A simple question came to me recently that needs to be discussed. A horse owner asked, “The above link is an article circulating on FB; I was curious if you’ve read this? Thoughts? Thank you so much!” Here is the link for those interested: https://blog.biostarus.com/on-the-subject-of-soy/
This was a well-written article. Many of the author’s points seem valid but her conclusion of using soybeans in horse feed avoids the differences between soybeans and soybean meal.
Whole soybeans, ground soybeans, soybean hulls and soybean oil are all inflammatory in humans and I would assume also inflammatory in horses. Green soybeans are toxic in all monogastric animals including horses and humans. Most if not all legumes are not well tolerated by humans (including miso and soy sauce) while legumes are well tolerated by equids (alfalfa, birdsfoot trefoil, etc). However, I know of no horses turned out on fields of soybeans or fed soybean hay. The peanut plant, another legume, is fed as hay to horses and the peanut (not a “nut”) is often fed as a treat to laminitis and insulin-resistant horses.
This article discusses soybeans and soybean oil but not soybean meal (SBM). Soybeans are first de-hulled when making SBM and then the oil is extracted. What remains is “toasted” using moist steam heat and then hammered into a coarse meal. The result is a highly digestible source of all essential amino acids for all animals.
The Objections According To The Article
There are two major objections to the feeding of soybeans to horses that I hear from everyone. These are their genetic modification to resist the use of glyphosate and the use of glyphosate on the crop.
In modifying the plant’s genes, the leaf no longer is affected by the broad leaf weed and plant killer glyphosate. The gene splicing is done at a specific location but I have not seen how any modification in one part of the genetic code affects any other part of the code. There are thousands of individual genes in plants and animals and each is influenced by the foods eaten, the environmental stresses, and the seasons in all animals and plants. I believe this lack of knowledge is what causes fear in people worried about how any genetic modification will affect any system or organism. Currently, there are no reports of illnesses or diseases caused by consuming genetically modified food in any animal including humans. But before you jump on me for saying this, consider that there are so many variables that it is impossible to isolate just 1 variant such as feeding a GM food versus feeding a non-GM food with all else being equal. Intellectually, there is obviously a difference. But there is no proof, and in fact, there is a lack of proof in this divisive subject where a specifically modified gene has caused a plant to be inedible or disease-producing.
It is evident that by genetically modifying soybeans there has been an increased yield of a less cost-to-produce product. This has increased the consumption of land and for this reason, genetically modified foods may be adversely affecting our planet. There is also a suspicion that GM foods may also be affecting the gut microbes so necessary for survival but we are waiting for substantial proof of this. There are so many other things affecting gut microbes that this possibility can only be added to a long list.
Glyphosate (made by about 8 different manufacturers and called different names, one of which is Round-Up) is an herbicide that kills broad leaf plants such as weeds as well as the leaf of the genetically unmodified soybean plant. It has a half-life of between 120 and 180 days. It is sprayed onto the genetically modified soybean crop to kill the competing weeds without killing the soybean plant. It is applied early in the growth cycle before the bean is evident. Therefore the soybean has no glyphosate on it or if it does, it has already diminished in strength by harvest time. In addition, any remaining glyphosate is removed when the hard shell of the soybean is removed in the de-hulling process when making soybean meal (SBM).
The Omega 3 and 6 oils she discusses in soybean oil are not a factor in discussing SBM as there is no oil. All fats including the Omegas come from the microbial digestion of cellulose in the hindgut of the horse.
Trypsin inhibitor protein (TIP) is found in soybeans. Some people believe that this is another reason not to feed SBM to horses but it is not mentioned in her article. This protein blocks the naturally occurring enzyme trypsin found in the small intestine (horses and humans) whose job is to break apart proteins into smaller peptides and amino acids. Thus theoretically the TIP in soybeans would prevent the proteins in SBM from being utilized. However, from what I can find out, the TIP may or may not be in SBM. Further, almost everyone agrees that SBM protein is absorbed well with a biological availability of between 74 and 80 percent. To date, there is no measurement available to accurately determine the precise movement of the amino acids from any food into the body of an animal including humans. However, it has been determined that SBM provides all the essential amino acids for humans and thus for horses. It is one of the few foods available to horses that do this. For this reason, I do not believe that TIP is a reason not to feed SBM.
The article suggests that mares being fed soybeans have an altered reproductive cycle affecting fertility and behavior. The article does not distinguish between horses being fed only soybeans, what form they are in (whole, ground or meal) or if they were also being fed other ingredients such as corn, wheat, oats or any grain byproducts or supplements. Many people trying the no grain diet see major behavioral changes such as focused attention, willing partnership and an improved work ethic. Maybe grain, grain byproducts, and supplements IN ADDITION TO soybeans in any form is why these mares and stallions have poor behavior as the season puts them through stressful reproductive cycles. The theory that these horses could also be chronically protein deficient is also not addressed. Hormones are proteins or protein-fat combinations that may struggle to be manufactured if there are not enough amino acids to make them.
The article mentions bloating caused by the large sugar molecules (oligosaccharides) found in soybeans. This is a common problem found in all animals consuming whole soybeans. However, these oligosaccharides are effectively removed or broken down in the making of SBM. In my experience, SBM has not caused bloat in horses or the dogs who beg for it at feeding time in the barn.
The Making Of Soy Bean Meal
The first step in the making of SBM is to remove the hard outer shell called the hull. The process is called de-hulling and the shell is either thrown out or put back into animal feed (Soybean hulls) as a source of fiber. A horse gets all the fiber it needs from the cellulose of grass and hay. This is a waste product and should not be fed to horses. In fact, the target of the whole soybean process is the creation of soybean oil used in the human food industry as inexpensive vegetable oil. To get this oil, the soybean must be de-hulled and is therefore a waste product.
The article describes the solvent extraction process where the oil is removed from the soybean. The oil and the solvent used called hexane are heated to remove the solvent from the oil. This heating denatures the oil making it even more inflammatory than if eaten raw. Hexane is also a pollutant though I am sure that it is well controlled in reputable manufacturing plants (even reused). But there is no mention in the article of the remaining meal. In reality, the meal is now devoid of oil and outer hull. There is no glyphosate, hull, oil or possibly any genetically modified material in the meal.
The final step in making SBM is toasting it which the de-hulled and de-oiled bean actually is gently heated with moist steam.
Conclusions From This Article
The article never addresses soybean meal specifically as a feed for horses. Rather it just says soybeans should not be fed to horses while never looking at SBM as an exclusive ingredient in horse feed. I agree with the article that any horse feed that has inflammatory ingredients such as soybean hulls, soybean oil or whole soybeans is not beneficial to horses. As a side note, soybean oil is added to lubricate the machines making the feed. Remember they must use food-grade lubricants to do this. SBM has no added oils because it is not made into a pellet. The dried flake is hammered into particles the size of coffee grounds. Most manufacturers add an anti-caking ingredient that apparently has no ill effects on horses. Some add molasses which is ridiculous and unnecessary.
Some people consider the effects of a genetically modified plant, the use of glyphosate and the destruction of forests for planting soybeans as reasons to not feed SBM to horses. The concern for horse owners, however, is the chronic protein deficiency seen when horses are dependent on carbohydrates (fed grain and “good” hay all year long). The most efficient solution is to stop the feeding of inflammatory ingredients and to supplement with an efficient source of protein which is SBM.
It is better to look at SBM as a treatment for an illness. The goal of feeding SBM is to replace lost amino acids. This will restore the proteins used in all of the body systems (connective, integument, immune, neurological, hormonal, vitamin, enzymes and more). Once restored, SBM can be removed. Like any other manufactured or holistic medicine, there is always a treatment protocol and there are always side effects. It is up to the user to weigh every side effect to the benefits of using a medicine. To date, both in my experience and in research, I have not found any adverse effects to the use of adding soybean meal to the diet of a horse for 1 to 2 years or until the amino acid reserves have been restored. The benefits of feeding SBM to horses in every health system of the horse far outweigh the objections, perceived or real.
If you disagree with this then at least stop feeding all the other things that are causing gut inflammation. Stop losing protein.