Horse Feed Preservatives: Better Living Through Chemistry

Horse Feed Preservatives: Better Living Through Chemistry

At a recent seminar I gave in Wellington, Florida, several questions were raised in the audience about certain preservatives in horse feed and supplements. Frankly, I don’t know much about the preservatives used in equine feed formulations, so I decided to hop down into the rabbit hole and find out….

Ethoxyquin: was developed over 35 years ago as a rubber stabilizer by Monsanto. Approved as a both a fungicide and a horse feed preservative, Ethoxyquin is used in feeds to protect fats from rancidity (lipid peroxidation).

The foundation of Ethoxyquin is Quinoline, which is made from coal tar (just like the B-vitamins found in pet supplements, human supplements, and equine supplements). Quinoline is also the foundation for an herbicide called Assert (Canadian trade name Spike-Up) and as a fungicide used as a growth regulator to protect apples and pears in harvest and storage.

Propionic Acid: is formed synthetically from ethyl alcohol and carbon monoxide. It is classified by the EPA as a fungicide and bactericide. BASF is the world’s largest manufacturer of Propionic Acid, producing 149,000 metric tons in 2010. Propionic acid is a component in apple cider vinegar (along with lactic, citric, and acetic acids) and is also a chemical component of human sweat. Propionic acid, as it is used in feeds and hay, is not from apple cider vinegar; it is the synthetic form.

The New Jersey Department of Health has a Hazardous Substance Fact Sheet on Propionic Acid (the synthetic form) and the greatest dangers seem to be to the humans using it to spray crops. It is listed as a carcinogen.

However, I could find no data at all about the dangers of propionic acid to horses. As propionic acid is used in various parts of the country on hay, it appears to be relatively safe for equine ingestion.

Citric Acid: component of citrus fruits, this horse feed preservative is not extracted from lemons, oranges, and limes but is made through a fermentation process of corn-steep liquor, molasses, and hydrolyzed corn starch. At the end of the fermentation process, citric acid is isolated by precipitating it with calcium hydroxide to yield calcium citrate salt that is then regenerated with sulfuric acid. The corn by -products used (corn-steep liquor, and hydrolyzed corn starch) are from genetically modified corn.

In 2007 world- wide production of citric acid stood at 1,600,000 tons with China the largest single country producer, manufacturing over 50% of the worldwide production of citric acid. Archer Daniels Midland (ADM) is the largest producer in the US.

Further Down the Rabbit Hole: people who are sensitive to MSG (monosodium glutamate) may not be aware that during citric acid processing not all the corn protein is removed, resulting in hydrolyzed protein which then yields free glutamic acid (MSG). Individuals with MSG sensitivities need to be aware that textured protein, soy protein, soy protein concentrate, soy protein isolate, whey protein, whey protein concentrate, whey protein isolate, and citric acid always contain processed free glutamic acid.

Natural Vitamin E: known as semi-synthetic vitamin E (d-alpha tocopherol). The oil form is sourced from soy, palm or vegetable oils, and then esterified using acetate. Acetate is made from acetic acid that can be produced by bacterial fermentation (for use in apple cider vinegar and called virgin acetic acid) but is predominately made by methanol carbonylation. This method, developed by Monsanto, uses methanol and carbon monoxide to produce acetic acid. Methanol is derived mostly from natural gas, although it used to be commonly produced from coal. The basic esterification process is a chemical reaction in which two reactants (commonly an alcohol and an acid) form an ester.

Though generally not used as a preservative, synthetic vitamin E (dl-alpha tocopherol or dl-alpha tocopheryl) is used by some companies in the feed and supplement industry for vitamin E supplementation.

Horse Feed Preservatives: Better Living Through Chemistry

Palm Oil

Oils sourced for Natural Vitamin E: keep in mind that the principle oils extracted for vitamin E (corn, soy, palm) are extracted using hexane; corn and soy oils are from genetically modified seeds unless stated organic. Palm oil which is becoming a world wide source of edible oil and biofuel has recently come under severe criticism as the deforestation of Indonesia (largest producer of palm oil) goes unchecked including rainforests (Borneo, Sumatra) as well as habitats for several endangered species including orangutans, Sumatran tigers, Clouded Leopards, and Sumatran Elephants. It is estimated that 1.87 million hectares are cleared each year in Indonesia for palm plantations.

Remember: natural Vitamin E is not the same as food sourced vitamin E. Food sourced vitamin E is the whole food itself: wheat germ, wheat germ oil, sunflower seeds, almonds, hemp seed oil, avocados, etc all of whom provide the family of tocopherols including alpha, beta, delta and gamma tocopherols.

Another Tunnel in the Rabbit Hole: As I was investigating Propionic Acid, I came upon a document from the Scottish Agricultural College, Edinburgh that focused on the microbiology of animal feeds. The document disclosed an unsettling fact about ruminant feed (not equine):

In many parts of the world poultry manure is used as a feed for ruminants. For example in the USA two poultry waste products are available for such use: dried poultry waste, and dried poultry litter. Dried poultry waste represents undiluted excreta generally derived from caged layer flocks, whereas dried poultry litter is a mixture of excreta and litter. ( Assesing Quality and Safety of Animal Feeds, J.P.F D’Mello, 2004)

So beef cattle and dairy cows in the US can be fed these poultry by-products. These poultry waste products are illegal to feed in Great Britain due to the outbreak of Mad Cow Disease in the 1990’s.

The circle widens…


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