Research Results

Lactational Feed Efficiency: Why Should We Talk About it?

Presented during the 2025 GESTAL Swine Summit, Dr. Carine Vier and Dr. Hyatt Frobose focused on redefining lactation feed efficiency in modern sows.

They challenged long-held assumptions around feed intake and sow body composition changes, introducing a new way to evaluate performance that includes both production and biological costs.

Carine Vier and Hyatt Frobose on stage during the GESTAL Swine Summit

Quick Insights

  • Lactation feed efficiency is more complex than traditional metrics suggest
  • Modern sows have higher demands but limited intake, increasing reliance on body reserves
  • Traditional measures can hide inefficiencies by ignoring fat and muscle loss
  • Sows with similar litter performance can differ greatly in body condition impact
  • There is high variation between individual sows, especially in gilts
  • New categories show that high production does not mean true efficiency
  • Early lactation feed intake is critical to overall efficiency
  • Better measurement and precision feeding are key to improvement

What Is Lactation Feed Efficiency?

Lactation feed efficiency is a sow's ability to convert feed intake and body reserves into milk production and litter growth while minimizing excessive body condition loss. It depends on three components: feed intake (external energy), body reserve mobilization (internal energy), and milk production and litter growth (output).

As Dr. Carine Vier stated during the presentation: "Feed efficiency during lactation is not just a feed metric… we need to take into account what is happening to the sow."

Traditional metrics such as feed per kg of litter gain or feed per pig weaned ignore body reserve mobilization and are therefore incomplete. Consider two sows producing similar litter growth: one eats less feed and appears more efficient by traditional metrics, but achieves that performance by mobilizing significantly more body fat and muscle. The other maintains or even gains body condition. The first sow is not truly more efficient. She is relying more heavily on her own body reserves, creating a higher biological cost that will require additional recovery in the next cycle and may reduce longevity and reproductive performance.

Importance of Lactation Feed Efficiency
Modern High-producing Lactating Sow

Why Modern Sows Demand a New Approach

Modern sows wean larger, heavier litters, are leaner, and face roughly 40% higher lactation demands than in the past. Because feed intake has not increased proportionally, reliance on body reserves has grown.

Gestation condition also matters directly. As Dr. Vier explained: "When sows are not gaining body weight during gestation… they will prioritize rebuilding their own reserves in lactation, even if it means the litter will not get as much milk." This creates a fundamental biological trade-off between supporting the litter and restoring the sow, and helps explain much of the variability in efficiency seen across animals.

The Fourth Efficiency Categories: Selfish, Inefficient, Martyr &Super

Study 1 Brenneman Pork (~900 sows, Iowa)

Using GESTAL Quattro Opti precision feeders to capture individual feed intake alongside body weight, backfat, loin depth, and litter data, sows were classified into four efficiency categories:

• Selfish: low milk, low catabolism
• Inefficient: low milk, high catabolism
• Martyr: high milk, high catabolism
• Super: high milk, low catabolism

Martyr sows were the largest group (~44% of gilts, ~36% of multiparous sows), while Super sows were a minority (<20%). Roughly 80% of gilts fell into high catabolism categories, making them the most at risk population. Notably, ~30% of multiparous sows were heavier at weaning than at farrowing, challenging the assumption that all sows lose body reserves during lactation.

The Fourth Efficiency Categories

The study also found that backfat change strongly correlated with estimated lipid mobilization, while loin depth showed weak correlation with protein mobilization, suggesting current equations may not accurately reflect muscle loss in modern lean genotypes. Body weight alone was not a reliable indicator of tissue mobilization.

Feed intake patterns also mattered. Sows were classified into six patterns: Rapid, Major, Minor, Gradual, Low High High (LHH), and Low Low Low (LLL). Approximately 75% of sows followed acceptable patterns, while ~25% showed suboptimal patterns. LLL sows, with chronically low intake, faced the highest risk. LHH sows, with poor early intake, missed the critical first week of lactation. Suboptimal intake patterns correlated strongly with higher catabolism and poorer efficiency, and gilts showed a higher prevalence of these patterns than multiparous sows. Early lactation intake was identified as a critical driver of milk production, body reserve mobilization, and overall efficiency.

Despite these differences in efficiency and catabolism, no significant short term reproductive impacts were observed in wean to estrus interval, estrus expression, farrowing rate, or subsequent litter size, though long-term effects remain unknown.

Can Capping Feed Intake Improve Efficiency?

Study 2 Brenneman Pork (~315 multiparous sows)

Given that some sows were gaining body weight during lactation, the study tested whether capping feed intake after peak lactation (~day 10) could improve efficiency without harming performance. The hypothesis was that after peak lactation, some sows no longer require unlimited feed intake.

Two strategies were compared: ad libitum feeding throughout lactation versus ad libitum feeding until approximately day 10 followed by feed intake capping during mid to late lactation.

Study 2: Controlling Max Feed Intake in Late Lactation

Results: the capped group consumed approximately 700 g/day less feed with no negative impact on litter size, litter growth, or reproductive performance. This suggests that some sows are consuming more energy than required in late lactation, and that excess intake does not translate into additional milk production but may instead contribute to body weight gain and inefficient nutrient use.

Study 2: Controlling Max Feed Intake in Late Lactation

What this Means for Precision Feeding Management

Conclusion

Both studies point to the same shift: lactation feeding should not be one size fits all. True efficiency requires measuring feed intake, body reserve mobilization, and production output together. Overfeeding and underfeeding both reduce efficiency. High production does not necessarily indicate true efficiency, and body reserve mobilization is a critical but often hidden component of the equation.

Key implications for swine production include:

  • Not all sows should be fed the same way during lactation
  • Early lactation feed intake remains a critical control point
  • Gilts represent the most vulnerable population and require targeted management
  • Measuring body condition through backfat and loin depth is essential to accurately assess efficiency
  • Precision feeding technologies that capture individual sow data are key to acting on these findings
Importance of Lactation Feed Efficiency - Take home Messages

As Dr. Hyatt Frobose concluded: "If we have the data, opportunities exist to personalize feed management."

Presentation: Lactational Feed Efficiency: Why Should We Talk About it?

Read the abstract

Defining Lactation Feed Efficiency Classifications Through Milk Production and Sow Body Composition Dynamics in Modern Gilts and Sows by Dr. Carine Vier, Dr. Hyatt Fobrose, Dr. Dalton Obermier, et al.

How do I stop my sow from losing too much weight during lactation?

Maximizing feed intake in the first seven to ten days after farrowing is the most effective lever. Research conducted with GESTAL Quattro Opti precision feeders on nearly 900 sows at Brenneman Pork (Iowa) identifies early lactation intake as the single most critical driver of body reserve mobilization. Sows with chronically low intake in that first week cannot compensate later and burn significantly more body fat and muscle throughout lactation.

Gestation condition compounds the risk. Sows entering the farrowing crate under-conditioned will prioritize rebuilding their own reserves over milk production, increasing body loss regardless of lactation feeding. GESTAL Quattro Opti feeders capture individual intake curves from day one, allowing producers to identify and intervene on at-risk sows before body condition damage accumulates.

How does body condition at weaning affect next litter size?

Sows that mobilize excessive body fat and muscle during lactation carry a biological debt into the next reproductive cycle. Research enabled by GESTAL Quattro Opti precision feeders, which track individual feed intake alongside body weight, backfat, and loin depth measurements, shows that even when short-term metrics like wean-to-estrus interval appear unaffected, the recovery demand on the sow increases with every high-catabolism lactation.

The study at Brenneman Pork using GESTAL Quattro Opti found that the majority of sows, and up to 80% of gilts, fall into high-catabolism efficiency categories during lactation. Over successive parities, this pattern is directly associated with reduced sow longevity and declining reproductive performance. A sow that consistently exits lactation having burned excessive reserves is not a productive sow. She is a sow in chronic recovery.

Body condition at weaning, accurately measured through backfat and loin depth, is the most reliable indicator of whether a sow enters the next gestation with adequate reserves or begins the next cycle already in deficit. GESTAL Quattro Opti's individual sow data makes it possible to identify which animals are on this trajectory and act before it costs a parity.

How do I feed gilts vs. multiparous sows differently?

Gilts cannot be managed with the same lactation feeding program as mature sows. Research using GESTAL Quattro Opti precision feeders on nearly 900 sows found that approximately 80% of gilts fall into high-catabolism efficiency categories during lactation, compared to roughly 36% of multiparous sows. Gilts also show significantly higher rates of poor early-lactation intake, the window that most determines body reserve loss for the entire cycle.

In practice, gilts require more intensive monitoring from farrowing day one and earlier intervention when intake falls below curve. A one-size-fits-all feeding program without individual intake visibility systematically under-serves gilts every parity. GESTAL Quattro Opti precision feeders provide the per-animal data that makes parity-specific lactation management actionable at commercial scale.

References

Baker, D.H., Becker, D.E., Norton, H.W., Sasse, C.E., Jensen, A.H., & Harmon, B.G. (1969). Reproductive performance and progeny development in swine as influenced by feed intake during pregnancy. Journal of Nutrition, 97, 489–495. https://doi.org/10.1093/jn/97.4.489

Bergsma, R., Kanis, E., Verstegen, M.W.A., van der Peet-Schwering, C.M.C., & Knol, E.F. (2009). Lactation efficiency as a result of body composition dynamics and feed intake in sows. Livestock Science, 125(2–3), 208–222. https://doi.org/10.1016/j.livsci.2009.04.011

Bruun, T.S., et al. (2018). Journal of Animal Science, 96, 2320–2331. https://doi.org/10.1093/jas/sky141

Dourmad, J.Y., Guingand, N., Latimer, P., & Sève, B. (1999). Nitrogen and phosphorous consumption, utilisation and losses in pig production: France. Livestock Production Science, 58, 199–211. https://doi.org/10.1016/S0301-6226(98)00207-0

Dourmad, J.Y., Étienne, M., Valancogne, A., Dubois, S., van Milgen, J., & Noblet, J. (2008). InraPorc: A model and decision support tool for the nutrition of sows. Animal Feed Science and Technology, 143, 372–386. https://doi.org/10.1016/j.anifeedsci.2007.05.019

Everts, H., & Dekker, R.A. (1995). Effect of protein supply during pregnancy and lactation on body composition of sows during three reproductive cycles. Livestock Production Science, 43(2), 137–147. https://doi.org/10.1016/0301-6226(95)00039-I

Frobose, H. (2022). Individual sow intake in lactation: What variation exists today and how can ADFI be optimized? GESTAL Swine Summit 2022, Third Edition. Jyga Technologies. https://jygatech.com/blogs/news/videos-from-gestal-swine-summit-2022

King, R.H., & Dunkin, A.C. (1986). The effect of nutrition on the reproductive performance of first-litter sows. 3. The response to graded increases in food intake during lactation. Animal Production, 42, 119–125. https://doi.org/10.1017/S0003356100017888

King, R.H., & Dunkin, A.C. (1986). The effect of nutrition on the reproductive performance of first-litter sows. 4. The relative effects of energy and protein intakes during lactation on the performance of sows and their piglets. Animal Production, 43, 319–325. https://doi.org/10.1017/S0003356100001938

Koketsu, Y., Tani, S., & Iida, R. (2017). Factors for improving reproductive performance of sows and herd productivity in commercial breeding herds. Porcine Health Management, 3(1), 1–10. https://doi.org/10.1186/s40813-016-0049-7

Manis, C., et al. (Unpublished). Effects of feed allowance after day 15 of lactation on litter growth and reproductive performance.

Mullan, B.P., & Williams, I.H. (1989). The effect of body reserves at farrowing on the reproductive performance of first-litter sows. Animal Production, 48,
449–457. https://doi.org/10.1017/S000335610000408X

National Research Council. (2012). Nutrient requirements of swine (11th rev. ed.). National Academies Press. https://doi.org/10.17226/13298

Noblet, J., Dourmad, J.Y., & Etienne, M. (1990). Energy utilization in pregnant and lactating sows: Modeling of energy requirements. Journal of Animal Science, 68, 562–572. https://doi.org/10.2527/1990.682562x

Stender, D. Iowa State
University Extension.

Vales, R. (Unpublished). Dynamics of sow body weight changes during gestation and impacts on lactation performance. Kansas State University.

Vier, C., & Frobose, H. (2025). Lactation feed efficiency in modern sows. GESTAL Swine Summit 2025. Jyga Technologies. https://www.youtube.com/watch?v=-13QtWlnMKE

Zak, L.J., Xu, X., Hardin, R.T., & Foxcroft, G.R. (1997). Impact of different patterns of feed intake during lactation in the primiparous sow on follicular development and oocyte maturation. Journal of Reproduction and Fertility, 110, 99–106. https://doi.org/10.1530/jrf.0.1100099

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