Calves peak-end memory of pain

Area of Science:

• Animal Behavior
• Pain Perception
• Animal Welfare

Background:

• The peak-end rule describes human memory, where experiences are judged by their most intense point and conclusion.
• Investigating this rule in animals can offer insights into their memory and perception of painful events.
• Disbudding is a common painful procedure in calves, making it a relevant model for studying pain memory.

Purpose of the Study:

• To determine if calves exhibit the peak-end rule in their memory of the painful disbudding procedure.
• To assess the relationship between pain behaviors during disbudding and subsequent memory of the event.
• To evaluate the effectiveness of analgesia timing on calves' aversion to the procedure.

Main Methods:

• Two trials were conducted using 22 calves each, with calves serving as their own controls.
• Calves underwent disbudding with varying analgesic administration timings (immediately after, 2 hours, or 4 hours post-procedure).
• Conditioned place aversion and reflex pain behaviors were used as proxies for real-time and retrospective pain assessment.

Main Results:

• No significant preference was observed for pens associated with analgesic treatment, regardless of timing.
• No correlation was found between conditioned place aversion and the sum, peak, or end of observed pain behaviors.
• The study's findings were inconsistent with the peak-end rule in calves' memory of pain.

Conclusions:

• Calves' memory of the painful disbudding procedure does not appear to be governed by the peak-end rule.
• Pain perception and memory in calves may be influenced by factors beyond the peak and end of the experience.
• Further research is needed to fully understand memory formation and pain perception in livestock.