Feeding Strategies for the Modern Horse

In Food for Thought, I described the basic anatomy of the horse’s digestive system and the importance of grazing for digestive health. This is a bit of a longer post examining 3 different feeding scenarios and the pros and cons of each in relation to anatomical structure and function, and the evolutionary feeding strategy of the horse.

Horse management techniques vary widely depending on a number of factors, including geographical location, climate, weather patterns, discipline and age of the horse, and available space. The 3 scenarios discussed here are 1) a 12-year-old easy keeper living in the Lower Mainland of BC, 2) a senior horse from Southern Ontario, and 3) a horse from Vancouver Island, BC, whose feeding is consistent year round.

Scenario 1: Henry, 12-year-old Shire/Paint/Warmblood. Summer in Vancouver, BC

During the summer months, Henry lives in the pasture full time with two or three other horses. There are four large fields, allowing for rotation as necessary. Henry never receives grain, and hay is eliminated from his diet once he’s on pasture full time. He is fed a vitamin/mineral supplement mixed with a handful of beet pulp twice a day, at 7:30 am and 4 pm, year round. Carrots and apples are fed once or twice a day. There are automatic watering troughs attached to the fence at several points.

Scenario 2: Shannon lived to be 36, Arabian/Welsh. Winter in Southern Ontario

Shannon lived out the last 10 years of her life as a single horse with free-run of a two stall barn and 2 acres of pasture. In the winter months, she got turn-out in either a ½ acre field or a 1 ½ acre field, depending on weather and ground condition, from about 7 am until 8 or 9 pm, with access to the barn at all times. Because of her age, Shannon was fed ¾ of a cup of Trimax Senior every morning. Along with this, she was given vitamins, a carrot and two flakes of short-cut fine hay in a hay net. She received a third flake of hay around 4:30 and 1 full cup of Trimax and a fourth flake of hay in the evening, along with another carrot. Fresh water was available in both the barn and paddocks.

Scenario 3: Gilligan, Vancouver Island, BC

There is very little difference between summer and winter management practices at the boarding facility Gilligan lives at. Gilligan does not have the luxury of pasture living or turn-out due to limited space and spends most days in a 30’x50’ paddock with no access to natural forage. He receives Timothy hay four times a day (7 am, noon, 4 pm, 9 pm) and 1 cup of grain morning and night. Fresh water is provided at all times.

How do these scenarios compare and contrast with the evolutionary feeding strategy of the horse?

The horse’s digestive system has evolved over millions of years. Given the small size of the horse’s stomach, it is essential that it eat small amounts of food frequently, as it is not equipped to handle large amounts of food at once. Eating large meals can result in severe health consequences such as colic, gastric ulcers, and laminitis.

A horse would naturally graze for about 16 hours a day and can survive on grass and hay alone. However, modern management techniques largely prevent this from happening because many horses are housed in barns or paddocks with limited access to natural forage. Wide ranges of feeding strategies are used, and the guiding principles listed here should be followed.

  1. Ensure clean, fresh water is always available.
  2. Feed little amounts of food often and adjust according to the workload, temperament, and condition of the horse.
  3. Establish a routine and try to maintain the same feeding hours each day, allowing for seasonal variations to account for changes in daylight hours and time spent at pasture.
  4. Feed adequate roughage consisting of grass and good quality hay.
  5. A horse should have either grass or at least some succulent food such as carrots, turnips, beets or apples every day.

In all 3 scenarios presented, all of the horses have access to fresh, clean water and are fed little amounts of food often. Of the three, the horse in Scenario 1, Henry, has the most natural diet in the summer months, with constant access to pasture.

The other two horses, Shannon and Gilligan, receive hay at set intervals throughout the day to mimic natural grazing patterns, Shannon three times, Gilligan four. In combination with grain morning and night, both horses receive sufficient calories and nutrition through a series of frequent feedings spread throughout the day. However, Gilligan could benefit from the addition of a carrot or apple to his diet for extra nutrients and moisture.

Which is “best” from the horse’s perspective with regard to anatomical structure and function?

Of the three scenarios presented, Henry’s, Scenario 1, is the best with regard to anatomical structure and function. Being on pasture all day most closely mimics the evolutionary feeding strategy of the horse and is the best type of diet for a horse’s digestive tract. In the wild, horses will cover vast distances foraging for food, grazing for up to 16 hours throughout the day.

If the horse goes for too long without food, it is susceptible to gastric ulcers and colic. It is also thought that the natural grazing position of a horse aids in digestion. When grazing with its head lowered, the horse will take smaller mouthfuls of food and chew it more thoroughly than it would when eating grain from a feed bucket. When the food is chewed slowly and thoroughly, more saliva is produced, increasing the presence of digestive enzymes and moistening the food, thereby reducing the risk of choke or impaction colic.

Furthermore, by not having any grain in his diet, Henry has a reduced risk of colic and laminitis. Grain is not a natural part of a horse’s diet and it is hard on the digestive system. Grain that is dry or fed in large, infrequent portions can cause impaction colic, and too much starch can cause laminitis.

In an ideal situation, a horse is able to get all of the food it needs from forage. Of course, this is not always possible. There are many instances where horses require grain in their diet, as illustrated in the cases of Shannon and Gilligan. When grazing is unavailable or insufficient, hay would ideally be the staple of a horse’s diet. However, hay is sometimes too low in calories or nutrients for some horses, and grain or processed feed is necessary to ensure proper nutrition and maintain a healthy weight.

What are the advantages and disadvantages of each management strategy?

Scenario 1: Living at pasture full-time with the ability to freely graze allows Henry to satisfy his evolutionary need to have a constant stream of food in his digestive system. The addition of a vitamin/mineral supplement mixed into beet pulp ensures his nutritional requirements are met and provides an additional source of highly digestible, high energy fibre. Potential disadvantages of beet pulp in the diet include an increased risk of choke when fed dry and in large amounts; nutrient imbalances when feeding large amounts of plain beet pulp without adjusting the rest of the diet accordingly; and if it contains molasses, high levels of potassium for HYPP1 horses; and high nonstructural carbohydrate levels for horses needing a low-sugar/starch diet.

Scenario 2: Trimax is recommended for hard keepers and is formulated to maximize gut health. As she aged, Shannon had a difficult time keeping weight on and was susceptible to colic. Trimax helped maintain a healthy weight and minimized incidences of colic. The short-cut fine hay was the only hay she was able to digest in her more advanced senior years, and 4 flakes spread throughout the day enabled her to graze a healthy amount.  Apart from one or two bouts of impaction colic a year, Shannon’s management routine kept her content, healthy and quite spry until the end. Although a mid-day feeding would have been ideal, the owner’s work schedule did not permit this on most days, so the decision had been made to give two flakes of hay in the morning in place of a mid-day feeding.

Scenario 3: I fail to see any advantages in poor Gilligan’s situation of a diet based solely on hay and grain with no access to pasture. Furthermore, Gilligan is susceptible to sand colic because his hay is often eaten from the ground, which is a sandy soil.

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A common disadvantage that each of these horses experiences is a diet void of selenium2. They all live in regions of Canada where selenium is scarcely found in the soils, therefore, the hay and grain they eat is selenium deficient. Selenium must be provided in a supplemental form and ideally, the horses should be tested once a year to make sure they haven’t developed a deficiency.

Notes

1Hyperkalemic periodic paralysis (HYPP) is a muscle disease which has been reported in certain lines of registered Quarter Horses, Appaloosas and Paints. Affected horses often display sporadic attacks of muscle tremors (shaking or trembling), weakness and/or collapse. Attacks can also be accompanied by loud breathing noises resulting from paralysis of the muscles of the upper airway. Occasionally, sudden death can occur following a severe paralytic attack, presumably from heart failure or respiratory muscle paralysis.

2Selenium is an important antioxidant element in the horse’s diet and a deficiency of it has been associated with nutritional myopathy known as white muscle disease. Most common in foals, acute or subacute white muscle disease can also affect adult horses, resulting in masseter (cheek muscle) myopathy. Horses affected by this have difficulty opening their mouths and therefore, difficulty eating.

Supplementation is especially recommended for horses that are kept solely on hay and/or pasture. A complete vitamin and mineral supplement is the best approach, as it will ensure your horse is getting sufficient amounts of all 17 vitamins and minerals that are key to preventing any mild deficiencies that may affect your horse’s immune system health and stamina.

Resources

Beckstett, A. (2015). “Beet Pulp FAQs.” The Horse, Oct. 12, 2015. Retrieved from http://www.thehorse.com/articles/33471/beet-pulp-faqs

EcoEquine. (2014). “5 Things Wild Horses Can Teach Us About Horse Care.” Retrieved from https://ecoequine.wordpress.com/2014/04/18/5-things-wild-horses-can-teach-us-about-horse-care/

Georgescu, S.E. et al. (2007). “Diagnostication of Hyperkalemic Periodic Paralysis in Horses.” Lucrari Stiinifice: Zootehnie si Biotehnologii vol. 40:1 2007: 96-100

Landels, J. (2012). “What’s on the Menu?” Academie Duello Retrieved from http://www.academieduello.com/news-blog/whats-on-the-menu-2/

Landels, J. (2016). “The Grain of the Matter.” Academie Duello Accessed Retrieved from http://www.academieduello.com/news-blog/the-grain-of-the-matter/

Pard, K. (2016). “Understanding Selenium.” Horse Journals Accessed 29 Sept. 2016 https://www.horsejournals.com/horse-care/feed-nutrition/understanding-selenium

Patton, K.M. (2008). “Hiding in Plain Sight: Selenium deficiency masks itself as different diseases.” The American Quarter Horse Journal May 2008: 60-62. Retrieved from https://themustangproject.files.wordpress.com/2010/01/aqha-hiding-in-plain-sight-selenium-deficiency-masks-itself-as-different-diseases.pdf

Purina Canada. (2016). “Equilibrium Trimax.” Retrieved from http://equipurina.ca/en/products/lines/equilibrium/trimax/

Streeter, R.M. et al. (2012). “Selenium deficiency associations with gender, breed, serum vitamin E and creatine kinase, clinical signs and diagnoses in horses of different age groups: A retrospective examination 1996–2011.” Equine Veterinary Journal vol. 44, 2012: 31-35

All About Gastric Ulcers

The horse’s digestive system has evolved over thousands of years and is not well-suited to the habits of well-meaning humans. Given the small size of the horse’s stomach, it’s essential that it eat small amounts of food frequently, as it is not equipped to handle large amounts of food at once. Ideally, the horse needs to graze almost constantly and failing that, it should be fed several small meals throughout the day on a set schedule.

There are a number of factors to consider when developing management techniques for your horse. Like humans, each horse will have different metabolic requirements which will vary throughout the year. Food requirements will vary based on work, temperament, and body condition of the horse. A routine should be established and maintained to make sure the horse is eating frequently throughout the day, allowing for seasonal variations to account for changes in daylight hours and time spent at pasture.

The highly acidic stomach of the horse

The horse’s stomach is lined by a mucous membrane called the gastric mucosa. It produces a highly acidic, enzymatic secretion that initiates the digestion of protein. Muscular activity in the stomach mixes boluses of food with the digestive fluid until they are reduced to small particles and solubilized before passing into the small intestine.

However, the gastric mucosa only protects part of the horse’s stomach. The stomach of a horse is divided into two regions. At the top is the non-glandular squamous or esophageal region that is lined by the same tissue that is found in the esophagus. The bottom region of the stomach is the glandular gastric mucosa, which is similar to the human stomach. But unlike the human stomach, which only produces acid in response to food, the horse’s stomach is constantly producing acid, up to 9 gallons per day.

Manageable causes of gastric ulcers

The primary causes of gastric ulcers are a combination of infrequent feeding, type of feed, exercise and travel.

Importance of grazing: Under natural grazing conditions, where the horse has a near constant flow of food through its system, the stomach acid is neutralized by food and saliva. But under modern management practices, a horse’s eating patterns are vastly altered and the prevalence of gastric ulcers is high. The highest rates of occurrence are in performance and show horses and any other horse that is fed a restricted and/or grain-based diet. Foals are also highly susceptible. Their stomachs begin to produce gastric acid as young as 2 days of age. 

Type of feed: Roughage is the best thing a horse can eat to help mitigate ulcers. Because of the amount of chewing it requires, eating roughage stimulates more saliva production which in turn helps neutralize stomach acid. In contrast, concentrated feeds and grain increase acid production in the stomach and require less chewing, which means less saliva is produced.

Exercise & Travel: There are many disruptions to the natural grazing routine of the horse. When engaged in exercise, particularly in the case of racehorses and show horses, they are prevented from grazing and are often forced to fast for long periods of time. The potential for damage in these situations is two-fold. In addition to the normal buildup of stomach acid, various stresses (exercise, transit) can increase acid production and decrease blood flow to the stomach, making it more susceptible to injury.

Overeating: Although less frequent, ulcers can also develop if the horse’s stomach is too full, thereby displacing gastric acid and causing it to come into contact with the upper, more delicate region of the stomach.

Symptoms

Ulcers occur most frequently in the upper region of the stomach, and occasionally in the lower region and the small intestine. Signs that your horse may have an ulcer include:

  • Reduced appetite
  • Slow eating
  • Change in attitude
  • Mental dullness
  • Irritability
  • Reluctance to work
  • Poor physical condition
  • Poor hair coat
  • Excessive time spent lying die
  • Mild colic
  • Weight loss
  • Loose feces
Diagnosis and Treatment

Gastric ulcers are diagnosed with a gastric endoscopy (gastroscopy) to confirm the presence, severity, and location of the ulceration. This is a minimally invasive procedure that allows the veterinarian to view the esophagus, both regions of the stomach and a segment of the small intestine.

Treatment consists of a combination of management practices and medication. The two main types of medication used in the treatment of ulcers are H2 blockers and acid pump inhibitors. H2 blockers partially limit acid production by blocking the histamines that stimulate acid production in the stomach. Acid pump inhibitors completely stop the production of stomach acid.

In addition to medications, it is important to address the root causes of ulcers and adapt management practices by increasing the amount of roughage in the diet, allowing the horse to graze for at least part of the day, increasing the frequency of feedings, and avoiding or decreasing the amount of grain. Limiting stressful situations like intense training and transportation will also be beneficial.

References

Clyde Vet Group. Ulcers – “How Susceptible is Your Horse?” Retrieved from http://www.clydevetgroup.co.uk/equine/newsletters/apr07.htm

Foster & Smith. “Equine Gastric Ulcer Syndrome.” Retrieved from http://www.drsfostersmith.com/pic/article.cfm?aid=1587 

Livesey, M. “The Structure, Function and Dysfunction of the Equine Digestive System.” University of Guelph Equine Research Centre. Date unknown.

Nieto, J. (2012). “Diagnosing and Treating Gastric Ulcers in Horses.” Retrieved from http://www.thehorse.com/articles/30850/diagnosing-and-treating-gastric-ulcers-in-horses