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Essential fatty acids (EFAs), particularly linoleic (n-6) and α-linolenic (n-3) acids, are crucial for reproductive health, but must be obtained through the diet. Supplementing these EFAs during lactation has been shown to improve post-weaning fertility, pregnancy retention, and reduce dead or mummified piglets, especially in mature sows.
Objective: This study explored how increasing the intake of these two key essential fatty acids, linoleic and α-linolenic acid, during different stages of the reproductive cycle could influence sow fertility.
Methods: A total of 309 sows were grouped based on age (either first-to-second parity or older, more experienced sows) and fed diets either low or high in these fatty acids. The higher levels were achieved using soybean oil, while tallow was used in the lower-fat diets. Researchers tested the effects of these diets during lactation or between weaning and breeding, aiming to better understand how the timing and amount of fatty acid supplementation could affect future reproductive outcomes.
Results: Feeding sows a diet high in EFA during lactation helped improve their reproductive performance later on. While it didn’t change how much they ate or how their piglets grew at that stage, it led to more sows becoming pregnant again (82.1% vs. 70.4%) and slightly fewer being removed from the herd. Interestingly, it also increased the number of piglets born alive per 100 sows weaned, even though the total number of piglets born was slightly lower. Younger sows (those in their first or second litter) benefited from these high-EFA diets during lactation by returning to heat sooner after weaning. However, older sows (with 3 or more litters) didn’t show this effect, but they were more likely to be bred quickly after weaning and had slightly more mummified piglets. On the flip side, giving high levels of EFA after weaning (instead of during lactation) had negative effects-especially for young sows. Their farrowing rate dropped, and more of them had to be removed from the herd. They also had fewer piglets born alive.
Conclusion: In summary, adding more essential fatty acids to sow diets during lactation can support better reproductive outcomes, but giving those fats after weaning, particularly to young sows, may have detrimental effects.
Shipman GL, Rosero D, van Heugten E. Supplementation of high levels of essential fatty acids using soybean oil in lactation diets benefits the subsequent reproduction of sows but can be detrimental to the performance of young sows if provided after weaning. J Anim Sci Biotechnol. 2025; 16(1):55. doi: 10.1186/s40104-025-01192-y