Hay is a whole food, right? It is if naturally cured prior to baling, otherwise it contains preservatives which may have adverse effects on you and your horse’s health.

The moisture content of hay is monitored prior to baling. With too little moisture, hay becomes brittle, loses nutritional value, and can potentially become unpalatable. Too much moisture can cause hay to mold and experience thermal expansion in storage severe enough to cause combustion creating a severe fire hazard. 

Optimum moisture content prior to baling is approximately 12-18% depending on the size of the bale. Spray on hay preservatives are used to enable a farmer to begin baling sooner, at moisture levels up to 30%. Various adverse health conditions can occur after long or short term exposure including inhalation and ingestion of “safe” levels depending on the concentrations applied and sensitivity of the livestock. 

Some common ingredients used in hay preservatives are:
Ammonium propionate (buffered propionic acid) and propionic acid (more corrosive) are organic acids and the most common main ingredients in hay preservatives. Propionic acid was 1st registered as a pesticide in the early 1970’s. In a chronic feeding study using propionic acid, the high dose rats had hyperplasia, ulcers and other effects in the forestomach.  Both can cause skin irritation, serious eye irritation and respiratory irritation. Classified by the U. S. Food and Drug Administration as "generally recognized as safe" (GRAS) but is not authorized as a food additive in Europe. 

Propylene Glycol is able to lower the freezing point of water and used as aircraft de-icing fluid but is classified by the U. S. Food and Drug Administration as "generally recognized as safe" (GRAS) for use as a direct food additive. It is prohibited for use in food for cats due to links to Heinz body anemia. Possible adverse reactions are: skin Irritation, allergic reactions, potentially toxic to the kidneys and liver, neurological symptoms, cardiovascular problems, respiratory issues, potentially bio accumulative.

Ammonium Hydroxide  is a colorless liquid chemical solution. It forms when ammonia dissolves in water and is found in many industrial products and cleaners. Some of these are flooring strippers, brick cleaners, and cements. Ammonium hydroxide is poisonous. FDA regulations classify ammonium hydroxide as safe (“generally recognized as safe” or GRAS) at certain levels. Potential adverse reactions are skin irritation, serious eye irritation and respiratory irritation.

Food Dyes; green No. 3, yellow No. 5 and blue No. 1 are commonly added to hay preservatives to present a fresh green appearance and improve marketability. These are carcinogenic.
 
 
What hays are more likely to contain preservatives?

Cool season grasses such as Timothy, Orchard and Rye because of the wet, cool climates where they are grown, cut, cured and baled in and alfalfa. Larger bales require lower baling moisture percentages; the risk of preservatives present in large square and round bales increases dramatically. Grass hays grown in arid climates (mostly warm season grasses) rarely if ever are sprayed with preservatives; the expense is not necessary. Feeding a combination of warm and cool season grasses is beneficial due to the diverse amino acid profiles and reducing the risk of preservatives in 100% of the hay fed.
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Unfortunately hay preservatives are necessary for farmers otherwise too many crops would be destroyed and the price of hay could skyrocket. To be as proactive as possible, ask your grower if they use preservatives. If so, what cuttings/loads/fields received the lowest concentrations and purchase that hay. Inhalation is as much if not more of a health risk as ingestion; your horse's nose is in close proximity of their mouth. Slow feeders may minimize inhalation of acid/chemical dust considering they can't bury their nose in the hay. If you experience skin or respiratory irritation handling hay, preservatives could be the cause. Whether these additives and preservatives are safe is debatable. If given the choice, I'd rather not handle or feed hay with any additives. Being well informed about the forage you are feeding is prudent and enables you to make educated choices.

​Our Nitrates In Hay Exposed article may be of interest. ​

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References:
Propylene Glycol: The Complicated Additive with Potentially Dangerous Side Effects, retrieved from: https://draxe.com/propylene-glycol/
What’s the Right Moisture Content for Your Hay Bales? , retrieved from: http://www.delmhorst.com/blog/bid/354011/What-s-the-Right-Moisture-Content-for-Your-Hay-Bales
Food Dyes Linked to Cancer, retrieved from: https://draxe.com/food-dyes-linked-to-cancer/
Ammonium hydroxide poisoning, retrieved from: https://medlineplus.gov/ency/article/002491.htm
Scientific Opinion on the safety and efficacy of propionic acid, sodium propionate, calcium propionate and ammonium propionate for all animal species, retrieved from: https://www.efsa.europa.eu/en/efsajournal/pub/2446  
US EPA Archive Document Propionic Acid, retrieved from: https://archive.epa.gov/pesticides/reregistration/web/pdf/4078fact.pdf 

   Following are helpful tips and realistic expectations when using any brand of slow feeder or small mesh hay net. Valuable information whether you currently use slow feeders or are debating to try them!

​1) Do consider ease of loading.
    Don’t discount slow feeding entirely due to the time required to load them. 10 minutes once or twice a day is a minimal time investment for your horse to have forage available 24/7.

2) Do provide access to forage 24/7. Meal fed individuals are typically anxious at feeding time which can result in the storage of body fat from stress and be more determined to eat as fast as possible. This can result in possible damage to teeth, gums and the slow feed device. Provide appropriate slow feeders to accommodate enough hay between feedings so there is always hay left. If your horse won't be "fed" for 12 or 14 hours you may need a bale net or multiple bags/nets.​
   Don’t expect any one slow feeder to have the capacity to provide a rate of consumption slow enough to provide forage 24/7 by offering limited amounts of hay; for example feeding 1% of body weight in a 24 hour period. If appropriate forage is available at all times they can typically eat more and maintain or lose weight by eliminating the stress associated with meals. A slow metabolic rate (body survival mode) created from forage restriction may take some time to speed up; include routine exercise.​

3) Do offer multiple locations regardless of the size of the enclosure; mobility promotes gut motility, increases metabolic rate and allows them to choose where they are most mentally and/or physically comfortable. Horses enjoy foraging for food. They were not designed to be stationary for extended periods of time.
    Don’t provide one location and expect voluntary movement.

4) Do experiment with slow feeders to determine the smallest mesh size (for overweight individuals) that enables your horse to extract hay without frustration. Frustration is counterproductive.
    Don’t continue the use of any device that stresses your horse; stress/frustration elevates cortisol levels. 

5) Do feed from ground level to enable a natural grazing posture and relaxed mental state.
    Don’t mount or hang a slow feeder any higher than 4” off the ground for barefoot individuals. Hanging bags are not optimum but you can minimize adverse physical effects. If there will be a length of rope long enough for possible entanglement slide a piece of PVC pipe over the rope and attach a swivel clip at the bottom to hang the bag from. 

6) Do offer tested low NSC (10% or below) straight grass hay for overweight individuals. Consult an equine nutritionist to ensure all vitamin/mineral requirements are being met in proper ratios and unique conditions addressed.
    Don’t offer the only source of forage in a new slow feeder; feed as you normally would and offer the slow feeder in addition.
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7) Do buy multiple slow feeders if you board your horse and fill them ahead of time if they are not willing to refill them. It’s a wise investment and you won’t spend anymore; a device that is used 25% of the time will last 4 times longer!
    Don’t expect all boarding facilities to be on board with slow feeding.
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    Most slow feed manufacturers are willing to offer advice on how to maximize your slow feed investment; call them. A phone call may make or break the success of their product for your individual situation and goals. Take advantage of their knowledge and experience.

Is a horse mentally comfortable in a cozy stall with shavings or a shelter with sides? Probably not. Horses are prey animals; their main form of defense is flight which requires sight and sound to detect predators in conjunction with other herd members standing guard and alerting each other. A horse may experience psychological tension if by themselves and/or sight and sound are impaired. When eating from ground level in an unobstructed area with herd members they feel more secure and safe. Horses typically prefer to eat outside in the open if given the choice despite most weather conditions. Mother nature provides them with a very effective thermoregulation system. 

​Horses are stoic by nature and don’t always exhibit outward signs of stress because that would make them more vulnerable to prey appearing as a weak individual in the herd. Providing multiple locations to eat from encourages movement and allows them to choose where they are most mentally comfortable. An enclosed confining area (stall or shed with sides) would be most human’s choice for physical and mental comfort in the elements, we are not prey!

My very vocal mare taught me this concept and it all made sense. She had a stall that included a 2 acre turnout. When it rained I provided multiple hanging bags in her stall, no hay outside. Even though she had free choice hay she would nicker to me when I refilled the bags that were getting low. It finally occurred to me she might want to eat outside. I provided Standard Hay Pillows on the ground in the turnout and she immediately walked outside and started eating in the rain. Her mental comfort took priority over any physical comfort she experienced in the stall. She will choose the stall only if the elements are extreme. Interesting feedback from customers duplicates my experience - if they provide a Standard Hay Pillow in a stall with an adjacent turnout the horses will pick them up and carry them outside in the rain and snow!

Providing your herd with appropriate shelter from the elements with forage available in multiple locations gives them the opportunity to be as mentally comfortable as possible and encourages a more natural lifestyle.

The most likely cause is self-medication due to discomfort stemming from physical and/or mental stress from lack of forage. Chewing activates saliva production which buffers gastric acid. The stomach produces acid 24/7 to prepare for constant uptake. Approximately 75% of foodstuff passes through the stomach within 30 minutes of consumption. Once feed stuff travels to the small intestine the stomach continues to produce acid with or without food present. Chewing buffers gastric acid and can give some relief even without food.

Prior to providing my horses with free-choice forage any object within reach was subject to mastication and destruction including lead ropes, halters, fly masks etc. Post free choice forage objects remained intact!

Horses are innately oral; they are mentally and physically designed to chew 18-22 hours a day. Young horses may require a firm surface to assist in exfoliation of baby teeth such as a log. 

Common Causes of Physical and/or Mental Discomfort/Stress & Vices

• Lack of forage
• Ulcers
• Weak digestive tract due to parasite load or low gut flora population
• Boredom
• Confinement
  
• Isolation
• Mineral/Vitamin deficiencies or imbalances
• Pain

Providing free choice forage, a mentally and physically healthy environment, resolving the source of pain and a well-balanced diet should keep your herd entertained and preserve your objects for their intended purpose. 

Following are easily implemented measures to decrease the risk of colic:

1) Feed loose salt to avoid dehydration in supplements/grain to ensure consumption; 2 tablespoons minimum per day for a 1,000 pound horse, additional depending on weather and loss from sweat. In addition offer free choice loose salt. Salt blocks were designed for cattle that have a much rougher tongue; your horse may not be able to consume their minimum salt requirements. Correct sodium balance in the horse is necessary for proper thirst response and body water equilibrium (electrolytes and hydration). The vast majority of diets do not provide sufficient sodium without supplementation. This can greatly reduce the risk of impaction colic due to dehydration.

2) Parasite control; cecal impaction from tapeworms, or damage to the blood supply of the intestines from chronic infestation of parasites are causes of colic. Fecal flotation tests are not an accurate method to determine tapeworm or small encysted strongyle populations.

​3) Free choice forage; optimal digestion and fermentation requires consistent ingestion and movement (avoid confinement). Mobility stimulates gut motility. Promoting consistent fermentation and a healthy population of beneficial bacteria, effectively keeping the hindgut weighted (to discourage twisting and encourage continued travel of undigested material motile). Muscles responsible for movement of the gut are better toned when utilized and can atrophy. 

Feeding meals of hay consumed too quickly results in large amounts of dry matter lacking sufficient saliva to forage ratio combined with large particle sizes from not properly masticating indigestible fiber. Consider slow feeders to increase chew time and further reduction of particle size. Chewing activates saliva production which provides moisture and aids in digestion.
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If you are concerned about caloric intake, offer tested low sugar/starch straight grass hay (NSC 10% or less), a well-balanced diet and routine exercise. Experiment with slow feeders to determine the smallest mesh size that enables your horse to extract hay without being frustrated. Frustration is counterproductive; it causes stress!

4) Feed from ground level. A natural grazing position allows the mandible (jaw bone) to come down and forward in the atlantoaxial and temporomandibular joints. This enables the mandible to move up and down, side to side, forward and back without any restriction; facilitating natural wear of teeth along with optimum mastication and reduction of particle size.

​5) Routine dental exams including all ages for retained caps, lost and/or broken teeth, abnormal or uneven bite planes, infected teeth and/or gums, periodontal disease and hooks which are sharp protrusions of teeth that can penetrate the opposing gum. Any condition causing pain can discourage required chew time necessary for proper digestion and may induce colic and/or choke. Optimal mastication (grinding) requires significant unobstructed motion of the jaw. Miniature breeds are especially susceptible to genetic deformities; they have the same number of teeth but whether they all fit in the reduced head size and line up properly is of concern.  

6) Fresh clean water available at all times. Buckets and tubs should be cleaned and changed daily. In colder climates heat the water to at least 45 degrees Fahrenheit. The quality of your horse’s water should be equivalent to that of a human! 

7) Avoid feeding hay pellets as a primary source of forage. The already reduced particle size does not provide the volume of indigestible fiber to properly keep the gut motile and weighted. In addition, the quality of hay (including mold and noxious weeds) is not visible after the processing occurs. Of course there are exceptions for individuals not able to masticate proficiently (typically older horses) due to dental challenges.
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Being proactive to reduce or eliminate the occurrence of colic is far more productive than being reactive. Eliminating probable causes is far less mental and financial stress for you and less physical distress for your horse.
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 References:
[i]Nathaniel A. White II DVM, MS, Diplomate ACVS , Prevalence, Demographics, and Risk Factors for Colic, retrieved from: https://www.vetmed.vt.edu/emc/welcome/bios/white/epidemiology_of_colic.pdf