A Gram Research analysis of a 2026 randomized controlled trial found that special pens with milk replacer feeders did not improve piglet growth in large litters and were associated with higher death rates (18.4% vs. 9.0%) between days 3-24. While the setup didn’t harm piglets during the first three days, it failed to help smaller piglets catch up to larger ones and ultimately resulted in worse outcomes overall, suggesting farms need different solutions to support very large litters.
When farm sows have too many piglets to feed at once, some babies don’t get enough milk and grow slowly. Researchers tested whether a special pen setup with milk replacer could help smaller piglets catch up. They compared two groups: one with the normal setup and one with a special enclosure where the smallest piglets got extra milk for a few hours each day. While the setup didn’t hurt the piglets, it also didn’t help them grow better overall, and surprisingly, more piglets in the treatment group died. The study suggests farms need different solutions to help all piglets thrive when litters are very large.
Key Statistics
A 2026 randomized controlled trial of 66 litters found that piglets in special pens with milk replacer gained weight more slowly than control piglets (2.034 kg/day vs. 2.529 kg/day), despite the extra nutrition intervention.
According to research reviewed by Gram, death rates in the milk replacer treatment group reached 18.4% between days 3-24, compared to only 9.0% in the control group—more than double the mortality rate.
In the special pen treatment group, the smallest piglets weighed only 4.104 kg by day 25 while the largest weighed 6.674 kg, showing that temporary milk replacer did not help smaller piglets catch up to their larger littermates.
A 2026 study of large piglet litters found no difference in death rates between treatment and control groups during the first three days (when milk replacer was provided), but significant differences emerged later in the nursing period.
The Quick Take
- What they studied: Whether a special pen with milk replacer feeders could help piglets grow better when there are too many babies for the mother pig to feed
- Who participated: 66 litters of piglets on a farm—33 in a normal setup and 33 in a special pen with extra milk feeders. Only piglets weighing more than 750 grams at birth were included
- Key finding: The special pen setup didn’t improve piglet growth compared to normal pens, and piglets in the special pen group actually had higher death rates (18.4% vs. 9.0%) between days 3-24
- What it means for you: If you work with farm animals or care about animal welfare, this research shows that simply adding milk replacers isn’t enough to solve the problem of too many piglets. Better solutions are still needed, though the special pen didn’t make things worse during the first three days
The Research Details
This was a controlled experiment where researchers randomly divided 66 litters of newborn piglets into two groups. The control group had the normal setup where 16 piglets nursed from their mother. The treatment group had 20 piglets, which is more than the mother could naturally feed. In the treatment group, the four smallest piglets got special milk replacer in an enclosed area for six hours, then the next four smallest got it for six hours, and the four largest got it overnight for 12 hours. The remaining eight piglets in the treatment group nursed normally from their mother.
Researchers weighed the piglets daily for the first three days, then again on days 11, 18, and 25 to track their growth. They also counted how many piglets died in each group during different time periods. This setup allowed them to see whether the extra milk help made a real difference in how well the piglets grew and survived.
The study was designed to follow European animal welfare guidelines that require more space for pigs. The researchers wanted to find a practical way to help farms manage very large litters while keeping the piglets healthy.
This research approach is important because it tests a real-world solution that farms could actually use. Instead of just studying what happens naturally, the researchers created a specific intervention and measured whether it worked. By randomly assigning litters to groups, they could be more confident that any differences were due to the special pen setup, not other factors. Tracking piglets from birth through weaning shows the full picture of whether the solution helps over time.
This study has good design features: it randomly assigned litters to groups, tracked piglets carefully with daily measurements, and measured both growth and survival. However, the sample size of 66 litters is relatively small, which means the results might not apply to all farms. The study was published in a peer-reviewed journal, which means other experts reviewed it before publication. One limitation is that this was done on one type of farm system, so results might differ on other farms with different conditions.
What the Results Show
The main finding was disappointing for farmers hoping this solution would work: piglets in the special pen group did not grow better than piglets in the normal group. In fact, the normal group gained weight faster overall—2.529 kg per day compared to 2.034 kg per day in the special pen group. This difference was statistically significant, meaning it wasn’t just random chance.
More concerning was the death rate. During the first three days, both groups had similar death rates, which was good news. However, from day 3 to day 24, the special pen group had significantly more deaths: 18.4% compared to only 9.0% in the normal group. This means that even though the special pen didn’t immediately harm the piglets, something about the setup led to more deaths later.
Within the special pen group, the largest piglets did much better than the smallest ones, which makes sense—they were already bigger and stronger. The smallest piglets weighed only 4.104 kg by day 25, while the largest weighed 6.674 kg. This shows that the milk replacer didn’t help the small piglets catch up to the big ones.
The study found that the smallest piglets in the special pen group benefited most from the milk replacer during those first three days—they gained weight at similar rates to other piglets during that period. However, this early benefit didn’t continue after they returned to nursing from their mother. The piglets that were reared entirely by the sow (the eight largest in the treatment group) did reasonably well, suggesting that the mother pig could handle some of the load when piglets were separated temporarily.
Previous research has shown that when piglets don’t get enough milk, they grow slowly and are more likely to die. This study confirms that problem exists but suggests that temporary milk replacer isn’t the complete answer. Other studies have found that piglet survival depends on many factors beyond just nutrition—including temperature, cleanliness, and how much space they have. This research adds to growing evidence that farms need multi-part solutions, not just one intervention.
The study only included piglets weighing more than 750 grams at birth, so results might not apply to very small or very large piglets. The research was done in one specific farm environment, so results might be different on other farms with different conditions or management practices. The sample size of 66 litters is relatively small, which means the results need to be confirmed with larger studies. The researchers didn’t measure some factors that might matter, like how stressed the mother pigs were or the exact temperature in the pens. Finally, the higher death rate in the treatment group raises questions about what went wrong, but the study doesn’t fully explain why.
The Bottom Line
Based on this research, farms should not rely on the special pen setup with temporary milk replacer as a solution for managing very large litters. The evidence shows it doesn’t improve growth and may increase death rates. Instead, farms should explore other approaches, such as using nurse sows (extra mothers to help feed), improving pen design further, or adjusting breeding practices to reduce extreme litter sizes. If farms do use milk replacer, they should monitor piglets very carefully and be ready to make changes if death rates increase.
This research matters most to pig farmers, especially those raising hyper-prolific breeds that have very large litters. It’s also relevant to animal welfare organizations, veterinarians, and farm equipment companies developing solutions for large litters. If you eat pork or care about farm animal welfare, this research shows that the industry still needs better solutions for managing piglet health on modern farms.
The effects of this intervention appeared quickly—within the first few weeks of life. Farmers would see whether the setup was working by day 25 (weaning age). However, the increased death rate between days 3-24 suggests that problems develop gradually, so farms would need to monitor piglets closely throughout the entire nursing period, not just the first few days.
Frequently Asked Questions
Does giving piglets extra milk replacer help them grow better when there are too many in a litter?
A 2026 study found that temporary milk replacer did not improve overall growth and was associated with higher death rates later. Piglets given milk replacer for a few hours daily actually gained weight more slowly than control piglets, suggesting this approach alone isn’t effective for managing large litters.
What’s the best way to help small piglets survive when the mother can’t feed them all?
This research shows that temporary milk replacer isn’t the complete answer. Farms may need multiple strategies, such as using nurse sows (extra mothers), improving pen design, adjusting temperature, or breeding for smaller litter sizes. More research is needed to find the best solution.
Why did more piglets die in the special pen group if they were getting extra milk?
The study doesn’t fully explain why death rates increased, but researchers suggest that separating piglets from their mother, even temporarily, may have caused stress or other problems. The higher death rate appeared after day 3, suggesting complications developed gradually during the nursing period.
Can farms use this special pen setup safely for large litters?
Based on this research, farms should not rely on this setup as a primary solution. While it didn’t harm piglets during the first three days, the significantly higher death rate between days 3-24 (18.4% vs. 9.0%) suggests the intervention created more problems than it solved.
How long does it take to see if this milk replacer solution is working?
Effects appeared within the first few weeks of life. However, the increased death rate didn’t show up until after day 3, meaning farms need to monitor piglets throughout the entire nursing period (until day 25) to catch problems early.
Want to Apply This Research?
- For farm managers using an app: Track daily piglet weights, death rates, and milk replacer consumption by group. Set alerts if death rates exceed 10% or if weight gain drops below 150 grams per day per piglet.
- Instead of relying on one intervention, use the app to compare multiple strategies: track outcomes when using nurse sows, when adjusting pen temperature, when increasing pen space, and when using different milk replacer formulas. Document which combinations work best for your specific farm.
- Create a long-term tracking system that monitors litter outcomes from birth through weaning and beyond. Compare results across multiple litters and seasons to identify patterns. Use the app to flag which litter sizes and piglet weight distributions lead to the best survival and growth rates on your farm.
This research describes a specific intervention tested on one farm system and should not be considered a universal recommendation for all pig farms. Results may vary based on farm conditions, piglet genetics, management practices, and other factors. Farmers considering changes to their operations should consult with veterinarians and animal welfare specialists. This article is for informational purposes and does not constitute professional agricultural or veterinary advice. Always follow local animal welfare regulations and work with qualified professionals when making changes to livestock management.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.