By Romy Helmons-Hendricks, Global Nutrition Specialist
Heat stress creates challenges for sows, particularly during lactation, as it can significantly reduce feed intake. This results in an undersupply of the sow’s nutrient demand, which negatively affects milk production and subsequent reproductive performance. You can overcome this challenge by implementing strategies to ensure daily nutritional requirements are met.

Romy Helmons-Hendricks has been Global Nutrition Specialist at Topigs Norsvin since 2021. She holds a master’s degree in Animal Sciences from Wageningen University and Research. In her role, she delivers technical support in nutrition to the Nordics, Baltics, UK, France, and South Africa. She also contributes to various technical materials, such as the nutrition manuals.
Nutrients and lactation
What is the effect of an undersupply of nutrients during lactation?
A sow will mobilize her body mass to compensate for her impaired milk production due to an undersupply of nutrients caused by a lower feed intake. This negatively impacts oocyte development, leading to smaller litter sizes in the subsequent cycle. I therefore advise taking two steps during lactation: 1) cover the daily nutritional requirements and 2) minimize excessive body weight loss. These measures support oocyte quality and improve litter size.
Feed strategies
Can you name some feed strategies that support feed intake?
I recommend using a transition and lactation diet to support feed intake during lactation. The transition diet bridges the gap between a gestation diet with lower energy and protein levels and a lactation diet with higher energy and protein levels that target high milk production. The higher fiber content in the transition diet also prevents constipation around farrowing. Another key aspect is anticipating the 10 to 25% drop in feed intake that can occur in summer. Do this by increasing the nutrient density of the lactation feed relative to the expected drop in feed intake. Finally, consider using feed additives, like antioxidants, enzymes, and toxin binders, to improve feed intake.
Feed management and feed hygiene
How can feed management be used to enhance feed intake?
My observations reveal that feeding at least 3 to 4 times per day in smaller portions supports daily feed intake. Avoid feeding when it is hot. Instead, shift feedings to early morning, late afternoon or during the night. Also, gradually increasing feed intake in the first 6 to 8 days of lactation supports overall feed intake throughout the lactation period. Lastly, ensure that pigs always have unlimited access to fresh, cold, and clean water.
How can proper feed hygiene contribute to supporting feed intake?
I believe that good feed hygiene is crucial for feed intake. Feed that is spoiled or has an off-taste will result in feed refusal. So make sure you regularly check the troughs for wet feed. Always start with a clean trough and remove old feed, especially in the summer. Also, remember to clean your silos at least twice a year.
Final tips
Do you have any final tips?
Yes, I do. The Global Nutrition and Female Reproduction Services team has created a leaflet called “Strategies to maximize feed intake in lactating sows under heat stress”. You can scan this QR code to access it.
