Evaluation of mechanical and thermal nociception as objective tools to measure painful and nonpainful lameness phases in multiparous sows

Abstract

The objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal nociception threshold (TNT) tests when sows were in painful and nonpainful transient lameness phases. A total of 24 mixed parity crossbred sows (220.15 ± 21.23 kg) were utilized for the MNT test, and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the TNT test. On induction day (D0), all sows were anesthetized and injected with Amphotericin B (10mg/mL) in the distal interphalangeal joint space in both claws of one randomly selected hind limb to induce transient lameness. Three days were compared: (1) D-1 (sound phase, defined as 1 d before induction), (2) D+1 (most lame phase, defined as 1 d after induction), and (3) D+6 (resolution phase, defined as 6 d after induction). After completion of the first round, sows were given a 7-d rest period and then the procedures were repeated with lameness induced in the contralateral hind limb. During the MNT test, pressure was applied perpendicularly to 3 landmarks in a randomized sequence for each sow: 1) middle of cannon on the hind limb (cannon), 2) 1 cm above the coronary band on the medial hind claw (medial claw), and 3) 1 cm above the coronary band on the lateral hind claw (lateral claw). During the TNT test, a radiant heat stimulus was directed 1 cm above the coronary band. The data were analyzed using the MIXED procedure in SAS with sow as the experimental unit. Differences were analyzed between sound and lame limbs on each day. For the MNT test, pressure tolerated by the lame limb decreased for every landmark (P < 0.05) when comparing D-1 and D+1. The sound limb tolerated more pressure on D+1 and D+6 than on baseline D-1 (P < 0.05). Thermal stimulation tolerated by the sound limb did not change over the 3 d (P > 0.05). However, the sows tolerated less heat stimulation on their lame limb on D+1 compared to D-1 levels (P < 0.05). Both MNT and TNT tests indicated greater pain sensitivity thresholds when sows were acutely lame. ABSTRACTThe objective of this study was to quantify pain sensitivity differences using mechanical nociception threshold (MNT) and thermal (TNT) tests when sows were in painful and nonpainful transient lameness phases. A total of 24 mixed parity crossbred sows (220.15 ± 21.23 kg)were utilized for the mechanical nociception threshold test and a total of 12 sows (211.41 ± 20.21 kg) were utilized for the thermal nociception threshold test. On induction day (D0), all sows were anesthetized and injected with Amphotericin B (10mg/mL) in the distal interphalangeal joint space in both claws of one randomly selected hind limb to induce transient lameness. Three days were compared (1) D-1 (Sound phase, defined as 1 d before induction), (2) D+1 (Most lame phase, defined as 1 d after induction) and (3) D+6 (Resolution phase, defined as 6 d after induction). After completion of the first round, sows were given a 7-d rest period and then the procedures were repeated with lameness induced in the contralateral hind l...

A Review of Pain Assessment in Pigs

“…In lame sows, a significant decrease in threshold values is revealed by pressure algometry (137, 138). The same methodologies have enabled researchers to assess the efficacy of NSAIDs in this context (80, 81).…”

Factors affecting mechanical nociceptive thresholds in healthy sows

“…; Mohling et al. ). During the past 15 years, livestock species have been under increasing scrutiny, as they are often affected by painful inflammatory conditions causing hyperalgesia that may be overlooked.…”

“…For this reason, a number of nociception studies have focused on normal versus abnormal processing of noxious stimuli in many species of veterinary interest. The principal aim was to investigate the presence of hyperalgesiawhich may develop both during and long after the original inflammation processand to verify the efficacy of anti-inflammatory and analgesic drugs (Whay et al 2005;Dixon et al 2007;Haussler et al 2007;Caplen et al 2013;Tapper et al 2013;Mohling et al 2014). During the past 15 years, livestock species have been under increasing scrutiny, as they are often affected by painful inflammatory conditions causing hyperalgesia that may be overlooked.…”

“…During the past 15 years, livestock species have been under increasing scrutiny, as they are often affected by painful inflammatory conditions causing hyperalgesia that may be overlooked. Limb disease is one example: lame dairy cows (Whay et al1998), sheep (Ley et al 1995;Colditz et al 2011) and pigs of different ages and gender had lower mechanical nociceptive thresholds (MNTs) in the affected limbs, whether tested at the site of the lesion or elsewhere on the limb (Sandercock et al 2009;Fosse et al 2011a,b;Nalon et al 2013;Tapper et al 2013;Mohling et al 2014).…”

“…Recently, MNT testing of the limbs has been described as a potentially objective tool to assess the efficacy of analgesic protocols in sows affected by lameness (Tapper et al 2013;Mohling et al 2014;Pairis-Garcia et al 2014). However, the methodology currently suffers from a number of limitations: MNTs in pigs differ substantially depending on the configuration of the instrument used (Nalon et al 2013), the size and shape of the probe tip (Fosse et al 2011b), the age and weight of the animals (Janczak et al 2012;Di Giminiani et al 2013), anatomical location (Di Giminiani et al 2013;Nalon et al 2013), as well as familiarity with the procedure (Di Giminiani et al 2015).…”