title: Intramuscular administration of ceftiofur sodium versus intramammary infusion of penicillin/novobiocin for treatment of Streptococcus agalactiae mastitis in dairy cows.
abstract: OBJECTIVE
  To determine the efficacy of intramuscular administration of ceftiofur sodium as treatment for intramammary infections attributable to Streptococcus agalactiae, compared with that for a standard treatment of intramammary infusion of penicillin/novobiocin.
  
  
  METHODS
  Prospective, randomized, controlled trial.
  
  
  METHODS
  72 lactating Holstein cows with intramammary infections caused by S agalactiae from 5 commercial dairies in Michigan.
  
  
  METHODS
  In 36 of 72 infected cows, ceftiofur was administered (2.2 mg/kg of body weight, IM, q 24 h) for 5 days; 150 mg of novobiocin and 100,000 U of procaine penicillin G was infused daily into each mammary gland of the other 36 cows for 2 days. Milk samples were collected aseptically at approximately 4 and 8 weeks after initial treatment. If cows were determined to be infected at 4 weeks after initial treatment, the treatment was repeated.
  
  
  RESULTS
  The cure rate at 4 weeks (91.7%) and at 8 weeks (96.8%) after initial treatment for the penicillin/novobiocin-treated cows was significantly (P < 0.0001) higher, compared with that of the ceftiofur-treated cows (2.8 and 9.1%, respectively). Somatic cell counts were significantly (P < 0.0001) lower in the penicillin/novobiocin-treated group after treatment.
  
  
  CONCLUSIONS
  Intramuscular administration of ceftiofur is not efficacious as a treatment to eliminate intramammary infections caused by S agalactiae and should not be used to reduce the prevalence of this organism in dairy herds.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing 48824, USA.
authors.forename: R J
authors.initials: RJ
authors.lastname: Erskine
authors.forename: P C
authors.initials: PC
authors.lastname: Bartlett
authors.forename: G L
authors.initials: GL
authors.lastname: Johnson
authors.forename: L W
authors.initials: LW
authors.lastname: Halbert
mesh_terms: D000818:Animals; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D002511:Cephalosporins / Q000008:administration & dosage*; D004359:Drug Therapy, Combination / Q000008:administration & dosage*; D005260:Female; D007263:Infusions, Parenteral / Q000662:veterinary; D007273:Injections, Intramuscular / Q000662:veterinary; D016015:Logistic Models; D008321:Mammary Glands, Animal; D008414:Mastitis, Bovine / Q000188:drug therapy*; D008892:Milk / Q000166:cytology; D009675:Novobiocin / Q000008:administration & dosage; D010402:Penicillin G Procaine / Q000008:administration & dosage; D010406:Penicillins / Q000008:administration & dosage; D013290:Streptococcal Infections / Q000188:drug therapy / Q000662:veterinary*; D013292:Streptococcus agalactiae; D016896:Treatment Outcome
chemical_list: D002511:Cephalosporins; D010406:Penicillins; D009675:Novobiocin; D010402:Penicillin G Procaine; C053503:ceftiofur