How does horse extract the energy to needs from a relatively small digestive system?

Recently I saw Inside nature's gaints episode on horse, and was fascinated about its internal organisation. And my question is that they have a very large lungs to accommodate, but a relatively smaller stomach. But other herbivores like the hippopotamus have a very large digestive system even though they need less energy than horse. How does horse manage this problem? How do they get that much of energy even though it had small digestive system and more over it is an herbivore?

The digestive system of a horse is by no means small:

  • They have 15 to 21 m (50 to 70 ft) of small intestine, with a capacity of 38 to 45 L.
  • They have a 1.2 m (4 ft) long caecum that holds 26 to 30 L.
  • They have 3.0 to 3.7 m (10 to 12 ft) of colon, capacity up to 76 L.
    (Figures sourced from Equine Anatomy (Wikipedia))

Certainly horse stomachs are comparatively small as they are hindgut fermenters, but that is not where most energy and nutrients are absorbed. Some food passes from the stomach to the small intestines before it is fully digested, which enables more continuous eating to keep up with their energy and nutrition requirements. Most proteins, carbohydrates, and fats are absorbed in the horse's small intestine. Some nutrients are absorbed in the large intestine as well, see Is there nutrient absorption in the large intestine of hindgut fermenters?.

The hippopotamus is a pseudoruminant, having a 3 chambered stomach (unlike the 4 chambers of a cow). Hippos are therefore considered to be foregut fermenters, and are not comparable to horses. In terms its digestive tract, the hippo is much more similar to a cow than a horse.

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Signs of Liver Insufficiency

Signs of liver insufficiency may not be evident until more than 60 to 80% of the liver is nonfunctional or when liver dysfunction is caused by disease in another organ system. Early vague signs of depression and decreased appetite may be overlooked. Jaundice (yellowing of the skin, gums, and whites of the eyes), weight loss, and abnormal behavior due to hepatic encephalopathy (see below) are common in horses with liver disease and liver failure. Skin changes due to a reaction to ultraviolet sunlight (photosensitization), fever, or abdominal pain (colic) may occur. Less often, harsh, high-pitched breathing sounds, diarrhea, or constipation, may be present. Anemia may be seen in horses with liver dysfunction due to parasitic diseases, some plant poisonings, longterm inflammatory diseases, or destruction of red blood cells. Because the liver produces important clotting proteins, horses with severe liver failure may bleed abnormally. Weight loss is a common sign in longterm liver disease and may be the only sign associated with liver abscesses.

How Does Liver Disease Affect the Skin (Light Sensitivity or Photosensitization)?

One of the main functions of the liver is the removal of toxic substances from the blood. When the liver is diseased, a toxin called phylloerythrin increases in the bloodstream. Phylloerythrin is produced by the breakdown of chlorophyll (green pigment) present in plants eaten by the horse, and it is sensitive to light. When phylloerythrin reaches the skin and is exposed to ultraviolet sunlight, it releases energy and damages the skin. Unpigmented or light-skinned areas absorb the most ultra-violet light, so they are most likely to be affected by light sensitivity (photosensitization).

Hepatic encephalopathy, a syndrome of neurologic problems caused by poor liver function, is seen in a number of liver diseases. The liver normally removes poisons from the bloodstream when the liver is not working properly, poisons build up and may affect the nervous system.

Signs of hepatic encephalopathy may include:

eating of non-food objects (pica)

Loud sounds while breathing and difficulty breathing due to collapse of structures in the throat occur in some cases of liver failure, especially in ponies. Although the signs can be dramatic, hepatic encephalopathy can often be reversed if the underlying liver disease is successfully treated. Horses with hepatic encephalopathy often show aggressive and unpredictable behavior that can result in injury to the horse or to its handlers. The animal may require sedation.

Liver disease can cause photosensitization, a condition in which the skin is unusually sensitive to ultraviolet sunlight. This disorder is caused by increased levels of a light-reactive chemical called phylloerythrin circulating in the bloodstream. Signs can include itching, mild to severe skin disease with reddened skin, extensive fluid accumulation (edema) beneath the skin, skin ulceration and peeling, eye inflammation and tearing, aversion to light, and cloudiness of the cornea. Skin inflammation and edema are particularly evident on nonpigmented, light-colored or hairless areas of the body (such as the lips and white markings on the face or legs) that are exposed to sun. Uncommonly, the underside of the tongue may be affected. Blindness, skin abnormalities, loss of condition, and occasionally death can result.

Either diarrhea or constipation can occur in horses with liver disease. Ponies and horses with hyperlipemia (high levels of fat in the blood) and liver failure may develop diarrhea, founder (laminitis), and fluid accumulation under the skin (edema). Some horses with liver disease have alternating diarrhea and constipation. Horses with liver failure and hepatic encephalopathy frequently develop intestinal impaction or obstruction due to decreased water intake.

Initially, your veterinarian will treat your horse to reduce the signs of severe hepatic encephalopathy, stabilize its condition, and perform laboratory tests. Your veterinarian will want to perform a liver biopsy to determine the type of tissue changes, degree of liver fibrosis present, and the regenerative capabilities of the liver cells before developing a more longterm treatment plan or providing you with an outlook for the horse’s recovery.

Heart rate and respirator rate response to exercise in horses (Proceedings)

The coordinated actions of the cardiovascular and respiratory systems result in the transport of oxygen and energy products (glucose, fatty acids) to the muscle fibers, where they are used for aerobic energy production, and the removal of waste products (lactate, carbon dioxide, water) from them.

The coordinated actions of the cardiovascular and respiratory systems result in the transport of oxygen and energy products (glucose, fatty acids) to the muscle fibers, where they are used for aerobic energy production, and the removal of waste products (lactate, carbon dioxide, water) from them. During exercise, oxygen delivery is improved by increases in the volume of air breathed, the amount of blood pumped by the heart, and the oxygen carrying capacity of the blood, together with a selective redistribution of the blood flow from the viscera to the working muscles. Many of these exercise-related adaptations are initiated by epinephrine release from the adrenal glands.

Cardiac Response to Exercise

VO2 Max: The athletic capacity of horses is attributable to a large number of physiologic and anatomic adaptations that allow an extremely high maximal rate of O2 consumption (VO2 max). VO2 max is the maximal volume of oxygen the horse's body can use per minute. VO2 max of a horse can be 200 ml/kg/min vs. 85 ml/kg/min in an athletic man. Various adaptations including large lung size, high cardiac output and stroke volume, high hemoglobin concentration and the capacity for splenic contraction increases the horse's oxygen carrying ability of blood by 50%. Training in horses usually increases VO2 max by 10-25%. In addition, horses have a very efficient thermoregulatory system which allows heat generated during exercise to be lost by evaporation from skin surface through the production of large volumes of sweat, evaporation from respiratory tract and from convective loss from skin and mucous membranes. Furthermore horses have developed an efficiency of anatomy and gait, whereby muscle mass makes up a large proportion (45-55%) of bodyweight and muscular work is halved by energy storage in elastic structures. The structure of muscle itself has various adaptations including a high mitochondrial content for aerobic energy production and large stores of energy substrates

Heart Rate Monitoring Methods:

Heart rate measuring technology is rapidly progressing in horses and is being used more and more by trainers in their training programs. Several methods have been available for many years.

1. Feel the digital or mandibular pulse. A simple, low cost method, however, it is difficult to consistently count heart rates above resting values, and it is impractical during exercise.

2. Stethoscope – more consistent than the finger pulse method. However, it is difficult to accurately determine the beats per minute at heart rates > 100 bpm and is impractical to use during exercise.

3. Electronic monitoring - Most reliable method during and while recovering from exercise. More recently they have become more affordable.

Heart Rate: The normal resting heart rate of a mature horse is between 30 to 40 beats per minute. This rate is difficult to obtain in some situations, as certain horses become excited by external stimuli, which elevates the resting heart rate. Although resting heart rate in humans can decrease dramatically as a result of physical conditioning, the resting heart rate of horses does not appear to change appreciably with fitness. Athletic horses often have low resting HRs. This indicates large stroke volume capacity. During exercise the rise in HR is the major contributor to the increase in cardiac output and it is responsible for 53% of the increase in oxygen consumption. At exercise onset, HR increases rapidly from approximately 30 beats/min to approximately 110 beats/min via parasympathetic withdrawal, with the consequence that at low running speeds heart rate may elicit an early over shoot. At faster speeds further elevations are achieved less rapidly and are driven by the sympathetic nervous system and circulating catecholamines.

The anaerobic threshold in horses is around 150 to 170 beats per minute. Heart rates below this threshold indicate that a large percentage of exercise is being performed aerobically. When exercise intensity or duration increase, the requirements of the cardiovascular system increase, which in turn results in an elevated heart rate. Heart rates above the anaerobic threshold characterize rates of metabolism that exceed the abilities of the oxygen dependant pathways supplying energy. Heart rates of 170 beats per minute or greater characterize a large percentage of metabolism occurring anaerobically or without oxygen. Anaerobic metabolism is supported primarily with glucose and glycogen as the fuel source. The threshold heart rate, like resting heart rate, does not change dramatically with physical conditioning in horses. It is likely that the threshold HR for anaerobic exercise may be influenced by genetics.

The maximal HR (HRmax) of a horse is in the range of 210-280 beats/min, which represents a 7 fold increase over resting values. Each horse has its own HRmax, which is reached at a particular exercise intensity. Once a horse reaches its HRmax a further increase in speed is still possible, but it does not elevate the HR any more. A horse with a high HRmax is favored as an athlete because it can perform more work at a specific heart rate (ie a horse with a lower HRmax works relatively harder at a given HR). Conditioning does not alter a horse's resting HR or the HRmax. After conditioning the horse reaches its HR max at a higher workload, and travels faster/works harder at a given HR. In humans HRmax decreases with age and an age related decline in HRmax has recently been described in horses such that as a horse ages it performs the same workload at a higher HR than in its youth. Maximal heart rates should not be used as a major part of conditioning programs rather, they should be monitored as a danger zone suggesting that fatigue may occur quickly. The speed or velocity a horse can achieve or sustain at a submaximal heart rate of 140, 170, 200 beats/min (i.e. V140, V170, V200) provides information about stroke volume and cardiovascular capacity and can be used as an indicator of fitness and racing potential i.e. as a horse gets fitter the velocity at which it travels at a heart rate of 170bpm should increase.

Stroke Volume: (SV)

Amount of blood pumped during each systole. At rest 450kg horse SV

900ml (2-2.5ml/kg), During exercise 450kg horse SV

1200 ml (increases by 33%). Typically SV increases sharply at exercise onset up to around 40% VO2max. This is as a result of increased blood volume, venous return, and filling pressures according to Frank-Starling's mechanism. Maximal stroke volume may not coincide with maximal HR as during very high heart rates diastole is insufficient, resulting in inadequate ventricular filling. SV will increase to a point with training.

Cardiac Output:

CO = HR X SV. The cardiac output is the amount of blood pumped by the heart each minute and is the most important means of increasing muscle oxygen delivery during exercise and thus is the principle determinant of VO2 max. Increases in CO are due mostly from an increase in HR and to a smaller degree by an increase in SV. During submaximal exercise CO increases linearly with running speed.

30-45 l/min. During exercise 450kg horse CO increases to a maximum of about 240 l/min. In very fit TBs the CO has been measured up to 350L/min. Marked adjustments in capacitance of blood vessels are needed to accommodate the large increase in CO and to distribute blood appropriately. At rest only about 15% of the circulating blood is delivered to the muscles, but this increases to as much as 85% during strenuous exercise.

Blood Pressure:

BP depends on HR, blood volume, force of ventricular contraction and resistance to blood flow from blood vessels. Systemic circulation is normally under high pressure due to the force of the left ventricular contraction and the high resistance of vessels. The systemic arterial pressure is about 155/110mmHg at rest, rising to 250/120mmHg during strenuous exercise. There is no change in the maximal arterial pressure with training.

Heart size and scoring:

Heart size is very important in horses performing exhaustive sports such as endurance, eventing. After training, ventricular mass and volume is increased. The amplitude and direction of the ECG provides some information about the size of the heart chambers and the pattern of electrical conduction. It is particularly useful in the diagnosis of arrhythmias and conduction disturbances and can be used to detect abnormalities that may interfere with the horse's athletic ability. ECG has been used by some researchers as a measurement of heart size. The "heart score" is measured as the average of duration in ms of the QRS complexes in leads I, II and III. Generally there is a positive correlation between heart size and racing performance, and some research indicates that there may be a correlation between heart score and racetrack earnings. However many cardiologists are skeptical of the accuracy of determining heart size from the duration of the QRS interval.

Cardiovascular Response to Exercise:

Increases in anticipation of exercise. The more excitable the more the anticipatory rise in HR. With the onset of exercise there is a rapid elevation of the horse's HR. When steady submaximal work is performed the HR rate shows an initial overshoot before falling to a plateau after 2-3 minutes. The size of the overshoot and the steady HR depends on the horse's fitness and work intensity. When the horse accelerates to top speed over a steady distance, there is no initial overshoot and the HR does not reach steady state. In horses galloping at a steady speed on flat ground, there is a linear relationship between speed and HR at speeds in the range of 350-700 m/min (13-26mph), which are roughly equivalent to HR of 140-200 beats/min. As the horse approaches HRmax, the HR response curve tends to flatten. The graph of HR vs. speed shifts to the left when the horse is sick and to the right with increasing fitness. When high intensity exercise ceases, there is a rapid deceleration of the HR, with the greatest reduction occurring in the first minute post-exercise. The rate at which the HR declines depends on the intensity and duration of the work, the horse's fitness and the environmental conditions (heat humidity). Generally the fitter the horse, the faster the HR returns to normal after a standard amount of exercise.

Effects of Conditioning:

The cardiovascular system shows considerable adaptations in response to conditioning and the changes occur relatively rapidly in comparison to the slow rate of adaptation of the musculoskeletal system. As the horse gets fitter there are reductions in the HR and CO at a given level of exercise, although HRmax does not change. The horse's ability to consume oxygen increases due to improvements in the efficiency of the CV system in delivering oxygen to the skeletal muscles and in the ability of the muscles to extract oxygen from the blood. There is an increase in capillarization of the muscles which slows capillary transit time and enhances gas exchange by allowing a longer period of contact between the RBCs and the muscle fibers. Some of the exercise induced changes in the CV system vary with the nature of the regular work. Endurance conditioning raises the plasma volume by about 20% and the hemoglobin concentration by about 34%. High intensity sprint conditioning stimulates greater increases in the PCV, RBCs and Hb than endurance exercise. There are short term changes in the WBC profile following strenuous exercise, and regular conditioning is associated with alterations in the total and differential WBC count.

Respiratory Response to Exercise

During exercise the primary function of the respiratory system is gas exchange which involves supplying oxygen and removing carbon dioxide from the blood in the pulmonary capillaries. The respiratory system also plays an important role in thermoregulation and acid-base balance. Horses are unusual in that they are obliged to breathe through the nose, unlike other animal species that have the option of breathing either through the nose or the mouth.


Respiratory Rate

Horses have a normal resting respiratory rate of 12-20 breaths per minute. During exercise the respiratory rate rises as high as 180 breaths per minute. At a walk and to a certain extent at a trot and pace, the horse selects an appropriate respiratory rate for the intensity of exercise. In the canter and gallop, however, the respiratory rate is usually coupled to the stride rate with a 1:1 ratio (locomotor: respiratory coupling).

Tidal Volume

Amount of air inhaled and exhaled at each breath. In a 450kg horse at rest the tidal volume is about 4-7 liters, rising to a maximum of about 10 liters during exercise. In resting breathing the dead space accounts for about 70% of the tidal volume and the alveolar volume is about 30%. With exercise there is a large increase in alveolar volume and a small increase in dead space.

Minute Volume

Amount of air passing in and out of the lungs per minute.MV = RR X TV

100l/min. At maximal exercise MV = 1500l/min (due to 7X increase in RR and 2X increase in TV)

Upper Airwary:

The resistance to airflow in the airways affects the energy expended to drive respiration. The greatest resistance occurs at the narrowest parts of the respiratory tract, which are the nostrils and the larynx. During exercise the resistance to airflow is reduced by flaring the nostrils and dilating the larynx. Other methods of reducing upper airway resistance during exercise include vasoconstriction of the nasal mucosa which increases the diameter of the nasal passages and straightening of the horse's head and neck, which decreases air turbulence by aligning the pharynx, the larynx and the trachea.

Respiratory Response to Exercise:

Rate and depth of breathing are controlled in part by chemoreceptors in the blood vessels which respond to changes in arterial oxygen tension, carbon dioxide tension and pH. A rise in respiratory rate is stimulated by a reduced oxygen tension, an increased CO2 tension or a reduced pH. At the onset of exercise, the respiratory rate and TV rise rapidly in accordance with the body's need for oxygen. In the canter and gallop and to a lesser extent the trot and pace the respiratory rate is coupled to stride rate and so the mechanics of locomotion override the chemical control of breathing. When exercise ceases, the respiratory rate decreases due to the cessation of the locomotor forces that drive respiration. Typically the horse takes a few deep breaths, and then the respiratory rate settles in the range of 60-100 bpm with the horse breathing deeply until the oxygen debt is repaid. Following repayment of the oxygen debt the respiratory response depends largely on the horse's body temperature. Panting is rapid shallow breathing, where air passes through the nasal passage but the tidal volume is small. It is therefore important to observe both the rate and depth of respiration, together with HR and rectal temperature to assess whether a horse is overheated after exercise.

Locomotor-Respiratory CouplingNG

In energetic terms the most economical breathing strategy minimizes the muscular effort of respiration. Horses accomplish this using a phenomenon known as locomotor-respiratory coupling (LRC) in which respiration is driven by the locomotor forces associated with weight bearing on the front limbs, the pressure of the abdominal organs against the diaphragm and changes in orientation of the body axis. These factors are gait dependant and as a result LRC is most effective in canter and gallop where there is a strict 1:1 ratio between the respiratory and locomotor cycles. In the trot and pace there is greater flexibility and horses will select a 1:2, 1:3 or 2:3 ratio between the respiratory rate and stride rate. In the canter and gallop one of the major contributors to LRC is the compression of the thorax between the two scapulae as the front legs bear weight. As both front legs bear weight simultaneously during canter or gallop this effect is maximized. The diaphragm is the principle muscle of inspiration. LRC augments this action through movements of the abdominal organs known as the visceral piston which have considerable inertia. When the front legs impacts the ground there is a moment of deceleration and when the leading front leg pushes off there is a moment of acceleration which moves the visceral piston. Thus as the forelimbs hit the ground expiration occurs and as the forelimbs push off into the suspension phase inspiration is stimulated. This effect is also helped by the rocking action of the horse's trunk during the canter and the movement of the head and neck up and down. In the trot and pace there less compression of the chest with forelimb loading and the body moves at a more consistent speed. In addition the body axis does not tend to pitch up and down, thus the horse has some choice in his breathing pattern.

Implications of LRC for Sport Horses

At a constant stride the visceral piston settles into the stride rhythm and the energy used in breathing is minimized. However, each time the stride rate changes it takes several strides before the visceral piston catches up with the new rhythm. During this time the energetic cost of breathing is increased. Therefore it is energetically efficient for a horse to change speed by adjusting its stride length, while maintaining the same rhythm. This is particularly relevant in which long periods of gallop are involved such as in eventing. In addition a horse with a longer stride length has a slower stride rate compared to a horse travelling at the same speed with a shorter stride length. This means that the longer striding horse can breathe more deeply, which favors its ability to maintain a speed over a longer distance. Short stride length will limit the time available for inspiration, effectively reducing the tidal volume.

Effects of Conditioning

Conditioning improves the function of muscles that hold the upper airways open during exercise, particularly the muscles of the nostrils, pharynx and larynx. Some horses that have a slight respiratory noise at the beginning of a conditioning program often will lose it as they get fitter. In the lower respiratory tract, conditioning has relatively little effect the alveoli, pulmonary capillaries, bronchioles, bronchi and chest wall show minimal adaptation in response to regular exercise. In addition there is little change in the MV and TV with training. This is in contrast to the marked adaptive responses of the CV and muscular systems and suggests that the respiratory system may be the limiting factor to athletic ability in a fit horse. In fact studies have shown that as horses get fitter they become more hypoxic and hypercapnic with exercise than pretraining blood gases. Consequently the respiratory system is regarded as the weak link in the oxygen supply pathway in horses.

Seven Feeding Myths Shattered

Despite the ability of many horse people to diagnose a strained suspensory at 30 paces, fix a faulty flying change with just a smidge more outside leg, or understand the intricacies involved in getting that recalcitrant tractor to start, a surprising number of us are baffled by the basic principles of equine nutrition. We’re content to believe the myths and misconceptions that flourished in our grandfather’s day, to feed whatever our neighbors are feeding … or to just plain get overwhelmed by the whole subject! The result is that a great many horses are fed more according to tradition than to sound scientific fact, and their overall health may suffer because of it.

MYTH #1: Horses need grain in their diets.

FACT: Horses evolved as grazing animals, and forage (pasture and/or hay) is still the basis of their dietary needs. The equine digestive system is designed to break down tough, stemmy plants and extract all the nutrition and energy they need from those materials. A great many horses get along very well on a forage-only diet if your horse has finished growing and is only in light work, is an easy keeper, or is basically a happy pasture potato, he has no need for grain.

So what’s the advantage of grain? It supplies concentrated energy, in the form of carbohydrates, which some horses need if they’re being asked to do more work than what they would normally do in the wild. Show horses, racehorses and nursing broodmares can all use the extra nutritional support of grain to help fuel their higher energy expenditure. But because the equine digestive system is poorly designed to digest large quantities of carbohydrates, there’s a limit to how much grain you can feed without risking dangerous conditions like colic and laminitis. As a rule of thumb, remember that every horse should consume between 1.5 and 3 percent of his body weight in feed every day, and at least half of that should be forage, by weight.

MYTH #2: A horse in hard work needs higher levels of protein in his diet.

FACT: In a pinch, protein can be used by the horse’s body as an energy source, but it’s a very poor way to fuel performance because molecule for molecule, protein doesn’t produce much energy, and the horse’s body has to go to great effort (chemically speaking) to extract it. Carbohydrates and fats are infinitely better energy sources—far more energy-packed than protein, and easier to break down and absorb.

Protein does play a role in the diet, however: It provides amino acids, the “building blocks” for the construction and repair of muscles, bones, ligaments and all the other structures of the body. Young, growing horses, and those being used for breeding have higher protein demands because they are building new tissues. However, mature horses not being used for breeding only need about 8 to 11 percent crude protein in their overall diets to provide enough amino acids for the occasional tissue repair. The need for protein doesn’t really increase as a horse’s energy demands do, either, so there’s no need to switch to a higher protein feed if your horse is in high-intensity work.

MYTH #3: Corn/oats/barley/sweet feed will make my horse “hot,” or high-spirited

FACT: Various feeds have gotten a reputation for altering a horse’s temperament and turning him into an instant wingnut, much like sugar gets blamed for causing hyperactivity in children. To set the record straight, it’s true that horses naturally want to burn off their excess energy, so if the diet is supplying more than their current level of exercise demands, they’ll start bouncing off the walls. It’s also true that a very fit horse tends to feel really good, so his level of exuberance may increase. But no one type of feed is likely to be responsible instead, it’s the amount of feed that’s at fault.

Certain grains may have gained a reputation for being “hot” feeds because they’ve been substituted indiscriminately for a similar volume of a lower-energy feed. Corn and barley, which have no fibrous hull, are more concentrated energy sources than oats, which do have a hull. So if you substitute a coffee-can of corn for a coffee-can of oats, then you’ll have a problem! This is why it’s so important to feed your horses by weight, not by volume. If you want to make a feed substitution, weigh your coffee-can full of oats … and then measure out the same weight in corn, or barley, or sweet feed, or whatever. Chances are, your coffee-can won’t be full! But you’ll be providing your horse with a similar amount of energy, so you won’t end up with an equine who thinks he’s one of the Flying Walendas.

Molasses, by the way, has gotten a bad rap. The amount of molasses in an average sweet feed only comes to about 1 to 2 percent of its total content—hardly enough to give your horse a “sugar buzz.” If your horse acts high when he’s fed sweet feed, it’s likely because he’s not used to the increased amount of concentrated carbohydrates.

MYTH #4: When you feed a complete feed, you don’t have to feed hay.

FACT: Well, sometimes. Definitions of “complete feeds” vary from manufacturer to manufacturer—sometimes the term is used to indicate a grain ration which is fortified with vitamins and minerals to make it “complete,” but is still designed to be fed with forage (hay or pasture). Sometimes it’s used to indicate the feed contains both concentrates (grain) and forage (chopped or pelleted hay, or another fiber source such as beet pulp), and is designed to make up 100 percent of your horse’s diet. Generally, it’s best if your horse does eat long-stemmed forage (hay or pasture) along with his grain ration, for two reasons: First, it will help keep his digestive system purring along as it should, and second, it will help satisfy his natural grazing urge. But if your horse suffers from severe allergies that prevent him from eating hay, seek out a “complete feed” with a high concentration of beet pulp (more on this ingredient below). Be aware, though, that if hay doesn’t make up part of the diet, your horse may get busy as a beaver, chewing his stall fixtures, the fencelines and anything else left within reach.

MYTH #5: Sugar beet pulp is high in sugar. And if it’s not properly soaked in water, it will expand inside your horse’s gut and cause a horrible gastric rupture.

FACT: Let’s explode the myths instead of the horse. Beet pulp is the fibrous substance that’s left over after the sugar has been extracted from sugar beets. It contains almost no sugar (unless the manufacturer has added a little dry molasses to improve the taste). Beet pulp is naturally quite high in moisture and thus prone to mold, so it’s dehydrated and made into pellets or “shreds” before it’s packaged.

Beet pulp is an excellent source of digestible fiber. It’s relatively low in protein (about 8 percent) and high in calcium, which makes it an appropriate feed for almost all adult horses. If you are feeding supplements, top-dressing corn oil, or giving your horse medications, beet pulp can be an excellent place to hide the yucky ingredients. It’s a great addition to the diet if your hay is of poor quality, or if your horse has dental problems and can’t chew long-stemmed forage, or for horses recovering from an injury or illness. Plus, it’s usually quite inexpensive.

The best way to feed beet pulp is to soak it in water a few hours before meal-time use twice as much water as beet pulp, and leave it to swell and absorb the moisture. (Because it has a tendency to ferment in warm weather, you’ll only want to make up one day’s worth at a time.) The resulting brown, fluffy stuff can be mixed in with your horse’s grain or served on its own. But don’t worry if you’ve added a little too much liquid, or too little. You can’t actually explode a horse with unsoaked beet pulp. In a study referred to in Lon Lewis’ “Feeding and Care of the Horse, 2nd ed.”, ponies were fed dehydrated beet pulp, up to a level of 45 percent of their total diet, with no ill effects whatsoever. Not only did they not explode, but they also suffered no signs of colic, nor did the water content in their manure change. However, most people prefer to soak beet pulp—it’s more palatable that way and less likely to cause choke.

MYTH #6: A weekly bran mash is good for my horse’s digestive health.

FACT: Wheat bran is actually junk food for horses. Yes, they love the taste, but it’s not really good for them. First, as a fiber source it’s not that digestible, and second, bran contains about 13 times as much phosphorus as calcium, an imbalance which can eventually affect a horse’s bone structure. Third, its famous laxative effect doesn’t really exist. Horses are quite sensitive to sudden changes in their diets, so when you feed your horse a bran mash instead of his regular meal, it causes a mild digestive upset, and the result the next day is loose manure. An occasional bran mash on a cold winter’s night does no real harm, but your horse’s digestive system would prefer beet pulp (soaked in warm water has a similar effect). If you feed bran on a daily basis, try to make it no more than 10 percent of his total diet. Avoid bran if you’re feeding a young horse—the calcium/phosphorus imbalance can interfere with his growth. On the whole, there are better feeds than bran.

MYTH #7: Alfalfa hay is the best-quality choice for my horse.

FACT: Though horses definitely seem to prefer alfalfa in a side-by-side taste test with grass hay, alfalfa is far too high in protein for most adult horses. Depending on when it’s harvested, it can range up to about 24 percent protein—too rich for any horse other than a young, growing one or a nursing broodmare. Though excess protein doesn’t do any major harm, the kidneys have to work overtime to excrete it—and the result is excess of urine with a strong ammonia smell, which means more mucking to do! Alfalfa is usually more costly, too, and in some parts of North America it may be infested with poisonous blister beetles.

Grass hay is a better choice for most adult horses, with timothy being the most common variety there’s also brome, bermuda and orchardgrass, among others. Though not quite as high in some vitamins, and not quite as sweet and tasty, it’s got a more appropriate protein level than alfalfa, doesn’t harbor blister beetles and is often less dusty. Mixed hays, which contain both legumes (alfalfa and/or clover or birdsfoot trefoil) and grasses, can be a good compromise too. You can get your local feed agent to do a hay analysis for about $20 to $40, which will tell you more about the nutrient content of your hay.

If you have more feeding questions, don’t be afraid to ask your veterinarian or the horse-feed specialist at your local feed store. They’ll be able to provide you with common-sense advice and help you make the best feed choices for your particular horse.

Kim Baierl &ndash March 4, 2021

Our vet recommended Elevate for both horses to maintain a strong immune system. In talking with Lisa Barry a 5* Eventer, she recommended Tage receive digestive support with Neigh-Lox Advanced.

Each horse gets a blue scoop of Elevate in AM and PM food. Additionally Tage gets 2 scoops of Neigh-Lox Advanced AM and PM.

Both products are easy to administer and eaten happily.

Dominique Lien &ndash August 25, 2020

“When I got my OTTB Blue, transitioning her diet was one of my biggest challenges. She was the definition of a hard keeper. It wasn’t until I started working with Kentucky Performance Products staff that we were able to fill in the holes in her diet and the changes were phenomenal. I trust KPP to help me with all of Blue’s nutritional needs.

Retired Racehorse Project participant and Thoroughbred Makeover competitor

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Proper nutrition is one of the main objectives to ensure the well-being and good performance of horses. It influences the growth, reproduction, performance capacity, and health of the horse. Horse feeding is challenging for many horse owners as well as horse trainers and breeders. Many horses suffer from overweight as well as many diseases associated with nutrition. Further, other management issues, including stable and environmental conditions and feeding systems, have a major impact on the health and well-being of horses. Vice versa, horses&rsquo management influences their environment. In addition, there are many innovations in horse feeding and management. The aim of this Special Issue is to publish original research papers or reviews concerning horse nutrition and management (including all breeds and different purposes and horse categories), and the interrelations between management, nutrition, health, wellbeing, and environment.

Areas of interest: nutrient availability and requirements of various horse categories effects of feeding and management on performance, growth, well-being and health of the horse, as well as on the environment feeds and feed ingredients

We invite you to share your recent findings through this Special Issue.

Dr. Markku Saastamoinen
Dr. Maria João Fradinho
Dr. Cecilia Muller
Guest Editors

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Ashwagandha is a plant with unique medical properties. The roots and berries of ashwagandha are used to make different types of medicine.

The plant is popular throughout the Ayurvedic (traditional Indian medicine) community for its ability to treat stress, fatigue, lack of energy, and other symptoms. It’s one of those plants that appears to have multiple benefits throughout the body and works to restore overall wellness and wellbeing.

The plant is also known as Indian ginseng. However, ginseng and ashwagandha are not actually related in any way. The plant is most similar to the tomato plant and belongs to the same family as the tomato.

The plant itself comes in the form of a plump shrub with oval leaves and yellow flowers. Its fruit are red and approximately the size of a raisin.

Ashwagandha grows naturally throughout the drier regions of India as well as northern Africa and the Middle East. As ashwagandha has become more popular, farmers in the United States have begun growing it in milder climates throughout the country.

Ashwagandha goes by a few different names, including Indian ginseng, winter cherry, dunal, and Solanaceae. Its taxonomical name is Withania Somnifera.

The name “ashwagandha” in Sanskrit actually means “smell of horse”, so some people refer to the herb under that name.

To most people, however, it’s simply known as ashwagandha.

Benefits of Ashwagandha

Ashwagandha is often used by traditional medicine practitioners to treat symptoms like:

In Ayurvedic medicine, practitioners will often recommend using ashwagandha to boost your overall energy and to “rejuvenate your wellbeing”.

More recently, studies have shown that ashwagandha can have benefits beyond just boosting your energy. Some of the recent studied benefits of ashwagandha include:

How Does Ashwagandha Work?

Ashwagandha is thought to work because it contains a variety of useful medicinal compounds. Some of the most important medical compounds in ashwagandha include:

— Withanolides (also Known As Steroidal Lactones)
— Alkaloids
— Choline
— Fatty Acids
— Amino Acids

One of the key reasons why ashwagandha is that it has adaptogenic benefits. Ayurvedic medicine believes that certain herbs have high levels of adaptogens, and these herbs provide valuable health benefits.

“Adaptogens” are nutrients like vitamins, minerals, amino acids, and herbs that help control your body’s response to stress. They’re called “adaptogens” because they help you adapt to the changing world around you in a healthy way.

When you’re comparing ashwagandha supplements online, you’ll notice that many manufacturers advertise “withanolides” content (say, between 1.5% and 3%). Withanolides are the active compounds in ashwagandha and include a variety of nutrients and herbal extracts.

Scientific Evidence for Ashwagandha

Ashwagandha has not been studied extensively over the years, but it has been studied in several major double-blind, placebo-controlled studies conducted by major research organizations. Here are some of the biggest and most important studies involving ashwagandha thus far:

2012 Study Shows that Ashwagandha Root Improves Resistance to Stress and Improves Quality of Life

One of the most influential studies on ashwagandha root was published in the Indian Journal of Psychological Medicine in July, 2012. That study involved 64 subjects with a history of chronic stress. Over the course of the double-blind, randomized, placebo-controlled study, participants who took ashwagandha were observed to have better resistance towards stress and a better self-assessed quality of life. Obviously, 64 subjects isn’t a very large sample number. However, other studies have reinforced these benefits even further.

2009 Study Shows Ashwagandha Reduces Anxiety

A 2009 study aimed to examine the effects of ashwagandha on people with severe anxiety. One participant group took 300mg of ashwagandha (1.5% withanolides content) twice daily over the course of 8 weeks. Both the placebo group and the ashwagandha group also received counselling. Ashwagandha supplementation was observed to provide a 56.5% reduction in anxiety symptoms as assessed by BAI, although the placebo group “only” experienced a 30.5% reduction.

2000 Study Demonstrates Anxiolytic Properties of Ashwagandha

One 2000 study published in the Indian Journal of Psychiatry laid the foundation for future studies of ashwagandha’s anti-anxiety properties. That study involved 39 subjects, 20 of whom received ashwagandha extract. Researchers observed that the extract had anxiolytic (anti-anxiety promoting) effects. Researchers also noted that “the drug was well-tolerated and did not occasion more adverse effects than did placebo.”

Study Shows Ashwagandha Can Significantly Reduce Total Cholesterol Levels

A study from the year 2000 involving 12 Indian men and women demonstrated that ashwagandha root powder could decrease blood glucose comparable to that of an “oral hypoglycemic drug” (i.e. traditional diabetes medication). Levels of LDL (bad) cholesterol were significantly reduced and researchers noted “no adverse effects.” That study was published in the Indian Journal of Experimental Biology.

16 Month Study Shows Ashwagandha Reduces Stress and Anxiety While Boosting Cardiovascular Health

This next study involved 98 people over a period of 16 months. Participants received 250 to 500mg of ashwagandha extract daily (either in two divided doses of four doses of 125mg). The study concluded that “daily consumption of standardized WSE [Withania somnifera extract]…reduced experiential feelings of stress and anxiety, serum concentrations of cortisol and CRP, pulse rate and blood pressure and increased serum concentration of DHEAS in the chronically stressed adults who completed the study.”

The study has faced some criticism because the authors were associated with two companies that produced ashwagandha supplements (Nutragenesis and Natreon). You can view the study online here.

How to Use Ashwagandha

Ashwagandha is relatively easy to add to your daily diet. The most common way to take ashwagandha is in capsule form. You can find countless ashwagandha supplements available online and from local supplement retailers.

Most supplements contain 600 to 1,000mg of ashwagandha extract. You take it once or twice per day. some people also believe that taking ashwagandha with a cup of hot milk or tea before bedtime is more beneficial.

How to Buy Ashwagandha Supplements

Some of the most popular ashwagandha supplements on the market include:

— Dr. Mercola’s Ashwagandha (90 Capsules Per Bottle): $17.47 on

— Herb Pharm Ashwagandha Extract Mineral Supplement: $10.37 on

— GNC Herbal Plus Ashwagandha Extract 470mg: $15.99 on

When comparing ashwagandha supplements, you should primarily look at two things: the amount of extract and the percentage of withanolides. Withanolides, as you may remember from above, are the active ingredients in ashwagandha and include multiple vitamins, minerals, and herbal compounds. You want the maximum amount of withanolides in your ashwagandha supplement to maximize the health benefits.

Digestive System of the Pig: Anatomy and Function

An overview of the pig's digestive system - mouth, stomach, small and large intestines by Joel DeRouchey and colleagues at Kansas State University's Applied Swine Nutrition Team, presented at the Swine Profitability Conference 2009.

The digestive system of a pig is well suited for complete concentrate based rations that are typically fed. The entire digestive tract is relatively simple in terms of the organs involved, which are connected in a continuous musculo-membanous tube from mouth to anus. Yet this multi-faceted system involves many complex interactive functions.

The goal of this paper is to describe the organs involved in digestive and biological functions (Figure 1).


The mouth serves a valuable role not only for the consumption of food but it also provides for the initial partial size reduction though grinding. While teeth serve the main role in grinding to reduce food size and increase surface area, the first action to begin the chemical breakdown of food occurs when feed is mixed with saliva.

There are three main salivary glands, which include the parotid, mandibular and sub-lingual glands. Saliva secretion is a reflex act stimulated by the presence of food in the mouth. The amount of mucus present in saliva is regulated by the dryness or moistness of the food consumed. Thereby in a dry diet, more saliva mucus is secreted while in a moist diet, only an amount to assist with swallowing is secreted. Saliva generally contains very low levels of amylase, the enzyme that hydrolyses starch to maltose. The contribution of digestive enzymes from saliva is minor but still noteworthy.

Once food is chewed and mixed with saliva, it passes though the mouth, pharynx and then the oesophagus to the stomach. Movement though the oesophagus involves muscle peristalsis, whichis the contraction and relaxation of muscles to move the food.


The stomach is a muscular organ responsible for storage, initiating the breakdown of nutrients, and passing the digesta into the small intestine.

The stomach has four distinct areas which include the oesophageal, cardiac, fundic and pyloric regions (Figure 2). The oesophageal region is located at the entrance of the stomach from the oesophagus. This region of the stomach does not secrete digestive enzymes but has significance in that this is where ulcer formation in pigs occurs. Irritation in this area due to fine particle size, stress or other environmental factors can contribute to ulcer formation in swine. Once food passes though this region, it enters the cardiac region.

In the cardiac portion of the stomach, mucus is secreted and mixed with the digested food. Food then passes into the fundic region which is the first major portion of the stomach that begins the digestive process. In this region, gastric glands secrete hydrochloric acid, resulting in a low pH of 1.5 to 2.5. This reduced pH kills bacteria ingested with the feed. Other secretions in this region are present in the form of digestive enzymes, specifically pepsinogen. Pepsinogen is then broken down by the hydrochloric acid to form pepsin, which is involved with the breakdown of proteins.

Finally the digesta moves to the bottom of the stomach, which is the pyloric region. This region is responsible for secreting mucus to line the digestive membranes to prevent damage from the low pH digesta as it passes to the small intestine. The phloric sphincter regulates the amount of chyme (digesta) that passes into the small intestine. This is an important function not to overload the small intestine with chyme so proper and efficient digestion and absorption of nutrients occurs. In addition, once the chyme leaves the stomach, the material is quite fluid in consistency.

Small Intestine, Pancreas and Liver

The small intestine is the major site of nutrient absorption, and is divided into three sections. The first section is the duodenum. The duodenum is approximately 12 inches long and is the portion of the small intestine that ducts from the pancreas and the liver (gall bladder). The pancreas is involved with both exocrine and endocrine excretions. This means the pancreas is responsible for secretion of insulin and glucagon in response to high or low glucose levels in the body. In addition, it has exocrine functions of secreting digestive enzymes and sodium bicarbonate.

The digestive enzymes secreted break down (hydrolyse) proteins, fats, and carbohydrates in the chyme. In addition, the sodium bicarbonate serves a vital role to provide alkalinity so chyme can be transported though the small intestine without causing cell damage because of the low pH after leaving the stomach. The pancreas serves as the most vial organ in the digestive process for producing and secreting enzymes needed for the digestion of chyme and the prevention of cell damage due to pH.

In addition to the pancreas secreting into the duodenum, bile, which is stored in the gall bladder and produced by the liver, is secreted as well. Bile salts, which are the active portion of bile in the digestion process, primarily assist in the digestion and absorption of fat but also help with absorption of fat-soluble vitamins and aids pancreatic lipase in the small intestine. Finally, bile salts are necessary for the absorption of cholesterol, which takes place in the lower small intestine and are circulated to the liver via the portal vein.

Once the chyme passes though the duodenum, the digestion process is in full swing. Upon leaving the duodenum, enters the middle portion of the small intestine, the jejunum. This portion of the small intestine involves both the further breakdown of nutrients as well as the beginning of absorption of nutrients. Nutrient absorption continues into the final section of the small intestine, the ileum. Absorption of nutrients in the jejunum and the ileum occurs in the area termed ‘brush border’, or the intestinal mucosa (Figure 3). The mucosa is comprised of finger-like projection called villi, which in turn contain more micro-size projections called microvilli. The tips of the microvilli form web-type structures called glycocalyx.

Amino acids and simple sugars released into the brush border membrane are absorbed into the microvilli first, then into the villi, and then pass into the circulatory system. Absorbed amino acids and simple sugars are taken directly to the liver via the portal vein. For dietary fat that is broken down and absorbed into the brush border, they enter the lymphatic system and are released into general circulation via the thoracic duct.

Large Intestine

The large intestine or hindgut encompasses four main sections. First, digesta from the small intestine passes into the caecum. The caecum has two sections, first a section that has a blind end, where material can not pass though. The caecum has a second portion where it connects to the colon, where digesta is passed to the rectum and anus where the remaining digesta is excreted.

The main function of the large intestine is the absorption of water. The chyme that passes through the small intestine and into the large intestine initially is very fluid. The large intestine epithelium has a large capacity for water absorption.

Once digesta passes though the ileum into the large intestine, no enzymatic digestion occurs. However, limited microbial enzymes activity does occur in the large intestine, which forms VFAs (volatile fatty acids). These can be readily absorbed in the large intestine. Generally these provide only enough energy to assist in the nutrient requirements of the epithelium of the large intestine. Also, B-vitamins are synthesised in the large intestine and are absorbed in a very limited amount, but not significant to alter nutritional supplementation of them.

With the majority of water removed, the digesta is condensed into a semi-solid material and is passed out of the rectum and anus.



Horse chestnut is an herbal supplement that can be purchased as a cream, capsule (dry) or liquid extract.

Today, most horse chestnut extracts are made from the seed as opposed to the leaf or bark since the seed contains the highest concentration of escin [28].


Because horse chestnut is not approved by the FDA for any conditions, there is no official dose. Users and supplement manufacturers have established unofficial doses based on trial and error. Discuss with your doctor which may be the optimal dose in your case.

With this in mind, horse chestnut dosage depends on the sought-after health benefit.

The maximum oral dose recommended for use in humans per day is 150 mg [4].

Standardized horse chestnut extracts contain around 20% of escin [1].

The studied dose for escin injections is 5-10 mg twice daily for up to 2 weeks [1].

Creams with horse chestnut contain 2% escin and are applied 3-4 times a day up to 2 months [15].

User Experiences

The opinions expressed in this section are solely those of horse chestnut users who, may or may not have medical or scientific training. Their reviews do not represent the opinions of SelfHacked. SelfHacked does not endorse any specific product, service, or treatment.

Do not consider user experiences as medical advice. Never delay or disregard seeking professional medical advice from your doctor or other qualified healthcare providers because of something you have read on SelfHacked. We understand that reading individual, real-life experiences can be a helpful resource, but it is never a substitute for professional medical advice, diagnosis, or treatment from a qualified healthcare provider.

Some users said horse chestnut seed extract helped them with irregular fat distribution (lipedema) and reduced swelling. However, one user reported frequent nausea and vomiting after taking the supplement.

Most users took horse chestnut with food to avoid stomach upset.

Many users mentioned that horse chestnuts were effective in reducing varicose veins and leg swelling. Some reported leg cramping as a major side effect, as well as chest pain, and headaches.

Experts are saying to avoid anything that causes inflammation during this Coronavirus pandemic, but some people have genes that make them more likely to experience inflammation. Check out SelfDecode’s Inflammation DNA Wellness Report for genetic-based diet, lifestyle and supplement tips that can help reduce inflammation levels. The recommendations are personalized based on YOUR DNA.

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Ana Aleksic


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