Disclaimer: Please don't judge based on the links. These articles are a few years old and the links may be outdated. I haven't checked. These are for examples of my work only.
Lethal White Syndrome
Lethal White Syndrome, sometimes called Overo Lethal White Syndrome or OLWS, is a devastating condition that affects some foals of primarily Paint Horse breeding.
First discovered in 1982, its exact causes are as yet unknown, but it is always fatal. Because of this, most OLWS foals are euthanized shortly after birth, or else they die painfully soon thereafter. The condition is most closely associated with Overo Paint horses, but carriers have also been found in Tobiano and Tovero, as well as some solid-colored animals.
Both the sire and dam must carry the specific genes that contribute to this condition in order for a OLWS foal to result.
Usually born snowy white, with pink skin and light blue eyes, afflicted foals generally appear normal in every way. Because of their unique coloring, they are unusually beautiful. It's unclear why coat color has any direct relation to the affliction, but it does. However, many white foals are born that have no trace of the disease, nor are they carriers of the gene that causes it.
The problem stems from the foals' colons or intestines, which are underdeveloped. Often, the intestine stops just short of the anal opening, preventing the foal from passing feces. Because of this, they will soon colic and die.
The affliction has also been found in a few other breeds, such as Thoroughbreds, Miniature Horses, half-Arabians, pintos, and sometimes in crop-out Quarter Horses (horses with too much white to be registered as Quarter Horses).
Occasionally, surgery has been attempted in an effort to save OLWS foals, but it has always proven to be unsuccessful. The condition just cannot be cured at the present time.
If you are planning on breeding horses, and think you may have a carrier for OLWS, have your horse or horses tested. Far better to learn of it before than to go through the heartache of having to destroy one more Lethal White foal.
For more information on Lethal White Syndrome, visit these sources:
Lavender Foal Syndrome
Lavender Foal Syndrome, also called Coat Color Dilution Lethal, is a rare genetic neurological disorder that affects foals of Egyptian Arabian breeding.
It gets its name from the unusual coat color of most affected foals; described as very pale chestnut, lavender or light purple, pewter, shimmering silver, or slightly pinkish.
These foals are unable to stand, the condition never improves, and there is no known treatment or cure, so the foals are usually euthanized. Symptoms include an inability to stand or sit upright, rolling or twitching eye movements, stiff legs or a 'paddling' or 'running' motion with the legs, and lying flat on the ground with the neck stretched back and out, and they often suffer seizures as well.
The eyes are often light colored, being described as grayish or with a bluish tint to them.
Like Lethal White Syndrome, both the sire and the dam must be carriers of the specific gene that contributes to the disorder.
Lavender Foal Syndrome has been recognized as far back as the 1950s, but surprisingly little research has been done until recently. Even now, because of the relative rarity and very few specimens to do research with, there is much mystery surrounding the affliction.
Both sexes can be affected by the disorder, but it only appears in horses of Egyptian Arabian bloodlines or their crosses.
There has been some suggestion that other Arabian bloodlines not related to Egyptian Arabians can also be carriers as well, but this is still up for debate.
Because even today, little is known of its causes, and because it is still quite rare, many veterinarians are unfamiliar with it and may misdiagnose a Lavender foal as having some other neurological disease. Much is being done in the area of studying the disorder, but there is still a long way to go.
For more info on Lavender Foal Syndrome, you can look at these sources:
http://risingrainbow. Blogspot.com/2007/06/lavender-foal-syndrome-arabian- horse.html