Affective Implications of Human-Animal Relationship on Pig Welfare: Integrating Non-Linear Heart Rate Variability...

Area of Science:

• Animal Behavior and Welfare Science
• Veterinary Physiology
• Human-Animal Interactions

Background:

• The quality of human-animal relationships significantly impacts animal welfare, influencing behavior and physiological stress responses.
• Gentle handling is associated with positive outcomes, while rough handling can induce fear and stress in livestock.
• Heart rate variability (HRV) analysis, including linear and non-linear parameters, offers a sensitive measure of autonomic nervous system activity and stress in animals.

Purpose of the Study:

• To investigate the effects of different human-animal relationship qualities on the behavior and HRV of nursery pigs.
• To compare the behavioral and physiological responses of pigs subjected to positive, minimal, or negative human handling over a six-week period.
• To evaluate the utility of linear and non-linear HRV parameters in assessing pig welfare in response to human interactions.

Main Methods:

• Thirty-six nursery pigs were divided into three groups (n=12 each) receiving positive, minimal, or negative human handling for six weeks.
• Pigs' behavioral responses were assessed in an experimental arena involving handler exposure and forced interaction.
• Physiological stress was measured using linear (LF/HF ratio) and non-linear (Lmean, RMSSD/SDNN, SampEn) heart rate variability parameters.

Main Results:

• Pigs subjected to negative handling displayed increased fear behaviors and reduced contact with handlers, alongside elevated LF/HF and Lmean values, indicating higher stress.
• Positively handled pigs showed affiliative behaviors, accepted more physical contact, and exhibited higher parasympathetic activation (RMSSD/SDNN, SampEn), suggesting a positive affective state.
• Minimally handled pigs showed some behavioral similarities to gently handled pigs, but physiological data suggested the positive handling was more rewarding.

Conclusions:

• The quality of human-animal relationships profoundly influences pig welfare, affecting both behavior and physiological stress indicators.
• Gentle and positive human handling promotes better welfare outcomes in pigs, characterized by reduced stress and increased affiliative behaviors.
• Non-linear HRV parameters provide valuable insights into the affective state of pigs and are recommended for comprehensive welfare assessments.