title: The pharmacokinetics and effects of meloxicam, gabapentin, and flunixin in postweaning dairy calves following dehorning with local anesthesia.
abstract: Approved analgesic compounds in cattle are not currently available in the United States due to the lack of validated pain assessment methods and marker residue depletion studies. In this study, we compared the pharmacokinetic parameters and effect of preemptive analgesics administered to calves subjected to dehorning with local anesthesia. Holstein steers were randomly assigned to receive one of the following treatments per os (PO) or intravenously (IV) (n = 8/group): meloxicam (1 mg/kg PO), gabapentin (15 mg/kg PO), meloxicam (1 mg/kg), and gabapentin (15 mg/kg) PO, flunixin (2.2 mg/kg IV), or a placebo. Plasma drug, haptoglobin, substance P (SP) concentrations, serum cortisol concentrations, ocular thermography, mechanical nociceptive threshold (MNT), and average daily gain (ADG) were evaluated. Data were analyzed using mixed-effects models and noncompartmental pharmacokinetic analysis. Meloxicam, gabapentin, and meloxicam with gabapentin at the present doses did not reduce cortisol concentrations. Analgesic-treated calves had significantly lower plasma SP concentrations and improved ADG compared with controls. Flunixin calves had reduced circulating cortisol compared with controls. Meloxicam-treated calves showed an increase in MNT at two horn bud sites compared with the other treatments. Analgesics improved ADG and reduced biomarkers of pain, but effects differed by compound and route of administration.
authors.affiliation: Department of Animal Sciences and Industry, Kansas State University, Manhattan, KS, USA.
authors.forename: H D
authors.initials: HD
authors.lastname: Glynn
authors.forename: J F
authors.initials: JF
authors.lastname: Coetzee
authors.forename: L N
authors.initials: LN
authors.lastname: Edwards-Callaway
authors.forename: J C
authors.initials: JC
authors.lastname: Dockweiler
authors.forename: K A
authors.initials: KA
authors.lastname: Allen
authors.forename: B
authors.initials: B
authors.lastname: Lubbers
authors.forename: M
authors.initials: M
authors.lastname: Jones
authors.forename: E
authors.initials: E
authors.lastname: Fraccaro
authors.forename: L L
authors.initials: LL
authors.lastname: Bergamasco
authors.forename: B
authors.initials: B
authors.lastname: KuKanich
mesh_terms: D000588:Amines / Q000493:pharmacokinetics* / Q000627:therapeutic use; D000779:Anesthetics, Local / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000493:pharmacokinetics* / Q000627:therapeutic use; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy / Q000517:prevention & control; D003002:Clonixin / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000627:therapeutic use; D003509:Cyclohexanecarboxylic Acids / Q000493:pharmacokinetics* / Q000627:therapeutic use; D003612:Dairying; D000077206:Gabapentin; D006733:Horns / Q000601:surgery; D008297:Male; D000077239:Meloxicam; D010147:Pain Measurement / Q000662:veterinary; D010149:Postoperative Pain / Q000188:drug therapy / Q000517:prevention & control / Q000662:veterinary*; D013843:Thiazines / Q000493:pharmacokinetics* / Q000627:therapeutic use; D013844:Thiazoles / Q000493:pharmacokinetics* / Q000627:therapeutic use; D005680:gamma-Aminobutyric Acid / Q000493:pharmacokinetics* / Q000627:therapeutic use
chemical_list: D000588:Amines; D000779:Anesthetics, Local; D000894:Anti-Inflammatory Agents, Non-Steroidal; D003509:Cyclohexanecarboxylic Acids; D013843:Thiazines; D013844:Thiazoles; C014557:flunixin; D005680:gamma-Aminobutyric Acid; D000077206:Gabapentin; D003002:Clonixin; D000077239:Meloxicam