title: Dose determination and confirmation for ceftiofur crystalline-free acid administered in the posterior aspect of the ear for control and treatment of bovine respiratory disease.
abstract: 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.
authors.affiliation: Pharmacia Animal Health, Kalamazoo, MI 49001, USA.
authors.forename: Beth
authors.initials: B
authors.lastname: Hibbard
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Robb
authors.forename: S Theodore
authors.initials: ST
authors.lastname: Chester
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Dame
authors.forename: W William
authors.initials: WW
authors.lastname: Moseley
authors.forename: W Lawrence
authors.initials: WL
authors.lastname: Bryson
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D002417:Cattle; D002511:Cephalosporins / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D004431:Ear, External; D006190:Haemophilus; D007279:Injections, Subcutaneous / Q000662:veterinary; D018942:Macrolides; D016978:Mannheimia haemolytica; D016979:Pasteurella multocida; D012766:Pasteurellosis, Pneumonic / Q000188:drug therapy*; D013535:Suspensions; D016896:Treatment Outcome; D015645:Tylosin / Q000008:administration & dosage / Q000031:analogs & derivatives*
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; D018942:Macrolides; D013535:Suspensions; C053503:ceftiofur; C052319:tilmicosin; D015645:Tylosin