Neu Perspectives

The 6-Panel Sum Up

In the performance world, we are basically confronted with six different diseases that are imperative to test for using the 6 panel test.

Funny, the things we think we understand and don’t.

For example, I used to believe that the phrase “layman’s terms” was actually “lame man’s terms”, as in — if you need it dummied down to that point in order to grasp a concept, you must be a lame man. 

Naturally, I said this aloud at some point and was corrected. (Did you know that a layman is simply someone who is not directly related to an area of specific expertise?) I was slightly embarrassed. And now you all know, too, and will be spared embarrassment (if you’re the kind of person to get embarrassed).

But the issue of not knowing things still arises with other topics. Strangely enough, the whole “6-panel test” via equine breed associations had me a bit baffled until late. Reading those acronyms was like deciphering a different language, and I reckoned that it was important information to know, especially as a breeder, buyer and professional of horses.

So, I’ve attempted to “dummy down” six of the mainstream issues below for folks like me that are craving a simple explanation. 

In the Western performance world, we are basically confronted with six different diseases that are imperative to test for when considering a breeding cross. The below acronyms equate to diseases and issues that can be traumatic, extremely debilitating and often fatal for our equine friends, so it’s good to be familiar with all of them. 

  1. HYPP
  2. HERDA
  3. GBED
  4. MH
  5. PSSM1
  6. IMM 

HYPP (Hyperkalemic periodic paralysis) is a muscular disease that is exhibited by weakness, muscle spasms, paralysis and even collapse.  It basically gets triggered in susceptible individuals from stress or high potassium feeds, which create the sodium channels within muscles to become leaky. This can occasionally affect the heart and cause sudden death. Horses that carry one copy of the gene (N/H) may exhibit symptoms, and horses with two copies (H/H) are often typically more strongly affected. It is primarily found in Quarter Horses, with the “Impressive” bloodlines being especially susceptible. 

HERDA (Hereditary Equine Regional Dermal Asthenia) is a degenerative skin disease that shows up as stretchy or sloughing skin, scarring along the withers and back, and severe skin wounds and lesions. Often, these symptoms start showing up as a horse is handled more and saddled their 2- or 3-year-old year. One copy of the gene (N/HRD) only proves the horse as a carrier, while two copies (HRD/HRD) are often a death sentence, as the symptoms are expressed and worsen with age. There is no treatment or cure. HERDA is found in Quarter Horses and breeds influenced by QH blood, with many cutting bloodlines responsible for being carriers. 

GBED (Glycogen Branching Enzyme Deficiency) is a fatal genetic disorder that stems from the body’s inability to store glycogen in several organs. This creates late term abortions and stillbirths in affected foals. One copy of the gene (N/G) means a horse is a carrier, while two copies (G/G) results in foals that are born weak, hypothermic, epileptic and often exhibit respiratory failure and cardiac arrest. All known cases of GBED positive horses have died or been euthanized within five months of birth. Quarter Horse bloodlines are susceptible to this disorder. 

MH (Malignant Hypothermia) creates a hypermetabolic state in an affected horses that is characterized by muscle contractions, excessive sweating, high temperatures and irregular heartbeats. Often, they are triggered into this state by anesthesia. Carriers of the gene (N/MH) will express symptoms and can pass the gene with a 50% chance of affecting their foal, while MH positive horses (MH/MH) are affected as well, and all of their offspring will have it. It can be treated with Dantrolene, alcohol and IV fluids, though there is no cure, and it creates life-threatening situations for the affected animals. 

PSSM1 (Polysaccharide Storage Myopathy) is a muscular disease that shows up as a horse “tying up” (reluctance to move, sweating, muscle spasms, shaking, stiffness and pain after exercise). It happens because the affected horses have an abnormal accumulation of sugar in their muscles. If a horse is a carrier (of N/PSSM1), he will exhibit symptoms and be affected. Most horses that suffer from this can maintain a semi-normal life with proper diet and exercise. Horses that are PSSM1 postive (PSSM1/PSSM1), often develop a more severe form of the disease. It has been diagnosed in over 20 different breeds, with QH and draft breeds more commonly observed as carriers.

IMM (Immune Mediated Myositis) is an autoimmune disorder that causes very quick and severe topline muscle atrophy and body stiffness after vaccinating a horse for diseases like strangles and influenza. Horses that carry two copies of the gene (IMM/IMM) are more likely to show symptoms than one copy (N/IMM). This disease, found in QH blood, is incurable but can be managed. The IMM test is not on the official American Quarter Horse Association five panel test, but it is becoming more prevalent on stallions’ ads and pages, and I thought it was worth mentioning. 

So, there we have it, hopefully with some knowledge gained and more embarrassment spared for each and every horse enthusiast out there. 

And though I haven’t fully eliminated the risk, I hope this means there’s one less reason for others to consider me a “lame man.”

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