Risk factors differ for viable and low viable crushed piglets in free farrowing pens

Area of Science:

• Animal Science
• Veterinary Medicine
• Agricultural Economics

Background:

• Crushing by sows poses significant welfare and economic challenges in newborn piglet survival.
• Existing studies often do not distinguish between crushing of low viable and viable piglets, potentially obscuring risk factors.

Purpose of the Study:

• To assess the importance of differentiating between low viable (secondary crushing) and viable (primary crushing) piglets in risk factor evaluation.
• To identify specific risk factors (sow, litter, environmental characteristics) associated with each category of crushing loss.

Main Methods:

• Utilized data from 740 litters (9,543 piglets) recorded by 11 Swiss farmers.
• Categorized piglet losses into not crushed, low viable crushed, and viable crushed based on farmer records, piglet weight, and signs of weakness.
• Employed a mixed-effects Cox model to analyze risk factors including parity class, gestation length, litter size, stillbirths, and high ambient temperatures (>30°C).

Main Results:

• Shorter gestation length and increased hours of temperature >30°C were identified as risk factors for viable piglet crushing.
• A higher number of live-born piglets in a litter was a risk factor for low viable piglet crushing.
• These specific risk factors differed between the two crushing categories, highlighting the importance of differentiation.

Conclusions:

• Differentiating between low viable and viable crushed piglets is essential for accurate interpretation of crushing loss risk factors.
• The findings suggest that distinct management and research strategies may be needed for each category of crushing loss.
• This differentiation should be incorporated into future breeding programs and scientific research to improve piglet welfare and farm economics.