Assessing the affective component of pain, and the efficacy of pain control, using conditioned place aversion in calves

Abstract

Pain in animals is typically assessed using reflexive and physiological responses. These measures allow inferences regarding nociception but provide little basis for conclusions about the affective component of pain (i.e. how negatively the experience is perceived). Calves routinely undergo painful procedures on commercial farms, including hot-iron disbudding, providing a convenient model to study pain in animals. The aim of this study was to investigate the affective component of post-procedural pain due to hot-iron disbudding, using conditioned place aversion. Calves (n = 31) were subjected to two procedures (one bud at a time): one without post-procedural pain control and the other with the use of a nonsteroidal anti-inflammatory drug (either meloxicam (n = 16) or ketoprofen (n = 15)). All procedures included the use of local anaesthesia (lidocaine). Place conditioning was tested 2 days after the last treatment by allowing calves to freely roam between the pens where they had previously been disbudded. Calves spent more time, and lay down more frequently, in the pen where they received meloxicam compared with the pen where they only received a local block. Surprisingly, calves avoided the pen where they received ketoprofen compared with the control treatment pen. We hypothesize that the shorter duration of action of ketoprofen resulted in increasing pain at the end of the conditioning period, explaining the increased aversion to this treatment. These results illustrate the value of place conditioning paradigms to assess the affective component of pain in animals, and suggest that the animal's evaluation of painful events depends upon the time course of when the pain is experienced.

Researching Human-Cattle Interaction on Rangelands: Challenges and Potential Solutions

“…Grandin et al (1994) [ 74 ] demonstrates that it is difficult for cattle to unpair negative experiences in a given location despite other experiences that may follow, which is especially notable on rangelands where there are infrequent handling opportunities. In addition to memory of past experiences causing fear and stress in processing environments [ 71 , 72 , 75 , 76 , 77 ], immediate procedures surrounding human-animal interaction research may also impact outcome measures. For example, if a study is using chute score and flight speed to measure fear of restraint by humans during or after some aversive or painful experience (e.g., branding), it would be difficult to disentangle fear of handling from expression of pain or anxiety caused by the procedure itself or from the sounds and stress hormones of other cattle that have been processed prior to the focal cow [ 78 , 79 , 80 , 81 ].…”

Conditioned place preference reveals ongoing pain in calves 3 weeks after disbudding

“…When given the choice between an environment paired with analgesic treatment and another paired with a control vehicle, injured rodents, but not their sham-treated counterparts, prefer the drug-paired environment 9 . A place conditioning paradigm has been used to demonstrate that calves will avoid an area where they experienced disbudding without post-operative pain control compared to an area where they received a sham procedure 10 or were disbudded with the use of an NSAID 11 . Place conditioning has not been used to assess ongoing pain in the weeks after the procedure.…”

Brain Waste: The Neglect of Animal Brains

“…There are indications that the cerebral cortex of Perissodactyls and Cetartiodactyls (including large herbivores, whales, and dolphins) works with a slightly different general organization, because of the prevalence of a less distinct lamination, instead of the well-known six layers typical of rodents and primates (Hof et al, 1999;Cozzi et al, 2017). We also know that the sensory world of farm mammals is partly different from ours: they do not see the same color spectrum, have wide eye fields with only limited stereoscopic capabilities (Ede et al, 2019). Furthermore, horses, cows, and pigs are endowed with an incredibly developed sense of smell, testified by the enormous olfactory bulbs, hippocampus, and related structures.…”