Skewbald

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A skewbald horse, chestnut with white patches American Paint Horse.JPG
A skewbald horse, chestnut with white patches

Skewbald is a colour pattern of horses. A skewbald horse has a coat made up of white patches on a non-black base coat, such as chestnut, bay, or any colour besides black coat. Skewbald horses which are bay and white (bay is a reddish-brown colour with black mane and tail) are sometimes called tricoloured. These horses usually have pink skin under white markings and dark skin under non-white areas. Other than colour, it is similar in appearance to the piebald pattern. Some animals also exhibit colouration of the irises of the eye that match the surrounding skin (blue eyes for white skin, brown for dark). The underlying genetic cause is related to a condition known as leucism. The term is also used to describe spotting patterns in various other animals, such as goats.

Contents

Horses

Terminology

In British equestrian use, skewbald and piebald (black-and-white) are together known as coloured, and the white markings are called patches. In North American equestrian usage, the term for all large-spotted colouring is pinto , and the markings are called spots, The specialized term paint refers specifically to a breed of horse with American Quarter Horse or Thoroughbred bloodlines in addition to being spotted, whereas pinto refers to a spotted horse of any breed. Americans usually describe the colouration of a pinto literally: black-and-white, chestnut-and-white, or bay-and-white.

Genetics

Genetically, a skewbald horse begins most commonly with a chestnut base coat colour (called "red" by geneticists), or some other set of colour genes other than black. Then the horse has an allele for one of three basic spotting patterns overlaying the base colour. The most common coloured spotting pattern is called tobiano, and is a dominant gene. Tobiano creates spots that are large and rounded, usually with a somewhat vertical orientation, with white that usually crosses the back of the horse, white on the legs, with the head mostly dark. Three less common spotting genes are the frame and splash overo genes, which create a mostly dark, jagged spotting with a horizontal orientation, white on the head, but dark or minimally marked legs. The sabino pattern can be very minimal, usually adding white that runs up the legs onto the belly or flanks, "lacy" or roaning at the edge of the white, plus white on the head that either extends past the eye, over the chin, or both. The genetics of overo and sabino are not yet fully understood, but they can appear in the offspring of two solid-coloured parents, whereas a tobiano must always have at least one tobiano parent.

Other animals

The term is also applied sometimes to goats and dogs, among other animals. Both piebald and skewbald are used in dog and goat breeding.

See also

Related Research Articles

Roan (color)

Roan is a coat color found in many animals, including horses, cattle, antelope and dogs. It is defined generally as an even mixture of white and pigmented hairs that do not "gray out" or fade as the animal ages. There are a variety of genetic conditions which produce the colors described as "roan" in various species.

American Paint Horse American horse breed defined by a part-colored coat

The American Paint Horse is a breed of horse that combines both the conformational characteristics of a western stock horse with a pinto spotting pattern of white and dark coat colors. Developed from a base of spotted horses with Quarter Horse and Thoroughbred bloodlines, the American Paint Horse Association (APHA) breed registry is now one of the largest in North America. The registry allows some non-spotted animals to be registered as "Solid Paint Bred" and considers the American Paint Horse to be a horse breed with distinct characteristics, not merely a color breed.

Lethal white syndrome

Lethal white syndrome (LWS), also called overo lethal white syndrome (OLWS), lethal white overo (LWO), and overo lethal white foal syndrome (OLWFS), is an autosomal genetic disorder most prevalent in the American Paint Horse. Affected foals are born after the full 11-month gestation and externally appear normal, though they have all-white or nearly all-white coats and blue eyes. However, internally, these foals have a nonfunctioning colon. Within a few hours, signs of colic appear; affected foals die within a few days. Because the death is often painful, such foals are often humanely euthanized once identified. The disease is particularly devastating because foals are born seemingly healthy after being carried to full term.

Piebald

A piebald or pied animal is one that has a pattern of unpigmented spots (white) on a pigmented background of hair, feathers or scales. Thus a piebald black and white dog is a black dog with white spots. The animal's skin under the white background is not pigmented.

Tricoloured horse

Tri-coloured refers to a horse with three different coat colours in a pinto spotting pattern of large white and dark patches, usually bay and white. This colouring is also commonly called skewbald. In modern usage in British English, skewbald and piebald horses are collectively referred to as coloured, while in North American English, the term pinto is used to describe the colour pattern.

Bay (horse) Hair coat color of horses

Bay is a hair coat color of horses, characterized by a reddish-brown or brown body color with a black point coloration of the mane, tail, ear edges, and lower legs. Bay is one of the most common coat colors in many horse breeds.

Pinto horse Horse with coat color that consists of large patches

A pinto horse has a coat color that consists of large patches of white and any other color. The distinction between "pinto" and "solid" can be tenuous, as so-called "solid" horses frequently have areas of white hair. Various cultures throughout history appear to have selectively bred for pinto patterns.

Tobiano

Tobiano is a spotted color pattern commonly seen in pinto horses, produced by a dominant gene. The tobiano gene produces white-haired, pink-skinned patches on a base coat color. The coloration is almost always present from birth and does not change throughout the horse's lifetime, unless the horse also carries the gray gene. It is a dominant gene, so any tobiano horse must have at least one parent who carries the tobiano gene.

Overo

Overo refers to several genetically unrelated pinto coloration patterns of white-over-dark body markings in horses, and is a term used by the American Paint Horse Association to classify a set of pinto patterns that are not Tobiano. Overo is a Spanish word, originally meaning "like an egg".There are at least three genetically different spotting patterns which fall under the "overo" classification: frame overo, sabino overo, and splash or splashed white overo.

Equine coat color Horse coat colors and markings

Horses exhibit a diverse array of coat colors and distinctive markings. A specialized vocabulary has evolved to describe them.

White horse

White horses are born white and stay white throughout their lives. White horses may have brown, blue, or hazel eyes. "True white" horses, especially those that carry one of the dominant white (W) genes, are rare. Most horses that are commonly referred to as "white" are actually "gray" horses whose hair coats are completely white and may be born of any color and gradually "grey" as time goes on and take on a white appearance.

Black horse Horse coat color

Black is a hair coat color of horses in which the entire hair coat is black. Black is a relatively uncommon coat color, and it is not uncommon to mistake dark chestnuts or bays for black.

Sabino horse

Sabino is a group of white spotting patterns in horses that affect the skin and hair. A wide variety of irregular color patterns are accepted as sabino. In the strictest sense, "sabino" refers to the white patterns produced by the Sabino 1 (SB1) gene, for which there is a DNA test. However, other horse enthusiasts also refer to patterns that are visually similar to SB1 as "sabino", even if testing indicates the gene is not present. Use of the term to describe non-SB1 "sabino" patterns in breeds that apparently do not carry the gene is hotly debated by both researchers and horse breeders.

Horse markings Colored areas, usually white, on a horse that differ from the body color

Markings on horses are usually distinctive white areas on an otherwise dark base coat color. Most horses have some markings, and they help to identify the horse as a unique individual. Markings are present at birth and do not change over the course of the horse's life. Most markings have pink skin underneath most of the white hairs, though a few faint markings may occasionally have white hair with no underlying pink skin. Markings may appear to change slightly when a horse grows or sheds its winter coat, however this difference is simply a factor of hair coat length; the underlying pattern does not change.

Rabicano

Rabicano, sometimes called white ticking, is a horse coat color characterized by limited roaning in a specific pattern: its most minimal form is expressed by white hairs at the top of a horse's tail, often is expressed by additional interspersed white hairs seen first at the flank, then other parts of the body radiating out from the flank, where the white hairs will be most pronounced. Rabicano is distinct from true roan, which causes evenly interspersed white hairs throughout the body, except for solid-colored head and legs.

A cropout, crop-out or crop out is a horse with body spots, including pinto or leopard complex spotting, or "high white" horse markings, with a sire and dam who both appeared to have been solid-colored. There are several variations in the definition, depending on the breed registry involved. There are multiple genetic reasons that may cause a horse to be a cropout. Sometimes solid-colored horses throw cropouts because some spotting patterns are recessive genes that are not necessarily expressed unless the relevant allele is inherited from both parents. Other times a gene may be a dominant or incomplete dominant but so minimally expressed that the horse looks solid but can pass flashy color on to its offspring.

Splashed white

Splashed white or splash is a horse coat color pattern in the "overo" family of spotting patterns that produces pink-skinned, white markings. Many splashed whites have very modest markings, while others have the distinctive "dipped in white paint" pattern. Blue eyes are a hallmark of the pattern, and splash may account for otherwise "solid" blue-eyed horses. Splashed white occurs in a variety of geographically divergent breeds, from Morgans in North America to Kathiawari horses in India. The splashed white pattern is also associated with congenital deafness, though most splashed whites have normal hearing. Splashed white can be caused by multiple variants across two different genes, for which genetic testing is available.

Dominant white Horse coat color and its genetics

Dominant white or white spotting is a group of genetically related coat color conditions in the horse, best known for producing an all-white coat, but also able to produce various forms of white spotting and white markings, several of which are sometimes referred to as sabino.

The Pinto Horse Association of America (PtHA) registers horses, utility horses, ponies and miniature horses of various pedigrees with certain kinds of pinto coat colors. The word pinto is Spanish for "paint." In general terms, pinto can apply to any horse marked with unpigmented pink-skinned, white-haired areas on its coat. The Pinto Horse Association of America provides the owners and riders of pintos with a show circuit and a breed organization. The primary requirement for PtHA registration is coat color; the pinto is not a true breed, but a color breed.

Roan (horse) Horse coat color pattern characterized by an even mixture of colored and white hairs on the body

Roan is a horse coat color pattern characterized by an even mixture of colored and white hairs on the body, while the head and "points"—lower legs, mane and tail—are mostly solid-colored. Horses with roan coats have white hairs evenly intermingled throughout any other color. The head, legs, mane and tail have fewer scattered white hairs or none at all. The roan pattern is dominantly-inherited, and is found in many horse breeds. While the specific mutation responsible for roan has not been exactly identified, a DNA test can determine zygosity for roan in several breeds. True roan is always present at birth, though it may be hard to see until after the foal coat sheds out. The coat may lighten or darken from winter to summer, but unlike the gray coat color, which also begins with intermixed white and colored hairs, roans do not become progressively lighter in color as they age. The silvering effect of mixed white and colored hairs can create coats that look bluish or pinkish.

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