Individual stability in vocalization rates of preweaning piglets

Area of Science:

• Animal Behavior
• Animal Welfare Science
• Bioacoustics

Background:

• Piglet vocalizations (grunts and screams) are key indicators of animal welfare.
• Understanding variations in vocalization rates is crucial for assessing piglet well-being.
• Different call types may convey distinct information about a piglet's internal state.

Purpose of the Study:

• To investigate the influence of individual and litter identity on piglet vocalization rates.
• To determine the stability of vocalization rates within individuals across different ages and situations.
• To examine littermate similarity in vocalization rates and its development.

Main Methods:

• Recording frequencies of grunts and screams in piglets during mild (Isolation) and moderate (Restraint) negative situations.
• Assessing vocalization rates at week 1 and week 4 of life.
• Analyzing individual repeatability and within-litter similarity of vocalization rates.

Main Results:

• Vocalization rates were stable within individuals across the suckling period (week 1 to week 4).
• Scream rates were stable across different negative situations, while grunt rates were not.
• Vocalization rates were significantly more similar among littermates than non-littermates, with no increase in similarity over time.
• Greater body weight was associated with lower screaming rates in the Restraint situation.

Conclusions:

• Both individual piglet identity and litter identity significantly impact vocalization rates in negative situations.
• Scream vocalizations exhibit higher individual repeatability across situations compared to grunts.
• Piglet vocalizations offer valuable, stable indicators of individual and group welfare.