Genetically Altered Feeds: Modified Munchies

It's the end of another long day. The stalls have been mucked, the horses fed, the barn swept, and the lights turned out. Now you're finally able to relax on the couch, put your feet up, and watch some TV. Flipping channels, you land on CNN, where the news anchor is describing in solemn tones an unearthly scenario: Hundreds of protesters, some dressed as life-size cobs of corn, are screaming and waving placards which say "Ban the Frankenfoods!" and "Don't Mess with Mother Nature!" The demonstration, the newscast tells you, is meant to publicize widespread concerns over genetically modified foods. And it hits you--could some of these genetically altered crops be in your horse's feed?

The simple answer is yes. Since their introduction on a commercial level in 1995, genetically modified organisms, or GMOs, have become widely incorporated in livestock feeds. It's estimated that some 80% of the genetically modified corn produced in the United States is used as animal feed, and that worldwide, approximately 70% of GMO soybeans are used for this purpose. But at the consumer level, most of us really don't know that much about GMO crops, or what their impact might be on the health of our horses. It's easy to get caught up in the alarmist hue and cry over these products, to denounce them as unnatural and insufficiently tested, to panic over the post-apocalyptic implications of altering plants at the genetic level. But is all this hysteria really warranted? Let's take a realistic look at what GMOs are (and what they're not) and see how they might affect your horse's nutrition.

Changing Nature's Design

The notion of tinkering with a plant's genetic makeup sounds like the worst kind of science fiction. Movie imagery of mutants running rampant through towns and villages aside, however, there's nothing particularly new about altering a plant's (or an animal's) genetic code or choosing one set of traits over another. We've been doing it by the process of selective breeding since the beginning of agriculture.

The ancestor of the modern corn plant was a grass with only a dozen or so kernels on its seed-head. Through a process of selecting and breeding the plants with the largest kernels and the longest seed-heads over many generations, we managed to create the robust, juicy cobs we're familiar with today. Similarly, the modern Thoroughbred horse was developed from much smaller Arabians (who lent speed and "quality") crossed with larger, coarser British mares (who provided the size). The fastest, leggiest offspring were bred back to each other to emphasize those qualities and weed out the less desirable traits.

Some sort of human manipulation of phenotype (physical traits) has had a hand in the development of nearly every modern variety of commercial crop and every breed of horse, dog, cat, or other domestic animal on the planet, not to mention the azaleas in your garden and the coffee in your cup. The difference is that since we've unraveled the mysteries of DNA, we're able to select much more accurately and specifically for the traits we want, rather than doing endless breeding by trial and error. Cracking the genetic code has allowed us to cut to the chase.

Manipulation of DNA has opened up new opportunities to transfer desirable traits from one species to another. This has also been done before--examples of successful hybrids include triticale (a nutritious crop which is a cross of wheat and rye), the "beefalo," and of course the mule. We've even combined genes from one kingdom to another. For instance, since 1982 medical science has been using modified bacteria to produce human insulin for diabetics--insulin that has fewer impurities and triggers fewer immune problems than that extracted from cattle and swine pancreas tissue. In fact, almost a third of the new drugs introduced in recent years have come from this technology.

Splicing genes from one species to another, however, is one of the factors that lead some to accuse scientists of creating "Frankenfoods"--plants incorporating genes that would ordinarily not be found in that species. But the technique can provide significant benefits. For example, one of the first and most successful genetically modified strains of corn is a variety called Bt corn. This corn incorporates a protein from a common soil bacterium called Bacillus thuringiensis, making it toxic to caterpillars. The result is that the corn is resistant to attack from the larvae of the European corn borer, a major source of crop damage and reduced yields. (More on Bt corn and its impact on the horse industry in a minute.)

Most of the GMO crops now commercially available have been tailored to make them easier for the grower to manage--they are resistant to a common pest, or tolerant of herbicides (such as RoundUp) used to kill weeds in the field. There are also crop varieties being developed that will have enhanced nutritional value or digestibility. One example is golden rice, a rice variety that has been engineered to produce extra beta-carotene (the precursor to vitamin A). The idea is to improve the nutritional profile of the rice, which is the staple diet in many Third World countries, which will help prevent blindness and infection, especially in children. (Even Greenpeace, which has taken an anti-GMO stand, acknowledges that golden rice "is a moral challenge to our position.")

Likewise, many commercial crops used for livestock feed are being tweaked to increase their nutritional content or provide higher yields on the same acreage. Improving cold-hardiness or drought resistance could also improve the odds for a good crop and consistently high nutritional value.

Finally, there's an exciting potential for GMO crops to become vaccines, lending our animals protection against disease. Gord Surgeoner, PhD, president of Ontario Agrifoods Technologies and a professor of plant agriculture at the University of Guelph, says, "This is at an experimental level right now, but it has the potential to be far less invasive and risky than injectable vaccinations. It would probably take the form of a special, one-time-only type feed."

Addressing Concerns

The big questions with GMO feeds, of course, are: Is it really safe to go messing around with DNA? Are we producing foods that might have uncalculated toxic effects? Could they trigger allergic reactions? What kind of impact will they have on the environment?

As with any new frontier, there are many unknowns, but one thing is certain. The perception that GMO foods are inadequately safety-tested is seriously undeserved. In fact, testing of these products is exhaustive and thorough, and it takes big bucks. Says Surgeoner, "Each GMO crop which is now commercially available has to have been approved by the Food and Drug Administration (FDA) in the United States or the Canadian Food Inspection Agency (CFIA) in Canada. It costs, on average, between $10 and $20 million for each variety to do that, so only the big players can really afford to do it. Companies only take that step when they feel they have a safe and beneficial product. The process takes about 10 years (from concept to commercial availability), so it's a major commitment."

When a GMO product is submitted for FDA or CFIA approval, the agencies demand a wide range of test results. "They look at the proteins created (by the genetic alteration), compare it to known allergens, do skin testing for allergic reactions, see how long the proteins last in the gut of an animal, and do nutritional studies on animals with a short reproductive turnaround, like mice or chickens," says Surgeoner. "They also examine the environmental impact of the crop--how long it takes for the proteins to break down in the soil, for example, and how it might affect beneficial insects."

Marnie Webb, Consumer Response Representative for the Food Biotechnology Communications Network in Guelph, Ontario, agrees that, "It's a common misconception that these products are not tested," and adds that testing doesn't stop when a GMO variety has gotten the thumbs-up from the FDA or CFIA. "The monitoring continues after the crop is approved," she says. More information on testing and approval procedures can be found at the Food Biotechnology Communications Network website at

There are some unanswered questions still to be addressed. Allergic responses are a real concern, and each GMO must be examined individually for its allergic potential. Another problem is that some crops that pollinate by air or by insects might distribute their genetically modified pollen to non-GMO fields--essentially letting the genie out of the bottle. Farmers of "certified organic" canola, for instance, have protested that their fields are being contaminated by pollen from nearby GMO canola. Canola pollen travels readily, Surgeoner says. There's less concern with other crops, such as soybeans and potatoes, because the pollen is less likely to drift.

Researchers are working to establish recommendations for "buffer zones" and other controls between GMO fields and unaltered varieties. "Weather is still not a controllable factor," Surgeoner admits. "A tornado could come through and spread pollen for miles. We can't completely eliminate the distribution of GMO plant material."

On the whole, though, the development and sale of GMO crops has become a tightly controlled, well-regulated industry with a high concern for safety.

Why, then, all the paranoia? Surgeoner says, "I think much of the hysteria has little to do with safety, and everything to do with anti-globalization and a backlash against large research corporations. Any time something new is introduced, there's bound to be consternation--I remember when we all got hysterical over microwave ovens."

In addition, he says, it's often hard for consumers to see the plus-side of GMO crops because the immediate beneficiary is the grower. Most of the GMOs available at the moment are tailored for herbicide tolerance and/or insect resistance, not for properties that are easily apparent to the horse owner or supermarket shopper. Consumers might not stop to consider that an insect-resistant crop variety doesn't need to be sprayed with pesticides, so it might arrive at the feed mill having been exposed to far fewer toxic chemicals.

In the case of Bt corn, insect resistance has another important benefit--corn which has been attacked by European corn borers becomes vulnerable to fungus and mold infestations, which can be fatal to horses. Because Bt corn isn't compromised by the corn borer, it has a much lower incidence of fungus and mold. That could mean fewer equine deaths due to moldy corn poisoning.

What's Out There Now, and What's on the Horizon?

According to Webb, there are several GMO varieties of corn tailored for insect resistance and/or herbicide tolerance that are now being widely grown across North America and which might very well find their way into horse feeds. Soybeans have also seen considerable attention from the biotechnology industry--generally, GMO varieties are designed to be herbicide-tolerant or provide higher digestibility of proteins. (Soybeans usually only find their way into horse feeds in small quantities as a protein supplement for broodmares and young growing stock.)

Two other crops that have GMO varieties and occasionally might be found in horse feeds are flax (a.k.a. linseed) and cotton, both of which serve as protein supplements in the form of linseed meal and cottonseed meal. Webb notes that there is a new GMO variety of sugar beets that was approved in November of 2000, but is not yet being commercially grown. It could eventually make up part of the beet pulp found in some high-fiber grain mixes.

Other grains commonly fed to horses, such as oats and barley, have not yet been the focus of much interest from the GMO industry because they're grown in such small amounts (compared to corn, soybeans, and wheat) that GMO varieties would not likely be commercially viable.

Pasture crops also could be genetically modified in the future. GMO varieties of alfalfa are currently in development, according to David Gauthier, PhD, MBA, of Foragen Technologies Management, Inc. "There's quite a bit of work being done on alfalfa right now," he says, "with respect to altering its sugar and carbohydrate levels, and making it more productive."

Surgeoner says there's considerable potential for improving cold and drought tolerance and the nutritional content of many types of forages.

The bottom line for most of us is still whether these products are truly safe for our horses. Surgeoner is confident that they are. "These products have been available for over five years now, and I have never seen or heard of a single animal or human incident that could be related to them," he said.

Jimmy Clark, PhD, a professor of ruminant nutrition at the University of Illinois, concurs. He recently did a review of literature on GMO safety in livestock species world-wide (including 23 experimental studies conducted over the past four years at universities throughout the United States, Germany, and France on livestock species including chickens, sheep, and dairy and beef cattle being fed genetically modified corn or soybeans). He found that in every case, there was no significant difference in the animals' ability to digest the GMO crops. There was also no significant difference in the weight gain, milk production, milk composition, or overall health of the animals when compared to animals fed non-GMO crops.

Clark says, "We tried to go over all the studies we could find on the nutritional impact of GMOs on livestock, and found that in terms of digestibility and nutrient content, there was no detrimental effect."

While reassuring, this data does have one snag--none of the tests were done on horses. Based on the expense involved in keeping research herds of horses, and their relatively minor economic impact in the agriculture trade (compared to cattle, pigs, or sheep), it's not likely that any tests will be done soon. But Clark feels relatively confident that we can expect similar results in equines. "I can't say that absolutely, of course, but normally you'd expect there to be no difference," he says.

In the end, you have to make up your own mind about GMOs. Unfortunately, there's no way to tell whether these crops have been incorporated into the sweet feed, pellets, or extruded feeds you buy because government regulations don't currently require them to be labeled separately. It's best to assume they're in there and that this will become more and more likely through the coming years. If you choose not to feed your horses GMO products, however, you can still do so by choosing straight oats or barley rather than a commercially mixed ration with corn and/or soy in it.

About the Author

Karen Briggs

Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.

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