title: Evaluation of pain and inflammation associated with hot iron branding and microchip transponder injection in horses.
abstract: OBJECTIVE
  To compare effects of hot iron branding and microchip transponder injection regarding aversive behavioral reactions indicative of pain and inflammation in horses.
  
  
  METHODS
  7 adult horses.
  
  
  METHODS
  In a randomized controlled clinical crossover study, behavioral reactions to hot iron branding and microchip transponder injection were scored by 4 observers. Local and systemic inflammation including allodynia were assessed and compared by use of physiologic and biochemical responses obtained repeatedly for the 168-hour study period. Serum cortisol concentration was measured repeatedly throughout the first 24 hours of the study. Sham treatments were performed 1 day before and 7 days after treatments.
  
  
  RESULTS
  Hot iron branding elicited a significantly stronger aversive reaction indicative of pain than did microchip transponder injection (odds ratio [OR], 12.83). Allodynia quantified by means of skin sensitivity to von Frey monofilaments was significantly greater after hot iron branding than after microchip transponder injection (OR, 2.59). Neither treatment induced signs of spontaneously occurring pain that were observed during the remaining study period, and neither treatment induced increased serum cortisol concentrations. Comparison with sham treatments indicated no memory of an unpleasant event. The hot iron branding areas had significantly increased skin temperature and swelling (OR, 14.6). Systemic inflammation as measured via serum amyloid A concentration was not detected after any of the treatments.
  
  
  CONCLUSIONS
  Microchip transponder injection induced less signs of pain and inflammation and did not seem to pose a higher long-term risk than hot iron branding. Consequently, results indicated that hot iron branding does inflict more pain and should be abandoned where possible.
authors: Department of Large Animal Sciences, Faculty of Life Sciences, University of Copenhagen, DK-2630 Taastrup, Copenhagen, Denmark.
authors: Casper
authors: C
authors: Lindegaard
authors: Dorte
authors: D
authors: Vaabengaard
authors: Mogens T
authors: MT
authors: Christophersen
authors: Claus T
authors: CT
authors: Ekstøm
authors: Julie
authors: J
authors: Fjeldborg
mesh_terms: D000823:Animal Identification Systems / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D000818:Animals; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D007249:Inflammation / Q000473:pathology / Q000662:veterinary*; D010146:Pain / Q000662:veterinary*; D012867:Skin / Q000473:pathology; D013997:Time Factors