrations were significantly lower on days 0 and 7 than concentrations for cattle that required > 1 treatment. Serum Hap concentrations and ratios of Hap to SAA on day 0 significantly correlated with the number of antimicrobial treatments required. Serum Hap concentrations at the time of initial treatment were significantly lower for cattle that required only 1 treatment, compared with those that required > 1 treatment.. Serum Hap concentrations are of potential value for use in assessing feedlot cattle that may become ill as a result of respiratory tract disease and for use in monitoring treatment efficacy.

Topics: Acute-Phase Proteins; Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Cephalosporins; Female; Macrolides; Random Allocation; Respiratory Tract Diseases; Thiamphenicol; Tylosin; Vitamin E