Effect of LA and LNA on reproductive performance, and proportion of female piglets

Project goal

This project set out to determine whether altering the quantity and ratio of n-3 and n-6 polyunsaturated fatty acids included in sow lactation diets during summer and winter would affect subsequent reproductive performance (weaning to oestrus interval, farrowing rate and subsequent litter size) and the proportion of female progeny produced in the subsequent litter.

Project summary

This project was designed to explore whether feeding sows with different levels of linoleic acid (LA) and α-linoleic acid (LNA) would affect reproductive performance in summer and winter and also the percentage of females born in the next litter.

Value for producers:

  • Reduction of the impact of seasonal infertility
  • Reduced boar taint due to a higher percentage of female piglets born


  • Feeding low level (0.13% LNA and 1.1-1.2% LA) diets during lactation reduced subsequent reproductive output
  • Feeding medium LA (0.27% LNA and 1.85-1.99% LA) diets during lactation reduced mummies and also the number of stillbirths in the next litter
  • Feeding high LA (0.13% LNA and 2.55-2.70% LA) diets reduced mummies, and increased the proportion of sows returning to heat within seven days of weaning in winter
  • The proportion of females born was not affected by diet in this trial, but future research is recommended
Research enquiries