In the world of equine nutrition, soy has long been a popular ingredient in horse feeds and supplements due to its high protein and fat content. However, recent research suggests that soy may not be the best choice for horses, especially for mares and stallions. While soy is cheap and easy to produce, it also comes with potential risks that may outweigh its benefits.
First, what is soy?
Soybean is a byproduct of oil extraction and also the most common ingredient added to animal feeds to boost the protein content. Majority of soy around the world is genetically modified so that it can survive being exposed to glyphosate (RoundUp). Although some experts say that the glyphosate is no longer detectable at the time of harvest, it's worth noting that glyphosate’s active ingredient has been implicated in potentially damaging the microbiome and interfering with mineral absorption. With 77% of soybeans produced globally being genetically modified, the potential risks of feeding genetically modified soy to horses cannot be ignored. Many tout soy as being an excellent source of protein however, it is also a source of phytoestrogens and inflammatory omega-6’s. There have been concerns about feeding soy to horses given the results of feeding soy to other livestock animals. Results from other species have confirmed that the feeding of soy is associated with some health benefits but that the risks may outweigh them.
Omega-6’s galore!
One of the main concerns with feeding soy to horses is its undeniably high content of inflammatory omega-6 fatty acids. The ideal ratio of omega-6 to omega-3 fatty acids suggested for horses is 1:1, but soy has a ratio of 6:1, which can promote inflammation within the body. While some experts suggest adding omega-3 supplements to counteract the imbalance found when feeding a soy rich feed, the wiser choice may be to avoid soy altogether. Choosing to veto feed which contains soy prevents the potential overload of omega-6’s and the chronic low-grade inflammation which is associated with them, one would also avoid the cost of adding another product which contains highly beneficial omega-3's to compensate for the soy product. You can learn more about the benefits of omega-3’s here.
On top of being a source of inflammatory omega-6’s, soy is also a rich source of phytoestrogens. Phytoestrogens are chemically similar to the hormone estrogen. When given as a supplement, these phytoestrogens may bind with estrogen receptors within the body. While phytoestrogens may have some positive effects, they are also known to adversely affect fertility and cause hormonal imbalances as well. Soybean meal has the highest concentration (versus say, soybean hulls) of phytoestrogens and this is an incredibly common ingredient within concentrated horse feeds, which the working and/or breeding mare or stallion may be fed even more of. There are many factors that can influence the levels of phytoestrogens found within soy. Environmental conditions affecting the plant, such as temperature fluctuations, pest pressure, and the availability of water and light, can impact phytoestrogen levels within the plant. Additionally, processing, heating and fermenting soy can affect the chemical forms of isoflavones and change the overall phytoestrogen exposure and potential estrogenicity of the feed and how it may impact the animals.
Phytoestrogens and their potential impact on fertility…
Some studies have shown conflicting results regarding the effects of phytoestrogens on horse fertility specifically, but plenty of others have confirmed the implications of phytoestrogens across species. For instance, research has shown that diets with high levels of phytoestrogens can lead to reproductive disorders in sheep and cows. Cows fed diets high in phytoestrogens have shown signs of ovarian dysfunction, cystic ovaries and abnormalities within their estrous cycles. Sheep have shown some of the same results with long-term fertility issues and even permanent infertility. While the effects of phytoestrogens and how they impact horses is a subject of ongoing research, it can not be overlooked and ignored the impact that phytoestrogens have had on other species.
Research is still ongoing regarding long-term implications soy may have on breeding horses however, one study revealed that mares consuming feed with soybean meal had detectable levels of phytoestrogens, such as equol and genistein, in their blood. These phytoestrogens were also present and detectable in their suckling foals which had been transferred through the mare's milk. While these studies have taken place they are still not considered conclusive as to the long-term implications of feeding soy…but it is food for thought.
Overall, while soy may be a cheap and convenient source of protein and fat for horses, the potential risks associated with its use, such as inflammation, hormone disruption, and its effects on fertility may outweigh the benefits. When it comes to the health and well-being of your horse, it may be worth considering alternative feed options that do not pose the same potential risks. As an informed consumer, it’s essential to weigh the potential consequences of feeding soy to horses and make the best decision for your horse's health and longevity until research says, without a doubt, that soy is safe for horses... especially those that are breeding.
The good news is that there are better options.
What to choose instead!
If you are a horse owner seeking to add protein or healthy fats into your horse’s diet but not sure how to escape the world of soy, consider the Inner Glow Omega Booster by Twenty Four Carrots. This product is a revolutionary whole food horse supplement that is packed with essential nutrients to support your horse's overall health and well-being. Inner Glow Omega Booster is a highly bioavailable whole food and nutrient-dense supplement containing all essential amino acids, making it a complete and rich source of protein. Furthermore, it is loaded with anti-inflammatory omega-3 fatty acids and antioxidants resulting in numerous benefits, including improving skin and coat health, supporting a healthy immune system, enhancing joint function, promoting muscle health and improving the topline. By making a simple switch and incorporating the Inner Glow Omega Booster into your horse's diet, you can ensure they receive the necessary nutrients for optimal health and performance without any negatives that are associated with feeding soy.
Sources:
Title:Soy for Horses: Facts and Fallacies , Website title:Kentucky Equine Research
Date published:January 8, 2024, Date accessed:August 6, 2024 Author:Katie Young
Title:Is Soy Good or Bad for Horses? [Review of Soybean Meal in Feeds] Website title:Mad Barn
Date published:September 1, 2022, Date accessed:August 6, 2024 Author:Christine Latham, Ph.D.
Title:Protein Punch: Soybeans in Horse Feeds Website title:Kentucky Equine Research
Date published:January 20, 2018 Date accessed:August 6, 2024
Title:The Effect of Phytoestrogens on Mare Fertility & Reproductive Health
Website title:Mad Barn
Date published:December 5, 2023 Date accessed:August 6, 2024 Author:Ana Mesa Ph.D.
Title:Whole Food Options to Boost Protein Quality
Website title:Getty Equine Nutrition, LLC
Date accessed:August 6, 2024 Author:Juliet M Getty Ph.D.
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