Several patterns of white hair occur on horses. Each one will be described by the appropriate pattern term that is accepted by the ISHR Association. These are the most complete and accurate variations that are used by this registry. "ASYMMETRICAL" white patches are typical of Paints/Pintos, and consist of irregular patches of white on any base color. "SYMMETRICAL" white patches are typical of Appaloosas and POAs. Several different patterns fall into these groups, each is a separate and distinct pattern. (On some Appaloosa's the patterns can be combined and grouped to form unusual pattern types).
(the terms "paint" and "pinto" usually mean any equine with the white asymmetric spotting patterns. There are at least 4 distinct patterns in the group of "paint/pinto", but the North American usuage most often lumps only 3 of these together.
ISHR uses the pattern types, "Tobiano", "Overo"(in which it encompasses the pattern "Frame"), "Tovero", "Sabino" and "Splashed White". Some breeders are trying for the "politically correct" usage for all terms, but, unless you have a very trained eye and educated in what patterns are exactly what - for the average horse person, it can be very confusing. While more and more different types of pattern genes are popping up in the science end of it, for the average horse person, it can be very trying. But, it is true that "spots" get a lot of attention no matter what the pattern type and that is what ISHR is looking for and all about.
(PLEASE - the board of ISHR asks that you refrain from emailing the office and asking that we change our pattern types and/or color types. The board will be happy to listen to any suggestion, but in letter form and mailed to the ISHR home office - THANK YOU!)
"PATCHWORK PAINTS"
TOBIANO (toe-bee-ah-no): is the most common type of white spotting seen on horses in the U.S. The white areas usually have a distinct, sharp edge to them. The back is usually crossed at some point by a white patch. All four lower legs are usually white, the head is usually colored with markings common on unspotted horses and the eyes, as a rules, are not blue. A tobiano can range from very little white to a horse that is largely white. (usually the head is colored and the body is white with very little color patches)
TOVERO (toe-vah-roh): is not a common pattern, but is a combination of spotting of that of both the tobiano and overo patches. Usually the head has a lot of white, while the body has the more distinct tobiano patches.
OVERO (oh-vah-roh): frequently, "frame, sabino & splashed white" are lumped together, but in fact, each is distinct. Overo is usually used in the North American term as meaning "non-tobiano". It was thought at one time that the overo gene was recessive, but has been investigated and learned that this genetic control is dominant. The white pattern is usually horizontal as opposed to the tobiano pattern, which is more vertically arranged. Overos often have one or more colored feet. (as seen in the above picture) Overos are rarely all white, most of the white foals die because of intestinal malfunctions a few days after birth. (this is called "fatal white")
SABINO (sah-bee-no): usually this is not identified as a separate pattern but is lumped with overo. It is a distinct pattern and sometimes called a "Flecked Roan, Calico, speckled, or particolor". It is very confusiing in terminology. The Sabino pattern usually involves extensive white leg and facial markings, body spots are usually on the belly and can either occur as roan or speckled areas and the white marks differ from usual white markings because they tend to be narrow extensions up on the legs or down and around the throat. (in the Clydesdale breed, the sabino pattern is very common) The white displayed takes the form of flecks and patches of white on the body in patterns similar to the overo pattern but is much more ragged and irregular. Exceedingly white sabinos maintain colored ears, a chest patch and maybe a colored patch on the flank and base of tail.(Medicine Hat)
There has been some level of expression that breeding a Sabino to Sabino WILL NOT produce the "lethal white foal" syndrome as when mating an Overo to an Overo.
***At this time there is no perponderance of scientific proof to support a single gene dominant basis for the inheritance pattern of the sabino, but that doesn't mean that the theory of a separate single gene is not correct, only that the amount of existing data doesn't validate it using scientific statistical analysis. Many people that have been breeding just for the sabino have not done scientifically documented extensive testing of hundreds of proven crosses. It is suggested by some that the genetic cause is definately not the overo gene - BUT, as stated before, extensive testing of thousands of horses MUST be done to prove the sabino gene inheritance pattern.
SPLASHED WHITE: is rare and is seen more commonly in North America in the paint/pinto breed. Horses with this pattern have a body where the white is ventrally. (picture a horse that is dipped into a vat of white paint when lowered feet first just to the lower half of the body) The head is extensively white (often completely white) and the eyes are blue as a rule. Sometimes the difference between a "splashed white" and "sabino" can be subtle, and makes identifying the pattern nearly impossible.
FRAME: horses with this pattern generally have dark legs and feet (or at least leg markings no more than expected of solid colored horses), heads are usually extensively white and horses tend to have a pigmented upper lip (sometimes called a mustashe) and blue eyes. The white spotted areas tend to have clean, crisp edges, but are sometimes more ragged than that of tobiano spots. The spots are horizonal, rather than vertical like the tobiano spots.
"APPALOOSAS"
BLANKET (spotted & solid): blankets of white vary in extent from small ones situated over the croup and hips of the horse to larger ones covering most of the body. Some blankets have roan edges, blending into the colored areas. Other blankets are solid white and sharply defined, and still others blend into the colored areas with flecks of white hairs. Many blankets show characteristics of all three and is difficult to cleanly separate the types. (roan, solid, or flecked)
LEOPARD (patterned-unpatterned-few spot): is used for horses that are all white, or that have extensive blankets, with colored spots on the white. These spots can vary in size. With the "Patterned Leopard", the spots appear to flow out from the flank and over the body of the horse. The "Unpatterned Leopard" the spots tend to be rounder and do not appear to flow out of the flank, but seem to be randomly scattered over the body. A "Few Spot Leopard" is largely white, but frequently retains the colored flank, neck, and head. Some are essentially white without spots (except the pigmented skin can be seen if the coat is wet down)Most Few-Spot Leopards are homozygotes, some are heterozygotes, not all homozygous horses are Few-Spot Leopards. The presence or absence of leopard spots is an inaccurate indicator of homozygosity or heterozygosity.
VARNISH ROAN: also referred to as "marble" is a pattern of white that varies from a simple roan blanket to white hairs dispersed over the whole horse. It differs from the usual pattern of roan in that the head has white hairs and the colored hairs are concentrated over the bony prominences (facial bones, withers, shoulders, knees, stifles, and pelvic bones). These darker areas are called "Varnish Marks". This pattern will likely change with the age of the horse, since many are born solid and develop this pattern later in life.
SNOWFLAKE (speckled): pattern is one that varies with the age of the horse. It begins with small spots that grow into the coat of a colored horse. The white spots can increase in number as the horse ages until the pattern stabilizes at some point. The more advanced pattern is then called "speckled", representing an end point of the "snowflake" pattern and not a completely separate pattern. (some speckled horses can be confused with "flea-bitten")
MOTTLED: refers to small points of white on the muzzle, on the genitalia and around the eyes. Mottling can occur over the entire body in a pattern that does not fit into any other pattern of white.
"PINTALOOSA"
The "Pintaloosa" has the characteristic spotting of both the Tobiano pattern of the paint/pinto and the scattered spots of an Appaloosa.
Generally, the Class "A" Pintaloosa will be distinct in both types of spotting. The larger patches resembling a Tobiano and the smaller spots resembling the spotting of an Appaloosa, usually on the rump and/or sides. (they can also have the tobiano pattern with the typical blanket of an Appaloosa) The "Pintaloosa" is becoming very popular as a new "Color" type breed in the spotted horse world.
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