What Impact Do Fatty Acids Have on Reproductive Performance?

The addition of fatty acids to dairy diets has piqued the interest of dairy producers and nutritionists in recent years, Dr Ronaldo Cerri, University of British Columbia, Faculty of Land and Food Systems.
calendar icon 1 July 2014
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That's because adding supplemental fatty acids to dairy diets has shown positive effects on reproductive performance, possibly due to effects on cows' energy balance.

This fat supplementation also has an independent effect on overall production and reproductive performance. However, there's still much more to learn and understand about how fatty acids impact dairy cow performance.

Transition Cow Implications

The last weeks of gestation and first weeks of lactation pose the greatest risk for disease for dairy cows. Metabolic events that occur during this period impact early lactation performance and, at times, compromise the entire lactation. As a result, much attention has focused on possible effects of specific fatty acids, or fatty acid mixtures on metabolism, health and reproduction.

The transition period is characterized by a shift in nutrient requirements of dairy cows, leading to coordinated metabolic and endocrine adaptations in an attempt to meet the increased demand for nutrients.

Research at the University of Florida in 2010 and 2012 has shown interesting results with regards to the effect of different dietary fatty acids on feed intake, milk yield and milk components.1

Researchers tested changes in the fatty acid profile of transition dairy cows' diets. This study evaluated the impacts of supplementing diets containing small amounts of long-chain fatty acid (< 1.8 per cent ) with either mostly saturated-free fatty acids or with calcium salts enriched with polyunsaturated fatty acids containing the essential fatty acids (EFA) linoleic and alpha-linolenic during the last 50 days of gestation and first 90 days of lactation. Results showed:

  • Cows fed EFAs had improved milk yield, particularly first-lactation cows.
  • Milk protein yield was greater for first-lactation cows fed EFAs, but fat yield did not differ
  • Cows fed EFAs had greater feed efficiency.

Impact on Reproduction and Fertility

Results for feeding supplement fat also tended to be positive on pregnancy rate, particularly when strategies included differential dietary fatty acid profiles during the transition and breeding periods.

Fertility responses to fat feeding were best when moderate amounts of unsaturated essential fatty acids of the Omega-3 and Omega-6 families were fed.

For multiparous cows, feeding fat during the transition period resulted in a numerical increase in milk production, but no difference with fat source was observed in more recent studies. When Omega-3 and Omega-6 essential fatty acids were manipulated in the diet, a positive effect in lactation performance and fertility were observed.

The benefits to fertility were observed primarily because of reduced pregnancy loss in the first 60 days of gestation.


  • Sources rich in Omega-3 fatty acid seem to increase pregnancy by improving embryo survival
  • Sources rich in Omega-6 fatty acid improve pregnancy because of increased fertilization and embryo quality
  • Overall, feeding supplemental fat has beneficial effects in follicle development, as well as oocyte and early embryo development, which seems to be independent of energy status.


1 Cerri RLA, Thatcher WW, Santos JEP. Nutrition and Reproduction: Focus on Fatty Acids. In Proceedings. 2013 Dairy Cattle Reproduction Council Annual Meeting.
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