Overo

Overo

Overo is a term used in the equine industry to describe a specific pattern of white coat coloration in horses, particularly in the American Paint Horse breed. This pattern is characterized by irregular, jagged white markings that do not cross the horse's back between its withers and tail. Overo is one of the several patterns of pinto coloration, which also includes Tobiano and Tovero.

Characteristics

The Overo pattern is known for its unique and often unpredictable appearance. The white markings typically originate from the horse's belly and spread upwards, often leaving the back and legs predominantly dark. The head is usually extensively marked with white, and blue eyes are common in Overo horses.

Genetics

The genetics of the Overo pattern are complex and not fully understood. It is believed to be caused by a combination of multiple genes. One of the known genes associated with the Overo pattern is the "Frame Overo" gene, which is linked to the lethal white syndrome when homozygous. This genetic condition results in foals that are born with an underdeveloped intestinal tract, leading to early death.

Types of Overo

There are several subtypes of Overo patterns, each with distinct characteristics:

• Frame Overo: Characterized by horizontal white patches that are framed by darker colors. This is the most common type of Overo.
• Sabino Overo: Features roaning or speckled patterns, often with white extending up from the legs and belly.
• Splashed White Overo: Appears as if the horse has been dipped in white paint, with white markings on the lower body and face.

Health Considerations

Horses with the Overo pattern, particularly those with the Frame Overo gene, should be carefully bred to avoid producing foals with lethal white syndrome. Genetic testing is available to identify carriers of the Frame Overo gene.

Breeding and Registration

Overo horses are popular in the American Paint Horse breed, and their unique patterns are highly sought after in the show ring. Breeders often aim to produce horses with striking and balanced Overo patterns.

Also see

• Pinto horse
• American Paint Horse
• Equine coat color genetics
• Lethal white syndrome