Factors affecting mechanical nociceptive thresholds in healthy sows

Area of Science:

• Veterinary Science
• Animal Physiology
• Pain Research

Background:

• Assessing pain in livestock is crucial for animal welfare.
• Mechanical nociceptive thresholds (MNTs) are a key indicator of pain sensitivity.
• Understanding factors influencing MNTs in sows is essential for accurate pain evaluation.

Purpose of the Study:

• To investigate anatomical and methodological factors affecting MNTs in healthy sows.
• To determine intra-site variability in MNT measurements.
• To provide insights for refining pain assessment protocols in swine.

Main Methods:

• Prospective, randomized validation study involving eight healthy pregnant sows.
• MNTs were measured using a hand-held probe and a limb-mounted actuator.
• Measurements were taken at nine body landmarks and at 1- and 3-minute intervals, analyzed with linear mixed regression models.

Main Results:

• MNTs were lower with the probe versus the actuator (p < 0.001) and in pelvic versus thoracic limbs (p < 0.001).
• Higher MNTs were recorded in subsequent measurements and in the morning versus afternoon (p = 0.04).
• Variability was lower in thoracic limbs and with the actuator (p < 0.001).

Conclusions:

• Anatomical location, measurement tool, and time of day significantly influence MNTs in sows.
• Intra-site variability in MNT measurements is affected by limb and measurement method.
• The methodology for assessing MNTs in sows requires meticulous attention to detail for reliable results.