And what is natural, anyway?

By Shelagh Niblock, PAS

The terms “natural” and “organic” are widely used in today’s horse world. The use of the term “organic” in the manufacturing and marketing of products aimed at horse owners is regulated by government agencies. The use of the term “natural” is not, and so a great deal more caution must be exercised by horse owners when sourcing these kinds of products for their horses. 

What about the care and husbandry of our horses? What is “natural” behaviour for horses, and are we doing them a favour when choosing to keep their lifestyles as “natural” as possible?

Evolution of the Horse

The horse evolved from the dog-sized, forest-dwelling Eohippus into the modern horse. But what does “natural” mean for our beloved equines after 50 million years of evolution? When we take on responsibility for a horse today, are we prepared to provide the care and management they need to live and thrive in our modern world? Illustration: Shutterstock/Aldona Griskeviciene

When we discuss what constitutes “natural” behaviour for our horses, we need to talk about equine evolution. Researchers agree that one of the reasons horses have competed so successfully against other species is because they possess the ability to habituate themselves to their surroundings. They can learn from previous experiences. Their survival instincts are excellent, and their trainability is what has made the horse/human interaction so successful.

In some respects, the deck is stacked against horses evolutionally because of their larger size. Large animals need more food. On a large animal the effect of gravity is greater, so the risk of wear and tear on joints is greater over time, as is the risk of an injury. Larger animals give birth to larger offspring, which means a longer pregnancy and the birth of single, not multiple, young. Longer pregnancies mean fewer offspring produced in the life of the animal, which can be a distinct negative in the survival of a prey animal species. Also, the maximal running speed of a larger animal is slower, making them more likely to be prey to the smaller predators. So why did horses get bigger as they evolved from the dog-sized Eohippus, the first known horse to have walked the earth?

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Predators are always looking for their next meal. Despite the evolutionary deck being stacked against larger animals, the horse endured thanks to its excellent survival instincts, and the ability to habituate to its surroundings and learn from previous experiences. Survival of the healthiest and fittest means the successful evolution of the species. Photo: iStock/Hkuchera

The Perfect Digestive Tract for Survival

The horse’s digestive tract evolved to adapt to any forage quality, allowing the feeding behaviour of wild horses to change as the quality and quantity of available forage fluctuated. With plentiful, nutritious forage in the spring, feed intake drops and the rate-of-passage through the digestive tract slows. When forage is poor in fall and winter, both intake and rate-of-passage increase. Pictured are wild horses in Utah in winter. Photo: Shutterstock/Tom Tietz

The bodies of horses have completely evolved around their digestive tract. The horse’s digestive tract is comprised of two parts: the foregut and the hindgut. Their foregut is very much like the digestive tract of any monogastric or single-stomached species, and functions on the action of an acidic environment and mammalian enzymes. The hindgut is very large and allows the horse to utilize fibrous forages with great efficiency. Because horses have such a complex and evolved digestive tract, they have an evolutionary advantage over other animal species. The ability to adapt to any forage or browse regardless of forage quality has given horses a unique ability to survive in a harsh world. A large and complex digestive tract needs a large body to house it, and so their bodies have evolved to be larger in size to accommodate this adaptation over time. 

When forage alone cannot fulfill the energy requirements of today’s working horses, concentrates, as well as vitamin and mineral supplements, may be required. Photo: Shutterstock/Panupong Prommongkol

For any species of animal, the ability to secure sufficient nutrients is of paramount importance. As an animal with hindgut fermenting capability, the horse has great flexibility evolutionally in terms of food sources. When horses are faced with abundant nutritious feed choices, the parasympathetic and sympathetic nervous systems associated with the digestive tract of the horse down-regulate intake, and as a result, feed passage rate through the tract slows down. When horses are faced with poor forage options, their feed intake naturally increases, and the rate-of-passage or the speed at which the feed moves through the digestive tract also increases. Horses gain weight and body condition in the spring when forage is plentiful, and lose it again in the late summer and in winter when feed options are limited. 

What is “Natural” Feeding Behaviour for a Horse?

Natural feeding behaviour for horses means consistent periods of grazing and/or browsing with periods of rest or flight in between. Research has shown that horses have eating periods of two to four hours in length, interspersed with rest periods of about the same length. In the wild, the forage they eat could range from abundant and nutritious in the spring, to sparse and of low quality during periods of drought or in winter. Feeding behaviour changes according to quality and quantity of forage. Poor quality feed dictates increased intake, as well as a higher rate-of-passage. The horse’s large, fermentative hindgut accommodates the adaption to forage conditions well. Better quality forage results in lower intake and a slower rate-of-passage. Feeding periods are controlled by hormones released by the sympathetic and parasympathetic nervous system.

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Comparing Wild and Stabled Horses

Horses in the wild gained weight during periods of abundant feed, and this helped them to survive the periods of poor forage. The high energy intake of spring forage allowed lactating mares both to support their foals at foot, and to readily become pregnant again for next year. The feed intake of horses dropped during periods of abundant feed. That was “natural.” Unfortunately, if we try to mimic “natural” feed behaviour now in our stabled domesticated horses by allowing free choice feeding, assuming they will self-regulate, there are several reasons why we could actually be putting their health at risk.

My Horse is an Eating Machine!

Too often our stabled horses are victims of boredom and will eat as a pastime rather than as a need for nutrients. The natural regulation of feed intake is not always well expressed in domesticated horses, and we see them get fat despite our best efforts to prevent it. When our horses eat to relieve boredom, it isn’t “natural” anymore, and they must be managed to help them adapt to their domesticated circumstances. Management practices such as this are not “unnatural” - they are good husbandry. 

Forages are Not the Same “Natural” as Before

Helping your horse adapt to modern forages means managing his feed intake, and keeping boredom at bay with slow feeding devices, grazing muzzles, pastures with limited grazing, and treat toys. Photo: Shutterstock/Groomee

Native forage species did not adapt well to the rigours of grazing, and thus, humans introduced forage species that would. Over the years, modern forage species have been selected by forage specialists to be tolerant to stresses such as intensive management, grazing, and disease conditions. The key to their greater survival under intensive management is their ability to store nutrients. The result of this is that they can provide energy in excess of what many horses need. Allowing horses to follow their natural tendency to eat these forages free choice can result in a higher calorie intake than that required for survival and health. Is grass forage a “natural” feed for horses? Absolutely. But nowadays, the nutrient content of the forages we commonly offer our horses is far from that of the forages they ate while evolving.

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Is it “unnatural” to adapt, along with your horse, to the feed sources available and to manage your horse’s feed intake? Determining a safe feed intake for your horses and following a plan to provide it falls once again under the heading of Good Husbandry. Yes, we know that horses do better when they can forage according to their own schedules and desires, but we also know that consumption of too much readily digestible, high nutrient hay can cause health problems for them. To help them adapt to a more controlled forage intake, we can offer them alternatives, such as timed feedings as often as our schedules can accommodate, as well as slow feeding devices, sacrificial pastures where grazing is limited, and the use of grazing muzzles. We can also provide devices and toys to keep them occupied if feed intake cannot be spread out enough to keep them content. This may not be the same “natural” feeding behaviour our horses’ ancestors evolved with, but it is common sense, and frankly, it is good husbandry.

Are Grain and Supplements Natural for Horses? 

Natural selection in the wild determined which horses survived and which did not. The ones who survived lived on to reproduce, and passed on their superior genetics to their offspring. In our modern world, the horses that reproduce are the ones possessing the characteristics we prefer to see in them. Many of the horses we revere as performance horses might never have survived in the wild. The natural ability of our domestic horses is to adapt, and our job is to assist them in doing that so they can be healthy, successful horses in today’s world. Sometimes that means supplements. Energy requirements for working horses can exceed what they can readily consume in forage, and we therefore complement their forage intake with concentrates when needed. We give them electrolytes, and vitamin and mineral supplements, to ensure they are getting what research has shown they need in order to do the jobs they were bred for. 

Is this “natural” for the horse? For the domesticated stabled horse in your barn, it is essential for health and success, not to mention an important part of good husbandry.

Housing, Husbandry, and Health

Horses in the wild did not have anyone providing housing, husbandry, or veterinarian care for them. No one decided if they needed shoes, or not. They were never vaccinated, nor were they on a regular parasite control program. As a matter of fact, in the world of our horse’s ancestors, the health issues caused by a body overrun with parasites may well be what determined which horse got selected by the lion as its next meal.

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The selection pressure applied to the horse population of the time was good for the survival and the successful evolution of the species. The horse with an immune system that could protect it from parasite infection was more likely to survive. But the reality is that parasites evolve as well, and we cannot and should not risk going “natural” by choosing to not deworm our horses. The risks of poor health outcomes are simply too great. Good husbandry calls for practicing a protocol for parasite control that works for your horse in your part of the world.

None of these management tools could be construed as “natural,” and yet, when we take on the responsibility of a horse, we need to be ready to provide all of them to some degree, depending on the job of the horse and where we live in the world. As owners of domesticated, stabled horses, we know that the term “natural” can generate much emotional and passionate discussion, but it is not the most important criteria in the decisions we make for our horses. What is important is what constitutes the best husbandry we can provide for our horses.

I Just Want What’s Best For My Horse

The biggest favour you can do for your horse is to practice good husbandry. That means making choices for him based on sound science and common sense. The desire to provide “natural” choices for your horse is a judgement call, and you should feel confident about assessing what your horse needs, whether “natural” or not. Remember that horses evolved to where they are today because they readily adapted to their environments. Many of their adaptations to the managed lives we provide them with have allowed them to live comfortably and safely for a long time. Horses in the wild did not live long, with a maximum life expectancy of approximately five to seven years before injury and disease caught up with them. Horses who are a part of the modern human experience have life expectancies that can exceed 30 years. 

Is good husbandry potentially the new “natural” for domesticated horses? Let’s assume it is. In the meantime, enjoy being discerning about the husbandry you provide for your horse, and be assured that you are providing him with the best life you can offer.

Related: How to Accurately Feed Your Horse a Forage-Based Diet

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Photo: Shutterstock/Vicuschka