***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The prophylactic administration of injectable tilmicosin for pneumonia in weaned beef calves was investigated in 1,806 animals . Comparisons were made among calves receiving an " on-arrival " injection of tilmicosin , calves receiving a single injection of long-acting oxytetracycline , and calves receiving no prophylaxis .  Morbidity and mortality attributable to pneumonia , morbidity and mortality attributable to all causes , and case fatality were significantly lower in the group of calves that received tilmicosin , compared with calves that received long-acting oxytetracycline and calves that received no prophylactic antibiotic .  Mean time to initial pneumonia treatment was significantly extended in calves that received prophylaxis , compared with those that received no antibiotic on arrival at the feedlot . Calves that received tilmicosin  gained significantly more weight than calves that received oxytetracycline . Calves that were not treated for pneumonia during the trial period gained significantly more weight than did those calves that were treated for pneumonia regardless of experimental group . The majority of mortalities were attributable to fibrinous pneumonia ( 31/34 ) . Important bacterial isolates ( Pasteurella spp , Haemophilus somnus , Actinomyces pyogenes ) obtained at necropsy did not have resistance to tilmicosin in association with administration of tilmicosin as prophylaxis for pneumonia . However , bacterial resistance to trimethoprim/sulfonamide and to oxytetracycline were commonly found in these postmortem isolates The objectives of this study were to determine ( i ) whether an association exists between individual pharmacokinetic parameters and treatment outcome when feeder cattle were diagnosed with bovine respiratory disease ( BRD ) and treated with gamithromycin ( Zactran ( ® ) )  at the label dose and ( ii ) whether there was a stronger association between treatment outcome and gamithromycin concentration in plasma or in the pulmonary epithelial lining fluid ( PELF ) effect compartment . The study design was a prospect i ve , blinded , r and omized clinical trial utilizing three groups of 60 ( 362 - 592 lb ) steers/bulls r and omly allocated within origin to sham injection or gamithromycin mass medication . Cattle were evaluated daily for signs of BRD by a veterinarian blinded to treatment . Animals meeting the BRD case definition were enrolled and allocated to a sample collection scheme consisting of sample s for bacterial isolation ( bronchoalveolar lavage fluid and nasopharyngeal swabs ) and gamithromycin concentration determination ( PELF and plasma ) .  Gamithromycin susceptibility of M. haemolytica ( n = 287 ) and P. multocida ( n = 257 ) were determined using broth microdilution with frozen panels containing gamithromycin at concentrations from 0.03 to 16 μg/mL. A two-compartment plasma pharmacokinetic model with an additional compartment for gamithromycin in PELF was developed using rich data sets from published and unpublished studies . The sparse data from our study were then fit to this model using nonlinear mixed effects modeling to estimate individual parameter values . The result ing parameter estimates were used to simulate full time-concentration profiles for each animal in this study . These profiles were analyzed using noncompartmental methods so that PK/PD indices ( AUC24 /MIC , AUC∞ /MIC , CMAX /MIC ) could be calculated for plasma and PELF ( also T > MIC ) for each individual . The calculated PK/PD indices were indicative that for both M. haemolytica and P. multocida a higher drug exposure in terms of concentration , and duration of exposure relative to the MIC of the target pathogen , was favorable to a successful case outcome . A significant association was found between treatment success and PELF AUC0 - 24 /MIC for P. multocida . The calves in this study demonstrated an increased clearance and volume of distribution in plasma as compared to the healthy calves in two previously published reports . Ultimately , the findings from this study indicate that higher PK/PD indices were predictive of positive treatment outcomes 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 Mixed treatment comparison ( MTC ) meta- analysis is a generalization of st and ard pairwise meta- analysis for A vs B trials , to data structures that include , for example , A vs B , B vs C , and A vs C trials . There are two roles for MTC : one is to strengthen inference concerning the relative efficacy of two treatments , by including both ' direct ' and ' indirect ' comparisons . The other is to facilitate simultaneous inference regarding all treatments , in order for example to select the best treatment . In this paper , we present a range of Bayesian hierarchical models using the Markov chain Monte Carlo software WinBUGS . These are multivariate r and om effects models that allow for variation in true treatment effects across trials . We consider models where the between-trials variance is homogeneous across treatment comparisons as well as heterogeneous variance models . We also compare models with fixed ( unconstrained ) baseline study effects with models with r and om baselines drawn from a common distribution . These models are applied to an illustrative data set and posterior parameter distributions are compared . We discuss model critique and model selection , illustrating the role of Bayesian deviance analysis , and node-based model criticism . The assumptions underlying the MTC models and their parameterization are also discussed 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 r and omly 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 OBJECTIVES To evaluate effects of tilmicosin when used in fever-based and metaphylactic treatment programs to attenuate acute undifferentiated bovine respiratory disease ( BRD ) in cattle that recently arrived at feedlots , and to evaluate the effects of tilmicosin for the treatment of BRD . DESIGN R and omized-block controlled study . ANIMALS 1,639 calves from livestock auctions . PROCEDURES Cattle were assigned to 3 groups . Cattle in the nonmedicated ( control ) group were not given antibiotics during processing . Cattle in the fever-based treatment group were given tilmicosin ( 10 mg/kg [ 4.5 mg/lb ] of body weight , s.c . ) during processing when their rectal temperature was > or = 40 C ( 104 F ) . All cattle in the metaphylactic treatment group were given tilmicosin ( 10 mg/kg , s.c . ) during processing . Calves with BRD were treated with tilmicosin ( 10 mg/kg , s.c . ) . RESULTS Morbidity rates in the metaphylactic ( 30.4 % ) and fever-based ( 44.7 % ) treatment groups were less than that for the nonmedicated group ( 54.8 % ) . Mortality rate for the metaphylactic group during the first 28 days ( 1.1 % ) and during the entire study ( 1.7 % ) was less than that for the nonmedicated group ( 3.3 and 4.6 % , respectively ) . Differences were not observed in therapeutic response rates among calves with BRD that were treated . CLINICAL IMPLICATION S Fever-based and metaphylactic treatment programs that used tilmicosin decreased the prevalence of BRD and improved growth of calves . Metaphylactic treatment decreased the number of fatalities caused by BRD in high-risk calves . Fever-based treatment was less effective than metaphylactic treatment for decreasing the prevalence of BRD in newly arrived cattle Feedlot calves ( n = 3784 ) were systematic ally r and omized and allocated in a 2 × 2 factorial study to receive metaphylactic oxytetracycline ( OTC ) on arrival or no antimicrobial , as well as florfenicol once subcutaneously or twice intramuscularly ( 48 h apart ) if diagnosed with bovine respiratory disease ( BRD ) . Calves of different treatment groups were comingled and followed from placement to re-implantation ( ~100 days ) . Animals receiving OTC had a reduced risk of BRD , an increased risk of arthritis , and no significant differences in average daily gain , BRD relapse , overall mortality , or BRD mortality . There were no significant differences between treatment protocol s. Deep nasal swabs ( n = 233 ) taken at arrival ( n = 122 ) , treatment ( n = 77 ) , and swabs from lungs and joints at postmortem ( n = 34 ) were cultured for Mycoplasma bovis from 61 animals ill or dying of chronic pneumonia and arthritis and from 61 healthy calves . There was significant variation in diversity among isolates ( n = 51 ) between study years and different cattle . Metaphylaxis or antimicrobial treatment did not affect the diversity of isolates . Except for tilmicosin , isolates were largely susceptible to tested antimicrobials R and omized controlled trials ( RCTs ) are the gold st and ard for evaluating efficacy of treatments under real world conditions and , as such , it is important that they are conducted with method ological rigour to prevent biased results . Many medical journals have adopted a st and ard checklist for reporting of RCTs , the CONSORT statement . The objective of this study was to evaluate clinical trials in livestock population s to assess method ological quality and completeness of reporting and to investigate the association between these criteria and treatment effects . A total of 100 clinical trials published between 2006 and 2008 in the English language were r and omly selected . For each trial , 2 review ers independently completed a checklist based on the CONSORT statement and a different 2 review ers completed a st and ard template describing the outcomes used and the statistical significance of all reported treatment effects . Disagreements among review ers were resolved by consensus . The results showed that there were substantive deficiencies in the reporting of many of trial features , both related to method ological quality and completeness of reporting . Details on key features such as r and omization , double blinding , and the number of subjects lost to follow-up were reported in only 67 , 4 , and 62 % of trials , respectively . Reporting of r and om allocation to treatment group was associated with a lower proportion of positive treatments effects within trials , as was reporting of inclusion /exclusion criteria for study subjects , details on the intervention , animal signalment , significance tests of baseline differences for at least one variable , and the methods used to measure all outcomes . The results suggest that there are deficiencies in the current reporting of important features of RCTs conducted in livestock species and that these deficiencies may be associated with biased treatment effects . The creation and adoption of 
    Output:
    
The results suggest that macrolides are the most effective antibiotics for the reduction of BRD incidence .
Injectable oxytetracycline  effectively controlled BRD compared with no antibiotics ; however , it was less effective than macrolide treatment .
Because oxytetracycline is already commonly used to prevent , control , and treat BRD in groups of feedlot cattle , the use of injectable oxytetracycline for BRD control might have advantages from an antibiotic stewardship perspective