Nutrition at Farrowing: Making the Case for a Blended Gestation-Lactation Diet

The transition period in pigs, which includes about one week before and after farrowing, is a time of major physiological change. During this period, sows must support rapid fetal growth, mammary development, and the start of milk production. In the weeks leading up to farrowing, a sow’s energy requirements can increase by up to 8%, while amino acid (lysine) requirements increase to a greater degree, by as much as 25%.

Traditional feeding strategies often rely on a gestation diet until sows are moved into the farrowing room. However, this approach may not fully meet the increased and dynamic nutrient and amino acid demands of the transition period. When nutritional demands are not met, sows rely on body reserves, such as backfat and skeletal muscle, to meet their energy and amino acid needs. Excessive use of these reserves can negatively affect sow body condition, milk production, and ultimately piglet performance.  

To address this concern, Dr. Nicole Gregory and colleagues from the lab of Dr. Lee-Anne Huber at the University of Guelph investigated an alternative feeding strategy during the transition period. The objective of the study was to determine whether feeding a blended gestation-lactation diet during the transition period would reduce maternal tissue mobilization and improve lactation performance. The researchers hypothesized that the blended diet would help sows better meet their energy and amino acid needs, resulting in improved outcomes for both sows and piglets.  

A total of 106 primiparous and multiparous sows were enrolled in the study approximately one week prior to farrowing and remained in the trial until weaning. Sows were randomly assigned to one of two treatments groups. The Control group was fed 2 kg of a lactation diet until farrowing, while the Transition group received a blend of gestation and lactation diets during the same period. In both treatments, after farrowing feed allowance followed a step-up approach, with small daily increases of the lactation diet until four days into lactation, after which all sows were fed ad libitum.  

After farrowing, litters were standardized to 13 piglets within each treatment group. Piglets were not offered creep feed so that weight gain would reflect milk production from the sow. Piglet weights were recorded at birth, on day one of lactation, and at weaning.  

Sow body weights were recorded at 104 and 110 days of gestation, within 24 hours after farrowing, and at weaning. In addition, a subset of sows, balanced by treatment and parity, had blood samples collected after a 12-hour fast on day one of lactation and at weaning. Blood serum was analyzed for beta-hydroxybutyric acid (BHBA), non-esterified fatty acids (NEFA), glucose and urea. These measurements were used to determine whether sows were meeting their energy and amino acid requirements through feed intake or by mobilizing maternal tissues.  

Results showed no difference in sow body weight between treatments prior to farrowing or at weaning. However, immediately after farrowing, sows in the Transition group had significantly greater body weight than Control sows. Transition sows also had lower BHBA and NEFA concentrations on day one of lactation, indicating less reliance on body fat for energy and greater use of dietary energy. Blood glucose concentrations were higher in Transition sows on day one of lactation, further supporting improved energy availability. By weaning, glucose concentrations did not differ between treatments, although primiparous sows had higher glucose levels overall compared to multiparous sows. No differences in blood urea concentrations were observed between treatment groups.

Piglets born to multiparous sows in the Transition group were the heaviest at birth and during early lactation. This was followed by piglets from primiparous Transition sows, multiparous Control sows, and primiparous Control sows. Despite these early differences, piglet weights did not different between treatments at weaning.  

Overall, the findings suggest that providing a blended gestation-lactation diet during the transition period can help sows minimize energy mobilization prior to farrowing, improve energy utilization from the diet, and better support piglets during late gestation and early lactation.

 

Written by Kristen Lutz and Kaley Rodman for the Livestock Research Innovation Corporation

Acknowledgment: Special thanks to Dr. Nicole Gregory and Dr. Lee-Anne Huber for reviewing this article and providing updates to their research.