Omega-3 fatty acids have many favourable health effects on horses, including joint, respiratory, and reproductive benefits. Supplementing pregnant mares with omega-3s late in gestation has advantages for their developing foals. However, not all types of omega-3 supplements fed to mares have the same effectiveness.

The two major sources of omega-3 fatty acids for horses are:

1. Plant-derived short-chain omega-3 fatty acids, primarily alpha linoleic acid (ALA). High levels of ALA are found in flaxseed, canola oil, and other feedstuffs, but ALA must be converted by the horse into long-chain omega-3 fatty acids, including DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid) for optimal use by horses.
2. Marine-derived omega-3s rich in the specific omega-3 fatty acids DHA and EPA. Provide a direct source of these omega-3 fatty acids may be preferred, as the conversion of ALA to long-chain fatty acids is limited in horses.

Researchers at Kentucky Equine Research (KER) carried out a study to measure omega-3 fatty acid levels in foals from supplemented mares. Three diets that provided a similar total amount of omega-3 fatty acids from two different sources were used. The first was a control diet, the second was the control diet plus a commercial flaxseed supplement, and the third was the control diet with a commercial marine-derived omega-3 supplement.

When mares were offered each of these diets during the last 30 days of gestation, only marine-derived supplementation resulted in a significant increase in DHA levels in foals.

No difference in foal DHA blood levels was observed between the control and flaxseed diets, which means these results support the recommendation to provide a direct source of DHA and EPA due to the low conversion rate of ALA to DHA.

It is recommended to continue supplementing mares throughout nursing until weaning as this will help maintain higher DHA levels in foals after foaling, which provides long-term advantages to growth and development.

An easy way to provide a direct source of marine-derived omega-3s within your broodmares diet is to feed Bluegrass Mare Prepare. Mare Prepare is a fully fortified Stud feed which has added marine-derived oil benefiting overall health, fertility and reproductive health for both broodmares and stallions. 

For more information or guidance on feeding pregnant mares, contact our nutritional helpline or fill out a diet request form on our website.