title: An evaluation of the relative efficacy of tulathromycin for the treatment of undifferentiated fever in feedlot calves in Nebraska.
abstract: A field trial was performed under commercial feedlot conditions in central Nebraska to assess the relative efficacy of tulathromycin (TULA) to florfenicol (FLOR) for the treatment of undifferentiated fever (UF) in feedlot calves that did not receive a metaphylactic antimicrobial or vaccines/bacterins containing Mannheimia haemolytica or Histophilus somni at feedlot arrival by comparing animal health, feedlot performance, and carcass characteristic variables. Two hundred recently weaned, auction market derived, crossbred beef calves that met the study-specific case definition of UF were randomly allocated in a 1:1 ratio to 1 of 2 experimental groups as follows: TULA, which received tulathromycin administered subcutaneously at the rate of 2.5 mg/kg body weight (BW) once at the time of allocation; or FLOR, which received florfenicol administered subcutaneously at the rate of 40 mg/kg BW once at the time of allocation. In terms of animal health, the first UF relapse (RR = 0.65), overall mortality (RR = 0.33), and BRD mortality (RR = 0.29) rates in the TULA group were significantly (P < 0.05) lower than in the FLOR group. There were no significant (P > or = 0.05) differences between the TULA and FLOR groups for the other animal health variables measured. There was no significant (P > or = 0.05) difference in average daily gain between the TULA and FLOR groups. There were no significant (P > or = 0.05) differences in the overall distributions of quality grade and yield grade between the experimental groups; however, a significantly (P < 0.05) higher proportion of carcasses in the TULA group graded yield grade USDA-4 as compared with the FLOR group. In the economic analysis, the benefits observed resulted in an economic advantage of $52.50 USD/animal in the TULA group due to lower first UF relapse and overall mortality rates, even though the occurrence of yield grade USDA-4 carcasses increased and the initial UF treatment cost was higher.
authors.affiliation: Feedlot Health Management Services, PO Box 140, Bay 7-87 Elizabeth Street, Okotoks, Alberta T1S 2A2. fhms@feedlothealth.com
authors.forename: Oliver C
authors.initials: OC
authors.lastname: Schunicht
authors.forename: Calvin W
authors.initials: CW
authors.lastname: Booker
authors.forename: P Timothy
authors.initials: PT
authors.lastname: Guichon
authors.forename: G Kee
authors.initials: GK
authors.lastname: Jim
authors.forename: Brian K
authors.initials: BK
authors.lastname: Wildman
authors.forename: Tom J
authors.initials: TJ
authors.lastname: Pittman
authors.forename: Tye
authors.initials: T
authors.lastname: Perrett
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D002417:Cattle; D004187:Disaccharides / Q000627:therapeutic use*; D006571:Heterocyclic Compounds / Q000627:therapeutic use*; D007279:Injections, Subcutaneous / Q000662:veterinary; D009329:Nebraska; D012766:Pasteurellosis, Pneumonic / Q000188:drug therapy* / Q000401:mortality; D012008:Recurrence; D013839:Thiamphenicol / Q000031:analogs & derivatives / Q000627:therapeutic use; D016896:Treatment Outcome; D015430:Weight Gain; D018942:Macrolides
chemical_list: D000900:Anti-Bacterial Agents; D004187:Disaccharides; D006571:Heterocyclic Compounds; D013839:Thiamphenicol; C035534:florfenicol; C485204:tulathromycin; D018942:Macrolides