Every minute counts in the farrowing barn. A slow start can signal serious trouble ahead. Prolonged labor increases the risk of fetal hypoxia, reduced piglet vitality and stillbirths, yet producers often lack clear, early indicators to intervene. New research led by Dr. Diego Leal and professor Tami Brown-Brandl, both from the University of Nebraska-Lincoln, shows that the timing of the very first piglets and specific sow behaviors can alert producers to high-risk, prolonged farrowings while there is still time to act.
“Although farrowing duration and inter-piglet intervals have been linked to piglet outcomes, less is known about whether early birth-timing measures and sow behavioral phenotypes are associated with indicators of compromised farrowing, such as prolonged farrowing and stillbirth,” Leal says. That’s why they set out to identify sow behavioral phenotypes and early farrowing kinetic measures associated with prolonged farrowing and stillbirth risk.
Labor Under the Lens
In a study examining 697 birth intervals at the USDA-ARS Meat Animal Research Center, farrowings from 52 crossbred sows were monitored using surveillance cameras. Piglet birth events, birth status (liveborn or stillborn) and sow postures, including standing, sitting, ventral lying and lateral lying, were time-stamped and manually annotated using custom Python-based video-annotation software. Prolonged inter-piglet intervals were defined as intervals greater than or equal to 60 minutes, and prolonged farrowing was defined as total farrowing duration over 300 minutes.
Generalized estimating equation logistic regression was used for interval- and piglet-level analyses, with sow as the clustering unit. Sow-level log-linear and logistic regression models were used to evaluate total farrowing duration and prolonged farrowing. Models were adjusted for parity, total born and crate layout where appropriate.
Postural Clues and the Cost of Delay
The team identified that early birth timing, and sow postures offer valuable real-time indicators of compromised farrowing progression. Most critically, when birth intervals stretched beyond 60 to 90 minutes, the odds of piglet stillbirth surged dramatically. However, that risk also depends on how long the sow has already been farrowing. For example, if the sow had only been farrowing for one hour, the predicted stillbirth probability was around 11%. But if she had already been farrowing for five hours, the predicted stillbirth probability was around 32%.
“Each 10-minute increase in the interval between piglet 1 and 2 increased total farrowing time by 5.6% and raised the odds of a prolonged labor (>300 min) by 34%,” Leal says.
Researchers found that a 10 percentage-point increase in ventral-lying (lying on belly) was associated with an 11.5x increase in the odds of prolonged parturition. Posture-changing activity was associated with prolonged inter-piglet intervals greater than or equal to 60 minutes, while each additional posture change increased the odds of a prolonged interval by 45%. Later interval order was also associated with greater odds of prolonged intervals.
The odds for stillbirth increased with longer previous inter-piglet intervals. Compared with piglets born after intervals less than 15 minutes, piglets born after intervals of 60 to 90 minutes and greater than or equal to 90 minutes had greater odds of stillbirth (60– 90 min: OR = 5.52, 95% CI: 2.34-13.01, P < 0.001; ≥90 min: OR = 14.61, 95% CI: 3.92-54.49, P < 0.001).
“Posture-changing activity, previous inter-piglet interval length and ventral lying may serve as candidate indicators of high-risk farrowings and warrant further evaluation for use in behavior- and birth-timing-based decision-support tools,” Leal says.
