tilmicosin and Pasteurellosis--Pneumonic

The efficacy of tulathromycin in the treatment (phase 1) and prevention (phase 2) of bovine respiratory disease (BRD) was evaluated on commercial farms in France, Germany, Italy, and Spain. In phase 1, commingled cattle with clinical BRD were treated with tulathromycin (n = 128) or florfenicol (n = 125) on day 0. Similar percentages of animals showed sustained clinical improvement at day 14 (tulathromycin 83.3% versus florfenicol 81.0%) and had not relapsed by day 60 (tulathromycin 63.3% versus florfenicol 58.4%). In phase 2, healthy in-contact cattle were treated with tulathromycin (n = 492), tilmicosin (n = 494), or saline (n = 265) on day 0. Significantly more (P = .0001) tulathromycin-treated cattle remained healthy to day 14 (92.4%) than tilmicosin-treated (83.7%) or saline-treated (63.7%) cattle, and this was maintained through day 60 (tulathromycin 85.4% versus tilmicosin 75.1% and saline 56.2%). Tulathromycin was highly effective in the treatment and prevention of BRD.

Topics: Animals; Anti-Bacterial Agents; Cattle; Disaccharides; Disease Outbreaks; Europe; Haemophilus somnus; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Mannheimia haemolytica; Mycoplasma bovis; Pasteurella multocida; Pasteurellosis, Pneumonic; Thiamphenicol; Tylosin

Efficacy and field safety of tulathromycin administered as a single-dose treatment to crossbreed beef calves with undifferentiated bovine respiratory disease (BRD) were evaluated in a multicenter field study conducted at four US feedlots. Two hundred castrated male calves were enrolled at each study site. The treatment groups were physiologic saline (n = 160) given SC at 0.02 ml/kg, tulathromycin (n = 320) given SC at 2.5 mg/kg, and tilmicosin (n = 320) given SC at 10 mg/kg. Nasopharyngeal swabs for bacterial culture were obtained before treatment. The cure rate for calves treated with tulathromycin (78%) and tilmicosin (65%) was significantly (P < or = .0001) higher than that of calves treated with saline (23.8%). The cure rate of calves treated with tulathromycin (78.4%) was significantly (P = .0007) higher than that of calves treated with tilmicosin (64.9%). No adverse events related to tulathromycin were reported. Under the conditions of this study, tulathromycin administered as a single-dose treatment was efficacious in the treatment of undifferentiated BRD.

Topics: Animals; Animals, Newborn; Anti-Bacterial Agents; Cattle; Disaccharides; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Male; Nasopharynx; Pasteurellosis, Pneumonic; Treatment Outcome; Tylosin; United States

Three studies conducted at feedlots in Colorado, Idaho, and Texas examined the comparative efficacy of tulathromycin injectable solution for the treatment of cattle at high risk of developing undifferentiated bovine respiratory disease (BRD). Each study randomly allocated 250 calves to receive tulathromycin at 2.5 mg/kg and 250 calves to receive either tilmicosin at 10 mg/kg (Colorado site) or florfenicol at 40 mg/kg (Idaho and Texas sites) on arrival at the feedlot. Calves were housed by treatment group in pens with 50 calves/pen. Beginning 3 days after antimicrobial treatment, cattle were observed for signs of BRD daily until harvest. In all three studies, the treatment success rates at 28 days after treatment and at harvest were significantly higher (P < or = .013) for cattle treated with tulathromycin than for cattle treated with either tilmicosin or florfenicol. Fewer tulathromycin-treated cattle were removed from the group as "chronics" or "mortalities" at 28 days posttreatment (P < or = .014) in all three studies. Tulathromycin demonstrated superior efficacy compared with tilmicosin and florfenicol when treating groups of high-risk cattle before the onset of signs of BRD.

Topics: Animals; Anti-Bacterial Agents; Cattle; Disaccharides; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Male; Pasteurellosis, Pneumonic; Recurrence; Risk Factors; Severity of Illness Index; Thiamphenicol; Treatment Outcome; Tylosin; United States

The efficacy of tulathromycin in decreasing the incidence of morbidity and mortality due to bovine respiratory disease (BRD) in 1,239 high-risk cattle was investigated at four US feedlots. Calves not exhibiting clinical signs of BRD received one of three treatments administered subcutaneously in the neck: physiologic saline at 0.02 ml/kg, tulathromycin at 2.5 mg/kg, or tilmicosin at 10 mg/kg. Each treatment group consisted of 413 calves. Calves with clinical signs of BRD and rectal temperatures of 104 degrees F or higher on days 1 through 14 were considered treatment failures (BRD morbidity). Nasopharyngeal swabs from saline-treated morbidities were submitted for isolation and identification of BRD organisms. Respiratory disease morbidity was highest in calves treated with saline and significantly (P < or = .0001) lower in calves administered tulathromycin or tilmicosin. Morbidity from BRD was significantly (P < or = .0001) higher in calves treated with tilmicosin than in calves treated with tulathromycin. Under conditions of this study, tulathromycin, given to calves at high risk of developing BRD, was significantly more effective in reducing BRD morbidity when compared to both saline- and tilmicosin-treated calves.

Topics: Animals; Anti-Bacterial Agents; Cattle; Disaccharides; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Male; Nasopharynx; Pasteurellosis, Pneumonic; Risk Factors; Treatment Outcome; Tylosin

The therapeutic efficacy and field safety of tulathromycin were evaluated in stocker calves with undifferentiated bovine respiratory disease (BRD) in three field studies conducted over two consecutive grazing seasons in Nebraska. Eight hundred calves exhibiting clinical signs of BRD and with rectal temperatures of 104 degrees F or higher were treated with tulathromycin (n = 340), florfenicol (n = 240), or tilmicosin (n = 220) and evaluated for approximately 60 days. Florfenicol and tilmicosin were administered as single SC injections according to labeled dosage. Tulathromycin was administered as a single SC injection of 2.5 mg/kg. In all three studies, the cure rate of calves 60 days after treatment with tulathromycin was significantly higher (P < or = .05) than that of calves treated with florfenicol or tilmicosin. Suspected adverse reactions were not reported for any of the study drugs. Tulathromycin proved to be significantly more effective than either florfenicol or tilmicosin in the treatment of BRD in stocker calves.

Topics: Animals; Anti-Bacterial Agents; Cattle; Disaccharides; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Male; Pasteurellosis, Pneumonic; Recurrence; Severity of Illness Index; Thiamphenicol; Treatment Outcome; Tylosin; United States; Weight Gain

Four studies conducted at feedlots in Greeley and Wellington, Colorado; Nebraska; and Texas compared the efficacy of tulathromycin to florfenicol or tilmicosin for the treatment of cattle with undifferentiated bovine respiratory disease (BRD) and subsequent feedlot performance and carcass characteristics. In each study, 100 calves with BRD were treated with tulathromycin given SC at 2.5 mg/kg body weight. At the Greeley, CO, and Nebraska study locations, 100 calves were treated with florfenicol given SC at 40 mg/kg body weight, and at the Wellington, CO, and Texas study locations, tilmicosin was given SC at 10 mg/kg body weight. Cure rate, a derived variable that included assessments of mortality, rectal temperature, and attitude and respiratory scores from day 3 to day 28 and day 3 through harvest, was the primary assessment of BRD efficacy. Cure rates of calves treated with tulathromycin were significantly (P < or = .009) higher than those calves treated with florfenicol. At Wellington, CO, the cure rate of calves treated with tulathromycin was significantly higher (P < or = .018) compared with tilmicosin-treated calves. The differences in cure rates between tulathromycin and tilmicosin treatment groups in the Texas study were not significantly different (P > .05). Tulathromycin was more efficacious in the treatment of undifferentiated BRD compared with florfenicol and, in one study, compared with tilmicosin.

Topics: Animals; Anti-Bacterial Agents; Cattle; Disaccharides; Heterocyclic Compounds; Injections, Subcutaneous; Macrolides; Male; Pasteurellosis, Pneumonic; Recurrence; Severity of Illness Index; Thiamphenicol; Treatment Outcome; Tylosin; United States; Weight Gain

Three studies were conducted to determine and confirm the effective dosage rate of ceftiofur crystalline-free acid sterile suspension (CCFA-SS, 200 mg ceftiofur equivalents [CE]/ml), a long-acting ceftiofur formulation, for control and treatment of bovine respiratory disease (BRD). In each study, CCFA-SS was administered once by subcutaneous (SC) injection in the middle third of the posterior aspect of the ear. Study 1 was conducted using an intratracheal challenge with Mannheimia (formerly Pasteurella) haemolytica and dosages ranging from 0 to 8.8 mg CE/kg to select a dosage for further field testing. In Study 2, a single dose of CCFA-SS at 0.0, 4.4, or 6.6 mg CE/kg was administered when uniform clinical signs of BRD were present in feedlot cattle. Study 3 was conducted in several feedlots to evaluate the efficacy, practicality, and safety of CCFA-SS at 4.4 or 6.6 mg CE/kg compared with a placebo control or tilmicosin for preemptive control of BRD. In Study 1, the effective dose was determined to be 5.35 mg CE/kg; therefore, 4.4 and 6.6 mg CE/kg were selected as the dosages for further field testing. Administration of CCFA-SS at 4.4 or 6.6 mg CE/kg improved treatment success compared with negative controls (P < or =.05 for both doses) in Study 2. In Study 3, a single administration of 4.4 or 6.6 mg CE/kg was comparable to tilmicosin (P <.001) and was significantly better than placebo (P <.001) for the control of BRD. Using the ear as an administration site was acceptable under field conditions and was well tolerated by all animals. These studies demonstrated that a single administration of CCFA-SS by SC injection in the middle third of the posterior aspect of the ear at 4.4 or 6.6 mg CE/kg is effective, safe, and practical for preemptive control and treatment of the bacterial component of BRD in feedlot cattle. Administration in an inedible tissue results in a short withdrawal time and no injection-site trimming at slaughter.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cephalosporins; Dose-Response Relationship, Drug; Ear, External; Haemophilus; Injections, Subcutaneous; Macrolides; Mannheimia haemolytica; Pasteurella multocida; Pasteurellosis, Pneumonic; Suspensions; Treatment Outcome; Tylosin

Tilmicosin is a potent antimicrobial with broad-spectrum activity against the bacterial agents involved in the bovine respiratory disease complex. Recent studies indicate that in addition to being bactericidal, tilmicosin is capable of modulating inflammation in the lung. A series of experiments were designed to determine whether tilmicosin alters alveolar macrophage-prostaglandin E(2) (PGE(2)) production induced by Escherichia coli (O55:B5) lipopolysaccharide (LPS). Twenty-two healthy Holstein bull calves were used to study the effects of LPS-induced PGE(2) production of alveolar macrophages after in vivo or in vitro treatment with tilmicosin. In Experiment 1, tilmicosin was given by subcutaneous injection (15 mg/kg) twice, 48 hours apart, to four calves; four control calves received no treatment. Twenty-four hours after the second treatment, alveolar macrophages were stimulated with LPS in vitro. In Experiment 2, alveolar macrophages from five untreated calves were harvested and treated in vitro with tilmicosin, followed by LPS stimulation. In Experiment 3, the ability of in vitro tilmicosin treatment to alter the expression of LPS-induced cyclooxygenase-2 (COX-2) mRNA was evaluated. In Experiments 4 and 5, secretory phospholipase A(2) activity was examined in untreated calves. Treatment of calves with tilmicosin resulted in reduced LPS-induced alveolar macrophage PGE(2) production. Similar reductions in PGE(2) by LPS-stimulated alveolar macrophages after in vitro tilmicosin treatment were noted. This in vitro tilmicosin treatment was not associated with reduction of the expression of LPS-induced COX-2. Alveolar macrophage phospholipase A(2) activity induced by LPS was significantly reduced by prior tilmicosin treatment in vitro. Tilmicosin (in vivo and in vitro) appears to reduce the PGE(2) eicosanoid response of LPS-stimulated alveolar macrophages by reducing the in vitro substrate availability without altering in vitro COX-2 mRNA expression.

Topics: Actins; Animals; Anti-Bacterial Agents; Cattle; Cell Line; Cyclooxygenase 2; Dinoprostone; DNA Primers; Injections, Subcutaneous; Isoenzymes; Lipopolysaccharides; Macrolides; Macrophages, Alveolar; Male; Pasteurellosis, Pneumonic; Polymerase Chain Reaction; Prostaglandin-Endoperoxide Synthases; Reverse Transcriptase Polymerase Chain Reaction; RNA, Messenger; Tylosin

A multicentre, controlled, randomized and blinded trial was carried out in 180 ruminating calves with pyrexia and respiratory sign(s) on nine Belgian, British and French farms. All animals were sampled for pathogenic bacteria before treatment and at failure/relapse. Calves were injected with either marbofloxacin (M) solution [Marbocyl (Laboratoire Vétoquinol, Lure, France) 10%] at 2 mg/kg/24 h for 4 days intravenously on the first day then subcutaneously, or tilmicosin (T) solution (Micotil, Elanco Products Ltd, Basingstoke, Hants, UK) at 10 mg/kg as a single subcutaneous (s.c.) injection. The animals were examined clinically eight times up to day 28. The bacterial pathogens were found to be sensitive to marbofloxacin: for Pasteurella haemolytica the minimum inhibitory concentration (MIC)90 was 0.08 microg/mL and for P. multocida the MIC90 was 0.04 microg/mL. Cure rates at day 4 for group M and group T were 84 vs. 82%, respectively (P > or = 0.05). However, overall clinical score was significantly lower after 1 day in group M (P < 0.05). There was no difference in either relapse rate or average daily weight gain between groups. Marbofloxacin was found to be better tolerated than tilmicosin at the s.c. injection site (77.5 vs. 42.2% calves without local swelling, P=0.001) and was well tolerated when injected intravenously. Marbofloxacin was shown to have comparable but faster efficacy and better local tolerance than tilmicosin in the treatment of bovine respiratory disease (BRD).

Topics: Analysis of Variance; Animals; Anti-Bacterial Agents; Anti-Infective Agents; Belgium; Cattle; Disease Outbreaks; Dose-Response Relationship, Drug; Drug Tolerance; Enzyme Inhibitors; Female; Fluoroquinolones; France; Macrolides; Mannheimia haemolytica; Pasteurella multocida; Pasteurellosis, Pneumonic; Quinolones; Tylosin

A field trial was performed under commercial feedlot conditions in western Canada to compare the efficacy of florfenicol and tilmicosin for the treatment of undifferentiated fever (UF) in calves that received metaphylactic tilmicosin upon arrival at the feedlot. One thousand and eighty recently weaned, auction market derived, crossbred beef calves suffering from UF were allocated to one of 2 experimental groups as follows: florfenicol, which was intramuscular (i.m.) florfenicol administered at the rate of 20 mg/kg body weight (BW) at the time of allocation (Day 0) and again 48 h later, or tilmicosin, which was subcutaneous (s.c.) tilmicosin administered once at the rate of 10 mg/kg BW on day 0. Five hundred and forty-four animals were allocated to the florfenicol group and 536 animals were allocated to the tilmicosin group. The chronicity, wastage, overall mortality, and bovine respiratory disease (BRD) mortality rates were significantly (P < 0.05) lower in the florfenicol group than in the tilmicosin group. There were no significant (P > or = 0.05) differences in first UF relapse, second UF relapse, hemophilosis mortality, or miscellaneous mortality rates between the florfenicol and tilmicosin groups. Average daily gain (ADG) from arrival at the feedlot to the time of implanting and ADG from allocation to the time of implanting were significantly (P < 0.05) lower in the florfenicol group as compared with the tilmicosin group. There were no significant (P > or = 0.05) differences in arrival weight, allocation weight, implanting weight, or ADG from arrival to allocation between the experimental groups. In the economic analysis, there was an advantage of $18.83 CDN per animal in the florfenicol group. The results of this study indicate that florfenicol is superior to tilmicosin for the treatment of UF because of lower chronicity, wastage, overall mortality, and BRD mortality rates. However, interpretation of these observations must take into consideration the fact that these calves received meta-phylactic tilmicosin upon arrival at the feedlot, which is a standard, cost-effective, management procedure utilized by feedlots in western Canada.

Topics: Animals; Anti-Bacterial Agents; Body Weight; Canada; Cattle; Drug Administration Schedule; Macrolides; Male; Pasteurellosis, Pneumonic; Risk; Thiamphenicol; Tylosin; Weight Gain

The therapeutic effect of a single injection of tilmicosin (10 mg/kg body mass) against natural cases of pneumonia of calves, compared to other conventionally used antibiotics, was examined under field conditions. The trials were conducted in three cattle herds and included the treatment of 135 calves with 82 controls. The animals' age ranged from 1 week to 4 months. Prior to the treatment and in case of death bacteriological examinations from nasal swabs and from the lungs were carried out. Clinical signs were recorded in all groups and in one group body mass gains were also recorded. After tilmicosin treatment, the body temperature returned to the normal level within 24 h and the animals recovered within 1 to 2 days. Ten calves (7.41%) showed relapse during the 3rd and 4th week after treatment in contrast to 9 (10.98%) in the control group. Three calves (2.22%) died in the groups treated with tilmicosin and 6 calves (7.32%) among the controls. In one of the treated groups the body mass gain was 6.2% higher compared to the controls at the age of 3 months. These results suggest that treatment with a single dose of tilmicosin is effective in most cases of calf pneumonia caused by bacteria.

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Macrolides; Mannheimia haemolytica; Pasteurella multocida; Pasteurellosis, Pneumonic; Pneumonia, Mycoplasma; Treatment Outcome; Tylosin

Topics: Animals; Anti-Bacterial Agents; Bronchopneumonia; Dyspnea; Injections, Subcutaneous; Lung; Macrolides; Pasteurella multocida; Pasteurellosis, Pneumonic; Pleurisy; Rabbits; Rhinitis; Sneezing; Treatment Outcome; Tylosin

To examine effects of danofloxacin and tilmicosin on continuously recorded body temperature in beef calves with pneumonia experimentally induced by inoculation of Mannheimia haemolytica.. 41 Angus-cross heifers (body weight, 160 to 220 kg) without a recent history of respiratory tract disease or antimicrobial treatment, all from a single ranch.. Radiotransmitters were implanted intravaginally in each calf. Pneumonia was induced intrabronchially by use of logarithmic-phase cultures of M. haemolytica. At 21 hours after inoculation, calves were treated with saline (0.9% NaCl) solution, danofloxacin, or tilmicosin. Body temperature was monitored from 66 hours before inoculation until 72 hours after treatment. Area under the curve (AUC) of the temperature-time plot and mean temperature were calculated for 3-hour intervals and compared among treatment groups.. The AUCs for 3-hour intervals did not differ significantly among treatment groups for any of the time periods. Analysis of the mean temperature for 3-hour intervals revealed significantly higher temperatures at most time periods for saline-treated calves, compared with temperatures for antimicrobial-treated calves; however, we did not detect significant differences between the danofloxacin- and tilmicosin-treated calves. The circadian rhythm of temperatures before exposure was detected again approximately 48 hours after bacterial inoculation.. Danofloxacin and tilmicosin did not differ in their effect on mean body temperature for 3-hour intervals but significantly decreased body temperature, compared with body temperature in saline-treated calves. Normal daily variation in body temperature must be considered in the face of respiratory tract disease during clinical evaluation of feedlot cattle.

Topics: Animals; Body Temperature; Cattle; Cattle Diseases; Circadian Rhythm; Fluoroquinolones; Macrolides; Mannheimia haemolytica; Pasteurellosis, Pneumonic; Pneumonia; Telemetry; Tylosin

Pneumonia caused by Pasteurella (Mannheimia) haemolytica was induced in weaned beef heifer calves, approximately 6 months of age. Calves were treated at 20 h after challenge with therapeutic doses of danofloxacin or tilmicosin. Peripheral blood neutrophils were collected at 3, 24 and 48 h after treatment. The ex vivo effects on neutrophil function, neutrophil apoptosis, and hematological parameters were examined, as was the effect on percentage lung consolidation. Neutrophil function assays included random migration under agarose, cytochrome C reduction, iodination, Staphylococcus aureus ingestion, chemotaxis, and antibody-dependent and antibody-independent cell-mediated cytotoxicity. Apoptosis was determined using a cell death detection kit. Killing was performed at 72 h after treatment. Statistical comparisons were made among the three groups of challenged-treated animals: saline, danofloxacin, and tilmicosin. Comparisons were also made between nonchallenged nontreated animals (NCH) and challenged saline-treated animals. There were no significant differences for any of the neutrophil function assays or neutrophil apoptosis among the challenged-treated groups. This suggests that danofloxacin and tilmicosin have no clinically significant effects on neutrophil function or apoptosis. There were also no significant differences in percentage lung consolidation among the challenged-treated groups. Significant differences were found between the NCH calves and the challenged saline-treated calves in several neutrophil assays, which were attributed to effects of P. haemolytica infection.

Topics: Animals; Anti-Bacterial Agents; Anti-Infective Agents; Cattle; Fluoroquinolones; Injections, Subcutaneous; Lung; Macrolides; Mannheimia haemolytica; Microbial Sensitivity Tests; Neutrophils; Pasteurellosis, Pneumonic; Phagocytosis; Tylosin

To determine the effect of tilmicosin treatment on number of Pasteurella haemolytica (PH) organisms in nasal secretion specimens of calves with respiratory tract disease.. 206 British mixed-breed beef calves, 2 to 5 months old.. In 2 separate studies of outbreaks, calves (study 1, n = 101; study 2, n = 105) that developed respiratory tract disease after transport to a feedlot were treated with tilmicosin. Nasal secretion specimens were examined for PH organisms to determine the status of colonization.. In both studies, PH serotypes A1 and A6 were isolated. In study 1, tilmicosin treatment eliminated or markedly reduced the number of PH organisms in calves on days 1, 4, and 5 after treatment. In study 2, tilmicosin treatment eliminated PH organisms in calves on days 1, 2, 5, and 6 after treatment.. Overall, tilmicosin treatment increased the number of culture-positive calves that became culture-negative and decreased the number of culture-negative calves that became culture-positive for up to 6 days after treatment. Tilmicosin treatment decreased the number of PH organisms in nasal secretion specimens, which indicated that fewer PH organisms were available to infect the lungs or to infect other calves. By reducing colonization, prophylactic use of tilmicosin before transport or at the time of arrival at a feedlot is likely to reduce the incidence of acute respiratory tract disease in calves for the initial several days after arrival, which is the period when they are most susceptible to infectious organisms.

Topics: Animals; Anti-Bacterial Agents; Body Temperature; Cattle; Colony Count, Microbial; Disease Outbreaks; Macrolides; Male; Mannheimia haemolytica; Nasal Mucosa; Nasopharynx; Pasteurellosis, Pneumonic; Specimen Handling; Texas; Tylosin

Twenty four (24) healthy male Holstein calves (< 70 kg) were each experimentally infected by intrabronchial inoculation of 4.0 x 10(9) viable cells of Pasteurella haemolytica-AI (B122) at Time = 0 h. At 1 h following inoculation animals received either: 1) Sham treatment with sterile 0.85% saline SC (n = 12); or 2) a single injection of 10 mg tilmicosin per kg body weight (n = 12). Calves that were non-infected and tilmicosin-treated were also included for determining tilmicosin concentrations in serum and lung tissue at 1, 2, 4, 6, 8, 24, 48, and 72 h (n = 3-per time). In the infected calves, response to therapy was monitored clinically. Serum samples were collected for determination of tilmicosin concentrations using HPLC. Any animal becoming seriously ill was humanely killed. Complete necropsy examinations were performed on all animals and included gross pathologic changes, bacteriologic analysis, histopathology, and determination of pulmonary concentrations of tilmicosin. Tilmicosin treated animals responded significantly better to therapy than saline-treated control calves. Clinical assessment of calves during the study indicated that tilmicosin-treated calves had significantly improved by T = 8 h compared to satine-treated animals (P < 0.05). At necropsy tilmicosin-treated calves had significantly less severe gross and histological lesions (P < 0.05) of the pulmonary tissue. Of the 12 saline-treated calves, 92% (11/12) had Pasteurella haemolytica-A1 in lung tissue, while of the tilmicosin-treated calves 0% (0/12) cultured positive for P. haemolytica. Mean (+/- standard error) serum tilmicosin concentrations in infected calves peaked at 1 h post-injection (1.10 +/- 0.06 micrograms/mL) and rapidly decreased to 0.20 +/- 0.03 microgram/mL, well below the MIC of 0.50 microgram/mL for P. haemolytica-A1 (B122), by 12 h. These serum concentrations were very similar to serum concentrations of tilmicosin in non-infected tilmicosin-treated calves. Lung tissue concentrations of the antibiotic were comparatively high, even at 72 h post-infection (6.50 +/- 0.75 ppm). Lung tissue concentrations at 72 h were significantly higher in experimentally infected calves than in non-infected tilmicosin-treated animals (P < 0.05). These data demonstrate that tilmicosin was effective in treating experimentally-induced pneumonic pasteurellosis as determined by alleviation of clinical signs, pathological findings at post mortem, and presence of viable bacteria from the lung. Co

Topics: Animals; Anti-Bacterial Agents; Cattle; Cattle Diseases; Chromatography, High Pressure Liquid; Dose-Response Relationship, Drug; Hemorrhage; Lung; Macrolides; Male; Mannheimia haemolytica; Pasteurellosis, Pneumonic; Random Allocation; Time Factors; Tylosin

A severe outbreak of undifferentiated respiratory disease affecting 119 of 144 (82.6 per cent) two- to five-month-old housed beef calves was studied by monitoring their clinical signs and rectal temperatures daily or every second day for two months. New cases of respiratory disease, which were first identified three weeks after the calves were housed, occurred over a period of 29 days. The cause of the outbreak was not conclusively determined although 20 per cent of the calves sampled showed serological evidence of recent infection with bovine respiratory syncytial virus and parainfluenzavirus 3. Seventeen of 61 calves (27.9 per cent) which were treated with tilmicosin had to be treated again, compared with nine of 58 calves (15.5 per cent) which were treated with both tilmicosin and flunixin meglumine and did not need further treatment, but this difference was not statistically significant.

Topics: Animal Husbandry; Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Cattle; Cattle Diseases; Clonixin; Disease Outbreaks; Drug Therapy, Combination; Infectious Bovine Rhinotracheitis; Macrolides; Meat; Parainfluenza Virus 3, Human; Pasteurellosis, Pneumonic; Respiratory Syncytial Virus Infections; Respiratory Syncytial Virus, Bovine; Respiratory Tract Diseases; Tylosin; United Kingdom

The minimal inhibitory concentration (MIC) of tilmicosin and oxytetracycline was determined for Pasteurella haemolytica isolated from Dutch cattle in 1991. The agar dilution method was used. Of the Pasteurella haemolytica strains examined, 96% (24) had a MIC for tilmicosin of 2 micrograms/ml or lower; in one strain the MIC was 8 micrograms/ml. The MIC for oxytetracycline was equal to or higher than 64 micrograms/ml in 19 strains (76%), whereas for 5 strains the MIC was 1 microgram/ml and for 1 strain 2 micrograms/ml.

Topics: Animals; Anti-Bacterial Agents; Cattle; Macrolides; Mannheimia haemolytica; Microbial Sensitivity Tests; Oxytetracycline; Pasteurellosis, Pneumonic; Tylosin