5 Disease Panel N/N
"What is the big deal, so many of the greats did just fine with these diseases?"
This is the question I see most about the 5 disease panel test; and it's true, many of them did just fine. But how many of their offspring didn't do so well, how many died early or lived a life of pain because the disease was passed on? Technology has given us an an advantage that breeders of even 20 years ago did not have, and Arrow Maker Ranch takes every advantage of that technology. All of the diseases that are tested for in the 5 disease panel can lead to death and/or a severely diminished quality of life.
If you are unfamiliar with the diseases that are tested in the 5 disease panel required by AQHA for breeding stallions, here's a quick guide:
HYPP = Hyperkalemic Periodic Paralysis Disorder
This disease can cause a horse's muscles to paralyze for no obvious reason, including the muscles that control breathing, causing a horse to suffocate to death, or the heart, causing a heart attack leading to death. It is a dominant disorder which means that if a horse even has one copy of the gene, it "has" the disease. This disease  can be traced back to Impressive who had a huge impact on the AQHA breeding industry and has many thousands of offspring still today.
HERDA = Hereditary Equine Regional Dermal Asthenia
A horse with two copies of the HERDA gene will suffer from skin lesions caused by things like the pressure of a saddle or even sunburn. The disease effects the "glue" that holds the skin of the horse in place; basically, the horse's skin will fall off. There is no solid known origin for HERDA, but it is suspected to have originated around Poco Bueno.  
PSSM1 = Polysaccharide Storage Myopothy 1(one)
PSSM1 is also a dominant disease that can cause severe muscle cramps to the point of tying up and being unable to move. It can range in severity from no symptoms at all to totally debilitating. Many times symptoms can be reduced or eliminated by a low sugar diet.
MH = Malignant Hyperthermia
This is a fairly rare genetic disease that only needs one copy for a horse to "have" the disease. It can cause death if a horse is exposed to anaesthesia for surgery or extremely high stress. Basically, the horse can not cool itself down and overheats, sometimes to the point of death. It can be made worse if the horse also has PSSM1.
GBED = Glycogen Branching Enzyme Deficiency
This disease is 100% fatal when a foal has 2 copies of the gene (homozygous). It is believed that most die in utero, but none that have been born lived past 8 weeks old. The disease effects the foal's ability to use the nutrients it eats for even basic life functions. Horses with only 1 gene are not effected but they can pass it on, so two carriers should never be bred together. 
So, yes, the greats did just fine with some of these diseases; but many of their offspring didn't even have the chance to become great because of them.
One more disease that is popping up more and more in registered AQHA horses, is Lethal White Overo (LWO), also known as Frame Overo. LWO can hide in quarter horses for many generations, only showing white well within the allowable areas for AQHA registations. Lethal White foals are the result of a cross between two LWO carriers that received 2 copies of the LWO gene. This condition is also 100% fatal to foals.
The disease causes malformation of the digestive tract and the foal can not poop. LWO foals are usually all, or almost all, white at birth. If not humanely euthanized, they will die within 3 days.
The only way to be absolutely sure that no foals from our program are effected by these diseases, is to breed negative (N/N) stock. Arrow Maker Ranch does its best to provide the highest quality horse for future owners, as well as, providing that horse with the highest quality of life that we can.