Posted April 16, 2015
Veterinarians have no approved drugs to reduce pain in pigs, but Dr. Michael D. Apley thinks they have extralabel use options.
He said drugs used in pets and others used in humans may be useable for anesthesia and analgesia in pigs, under federal regulations that allow use of those drugs in the absence of options approved for use in food animals. But he warned that any residues from drugs without established tolerance levels would be illegal, and the Food and Drug Administration would need to establish residue tolerance levels for veterinarians to determine what withdrawal times are needed between treatment and slaughter, especially as residue detection ability improves.
Dr. Apley, a professor of production medicine and clinical pharmacology at Kansas State University, was among presenters on pain management in pigs during the American Association of Swine Veterinarians annual meeting, which this year ran Feb. 28-March 3 in Orlando, Florida. Dr. Ronnie L. Brodersen, who became AASV president during the meeting and chaired the program committee, said in an interview that pain management is an important issue in swine medicine.
“I think that the challenge is having tools approved by FDA for that purpose,” he said. “There are tools, and I think we will acquire them as time goes on.”
Dr. Locke A. Karriker, director of the Swine Medicine Education Center at Iowa State University, said the public has increasing concern about pain control in animals raised for food, particularly with regard to husbandry practices such as castration and tail docking. A lack of objective pain assessments has been a limiting factor in creating dosage regimens, he said, and pharmacokinetic data for one pig age group cannot be extrapolated to others.
Dr. Karriker described a study that indicated meloxicam, an NSAID, administered orally to a sow could be passed to nursing pigs through milk. That study indicated those nursing pigs had values such as lower plasma cortisol concentrations than did control pigs as well as higher cranial temperatures likely related to reduced pain- or stress-associated vasoconstriction in comparison with control pigs.
Dr. Apley indicated in his presentation and proceedings published by the AASV that veterinarians may be able to provide anesthesia to pigs with drugs such as acepromazine, xylazine, and ketamine. All have extralabel use–related withdrawal times for some regimens, available from the Food Animal Residue Avoidance Databank. For analgesia, veterinarians may need to ask FARAD for withdrawal duration advice on drugs such as lidocaine, ketoprofen, meloxicam, and carprofen.
Dr. Blaine Tully, a partner at Swine Health Professionals in Steinbach, Manitoba, noted in another presentation that Canadian practice code revisions enacted in 2014 now state, among other changes, that anesthetics and analgesics are required to control pain during castration of any pig more than 10 days old, and pain management is required for tail docking of any pig more than 7 days old. Analgesic administration will be required for castration or tail docking of all pigs in Canada starting July 1, 2016.