Presented at the GESTAL Swine Summit 2025, Thomas Sønderby Bruun explored one of the biggest challenges in modern sow production: how to feed hyperprolific sows efficiently without sacrificing longevity, piglet survival, or reproductive performance. His work at SEGES Innovation has helped shape much of the current understanding of sow nutrition and management in hyperprolific systems.
As litter sizes continue to increase, producers face a new reality: more piglets per litter does not automatically translate into more pigs weaned. In many cases, it increases pre-weaning mortality, raises metabolic stress on the sow, and makes feeding management far more complex. The question is no longer simply how to maximize litter size, but how to support the sow behind the litter.
What Is a Hyperprolific Sow?
A hyperprolific sow can be defined as a sow that gives birth to more piglets than she has functional teats, meaning she cannot fully nurse every piglet without intervention. This definition aligns with broader research on large litter management, including work by Thomas Sønderby Bruun on nurse sow strategies and piglet survival systems.
This shift toward larger litters has happened quickly. Danish production data shows total piglets born per litter increased from fewer than 12 per sows in 1992 to more than 20 today, while the number of piglets weaned grew more slowly pointing to rising pre-weaning mortality.
As litter sizes have expanded, the biological demands on the sow have changed drastically. Larger litters bring a cascade of downstream challenges:
- Higher overall nutrient requirements
- Lower colostrum availability per piglet
- Greater body reserve mobilization
- Increased reliance on nurse sows
- Greater risk of sow breakdown over multiple parities
As larger litters place increasing pressure on both sow physiology and piglet viability, these challenges make feeding strategy more critical than ever.
Does More Feed During Gestation Improve Piglet Outcomes?
One of the key findings from Bruun’s work is that increasing gestation feed or lysine levels does not consistently improve piglet birth weight. His published research on fetal and placental development in early gestation helps explain why nutrient partitioning during this stage is more complex than simply increasing feed.
Across multiple Danish studies, researchers found:
- Heavier sows produced larger litters, but not more weaned pigs
- Higher lysine during gestation showed no improvement in total born or piglet birth weight
- Late-gestation “bump feeding” increased maternal body weight, but not piglet birth weight
These findings challenge a common assumption in sow nutrition. More feed often improves maternal gain rather than fetal growth. That distinction matters because heavier sows cost more to maintain without necessarily improving piglet outcomes.
Why Flat Feeding Curves May Be More Efficient
Traditional gestation programs often focus on restoring body condition early, then restricting feed later. Bruun questioned this strategy, presenting research suggesting flatter feeding curves may perform just as well, or even better, than aggressive feeding peaks.
In one trial:
- A flat 2.8 kg/day curve produced slightly heavier piglets
- A bumped curve rising to 3.4 kg/day added 6 kg of sow body weight
- Piglet birth weight did not improve
This suggests that the sow naturally prioritizes fetal growth, even under flatter intake patterns. As Bruun’s gestation research has shown, overfeeding during gestation may increase sow maintenance costs without increasing production output.
Why the Transition Period Matters More Than Most Producers Think
The days immediately before farrowing may be one of the most overlooked feeding windows in sow management. Bruun highlighted research showing that sows farrowing within three hours of their last meal had shorter farrowing durations, reinforcing the importance of feed timing as well as feed quantity.
This builds on published transition-feeding research from Aarhus University and SEGES Innovation, where Bruun and colleagues examined how feeding strategies in the last week of gestation influence farrowing performance and early lactation outcomes.
Additional findings showed that feeding 3.7–4.0 kg/day from day 108 to farrowing:
- ✓ Shortened farrowing duration
- ✓ Reduced the need for manual farrowing assistance
- ✓ Was associated with lower stillbirth rates
This is where precision feeding becomes especially valuable. Rather than treating the transition period as a simple extension of the gestation diet, producers may need a distinct strategy to support farrowing performance and early lactation.
Lactation: Push vs Pull
One of the most practical concepts in the presentation was the “push and pull” model developed by Dr. Peter Theil, which helps explain how lactation performance responds to feed.
The model works in two ways:
Push: In underfed sows, increasing feed improves milk production
Pull: In well-fed sows, piglet demand drives intake and milk production
Bruun’s data strongly supported the “pull” model in well-managed herds. This aligns with earlier lactation studies co-authored by Bruun showing that high-producing sows often combine both higher feed intake and greater body reserve mobilization.
His findings showed:
- Larger litters increased sow weight loss by 5–6 kg
- Additional feed helped offset body loss
- Extra feed did not significantly improve litter gain
This means feeding more does not always produce more. In many cases, the extra feed provided is used to preserve the sow’s body condition, which becomes critical for longevity and future reproductive performance.
The Real Risk: Sow Mortality and Longevity
Bruun identified sow mortality as his biggest concern, with Denmark reporting a sow mortality rate of 16.4% in the most recent year.
At the same time, several trends continue to intensify the pressure on modern sows:
- Hyperprolific genetics continue to push litter sizes upward
- Pre-weaning mortality remains persistently high
- Feed efficiency selection can undermine sow robustness
Together, these trends create a dangerous imbalance. If genetic progress focuses only on litter size, the sow may become biologically unsustainable. This concern is echoed in Bruun’s broader body of work, which consistently points to the need for balancing production efficiency with sow resilience.
The future of hyperprolific systems depends on finding the right balance between:
- Production
- Body condition
- Recovery capacity
- Longevity
- Piglet survival
What This Means for Precision Feeding
The biggest takeaway from this session is simple: hyperprolific sow management cannot rely on one feeding curve for every sow.
Different animals have different needs depending on:
- Parity
- Body condition
- Recovery history
- Litter size
- Stage of gestation
Bruun’s conclusion points toward more individualized nutrition strategies, including:
- Separate early-gestation diets
- Dedicated transition diets
- Flatter feeding curves during gestation
- Targeted recovery diets after heavy lactation losses
Precision feeding systems make this practical by allowing producers to adjust intake based on each sow's actual condition, not the average sow in the barn. As hyperprolific genetics continue pushing litter sizes upward, the future of sow feeding will depend less on standardized curves and more on adaptive, data-driven management.
Read the abstract
Bruun, T. S. (2024). Management and future of hyperprolific sows. In Proceedings of the 27th International Pig Veterinary Society Congress (IPVS) and 15th European Symposium of Porcine Health Management (ESPHM). Leipzig, Germany, 4–7 June 2024. Proceedings_IPVS&ESPHM2024.pdf
