Your complete guide to horse breeds, care, and riding from around the world

Horse Fact #21

Horses have a prehensile upper lip. Prehensile means "adapted for seizing, grasping, or taking hold of something." Their upper lips are very sensitive and capable of feeling the smallest of differences in objects.

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Tölt Gait

The Tölt (also, less correctly, Tolt) is a gait that is often described as being unique to the Icelandic Horse. In its pure form, the footfalls are the same as in rack, but the gait in the Icelandic horse has a different style with more freedom and liquidity of movement. The most prized horses have a very long stride and considerable lift with their forelegs. Icelandic Riders will demonstrate the smoothness of a tölt by going at the speed of a gallop without spilling a drink they hold. However, some horses have a tölt that is considered imperfect, and may be described as a "trotty tölt" or a "pacey tölt".The Tölt differs from the rack as the horse is not supposed to hollow its back.


The majority of Icelandic horses can also perform a type of pace called flugskeið or a "flying pace," and are thus called "five-gaited". (Walk, trot, canter, tölt, pace.) Good pacers are held in high regard in this breed, but for a pacer to stand out the horse has to be able to perform the pace at a high speed.Slow pacing in Icelandic horses is considered a major flaw. A horse that goes at a slow pace, or "piggy-pace," is referred to as lullari.


The Faroese Horse and the Nordlandshest/Lyngshest of Norway share common ancestry with the Icelandic horse and some individuals of these breeds have the capacity to tölt, although it is not as commonly used.

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Horse Facts #20

Horses have about 175 bones in their body. Horses leg joints are not fully fused (grown) until the age of 3.5yrs.

A horse's splint bones are thought to be remnants of toes from prehistoric horses. The splint bones are small bones (about the size of a pencil at the top and tapering down to be much smaller) found on each side of the cannon bone.

Sometimes a small bulge will appear on the horses lower leg, this is usually a splint bone that has popped. This happens when the splint bone becomes detached from the cannon bone. A splint might become detached due to a nutritional imbalance or trauma. It is usually not a cause for concern. In most cases a popped splint will cause mild pain to the horse but when the splint has "set" or healed it is completely pain free and is not a health or soundness concern.

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Cayuse horse

Cayuse is an archaic term used in the American west, usually referring to a feral or low-quality horse or pony.

In British Columbia, the variant word cayoosh refers to a particular breed of mountain pony with shorter legs and large hindquarters, typically also of Indian husbandry.

The origin of the word is a Native American adaptation of the Spanish caballo, with the -s ending a noun form in Salishan languages. A variant adaptation, kiuatan, with a Sahaptian -tan ending, is the main word for "horse" or "pony" in the Chinook Jargon, although cayuse or cayoosh was also used in some areas. For this reason, some horses owned by Native American people were dubbed "cayuse," often with derogatory intent.

Although the settlers called most horses raised by the American Indians "cayuse ponies", the Cayuse Indian Pony of the Northwest is a distinct breed which originated in the 1800's. Its conformation and its background set it apart from the mustang, Spanish Barb or other wild horses.

Small and stocky, the Cayuse Indian Pony has high withers and an unusually long canon bone. In addition, its distinctly sloped pastern gives it a broken walking gait. Any rider, especially younger children, will find this an extremely pleasant and easy seat. 

Frederic Remington, who is famous for his artistic representations of the Old West, sketched many of the wild horses he found in the late 1800s. He described the Cayuse Indian Pony as "generally roan in color, with always a tendency this way, no matter how slight." Remington wrote that his subject was heavily muscled, and while only about fourteen hands high, was still very powerful.

 The Cayuse breed's history is obscure and difficult to trace.

It has been generally accepted that the Cayuse Indian Pony descended from the French-Norman horses imported into Canada in the 1600s. Most of these French horses were Percherons, which the Canadians used to improve their domestic breeds. The Percheron was a good choice -- it continues to be one of the only work horses which can easily trot for extended periods of time.

Years later, the French Canadians brought their horses into what is now American territory. It was recorded that they bartered their horses in St. Louis with the Pawnee Indians, who then took them further west. Eventually, the Indians crossed their sturdy French horses with the lighter Spanish Barbs to produce a horse which had not only speed, but endurance.

By the 1800s, the Cayuse Indian Pony had become a separate breed. The Cayuse Indians, known throughout the Northwest for their expert horsemanship, continued to develop this French-Spanish Barb strain through selective breeding.

Because the French horse had the ability to pass on its tendency for spots or a profusion of white markings, the Cayuse Indians were able to produce some very colorful horses. In fact, the Appaloosa, Paint and Pinto breeds have all been influenced by the blood of the Cayuse Indian Pony.

 Today, the Cayuse Indian Pony breed is seldom seen outside California.

Only a handful are even still in existence. Jeff Edwards, co-founder of the Wild Horse Research Center in Porterville, California has gradually been trying to rebuild a herd and protect it from extinction. Over 100 head of Cayuse Indian Ponies were lost several years ago when their pasture land was sprayed with a toxic herbicide.

 But the Wild Horse Research Center is optimistic about the breed's recovery. Recently, they donated a Cayuse Indian Pony to the Kentucky Horse Park near Lexington with the hope that more people could discover the saga if this unique horse. They are also working with one small stud bunch at the farm and anxiously await the spring foals each year.

The Center has also established a registry for wild horses and ponies possessing barb blood. The Cayuse Indian Pony can now be officially registered as one of the "Horse of the Americas" breeds. Edwards determined the purity of each horse based on its physical characteristics and charts researched by the Wild Horse Research Center.

 For additional information contact Jeff Edwards, Wild Horse Research Center, 248 N. Main Street, Porterville, California 93257

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Horse Trivia #17

A horse isn't considered an adult until it reaches age four.

A female horse over 4 years old is called a mare.

A father horse is called a sire.

A mother horse is called a dam.

A young female is called a filly.

A young male is called a colt.

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Inheritance of Curly Hair in Horses

Dominent curly horse gene

This is a theoretic genetic formula for how the dominant curly gene, the straight haired gene, and the recessive curly gene appear to interact. At the moment this is the best explanation we have that fits all the information we have. We do not yet have a DNA test for any "curly gene."





First, for a basic explanation of genetics, adapted from the UC Davis website:




In every living being, millions of instructions called 


Every cell contains two copies of each gene, one contributed at conception by the mother and one by the father. The gene sets contain similar, but not necessarily identical, information in each gene. For example, both genes in a set may contain instructions that determine hair structure, but one gene may contain the instructions for straight hair and the other for curly hair.


The alternative forms of each gene are called alleles.
If both alleles are identical, then the individual is Homozygous at that gene locus (location). If the alleles are dissimilar, then the individual is said to be Heterozygous for that gene set. Information about the homozygosity or heterozygosity for various genes can be inferred from information about parents and/or progeny and can be used for predicting the outcome of matings.


Often when the gene pair is heterozygous, one allele may be visibly expressed but the other is not. The expressed allele in a heterozygous pair is known as the Dominant allele and the unexpressed one as the Recessive allele. The term dominant is given an allele only to describe its relationship to related alleles, and is not to be taken as an indication of any kind of physical or temperamental strength of the allele or the individual possessing it. Likewise, possession of a recessive allele does not connote weakness.


In any individual expressing the dominant allele of a gene, it cannot be determined by looking at the individual whether the second allele is a dominant or recessive. The presence of a recessive allele may be masked by a dominant allele, which leads to the expression Hidden Recessive. A dominant alleles is never hidden by it.s recessive allele.


For simplicity in constructing models, geneticists symbolize genes by letters such as A, B, C and so on. A dominant allele of a gene can be symbolized by an italicized capital letter, e.g., A, and the recessive by an italicized lower case letter, e.g. a...



A workable genetic formula for equine hair structure:



  • C = dominant Curly gene

  • c = recessive straight allele in same location as dominant Curly gene


  • R = dominant Straight gene unrelated to straight gene at the C locus

  • r = recessive curly allele at same location as the dominant Straight gene

Options:


CC RR - Homozygous dominant curly, looks curly, always throws dominant curly foals. Has normal straight genes at recessive loci.


Cc RR - Heterozygous dominant curly, looks curly, has normal straight genes at recessive loci. Throws curly gene 50% of time.


CC Rr - Homozygous dominant, heterozygous recessive. Looks like a curly, can throw recessive curly if bred to another recessive carrier or recessive curly 50% of the time. Won't be able to tell when since all foals will be curly due to 100% transmission of a dominant curly gene.


Cc Rr - Heterozygous dominant and heterozygous recessive. Is dominant curly visibly, and can produce dominant curly foals off straight mares 50% of the time and can transmit recessive gene 50% of the time.


CC rr - Homozygous dominant & homozygous recessive. Curly coat. Will always throw curly foals and will always transmit one recessive curly gene.


Cc rr - Heterozygous dominant curly and homozygous recessive curly. Always curly coated, and always transmits a recessive gene, but only throws dominant gene 50% of the time, so can throw straights off non recessive curlies, or straight horses.


cc RR - Normal straight horse. No curly signs visible. Don't know about hypoallergenicity. Can't throw any curly gene.


cc Rr - Straight coated horse. Carries one recessive gene. If paired with a recessive curly or recessive curly carrier can throw a curly.


cc rr - Recessive curly. No dominant Curly gene, but two recessive curly ones. Will always throw a recessive curly gene, but will only parent a curly if the other parent also throws in a recessive curly gene.

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Horse Trivia #15

Horses can see in two directions at once. Most of the time, a horse has monocular vision. This means a different image is seen by each eye so that a horse is seeing two different pictures at the same time.

Your horse can also have binocular vision. Binocular vision is when both eyes work together to see one picture (humans have binocular vision). A horse only has binocular vision when it is looking down its nose.

Your horse has a wide visual range. Your horse can see completely around its entire body except for two small blind spots. One directly in front of its face, underneath its head, and the other directly behind itself. This is why it's very important not to walk up, directly behind a horse - you are in its blind spot and if you startle it you can get kicked.

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Horse Trivia #13

The smallest horse breed is the Falebella miniature horse of Argentina.

  • The tallest recorded member of the breed stands just 74cm (30 inches) at the shoulder.
  • The smallest pony in history was a stallion named "Little Pumpkin". He stood just 14 inches tall and weighed only 20lbs.
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Horse Trivia #12

The World's Largest Horse was a purebred Belgian stallion named Brooklyn Supreme. He stood 19.2hh (6'6") at his withers. He weighed over 3,200 pounds and is entered in the Guiness Book of World Records. He was foaled in 1928 and died in 1948. He lived in Iowa, USA.

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Horse Trivia #7

  • Most horse breeds have 18 ribs.
  • The Arabian horse has 17 ribs.
  • Most horses have 6 lumbar bones.
  • The Arabian horse has 5 lumbar bones.
  • Most horses have 18 tail vertabrea.
  • The Arabian horse has 16 tail vertabrea.
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    Horse Trivia 6

    A mule is a cross between a male donkey (a jack) and a female horse (a mare). A hinny is a cross between a male horse (a stallion) and a female donkey (a jenny). Mules and Hinnies are usually sterile.

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    Long Necks in Horses

    A long neck for a horse is a neck that is much more than 1/3 the length of the horse.

    Long necks are common, especially in Thoroughbreds, Saddlebreds, and Gaited Horses.

    A long neck  may make it hard to balance the horse, and the horse may fatigue more quickly as a result of carrying too much weight on its front end.

    Lengthy neck muscles are difficult to develop in size and strength. A long-necked horse needs broad withers to support the weight of head and neck.

    It is easier for the horse to fall into the bend of an S-curve than to come through the bridle, which causes the horse to fall onto his inside shoulder. This makes him difficult for the rider to straighten.

    The horse with a long neck  is best for jumping and speed sports (without quick changes of direction), or for straight line riding, like trail riding.

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    How big is a hand?

    Equines are measured in units. Which unit of measure is used depends on the association doing the registration. Some registries use inches to determine size, since it is easier than trying to convert to hands. Other registries record measurements in hands.


    A hand is four inches. The story behind this unit of measurement is that a farmer went to measure his favorite horse. Not having a device to measure with, he used the only thing he knew would be consistent: the palm of his hand. Since then, the hand has been the unit of measure for equines.





    Abbreviations for hands


    The letters HH or hh after the numbers stand for Hands High. The single letter H or H may be used, standing just for "hands".

    Parts of a hand are given after the whole unit, following a decimal. 10.2 hands (can also be read as just Ten-two) means ten hands and two more inches. (4 inches x 10 hands equals 40 inches, plus two additional inches, so 10.2 is 42 inches tall). 10.3 would be 10 hands and 3 inches, forty-three (43) inches. There is no such thing as 10 hands 4 inches, as 4 inches would be an additional hand. However, even fractions of an inch can be listed, such as 10.3 ¾ hh. (Ten hands, 3 ¾" inches, or Ten-three and three-quarters: just ¼" shy of a full 11 hands.)

    Some examples of hand measurements


    3.3 hands - 15 inches at the withers, the smallest horse ever documented. Too Small! But, this animal reportedly only lived to be two years old (just short of what anyone would call mature).


    4.2 hands - 18 inches.  A few Miniature foals are only 18 inches high at birth.


    6 hands - 24 inches. There have been a few Miniature Horses reported at this height (short?) in recent years.


    6.1 hands - 25 inches - unverified report of the smallest known mature Miniature Donkey


    6.2 hands- 26 inches - the height of the smallest known breeding Miniature donkeys (in the USA) and also the height of the smallest known mule in the world (General Grant).


    7 hands - 28 inches. A few Miniature donkeys this small, difficult for females in pregnancy and birthing. Animals this small prized in some circles, but conformation tends to suffer.  Either malproportioned in some cases, or very tiny with weak bone.


    7.2 - 30 inches. Was once being debated as the cut-off point for breeding size in Miniature donkeys (no plans by ADMS to do this)


    8 hands - 32 inches. Miniature size for horse, donkey or mule. Good average for Miniature Donkey height.


    9 hands - 36 inches - breakover point from Miniature to Small standard for donkeys with no pedigree (Maximum height 36") . Still miniature height for mules.


    9.2 hands - 38 inches. Maximum allowable height for Miniature donkeys with BOTH parents registered as Miniature. Still classified as Oversized in MDR.


    10 hands - 40 inches. Breakover for small standard to Standard donkeys. (Still Miniature height for mules)


    11 hands - 44 inches. Standard donkeys in this height range. Common height for most of the Plains zebras (Grants, Damaraland, Chapmans)


    12 hands - 48 inches. The breakover from Standard to Large Standard in donkeys


    12.2 hands - 50 inches. The breakover from Miniature to Saddle Mules.


    13 hands  - 52 inches - large Standard donkeys. Considered Pony height in horse breeds. Top end height for zebras, only Grevy's species usually get this tall.


    13.2 hands - 54 inches - breakover from Large Standard to Mammoth height in Jennets


    14 hands -  56 inches - breakover point from Large Standard to Mammoth for Jacks and Geldings


    14.2 - 58 inches - in horses considered the line between Pony (under 14.2) and horse height. Typical size of many Mustangs, although a recent infusion of outside blood in some herds produces larger animals now.


    15 hands - 60 inches - typical for many saddle horse breeds, mules, and reaching the top end for Mammoth height. About average height for Arabians and some Gaited breeds.


    16 hands - 64 inches. Getting pretty large for a donkey, but a few jacks reported close to this height. Typical range for saddle mules, draft horses, and many saddle horse breeds.


    17 hands - 68 inches. Extremely large for a donkey, they tend to "fall apart" in conformation at this height. Commonly seen in some Draft horse breeds, Warmbloods, and a few saddle mules.


    18 hands - 72 inches. A few specimens this tall, but unusual in all but a few breeds, mainly Warmblood or Drafters.


    19 hands - 76 inches! (6 foot, 4" at the withers). Taller than most men!


    19.1 hands - 77 inches high, 6 foot 5 inches at the withers. The height of the tallest Mule in the World, according to the Guinness Book of World Records. Apollo, (b 1977, in TN) is listed with teammate Anak at 18.3. (75 inches)


    20 hands - 80 inches.


    21 hands -  84 inches


    21.2 ½ hands - 86 ½ inches at the withers. Tallest horse ever documented, a Shire gelding named Sampson (aka Mammoth with good reason!) measured in 1850 and listed in the Guinness Book of World Records.



    The information provided in this article is courtesy of the American Donkey and Mule Society and is (c) by the ADMS.  Permission is granted to copy for educational purposes (ie school papers, 4-H work, general education websites, fairs, expos) provided that the work is sited as provided coutesy of the American Donkey and Mule Society.  (c) 2001, 2002, 2003, 2004


     

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    Anatomy of the Horse Foot



    A horse's hoof is composed of the wall, sole and frog. The wall is simply that part of the hoof that is visible when the horse is standing. It covers the front and sides of the third phalanx, or coffin bone. The wall is made up of the toe (front), quarters (sides) and heel.


     



    When the foot is lifted off the ground, the sole and frog are visible, as well as the bars of the wall and the collateral grooves (Figure 1).


    Figure 1 - The wall, bars and frog are the weight-bearing structures of the foot.


    Structures of the horse foot



    The wall of the hoof is composed of a horny material that is produced continuously and must be worn off or trimmed off. The hoof wall does not contain blood vessels or nerves.

    In the front feet, the wall is thickest at the toe; in the hind feet the hoof wall is of a more uniform thickness. The wall, bars and frog are the weight-bearing structures of the foot. Normally the sole does not contact the ground.


     



     


    Figure 2a - Internal structure of the horse foot.


    Internal structure of the horse foot



    These cartilages are flexible, but as the horse ages, they are usually ossified and replaced by bone. Between the second and third phalanges and above the deep flexor muscle tendon is a small bone called the navicular bone (Figure 2b).



    Internal structure of the horse foot


     Inside the hoof, lateral cartilages extend back and up from the inner and outer sides of the third phalanx. (Figure 2a).


                              Figure 2b - Internal structure of the horse foot.


    The navicular bone and its associated bursa — a fluid-filled sac that reduces friction between the tendon and the bone — are involved in navicular disease, which is a common cause of lameness.


     


    Figure 2c - External structure of the horse foot.



    External structure of the horse foot Flexible structures in the horse's hoof expand and contract with each step as weight is transferred from one foot to another.

    The digital cushion is a mass of flexible material that contributes to the formation of the heels (Figure 3). This structure is one of the primary shock absorbers of the foot.

    As weight is placed on the hoof, pressure is transmitted through the phalanges to the wall and onto the digital cushion and frog. The frog, a highly elastic wedge-shaped mass, normally makes contact with the ground first. The frog presses up on the digital cushion, which flattens and is forced outward against the lateral cartilages.


    Figure 3 - The frog also is flattened and tends to push the bars of the wall apart.


    Flexible structure in the horse's hoofWhen the foot is lifted, the frog and other flexible structures of the foot return to their original position.

    When the foot is placed on the ground, blood is forced from the foot to the leg by the increase in pressure and by the change in shape of the digital cushion and the frog.

    The pressure and the change in shape compress the veins in the foot. When the foot is lifted, the compression is relieved and blood flows into the veins again. In this way, the movement of these structures in the hoof acts as a pump. Exercise increases the blood circulation in the foot and favors good hoof growth. Lack of exercise, dryness of the horny wall, and poor nutrition inhibit hoof growth.

    Normally, the hoof wall grows at the rate of about three-eighths inch per month. New layers of hoof wall are produced continuously from just below an area called the coronet at the junction of the skin and the hoof wall (Figure 2c).

    The hoof wall is covered with material that prevents evaporation of moisture. When this material is deficient, the hoof wall becomes dry and excessive flaking and cracking may occur. A good hoof paint aids in preventing excessive drying.

    This publication was originally written jointly by Robert C. McClure, Gerald R. Kirk and Phillip D. Garrett. Kirk and Garrett are former faculty members in the Department of Veterinary Anatomy, College of Veterinary Medicine. Illlustrations are by Phillip D. Garrett.

     


     


     



     

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    Fallen crest

    A  large crest or fallen crest refers to a horse that has an overly large crest to it's neck that may fall to one side in extreme cases.

    Fallen crests are relatively uncommon, although any horse can develop an excessively large crest. It is usually seen in stallions, ponies, Morgans, and draft breeds.

    It is usually from fat deposits above the nuchal ligament. An excessively large crest not only looks bad, but it puts more weight on the forehand. A horse with an excessive crest due to obesity needs a proper conditioning program.

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    Horse Trivia #10

  • More foals are born between April 15 and May 15 than at any other time.
  • Mares usually foal at night.
  • Foaling mares don't like being watched. They will stop foaling and wait till a person leaves.
  • A mare may give birth in as little as 15 minutes, but usually no longer than an hour.
  • If a mare is still straining after an hour has passed, something is seriously wrong.
  • If you have to help pull a foal out, NEVER pull up! Always pull down, toward the mares feet.
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    White Brindle Left Side Only

    Brindle is a rare color for horses, although it occurs frequently in cattle and dogs. These pictures of a white brindle horse are of a 2002 Dutch Warmblood mare by Celano, imported from the Netherlands in May 2008. Her pattern is strictly on her left side, even throughout her mane and tail. She seems to have a seam along her backbone the brindle markings don't cross. However, she has a few funny little circles on the right side on her head and neck.
















    White Brindle Horse
    White brindle horse picture Right side of horse
    White brindle left side of tail White brindling only on left side
    White brindle color pattern Note white pattern on left side only
    white brindling on horse

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    Akhal-Teke Genetic Diseases

    Akhal Tele Hairless Colt

    There are several genetic diseases of concern to Akhal-Teke breeders. The genetic diversity of the breed is relatively low with an AVK of 30-50%, which raises concerns for dealing with an increase in carriers of these conditions, and even some risk of inbreeding depression. To date, there are no DNA tests for these conditions.



    Hairless Akhal-Tele colt caused by a genetic disorder


    Naked Foal Syndrome or Hairless Foal Syndrome is most likely an autosomal, lethal recessive gene, though the exact inheritance pattern has not yet been verified. It appears to be similar in clinical signs, though not identical to junctional epidermolysis bullosa (JEB) found in the Belgian horse and another condition of a similar nature identified in the American Saddlebred.


    The defect causes foals to be born without any hair coat, mane or tail. In some cases, the front teeth are in at birth or molars grow abnormally from normal jaws. Other symptoms include persistent diarrhea, frequent digestive disorders and laminitis-like, treatment-resistant rotation of the coffin bones in the hooves.


    Due the lack of normal skin protection, secondary symptoms include scaly, dry and inflamed skin, as well as severe cases of sunburn in summer and frequent pulmonary infections during winter. NFS is always fatal, most foals die within weeks of birth, although some horses have survived up to the age of two years.


    Early demise is usually caused by digestive problems, whereas older horses need to be humanely euthanized because of severe laminitis-induced pain. Cases were recorded within the Akhal-Teke breed as early as 1938. In spite of the breed's limited population, naked foals have been born in every country in which the breed is represented, including the USA.


    Some 35 carriers have been ascertained, including 943 Arslan, 736 Keymir, 2001 Mariula or 1054 Gilkuyruk, but the estimated number of unknown cases is very likely much higher, as several Russian and Turkmenian breeders have acknowledged that many NFS foals are often just reported as stillborn or aborted.


    Hereditary cryptorchidism is very common within the Akhal-Teke breed and many cases exist where afflicted stallions can be traced through multiple generations. The influential foundation sire, 2a Boinou, was a cryptorchid according to experts of the breed. Other verified cryptorchids include 779 Peren, 1248 Orlan, 971 Khalif, and Garayusup. 1069 Kortik produced three cryptorchid sons. Unlike most European and many North American breed organisations, neither Russia nor Turkmenistan bar cryptorchids from breeding. Cryptorchidism is said to be related to health and character problems, such as testicular cancer and malignant behaviour. Affected horses cause significantly higher costs when castrated.


    Wobbler syndrome, seen in a number of breeds, including the Thoroughbred, is thought to be on the increase in the Akhal-Teke. Of particular concern is the form known as cervical vertebral malformation (CVM), which may also be linked to Osteochondritis dissecans (OCD) to a certain extent. There is a genetic component to Wobbler's, but factors such as breeding Akhal-Teke horses for certain conformation in the neck and management of young stock for forced growth and greater size may also play a role.


    The Akhal-Teke is one of several breeds that is prone to degenerative suspensory ligament desmitis (DSLD) Some animals also have a condition known as "Kissing Spine."

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    What is the ‘horsepower’ unit of measurement based on?

    Horsepower (HP) is the name of several units of measurement of power. The most common definitions equal between 735.5 to 746 watts. The horsepower is not recognized in the International System of Units (SI).


    The horsepower was originally defined to compare the output of steam engines with the power of draft horses. The unit was widely adopted to measure the output of piston engines, turbines, electric motors, and other machinery. The definition of the unit varied between geographical regions. Most countries now use the SI unit watt for measurement of power.


    The definition of the horsepower also has varied between different applications:



    • The mechanical horsepower of 550 foot-pounds per second is approximately equivalent to 745.7 watts.

    • The metric horsepower of 75 kgf-m per second is approximately equivalent to 735.499 watts.

    • The boiler horsepower is used for rating steam boilers and is equivalent to 34.5 pounds of water evaporated per hour at 212 degrees Fahrenheit, or 9,809.5 watts.

    • One horsepower for rating electric motors is equal to 746 watts.

    • The Pferdestärke (German translation of horsepower) is a name for a group of similar power measurements used in Germany around the end of the 19th century, all of about one metric horsepower in size.

    • The Royal Automobile Club (RAC) horsepower or British tax horsepower is an estimate based on several engine dimensions.

    The development of the steam engine provided a reason to compare the output of horses with that of the engines that could replace them. In 1702, Thomas Savery wrote in The Miner's Friend: "So that an engine which will raise as much water as two horses, working together at one time in such a work, can do, and for which there must be constantly kept ten or twelve horses for doing the same. Then I say, such an engine may be made large enough to do the work required in employing eight, ten, fifteen, or twenty horses to be constantly maintained and kept for doing such a work…"


    The idea was later used by James Watt to help market his improved steam engine. He had previously agreed to take royalties of one third of the savings in coal from the older Newcomen steam engines. This royalty scheme did not work with customers who did not have existing steam engines but used horses instead. Watt determined that a horse could turn a mill wheel 144 times in an hour (or 2.4 times a minute). The wheel was 12 feet in radius, therefore the horse travelled 2.4 × 2π × 12 feet in one minute. Watt judged that the horse could pull with a force of 180 pounds. So:


    formula for horsepower


    This was rounded to an even 33,000 ft·lbf/min.


    Others recount that Watt determined that a pony could lift an average 220 lbf (0.98 kN) 100 ft (30 m) per minute over a four-hour working shift. Watt then judged a horse was 50% more powerful than a pony and thus arrived at the 33,000 ft·lbf/min figure.


    Engineering in History recounts that John Smeaton initially estimated that a horse could produce 22,916 foot-pounds per minute. John Desaguliers increased that to 27,500 foot-pounds per minute. "Watt found by experiment in 1782 that a 'brewery horse' was able to produce 32,400 foot-pounds per minute." James Watt and Matthew Boulton standardized that figure at 33,000 the next year.


    Most observers familiar with horses and their capabilities estimate that Watt was either a bit optimistic or intended to underpromise and overdeliver; few horses can maintain that effort for long. Regardless, comparison with a horse proved to be an enduring marketing tool.


    A healthy human can produce about 1.2 hp briefly (see orders of magnitude) and sustain about 0.1 hp indefinitely; trained athletes can manage up to about 2.5 hp briefly and 0.3 hp for a period of several hours.


    Horsepower from a horse


    R. D. Stevenson and R. J. Wassersug published an article in Nature 364, 195-195 (15 July 1993) calculating the upper limit to an animal's power output. The peak power over a few seconds has been measured to be as high as 14.9 hp. However, for longer periods, an average horse produces less than one horsepower.

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    Bull Neck

    Bull Neck

    The horse with a bull neck has a short, thick, and beefy neck with a short upper curve. The attachment to its body is beneath the half-way point down the length of shoulder. This trait is fairly common, especially in draft breeds, Quarter Horses, and Morgans.

    With a bull necked horse, it is generally more difficult to maintain balance if the rider is large and heavy or out of balance, which causes the horse to fall onto its forehand. Without a rider, the horse is usually fine.

    A bull neck is desirable for draft or carriage horses, so as to provide comfort for the neck collar. The muscles of the neck also generate pulling power.The horse with a bull neck  is best for non-speed sports.

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    Dished face

    If a horse has a concave or dished face profile, it is often further emphasized by a slight bulging of the forehead (jibbah). Dished heads are associated with Arabians and Arabian-influenced breeds, which excel at endurance riding and were originally bred in the arid Arabian desert. There are several theories regarding the adaptive role of the dished face. It may be an adaptation to reduce airflow resistance and increase aerobic endurance. It may also have a role in cooling inspired air, or cooling blood headed to the brain.

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