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Working for better management options and cohabitation through compromise and communication for the American Wild Mustang

You Be the Judge, 7th Edition, January 22, 2010: How does a wild horse keep warm?

Posted by Texas Mustang Project on January 22, 2010


You Be the Judge
7th Edition
January 22, 2010
By: Tracie Lynn Thompson

           Recently, there have been many questions about whether or not to provide shelter and windbreaks for the wild horses being held at BLM facilities with inclement weather on its way. There have been claims and accusations of cruelty, inhumanity, and down-right cold-heartedness directed at the BLM and the Cattoor Livestock employees.   

            This conflict begs an even bigger question… How does a wild horse stay warm? He was born on the range, in the wild, with no man-made shelters or windbreaks. He has lived his life up until now in that environment, and his ancestors lived in this manner for 45-55 million years beginning with hyracotherium and eohippus. So how does he maintain warmth and survive in an environment with temperatures that have been known to stay below freezing for months at a time?   

            This edition is an attempt to explain the physiology of the equine’s thermoregulation mechanism. I will admit that there are points in this edition that are technical and scientific, but I will do my best to keep them to a minimum. I encourage you all to learn as much as you can about this particular subject; it’s not over yet, no, far from it.   

           Before we get started, I’d like to dispel a myth: Horses do not require physical activity such as running or trotting to generate heat. In cold weather conditions, more heat is lost while the horse is exerted than is retained. Therefore, a horse standing or lying still is typically better able to retain body heat than a horse that is active. I will explain all of this in this edition.  Story from a friend of mine in the Northern US:   

           “During a nasty winter a few years ago, the snow ended up nearly 6 feet high and the wind just about blew the doors and windows of the house in on us. We went out to check on the horses as often as we could, fearing each time that they would be frozen solid. One day, we walked up the hill only to find the walk-in shed empty. Pulling our coats and scarves tighter, we hiked off into the hills to find the horses. We topped one of the hills in the wind-whipped pasture and just stood stunned at what we saw: Far from the shelter of the shed, here were the horses trotting along in the snow, bucking and playing, having them a large time as if it were the first day of spring! Even our ‘grandma’ mare appeared absolutely blissful and young again, snug as a bug in a rug in a winter coat that made her look more like a wooly mammoth than a horse. The horses were not simply ‘tolerating’ the cold – they were having a blast in it and looking at us as if to say, ‘What?’”   

           In a test of horse and human against the winter elements, you would think that our species – armed with its dazzling array of high-tech fabrics and insulators – would easily be the winner. Think again. Any horse owner who’s ever pulled on some of that high-dollar space-age winter-wear and stumbled through mushy, winter ground out to the pasture on a January day knows very well who’s ahead in the fight to stay warm outdoors. We humans may pride ourselves on being able to survive in the Antarctic, but we don’t have a thing in the bag to match the efficient, ingenious, cold-beating mechanisms of Equus caballus.              

So! The normal range for the core body temperature in a horse is between 99 and 100.5 degrees Fahrenheit. How does the horse maintain that temperature in sub-freezing temperatures? The basis of evolution: Adapt, and Overcome! 

Crafted for Cold   

            Thermoregulation is the ability of an organism to keep its body temperature within certain boundaries, even when the surrounding temperature is very different. This process is one aspect of homeostasis, which is a dynamic state of stability between an animal’s internal environment and its external environment.   

           Being warm-blooded, equines have the ability to generate heat by increasing the rate at which they “burn” fats and sugars through metabolism called thermogenesis. Regulation of metabolic rates is one of the principle methods utilized by warm-blooded animals to achieve homeostasis. This requires a much greater quantity of food and calorie intake than required by cold-blooded animals in order to replace the fat and sugar reserves burned during this process. Warm-blooded animals also have much greater stamina than cold-blooded creatures of the same size and build because their faster metabolisms quickly regenerate energy supplies (especially adenosine triphosphate, or ATP) and break down muscular waste products (especially lactate, or lactic acid) as long as they are provided with adequate food supply. Warm-bloodedness generally refers to three separate aspects of thermoregulation:   

  1. Endothermy is the ability of some creatures to control their body temperatures through internal means such as muscle shivering or fat burning.
  2. Homeothermy is thermoregulation that maintains a stable internal body temperature regardless of external influence. This temperature is often (though not necessarily) higher than the immediate environment. (Horses are homoeothermic.)
  3. Tachymetabolism is the kind of thermoregulation used by creatures that maintain a high resting metabolism.

           The human body is built to dissipate heat, while the horse’s body is constructed to produce and maintain heat. It’s all a matter of physical adaptation through evolutionary processes. Thermolysis, or heat loss, in mammals occurs in four different ways:   

            *Convection              *Conduction             *Radiation                 *Insulation   

           Conduction describes the transfer of heat between two surfaces that are in direct physical contact. The horse may either gain or lose heat by conduction. The rate at which heat is exchanged is dependant on the area in contact and the temperature difference between the surfaces.   

           For example, a horse standing on hot sand would gain some heat by conduction resulting in heating of the hooves. Standing, the total surface area in contact with the sand would be small and unlikely to elevate body temperature. But, if the horse were to lie on the sand, perhaps 1/3rd of its body surface area could be in contact with the sand and this could result in sufficient heat gain to increase body temperature.   

           Convection describes the movement of heat within a “fluid”, in this case, the blood. This process describes the heat exchange between warm skin/coat and the surrounding air in conditions of no air movement over the skin. In the case where there is continual or intermittent movement of cooler air over the warmer skin, the process is referred to as forced convection and the rate of heat loss is greater.   

           In cold weather, the coat hairs stand up (piloerection), which causes entrapment of the air in a “boundary layer” formed between the skin surface and the outside environment. Due to the blood exchanging heat with the warmer “microclimate” created by the boundary rather than the colder environment of the air outside of the boundary, the air temperature here is warmer. This process slows the rate of heat transfer.   

           Radiation is a mechanism by which heat can be transferred between two bodies without direct physical contact. The best approach to understanding this mechanism is to consider solar radiation. The sun is a large body which is hotter than the horse and it can radiate heat which warms the surface of the horse. Radiation may be direct or reflected from the ground or other physical surfaces (e.g. walls).   

           Sand surfaces are highly reflective while grass and other vegetation have a high capacity to absorb radiation. Heat may also be lost from the horse by radiation. Consider a horse in a cold stone stable. The horse is now the equivalent of the sun, being the hotter body, and can radiate heat to the cooler surfaces of the stable walls. However, a horse lying in a bed of straw maintains heat better because both the horse and the straw are able to absorb the heat.   

            Evaporation is the process whereby a liquid changes to a vapor; this process is endothermic as it consumes energy and therefore lowers temperature. The efficiency of evaporation is dependant on both temperature and humidity. The rate of evaporation increases with increasing air temperature but decreases with increasing humidity. When air is fully saturated (100% relative humidity) then no evaporation can take place, irrespective of the air temperature.   

            The thermoneutral zone of an animal is the temperature range within which it does not have to actively regulate its body temperature other than by modulation of peripheral blood flow and convective heat loss and within which metabolic rate is constant. All warm-blooded creatures can tolerate a broad range of temperatures but each species has a natural “comfort zone” that reflects the climate in which it evolved. Equus caballus evolved in colder, north-of-the-equator climates and therefore have higher comfort zones than that of an animal whose evolution occurred closer to the equator.   

           Several bodily adaptations allow the horse to run hot in cold environments. First, there’s his massive digestive tract which processes a mostly fibrous diet and generates a huge amount of heat by the very act of digestion. The smooth muscle tissue of the digestive system produces heat as a byproduct of kinetic energy. This heat is then used by the body via heat conduction to warm the tissues and blood vessels surrounding the digestive system.   

           Even the extremities of the horse are marvelously adapted for colder temperatures. A horse’s legs have proportionally less muscle than those of a human therefore the cells require less blood circulation for maintenance and consequently lose less heat. This lower metabolic need also means that a horse’s legs have no problem with the reduced cellular activity brought on by cold.   

           The hoof of the horse encases the second and third phalanx of the lower limbs, analogous to the fingertip or toe tip of a human. The hoof wall is a much larger, thicker and stronger version of the human fingernail or toenail. Hooves are made up of similar materials, primarily keratin, which is a very strong protein molecule. The horse’s hoof contains a high proportion of sulfur-containing amino acids which contribute to its resilience and toughness. This makeup of the hoof wall results in an appendage very well suited for colder temperatures without a high risk of temperature-related injury (like frost-bite).   

           Consider also the equine nasal structure. It is richly supplied with blood and can therefore withstand bitter cold without freezing due the continual re-supplying of warmth from the circulatory system. And the horse’s nasal structure is divided into two passage ways and protruding into each of these are bony projections called turbinates. Turbinates help to increase the surface area of the inside of the nose. Their purpose is to warm the frigid air before it can reach the lungs and potentially decrease the horse’s core body temperature.

On the Spot Cure for Chill
           
Horses are much better equipped to deal with cold than humans, among other mammals. For humans, the impact of conduction on body temperature is significant as researcher Paul Siple found back in 1939. Mr. Siple’s research concluded that at 0°F, a 40 mph wind produced a cooling effect on the human body equivalent to a temperature of -55°F. Luckily for the horse, he is far better equipped to deal with 40 mph winds that the mere human. But that doesn’t mean he’s completely impervious to winter weather. The four processes by which thermolysis is achieved can cause many problems, but the main concern is hypothermia.   

           Hypothermia occurs when the body’s capability to stay warm is inhibited to the point of lowering the body’s core temperature. Severely hypothermic animals are diagnosed when the body’s core temperature reaches 86° F or lower. Any of the thermolitic processes can cause hypothermia if the horse does not have adequate food supply or is ill. Newborns and aged horses are the most susceptible to heat loss caused by exposure to adverse climate conditions. Ambient temperature, relative humidity, precipitation, wind velocity and solar radiation are the five climate conditions that affect the level of environmental stress.   

           The most influential of the five is the ambient temperature but the others also come into play. Wind will create a wind-chill factor adding to the stress. Rain increases evaporative heat loss by reducing thermal insulation (boundary layer) of the coat and increases convective losses. Snowfall is less cooling than rain for cold-adapted horses with dense, winter coats because the boundary layer the coat creates insulates against an increased loss of body heat vs. a horse without a winter coat. Because of its insulating properties, this boundary layer prevents the snow that has accumulated on this body’s surface from melting. Conclusively, if you see snow accumulated over the horse’s back, it’s a good thing. If the snow melts and the temperatures are still below freezing, it may be a sign that the horse is losing too much body heat.   

           The horse is also equipped with emergency heat-generating mechanisms, called acclimation responses, to cope with the threat. These are also referred to as “fast-acting” responses. Acclimation responses work at two levels: at the surface of the body and at the core.   

           To explain the responses at the surface (peripheral) level, imagine that an icy wind begins to blow across the range. The horse hunkers down with his back to the blast, but before long he is losing heat faster than his body can generate it. That’s when the acclimation responses kick in with peripheral blood vessels constricting and hair shafts standing on end (piloerection) to create the boundary layer. Shivering comes next.   

           The extent of the response is dependent on the intensity, duration and location of the chilly stimulus. A brief blast of wind may result in only a quick surface heating response, but if the cold persists, acclimation mechanisms in the core of his body swing into action, boosting your horse’s metabolic rate and thus his body temperature. These responses operate through a complex, interactive system of feedback loops that connect the brain, the central nervous system and the adrenal glands. When body temperature falls, cold-sensing nerve cells throughout the horse’s body fire warnings to one or more central heat-regulating hubs in the spinal cord and brain.   

           These nerve-cell ‘thermostats’, called thermoreceptors, within the thermoregulatory centers can be triggered by lower-than-normal temperatures in the body, both on the body surface (peripheral thermoreceptors) and in certain deep tissues (central thermoreceptors). The chief command center for thermoregulation is the hypothalamus, a small but life-critical structure deep in the base of the brain. It is the junction, or connection, between the central nervous system and the endocrine system and it can release hormones to promote homeostasis when thermoreceptors are triggered. This evolutionary process in particular is one of the most basic survival mechanisms of the horse’s body.   

           It is very difficult to recognize when a horse first becomes hypothermic. If you can see the horse shivering, this is a good sign regarding hypothermia. Once hypothermia has set in, you will not see the horse shivering as they no longer have the energy stores needed to shiver. Remember that shivering is an active muscle contraction at its basic kinetic level, and therefore the act of shivering produces heat for the body. But if there are no calories left to produce the fuel for this process to occur, there will not be any heat produced by this process.   

           Shivering is a defense mechanism used by most all warm-blooded mammals. When the body perceives a serious drop in temperature, the central nervous system commands motor neurons in each major muscle group to set off a single, vigorous contraction. But almost instantaneously, tension-sensing proprioceptive nerves perceive the muscle as too tense and fire a command to halt the contraction. As the muscle relaxes, the proprioceptive nerves stop firing, allowing the muscle to contract again; the result is shivering.   

           With their enormous blocks of muscle, horses are superb at shivering and in fact appear to shiver more comfortably and readily than humans. Since nearly all the muscle action is converted to heat, shivering is a highly effective method of creating body heat. However, its effectiveness is also highly dependent upon the amount of calories available to produce fuel for the muscle movements. This is a give-and-take process that coincides with the countercurrent heat exchange.   

           In nature, countercurrent heat exchangers create gradients by transferring heat or molecules from one vessel to another whose flow is opposite to that of the original vessel. The uppermost layers of a horse’s skin are suffused with veins that normally circulate the blood close to the outer air before returning it to the lungs. In hot weather, the resulting heat radiation is desirable, but under frigid conditions the heat loss could be dangerous.   

           To minimize surface radiation in the cold, the horse’s venous blood takes a detour. Orders from the thermoregulatory centers block blood flow into peripheral veins (cool/cold) and reroute it into vessels called venae comitantes, which run deep under the skin right next to arteries (heat). The result: blood returning to the heart and lungs is warmed by the outgoing (countercurrent) arteries preventing cold blood from penetrating the body core and possibly reducing the core body temperature. This is the reason why the horse’s skin may feel cold to the touch while the horse’s core body temperature is still adequate and efficient.   

           Protection of extremities is another strategy by which the horse fends off cold temperatures. Earlier, I spoke of how a horse’s legs require less cellular metabolism due to their proportionately less amount of muscle tissue. Although the horse’s body lacks a mechanism for increasing blood flow to the feet, it has developed a system to prevent them from freezing. After countercurrent heat exchange begins, little warmed blood flow reaches the foot. It is normally diffused (and thereby cooled) in the capillaries that serve the foot cell’s limited metabolic needs.   

           When the body’s thermoregulatory mechanisms get a message that the feet are too cold, direct shunts open up in the feet so that blood flows from the smallest arteries directly into larger veins, called venules, without passing through the capillaries, bypassing the diffusion process. After the feet have warmed sufficiently, the shunts close again to restore nutritive capillary flow. Shunts are also used in the tail and ears.   

           Another means of warming critically exposed areas, such as the muzzle, is to open more subsurface blood vessels to compensate for surface heat losses. Stallions have an additional vulnerable ‘extremity’, the scrotum. Normally exposed so it can maintain a slightly lower operating temperature for optimum fertility, this nearly hairless organ is protected against winter weather by a muscle called the dartos which ‘puckers’ the scrotum up against the body during cold conditions.   

           As cold continues to stress the body, the thermoregulatory centers turn their attention to generating more internal heat, sending out messages to the adrenal glands to boost core metabolism. Nerve impulses signal the adrenal medulla to release epinephrine and norepinephrine, neurotransmitters that raise blood pressure and heart rate, and increase metabolism by stimulating the release of free fatty acids and the breakdown of glycogen. At the same time, the hypothalamus spurs the pituitary gland into action, ordering the release of large amounts of adrenocorticotropic hormone (ACTH) into the bloodstream. Arriving in the adrenal cortex, ACTH triggers the production of cortisol, a steroid that increases the body’s heat-generating metabolism of fat, carbohydrates and protein. The result: a warmer, happier horse.

Gearing Up for Winter   

           Short-term measures can warm a horse through a cold snap, but because many acclimation responses tend to drain energy stores, they aren’t likely to be sustainable throughout the winter months. To avoid exhausting himself in an effort to keep warm, the horse needs an energy-efficient means of generating and retaining heat over long periods of time. At the same time, whatever process prepares him to withstand colds has to be reversible when the warm weather returns. Fortunately, there is such a mechanism of seasonal adjustment to temperature change: acclimatization.   

           The horse’s acclimatization for cold actually begins long before winter. Just after the summer solstice (around June 22), receptor’s in the horse’s eyes detect the incremental shortening of daylight and relay the information to the pineal body, a primordial organ in the brain. (Some studies have suggested that even blind horses experience acclimatization changes at this time as well, suggesting that other receptor points may be modulated through the pineal body).   

           These subtle hints of coming winter trigger the release of hormones that shift the winter coat from its resting phase into a growing phase. Inside the follicles that house the horse’s thin and short summer hairs, thick and long winter hairs begin to grow, pushing the summer hairs ahead of them. Some horses’ winter coats can be seen peeking out in late August depending on which region they inhabit. By late September or early October, the winter hairs start to push the summer hairs completely out of the follicles. The result is shedding.   

           During the fall, ambient temperature determines how long and thick the horse’s winter coat grows. If he is exposed only to warm air – as occurs in southern climes, or when he is blanketed or kept continuously in a warm barn – his winter coat will grow in only slightly heavier than his summer coat. Even the slightest change in exposure can have an effect on the growth of his winter coat, possibly robbing him of much needed protection from the elements.   

           On the other hand, if he’s exposed to extreme cold during this time, his coat will be correspondingly thick and long, thus ensuring his ability to withstand the colder temperatures and winter elements. Ambient temperature continues to influence the weight of the coat until the winter solstice (around December 22). Around this time, the lengthening daylight hours trigger receptors for the pineal body and the first summer hairs begin to grow in the follicle. After this process begins, the winter pelt can no longer adjust to climate changes.   

           The horse’s winter coat has long, dense, fine ‘pile’ interspersed with longer, bristle-like ‘guard’ hairs that prop up his fur. This is what creates the foundations for the boundary layers. The downward tilt of his hairs deflects falling raindrops and snowflakes before they reach the skin and directs them to the hair tips where they fall harmlessly to the ground. That’s why a horse’s skin often remains dry even in mild to moderate rain or heavy snowfall. And, finally, the thick winter coat makes an excellent windbreaker.   

           As the temperature drops, the horse’s caloric consumption increases, boosting heat-generating digestion and metabolism. Mother Nature helps the progress along by ensuring that the grazing horse puts on a few pounds in the fall. Among wild horses, this weight gain comes primarily from increased consumption of dry matter as grass dries out. But, if the range is viable, it may be boosted by supplements such as wild rye and wild oats which go to seed as winter approaches. The extra fat layer requires little energy to sustain, has few heat-radiating capillaries within it and insulates well. This is why some wild horses often look “plump and healthy” during winter months. Come Spring, this extra insulation is quickly shed.   

           On the cellular level, heat-generating metabolism is also nudged up for the winter, though in a far less dramatic and taxing manner than occurs with the short-term metabolic changes of acclimation. As cold sets in for the long term, the hypothalamus signals the pituitary to release thyrotropin or thyroid-stimulating hormone (TSH). Reaching the thyroid gland in the neck, TSH triggers the release of thyroid hormones that slowly boost metabolism for the long haul.   

           The impact of all these changes is a marvel of thermoregulation. Efficiently generating more heat while increasing his layers of insulation, the acclimated horse has greatly improved his ability to tolerate cold. It takes a severe cold spell to force him to resort to fuel burning and emergency warming responses like shivering. The acclimatized horse is so ideally suited to the frozen tundra that – given adequate supplies of food and unfrozen water – he can survive and even thrive in temperatures as low as minus 40◦F.   

           Bundle yourself up in the best parka, scarf and toboggan you can buy; grab some hunter’s hand-warmer-packs from the local sporting goods store. I guarantee that you will still be standing in the cold, freezing your patookus off, and thinking, “Oh boy, I can’t wait until summer gets here!” And you may question the decision to leave horses in the elements without man-made shelters or windbreaks. You needn’t worry.   

           Equus caballus is an evolutionary cold-weather marvel whose abilities for staying cozy in breath-stopping temperatures far outweigh your own. Thanks to a collection of heat-generating and insulating mechanisms, he’ll be just fine. You, on the other hand, should probably get back inside with an electric blanket!  (Links to some reference articles below.) 

As always, stay safe… And never give up!   

    

Thank you,   

Tracie Lynn Thompson   

Owner & Lead Instructor   

Lessons Learned Equine Instruction   

(409)658-4491 cell   

tracielynnthompson@yahoo.com   

themustangprojectblog-messages@yahoo.com   

The Mustang Project Blog Page    

Working for Better Management Options and Cohabitation Through Compromise and Communication for the American Wild Mustang   

 © 2010 Tracie Lynn Thompson. All rights reserved.    

 Winter brings additional energy demands for horses Research from South Dakota University  

 Is Your Horse Ready For Winter?  article from eZine  

 Internal Combustion article on TheHorse.com 

 

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6 Responses to “You Be the Judge, 7th Edition, January 22, 2010: How does a wild horse keep warm?”

  1. Reply to an email sent from a blog reader:
    Keeping with the physiological and biological aspect of the edition, the horse who is exerted will sweat as a thermolytic reaction to the heat built up in his cells. Thermolysis is literally the breakdown of heat. (lysis = breakdown or destruction; thermo = heat or temperature)
    Sweating is one of the body’s coping mechanisms to prevent hyperthermia by the process of evaporation. This is an advantage when the temperature is moderate to severely hot. This is definitely a disadvantage when the temperatures are in the opposite direction. Horses who are wet from the process of evaporation through sweating have already started the physiological process of heat release, and heat loss is increased by further evaporation and to some degree convection.
    The presence of these processes in the colder temperature gradients collectively with the moisture from the sweating and the horse’s body trying to regain homeostasis places the horse at a higher risk of being immunocompromised if measures are not taken to provide supportive care and assistance, such as placing a blanket on the horse. However, the blanket that is placed on the horse while wet should never be left on the horse after sweating has ceased for a few reasons.
    1.) Moisture can be retained in the lining of the blanket, thereby prolonging the thermolytic processes because it takes the horse longer to get dry. Imagine like when you first get out of the shower on a cold day. You wouldn’t use a wet towel, or even a damn towel to dry off with; you’d find the driest and warmest towel you could to expedite the drying and consequently the warming of your body’s cells. (Yes, the manufacturers claim to have waterproof linings in some of their blankets, but I’ve tried just about every one of them out there and they have all been not waterproof to some degree.)
    2.) Dampness and moisture are the play-land wonder-grounds for bacteria. They just love to get into the smallest little spaces that we can’t see and produce lots of “children”. Thorough cleaning of your horse’s saddle pads and blankets are a good measure to help prevent the spread of such bacteria. However, if the horse is experiencing the effects described in #1, he is already on his way down the path. The bacteria is an eager and opportunistic hitchhiker along that path. Its sort of like the concept of “don’t add fuel to the fire”.
    3.) Misjudgments in the actual core temperature of the horse’s body could lead to a rise in core body temperature. If his temperature is really higher than what you think, placing a blanket on him is inhibiting his body’s natural thermolytic process of releasing heat. If the heat cannot escape the coverings of the blanket, it builds next to the horse’s skin, and adds to the already heightened core body temperature.
    I have a few general rules of thumb about blanketing any horse in my barn. They’ve worked for many years now, but we are speaking of domesticated horses, not wild or feral horses. Mostly the horses stay stalled at night due to the high population of coyotes in my area. Its just a safe practice.
    1.) If the environment is cold and wet, (falling temperatures mixed with high humidity) the ill, younger, older and smaller horses will wear a blanket.
    2.) If the environment is cold and dry and the horse does not fall into one of the aforementioned categories, I will typically not use a blanket.
    3.) If the environment is in any way cold or wet, I do not work the horses to the point of profuse lathering.
    For the wild horses, rules #1 and #2 could apply. However, #3 is a totally uncontrollable variable from our positions. The horses that I have seen coming into the gathering sites have been winded, and some have been what I would term “slightly” lathered. Again, these are just the ones that I personally have seen – and that’s through pictures – so I can’t speak certainly. For the most part, I have seen horses that would fare well without a blanket or covering based on the environmental variables and their physiological makeup.
    They are not lathered to the point of “frothing”, and there is no sign in the pictures of them having extreme thermolytic processes in place. Therefore, given the fact that they are wild horses and the variables mentioned, I would not have them wear blankets. Doing so may result in the first #3 – hyperthermia – and the added stress of attempting to apply any type of blanket to a wild horse who is not yet gentled would most definitely result in an increased core body temperature, consequently setting off further physiological and psychological processes that are not warranted.
    As for shelters, the wild horses would most likely not use any man-made shelter for the simple fact that it would be man-made. Imagine that you were one of the wild horses who had just been gathered. Your sense of smell is almost unparalleled in the animal kingdom; you can smell a man from a mile away. Your instincts are telling you that man is the enemy because of the ordeal you have just experienced. Would you like to be near anything that smelled or resembled man? And because they have been bred, born and raised in the wild, their systems are more accustomed to the driving snow and effects of winter.
    Yes, the different breeds of domesticated horses have different regulatory systems among them. This is mostly due to the human-effect on their breeding, meaning that humans selected which genomes where paired and which were not; a process known as selective breeding. In the wild, a horse chooses its mates by its strength and ability to survive. This allows the genes of the strongest horses to continue in the gene pool, while the genes of the weaker horses do not. This is known as natural selection. Again, this is one of the fundamental processes of evolution.
    The stress factor is definitely one to consider. Being shocked and scared by an unknown object flying through the sky towards you and your family is not exactly a walk in the park. Add to that the distance travelled in an attempt to rid yourself of this intruder, and the attempts themselves, and you’ve got a very psychologically stressed state of mind. However, the mind of the horse is very resilient in some cases, especially so with wild horses.
    Remember, a wild horse lives everyday of his life in anticipation of the next big event because he is not exposed to situations in the same manner that domesticated horses are during their desensitizing training. With our domesticated horses, we pose situations in mostly controlled environments to protect not only the horse but ourselves and those around us. This allows the memory markers to be placed in the mind which associate the variables of the situation with no fear over time.
    Wild horses, on the other hand, have fight or flight instincts. “I’m either going to stand and fight, or I am going to get the heck out of here!” This is not to say that horses in the wild cannot become desensitized to some situations in the wild. It is merely to say that they are not similar situations to those of a domesticated horse. As a result, their evolutionary processes have still maintained the natural survivalist instincts, allowing their coping mechanisms to respond easier and quicker than those of a domesticated horse.
    I have been in close contact with both the BLM and the contractor personnel over the course of this gather. The subject of windbreaks and shelters has indeed come up, and my recommendations to have windbreaks installed for the ill, younger, older and smaller horses have been taken into serious consideration by all parties. I have also supplied information regarding the stress factors affecting the wild horses, and the possible consequences of those factors. These too have been taken into consideration.
    As of yesterday evening, there are instructions from the BLM to the contractor to being installation of windbreaks in 12 of the holding pens at the Fallon facility. These will be similar to the ones installed at the Palomino facility. These 12 pens are segregated for the sick and lame members of the herds, but exceptions can be made for the smaller or weaker members if need be.
    *T*

  2. R.Thompson said

    Excellent article and excellent reply to an emailed question. Both reflect my own personal and hands on experience with domestic horses kept in pasture 24/7/365 in a northern state in rural but reasonably near urban environments. That means within an hour’s drive or so of the city. That means we have some Coyotes, but not enough to worry about, and the wolves that are here venture no where near the areas I’ve kept horses. Cougars are suspected to be re-colonizing or expanding here, but until very recently no evidence has been found to substantiate this phenomena. In short, we do not have predator problems other than horse thieves who steal to sell for horse meat. A few big dogs usually solves that problem. Our horses had a large “run-in” shed , open to the south-south east, that they used periodically, usually in a cold driving rain, not snow or general winter cold periods. Although southern western bred (Texas) Quarter Horses, they grew wooly coats and fetlock fringe, one red dun so much that it would have done an English Shire horse proud. We supplemented natural grown grass mixtures with 2nd cutting alfalfa once or twice a day depending upon weather and energy expenditure activities, as well as daily rations of sweet feed or crimped oats, which ever was appropriate to the horses’ activity.

    In a blizzard the horses wound be standing snow covered in a group, not the shed. If sunny and cold they’d be racing around acting like yearling meatheads at play. We tried feeding the supplemental feeds in the shed, they demurred, preferring the usual flakes on the ground and grains in a fence post hung bucket. Only problem was keeping water flowing to the reservoir in winters where frost reaches down up to 60 inches at times. Hint: do not run the piping under a direct dirt or gravel driveway to the pasture gate, because the frost goes deeper there.

    One comment about our experience with stalling horses in communal barns. Our vet bills were 5 times plus for stalled horses versus pastured horses, and without normal grazing and with “timed” feedings, there was more potential for colic. None of ours, but plenty of those around us who insisted on “hot” feeds for essentially sedentary horses. Only for preparation for competitions were our horses in any barns.

    Last, but no least, my experience with large furry dogs is similar vis a vis seasonal hair growth. Our big shaggy long haired German Shepherd of today relishes snow and it does not melt on his fur, but builds up to the point I use a whisk broom to clean him off when he comes indoors. He has an under coat a Malamute would take pride in, so there goes another bit of “conventional wisdom” that long haired German Shepherds have no under coat…thus it is considered a “defect” by the “show fancy.” Please, come curry out our big boy, then, please. Just routine working the fur to clear any matting will half fill a 13 gallon kitchen waste bag. Our plush coated stock hair females are no different, just more pleasing to the “fancy.”

    Conclusions: Animals adapt to environments, naturally, if fed well, and the adaptations are there even in domesticated animals that are descended from wild originators. Man is the one with the problems with cold.

  3. LOUIE COCROFT said

    IN THE WILD, THEY WOULD FIND DRAWS AND NATURAL WINDBREAKS WOULDN’T THEY? I ALSO BELIEVE THAT, AS GINGER KATHRENS HAS OBSERVED, THEY WOULD BE CONSERVING THEIR ENERGY IN THE WINTER. IT WOULD NOT BE THE NORM FOR THEM TO BE RUN AS THEY ARE WITH THE HELICOPTERS. FOR THEM TO BE JUST STANDING IN OPEN PENS WOULD SEEM TO LEAVE THEM VULNERABLE TO THE CHILL OF THOSE WINDS. ALSO, ARE THEY JUST STANDING IN THE MANURE. DO THEY CLEAN THE PENS. IN THE WILD THEY WOULD PROBABLY NOT BE STANDING IN ANY ONE PLACE FOR LONG.

    • Yes, that is correct. Wild horses have a natural instinct to find shelter from the weather. These are usually, as you stated, the various draws and natural windbreaks provided by Mother Nature.
      Ginger is correct in the aspect of conserving their energies vs. being run with the helicopters, and no, this is not the norm. However, the horse also has compensatory systems as discussed. His metabolic systems will draw upon whatever stores of cellular fuel it has (i.e. stored fat cells) in order to maintain a regulated core body temperature, and if need be, will compensate for the colder temperatures of his current environment. Now if the horse was not given nutrition to replenish those stores, then he would begin a downward spiral towards malnutrition and hypothermia; the logic being that even the healthiest of horses cannot continue to maintain homeostasis without adequate caloric intake.
      However, these horses are being supplied with ample amounts of nutrition, and have already begun to gain weight in the short time that they have been in the holding pens. Therefore, the need to “conserve energy” is no longer as high of a priority as it would be if they were still in the wild where nutrition is possibly not at easily obtained.
      Yes, standing in the pens without the natural windbreaks and draws they would be afforded in the wild does leave them somewhat vulnerable. This is why several others and I have made the suggestion several times to construct some sort of windbreak around the holding pens. As reported yesterday, the contractor has been instructed by the BLM to install said windbreaks as soon as possible.
      Please understand that YBTJ, 7th Edition was not directed specifically at the horses currently in holding. As previously stated, the YBTJ series is for informational purposes. It was simply an explanation of how wild horses stay warm in the winter from a physiological and biological perspective. Yes, the principles discussed in the edition do apply to horses in holding because they are horses, but obviously they would not apply directly to them because of their current situation. (being gathered, no longer in the wild, etc.)
      To my knowledge, the pens are cleaned as much as possible. Again, remember that these are still wild horses who have been through a very stressful ordeal and are still in the early stages of recuperating their psychological balance. Because there are so many pens, and because there are so many horses, it is difficult to clean without adding additional stress to the them. Of course, the pens do need to be cleaned because of the hygienic problems that could arise were they not cleaned. It’s a very touch and go type situation; almost the “damned if you do, damned if you don’t” scenario.
      *T*

  4. reveil39 said

    Just how long does it take for a horse to be able to eat after he’s run for miles pursued by a helicopter?
    How long does his normal body mechanism tale to re adapt after heavy stress?
    It might be crucial to offer not only the correct feed but extra protection as well (in the form of windbreaks for weak or normal animals to allow the defense mechanism to kick in. I think that when horses are pursued, they typically run for cover.
    But here they are pursued and they end up in an open space surrounded by a foreign species, man, which they would normally run away from.
    This has to have an effect on their nervous system as well, since it breaks down their fight or flight mechanism.
    A mare might want to protect her foal but she can’t, and it might make things worse for her when her foal is separated from her, even for the best intentions to provide him with adequate care.
    Could there be more compassion in caring for mares and foals? If the foal needs more care, could the mare be allowed next to him, even if she does not need special care?
    I am willing to bet that some of the so called “normal” horses develop behavioral and health problems later on due to the fact that not only the switch from wildlife to captive life is brutal, but also that their normal defense mechanism is prohibited to kick in because they can’t run for shelters. Add to that the extra stress of being mixed up with other herds, other band stallions, It’s a recipe for disaster!
    I think that is one of the reason people get so upset about the round ups. It’s like asking for something beautiful and wild to suddenly react like a barn horse. If their genes are made to live in the wild, their genes have a blueprint as well to react to stress, fear and exhaustion, and after reading the above studies there seems to be a gap between the study of a horse making his own choices in the presence of the elements and the reality of the horse desperately wanting to flee or even just join his herd and not able to do so.
    Since entire herds are round up at the same time, why do they get mixed up with other herds? This is destructive to the natural structure by which the wild horse lives his life. Could there be more improvement on the matter?
    What about all the horse gentlers? Every one has seen the movie the Horse Whisperer. Since then they are many horse whisperers out there, why not involve their knowledge into the round ups?
    It is a separate issue from the round ups, just in the same way that wild horse health and regular horse health are separate issues. I would be surprised to get the advice of specialist who is willing to bring something else to the table.
    These steps might not seem important to let’s say, a cowboy, but again, there are huge advances in understanding the world of sentient beings and many proofs that once we involve the horses in their own recovery, they also react positively to the change.
    That’s also what I mean when I am talking about studies stuck in the past. We need to bridge the gap between the understanding of the wild horse not only from a veterinarian point of view but also from the point of view of people who get amazing results by dealing with horses in a more gentle and dare I say, “modern” way.
    I think from that point of view, the horse would benefit, the vet bills might come down, the budget might even have a bigger beneficial margin since more horses might be keen to be either adopted or at least adapt better to their new environment.

    • I’m going to do my best to answer these questions, but my answers are only from the domesticated side of things as, obviously, my horses are domesticated. I will however forward them on to others who may be able to answer them better from the wild horse side of things… (You makin’ me think today LOL!)
      *Just how long does it take for a horse to be able to eat after he’s run for miles pursued by a helicopter?
      -Ok, not pursued by a helicopter, but I have always allowed at least 30 minutes to an hour before any exertion, dependent upon several factors, but mainly the size of the meal that he’s just had. Grass and hay usually don’t “count” as a “meal” for our horses because they are fed prepared feed.
      *How long does his normal body mechanism tale to re adapt after heavy stress?
      -This one is the same for all horses. As soon as there is an imbalance in the body that alters his homeostatic state, regulatory mechanisms kick in and begin trying to regain homeostasis. The length of time it takes to regain that state varies. If he is young, healthy, and in good shape, it’s usually not very long; maybe 15-20 minutes. If he is older, of poor body condition, and possibly ill, the process will take longer for logical reasons. Not only will the body be trying to regain homeostasis, it also might be trying to defend its tissues and cells from invading organisms, i.e. infections, diseases. There are other factors that come into play as well such as the climate conditions – cold/hot, humid/dry – but again, these will play more into what condition the horse is in as to how it effects his “rebound” time.
      *It might be crucial to offer not only the correct feed but extra protection as well in the form of windbreaks for weak or normal animals to allow the defense mechanism to kick in. I think that when horses are pursued, they typically run for cover.
      -I agree. This suggestion was also brought up and has been taken into consideration. No word yet on definite plans though.
      *But here they are pursued and they end up in an open space surrounded by a foreign species, man, which they would normally run away from. This has to have an effect on their nervous system as well, since it breaks down their fight or flight mechanism.
      -Not exactly, and yes exactly. When speaking of the physiology of the equine body, the “fight or flight” mechanism is actually not psychological, but biological. The “fight or flight” mechanism is actually the sympathetic nervous system & the “feed or breed” mechanism is the parasympathetic nervous system. The two are sub-systems of the autonomic nervous system which controls the involuntary processes of the body, such as heart rate, respiratory rate, blood pressure, digestion, metabolism, etc. Basically, they control the responses in the body that do not require an active thought to control. The sympathetic nervous system works on the adrenergic receptors (alpha1, alpha2, beta1, beta2) and the dopaminergic receptors and is activated when there are stresses on the body which cause a loss of homeostasis. The parasympathetic system is the “always on” system, running in the background and controlling vital signs, etc. within normal ranges. When the sympathetic system kicks in, the parasympathetic system “sleeps” or “steps aside”. The purpose of these two sub-systems is to allow the body to compensate when faced with environmental changes inside and outside of the norm.
      Going back to the psychological side, not the biological, the fight or flight mechanism is the brain’s way of surviving when faced with a dangerous situation. (See more below.)
      *A mare might want to protect her foal but she can’t, and it might make things worse for her when her foal is separated from her, even for the best intentions to provide him with adequate care. Could there be more compassion in caring for mares and foals?
      -Yes, in a way there could be. However, this is more a question of “risk vs. benefit”. Would it benefit the foal more to be separated from his dam, vs. to risk him developing an infection if not treated?
      *If the foal needs more care, could the mare be allowed next to him, even if she does not need special care?
      -When a wild mare thinks that her foal is being threatened, you don’t want to be anywhere near her or the foal. She is still a wild animal, and will still react in a fiercely protective manner, possibly injuring herself, her foal, and any handler who might be in her way.
      *I am willing to bet that some of the so called “normal” horses develop behavioral and health problems later on due to the fact that not only the switch from wildlife to captive life is brutal, but also that their normal defense mechanism is prohibited to kick in because they can’t run for shelters. Add to that the extra stress of being mixed up with other herds, other band stallions. It’s a recipe for disaster!
      -Absolutely. As a trainer myself, I have dealt with this situation first hand. While in Washington, D.C. back in September 2009, I relayed the following story directly to Ed Roberson during a meeting at his office with myself, Elyse Gardner and Craig Downer:
      In 2004, my biological mother adopted two fillies from the BLM adoption in Lake Charles, LA. They were the cutest little darlings in the world, and so curious! In all my years of training horses, I never had then and I haven’t since met two fillies who were more inquisitive. They wanted so badly to figure me out, but they were hesitant. I assessed both of them on the second day after their arrival. (I gave them the first day to get a little more acclimated to their new surroundings.) They were in my round pen, which was 40 foot in diameter. I am only 5 foot tall, and I weigh in at a buck and a dime. They regarded me as though I was the biggest and meanest grizzly bear this side of the Rockies. No matter how submissive and no matter how dominate my approach was, they wouldn’t budge. (With Natural Horsemanship, the Language of Equus is used to communicate with the horse. This is reminiscent of their times with their dams, and therefore is a much gentler and easier transition into the mutual trust with a human.) I was amazed at how much they wanted to get closer to me but just wouldn’t close that 40 foot gap, not even a foot! They hugged the side of the side pen as best they could, and judging their reactions, I didn’t dare push them any harder. After 3 weeks of this same game, the smaller and feistier of the two finally gave a little. She closed 5 foot, and then 10 foot. The other filly, not wanting to be left vulnerable without her “herd” began to hesitantly follow. Over the next 3 weeks, we closed the gap completely. I was so proud of them, and they were even proud of themselves, but I think more relieved because the curiosity was about to kill them! They became very good students over the next 5 months, and are now living with an ER nurse who worked at the same hospital as I did.
      I relayed this story to Ed for two reasons. One, I wanted to express to him how highly unusual it is to have a horse – no matter his background – to react in such a manner for such a long period of time. Initially, yes, there are those who will be aching to bridge the gap but just can’t do so because of the memory markers psychologically imprinted in their minds. Two to three weeks at the most, and those are the really bad cases. (When using their language, they begin to almost recognize you as part of their herd, thus making the transition not such an obstacle.) These two fillies had been imprinted with memory markers that prevented them from following their own natural instincts and language. For a mind to go against its own native form of communication, there has to have been severe psychological trauma; otherwise known as post traumatic stress syndrome.
      The second reason was because just before I relayed the story of the two fillies, Elyse Gardner had shown the video footage of Lily Thomas striking the horse known as “Floyd” with a blue paddle on a long stick. It is my understanding, from various sources, that Lily was attempting to move “Floyd” into the chute for examination, etc. When “Floyd” resisted, Lily used the paddle as an extension of her arm, just as is done in Natural Horsemanship training. However, the video showed Lily actually striking the horse, not placing the paddle against his body to induce the pressure zones, hence a movement away from pressure. I have to admit that I was a little less than “diplomatic” at first. Speaking, typing, reading or hearing about a horse being struck invokes a reaction of anger but it’s one that I can usually control for the sake of diplomacy. Witnessing the act is a totally different situation. With Elyse’s help, I was able to regain my composure enough to offer my services to Ed and the BLM as a whole. I offered free clinics on Natural Horsemanship and the Language of Equus – clinics I usually charge $25 per student, per day to give. Ed took my offer into consideration, and has on numerous occasions brought it up in our conversations. Unfortunately, I have not been any clinics given to date to any employee of the BLM. The reasoning, I am told, is due to the overwhelming response to the gathers by the public, and therefore the BLM is in an “all hands on deck” situation. I always remind them though, there is a standing and open invitation to take me up on this offer. (I’ll let you know if that invitation is ever accepted! ;p )
      *I think that is one of the reasons people get so upset about the round ups. It’s like asking for something beautiful and wild to suddenly react like a barn horse. If their genes are made to live in the wild, their genes have a blueprint as well to react to stress, fear and exhaustion, and after reading the above studies there seems to be a gap between the study of a horse making his own choices in the presence of the elements and the reality of the horse desperately wanting to flee or even just join his herd and not able to do so.
      -Agreed.
      *Since entire herds are rounded up at the same time, why do they get mixed up with other herds? This is destructive to the natural structure by which the wild horse lives his life. Could there be more improvement on the matter?
      -My best guess is the reasoning would have something to do with time and space constraints; meaning that in a gather of this magnitude, there simply is not enough space or time to separate the bands/harems into individual pens. However, during the Pryor Mountain HMA Gather in 2009, Matt Dillon was a volunteer and was able to help distinguish which mare or weanling went with which harem or stallion. This proved to be very beneficial at the time, but there were mixed reviews about the overall success after the fact.
      *What about all the horse gentlers? Every one has seen the movie the Horse Whisperer. Since then they are many horse whisperers out there, why not involve their knowledge into the round ups? It is a separate issue from the round ups, just in the same way that wild horse health and regular horse health are separate issues. I would be surprised to get the advice of specialist who is willing to bring something else to the table.
      -LOL, see above. As well, I have been told by BLM and Wild Horse and Burro Program officials that the gather personnel do attend such clinics, regularly. One in particular is Ross. (I am soooo sorry! I can’t remember his last name at the moment!) Anyway. I have been told by several individuals who have seen him at gather operations that he is really great with the horses, employing a lot of the same techniques used with Natural Horsemanship Training and Equus.
      *These steps might not seem important to let’s say, a cowboy, (*or cowgirl!*) but again, there are huge advances in understanding the world of sentient beings and many proofs that once we involve the horses in their own recovery, they also react positively to the change. That’s also what I mean when I am talking about studies stuck in the past. We need to bridge the gap between the understanding of the wild horse not only from a veterinarian point of view but also from the point of view of people who get amazing results by dealing with horses in a more gentle and dare I say, “modern” way. I think from that point of view, the horse would benefit, the vet bills might come down, the budget might even have a bigger beneficial margin since more horses might be keen to be either adopted or at least adapt better to their new environment.
      -I couldn’t have said it better myself, and ironically enough, have said it almost the same way to “the powers that be” multiple times. It’s all about how you “talk” to the horse. It’s amazing what you might “hear”.
      T.

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