PSSM: The Rest Of The Story

I noticed upon visting our blog half of the post was dropped. I have re-entered the entire post including Dr. Valberg's exerpts. Sorry for the inconvenience and I apologize for the lost comments at the end of the article. This post is intended to share the updates from people that have had years of education and experience and are recognized as the true experts in the field.

Update: PSSM in Horses

The gene that identifies type 2 PSSM one can only be found with a full muscle biopsy. Type 2 PSSM seems to be more prevalent in performance based horses.

With the more easily performed test for type 1 PSSM, we have seen the gamut of responses from armchair Veterinarians (generally those with performance bred horses) how relieved they are to find their horses PSSM free. They would lead you to believe all horses with PSSM are doomed to die,” and in the process would want you to believe their horse is PSSM free, merely because one test came back in their favor.

The more reasonable approach.

"There is more to this test that needs to be considered."

Many horse enthusiasts have taken the identification of the type 1 PSSM gene and have been able to better understand their horse’s behavior under stress. Unfortunately, some misinformed owners/breeders continue to believe every misstep can be tied to this one type of PSSM. They believe this one test will remove all things bad in the industry.

The more dangerous "expert" deliberately fails to address, there is more than one form of PSSM and there are additional genes that affect the severity of the PSSM condition. These same people want you to believe the elimination of type 1 PSSM will correct all the tying-up issues in the entire equine industry. They would like you to look past their breeding herd that has NOT been diagnosed PSSM negative with a muscle biopsy.

These people will show you a $35 test and ask that
you join them in their celebration their horse is PSSM FREE!

To date, a muscle biopsy is the ONLY

way to identify type 2 PSSM.

Type 2 PSSM is more prevalent in performance horses.
As seen by a plethora of posts in numerous forums by the self-proclaimed “experts”. These armchair Veterinarians seem to be practicing Veterinary Medicine without a license. These “experts” can be found on YouTube diagnosing PSSM to misbehaving horses merely by watching a naughty horse in a video. You will find the same people on Facebook proclaiming the demise of the equine industry to horses with PSSM. They have assigned every bad behavior and injury (from abscess to overwork) to PSSM. These “experts” have not tested their horses for type 2 PSSM or the additional genes that amplify PSSM symptoms.

In this scenario, some knowledge is more

harmful than no knowledge, by leading you to believe a

$35 test represents a clear bill of health.

Setting The Record Straight
As for us, at Smith Show Horses, we feel the industry needs to know all of the facts and you need to know that there are more undiagnosed cases of PSSM than the simple pulling of mane hair cannot detect.

Before you book your mare to a stallion represented as PSSM free, and if you are worried about symptoms associated with PSSM, ask to see their PSSM results. There are many breeders that will tell you they have the $35 test confirming their horse does NOT have PSSM.

A horse with a Negative type 1 PSSM test does not mean the horse is a negative for PSSM. Through Dr. Valberg's explanation, unless, a muscle biopsy has been done on a horse that tests negative for type 1 PSSM, you may be living with a false security.

Omission by ignorance is wrong...

...Omission by intention is deceitful.

Before any breeder can proclaim their horse PSSM free… ALL of the tests need to be completed with negative results. It is much easier to point fingers at one part of an industry and compartmentalize all problems lead to one gene. The last time I saw someone pointing their finger at someone, there were 3 pointing back at them.

___________________________________________

Update: PSSM In Horses
By Kentucky Equine Research Staff · September 29, 2011

At the 2011 Texas Equine Veterinary Association (TEVA) conference, one of the leading researchers in equine muscle problems, Stephanie Valberg, D.V.M., Ph.D.,of the University of Minnesota College of Veterinary Medicine, brought the audience of veterinarians up to date on polysaccharide storage myopathy (PSSM), one cause of tying-up, September 29, 2011.

What is Tying-Up?
When tying-up happens on a regular basis, it is termed recurrent exertional rhabdomyolysis (RER or chronic tying-up). RER can be caused by several muscle problems. According to Valberg, three genetically identifiable causes of muscle malfunction are

1. Exertional Rhabdomyolysis type 1,
2. PSSM type 1
3. Malignant Hyperthermia. Dr. Valberg, also, warned that there might be other unrecognized causes of RER.

PSSM
…“While some horses sporadically develop exertional muscle damage as a result of nutritional, training, or environmental factors, others develop RER in spite of a sound diet and environment,” noted Valberg. “Many of these chronic cases are due to an intrinsic and inherited dysfunction of muscle metabolism or muscle contraction.”

In short, horses with (any type of) PSSM are unable to normally store and use sugar in skeletal muscles. There are extenuating circumstances that cause the severity of symptoms exhibited by horses with PSSM.

There has been much progress made in diagnosing PSSM. In fact, more than one form of PSSM exists today. Only laboratory tests determine which specific genetic mutation is causing the tying-up. Type 2 PSSM can only be diagnosed with a muscle biopsy, which in most cases has not been done on an entire herd.

“For clarity, the form of PSSM caused by a GYS1 (a specific gene) mutation is now termed type 1 PSSM. The location of the specific gene that identifies PSSM that is NOT caused by the GYS1 is yet unknown. That form of PSSM is now termed type 2 PSSM,” explained Valberg. Type 2 PSSM can only be diagnosed with a muscle biopsy.


TYPE 1 PSSM vs. TYPE P2 PSSM

Type 1 PSSM
Research has shown that the genetic mutation at GYS1 responsible for type 1 PSSM can be found in more than 20 breeds of horses. “It is estimated to have emerged as far back as 1,600 years ago, when the great horse was being developed from European draft and light horse breeds to carry knights with heavy armor into battle,” noted Valberg.

Dr. Valberg noted in her presentation that the highest prevalence of PSSM appears to occur in draft horses derived from Continental European breeds (90% prevalence of PSSM in Trekpaards, a draft breed, with 40% of tested Belgian Trekpaards being homozygous for the trait).

While the complete cycle of how the genetic mutation causes problems in the storage and use of muscle glycogen is under investigation, it is known that diet and exercise can be used to manage the problem in many horses.

In postulating why this genetic mutation has become more prevalent in some breeds, it has been noted that owners of horses with type 1 PSSM often describe their horses as having a calm and sedate demeanor.

Clinical signs of chronic PSSM
A small number of stock horses have both the GYS1 mutation AND a genetic mutation (RYR1) for malignant hyperthermia (MH), which results in more severe signs of tying-up and a limited response to diet and exercise changes. In horses with the RYR1 mutation, during an episode of tying-up they can experience excessively high body temperatures and sudden death can occur.

Diagnosis
Blood or hair samples can be used to test for type 1 PSSM, MH, and other genetic diseases of horses. Muscle biopsies would be needed to definitively diagnose a problem other than Type 1 PSSM.

Type 2 PSSM
Some horses with PSSM do not have the genetic mutation, Type 1 PSSM and are called type 2 PSSM cases. There is ongoing research to learn more about these horses. Valberg noted there are cases of PSSM diagnosed by muscle biopsy in Quarter Horses do not have the GYS1 mutation.

"Type 2 PSSM also occurs in Arabians; however, in my experience this breed is distinct in that it often has amylase-resistant rather than amylase-sensitive polysaccharide but is negative for the GYS1 mutation,” said Valberg.

The diagnosis of type 2 PSSM is done with a muscle biopsy. Valberg advised that mild PSSM cases should receive a full physical examination to ensure that there are not other underlying causes for performance problems.

Managing A Horse With PSSM
Understanding the horse’s caloric requirements and ideal body weight are important factors, stressed Valberg. “Many horses with PSSM are easy keepers and may be overweight at the time of
diagnosis.”

“Regular daily exercise is important for managing horses with PSSM,” stressed Valberg. “Even 10 minutes of exercise has been shown to be extremely beneficial in reducing muscle damage with exercise. Once conditioned, some PSSM horses thrive with four days of exercise as long as they receive daily turnout. For riding horses with type 2 PSSM, a prolonged warm-up with adequate stretching is recommended.”

Here is the entire article from Dr. Valberg and links to more specific questions.

Update: PSSM in Horses by Kentucky Equine Research by Staff· September 29, 2011

• On a final note, we at Smith Show Horses feel there is benefit to the less expensive PSSM1 test, but also realize a horse that tests PSSM1 n/n could very well have PSSM2. Even though, ALL of our horse are symptom free we have tested our entire herd and encourage all breeders and mare owners to do the same. Dr. Valberg and the AQHA continue to search for the location of the gene that identifies PSSM2. As of this writing a muscle biopsy should be on file to declare your horse PSSM free.

Setting The Record Straight

Update: PSSM in Horses

By Kentucky'>http://www.ker.com/">Kentucky Equine Research Staff · September 29, 2011

The gene that identifies type 2 PSSM one can only be found with a full muscle biopsy. Type 2 PSSM seems to be more prevalent in performance based horses.With the more easily performed test for type 1 PSSM, we have seen the gamut of responses from armchair Veterinarians (generally those with performance bred horses) how relieved they are to find theri horses PSSM free. They would lead you to believe all horses with PSSM are doomed to die,” and in the process would want you to believe their horse is PSSM free, merely because one test came back in their favor.

The more reasonable approach.

“There is more to this test that needs to be considered”.

Many horse enthusiasts have taken the identification of the type 1 PSSM gene and have been able to better understand their horse’s behavior under stress. Unfortunately, some misinformed owners/breeders continue to believe every misstep can be tied to this one type of PSSM. They believe this one test will remove all things bad in the industry.

The more dangerous "expert" deliberately fails to address, there is more than one form of PSSM and there are additional genes that affect the severity of the PSSM condition. These same people want you to believe the elimination of type 1 PSSM will correct all the tying-up issues in the entire equine industry. They would like you to look past their breeding herd that has NOT been diagnosed PSSM negative with a muscle biopsy.

These people will show you a $35 test and ask that you

join them in their celebration their horse is PSSM FREE!

To date, a muscle biopsy is the ONLY

way to identify type 2 PSSM.

Type 2 PSSM is more prevalent in performance horses.As seen by a plethora of posts in numerous forums by the self-proclaimed “experts”. These armchair Veterinarians seem to be practicing Veterinary Medicine without a license. These “experts” can be found on YouTube diagnosing PSSM to misbehaving horses merely by watching a naughty horse in a video. You will find the same people on Facebook proclaiming the demise of the equine industry to horses with PSSM. They have assigned every bad behavior and injury (from abscess to overwork) to PSSM. These “experts” have not tested their horses for type 2 PSSM or the additional genes that amplify PSSM symptoms.

In this scenario, some knowledge is more

harmful than no knowledge,by leading you to believe a $35 test

gives their horse a clear bill of health.

At the 2011 Texas Equine Veterinary Association (TEVA) conference, one of the leading researchers in equine muscle problems, Stephanie Valberg, D.V.M., Ph.D., of the University of Minnesota College of Veterinary Medicine, brought the audience of veterinarians up to date on polysaccharide storage myopathy (PSSM), one cause of tying-up.Setting The Record StraightAs for as, us, at Smith Show Horses, we feel the industry needs to know all of the facts and you need to know that there are more undiagnosed cases of PSSM than the simple pulling of mane hair cannot detect.Before you book your mare to a stallion represented as PSSM free, and you are worried about symptoms associated with PSSM, ask to see their PSSM results. There are many breeders that will tell you they have the $35 test confirming their horse does NOT have PSSM.A horse with a Negative type 1 PSSM test does not mean the horse is a negative for PSSM.

Through Dr. Valberg explanation, unless, a muscle biopsy has been done on a horse that tests negative for type 1 PSSM, you may be living with a false security.

Omission by ignorance is wrong.

Omission by intention is deceitful.

Before any breeder can proclaim their horse PSSM free… All of the tests need to be completed with negative results.It is much easier to point fingers at one part of an industry and compartmentalize all problems lead to one gene. The last time I saw someone pointing their finger at someone, there were 3 pointing back at them.

I have included excerpts from Dr. Valberg’s discussion that validates what we have felt when the test was first discovered. Our horses were symptom free. Our oldest will be nine in 2012. As more information comes out, we will again regain sanity and realize how much we really don't know. You will find a link to Dr. Valbergs entire discussion at the link at the end of this article.What is Tying-Up?When tying-up happens on a regular basis, it is termed recurrent exertional rhabdomyolysis (RER or chronic tying-up). RER can be caused by several muscle problems. According to Valberg, three genetically identifiable causes of muscle malfunction are 1). Exertional Rhabdomyolysis type 1, 2). PSSM type 1, 3). Malignant hyperthermia. Dr. Valberg, also, warned that there might be other unrecognized causes of RER.PSSM…“While some horses sporadically develop exertional muscle damage as a result of nutritional, training, or environmental factors, others develop RER in spite of a sound diet and environment,” noted Valberg. “Many of these chronic cases are due to an intrinsic and inherited dysfunction of muscle metabolism or muscle contraction.”

What happened to manners?

“Manners are a sensitive awareness of the feelings of others. If you have that awareness, you have good manners, no matter what fork you use.”
– Emily Post


Juli S. Thorson really nailed it again…with her blog discussing social graces and the lack of social manners, the internet disturbance of the peace, if you will … some people feel they are compelled to share their opinions, while most people find those same people to be offensive. The language and crude behavior is usually recognized for what it is.
In reference, I looked up what Emily Post would have to say about manners. Now, I understand many of these people that abuse our right to peace were born well after the last printing of Emily Post’s, Etiquette (probably last printed in the 1940’s).
According to Emily a snob is a person who is always animated by the impression he/she wants to make, and the exalted regard in which he/she strives to be held by others.
"The discriminating person cares nothing whatever about the opinion of those individuals, but chooses his/her interests and companions according to their personal taste and inclination.
The difference between a real snob and regarded as merely reserved and selective, is the entire distance between being contemptible and admirable—between worst and best."
Etiquette – Emily Post

Some people seem to feel times have changed. I am thankful the people I call friends still feel manners should remain timeless.

Juli and Emily say it so much better than I can.

Find Juli's Link below.

Juli's Blog

http://blogs.equisearch.com/horsetalk/2011/12/07/please-pass-the-emote-control/

Merry Christmas

As we approach the holiday season,and we look back at the past year and remember the catatrophic tragedy our entire country has endured from hurricanes, floods, tornadoes to drought. Our breed has lost long time mentors and modern day heroes. These wonderful leaders, members and competitors leave us great memories and moral values that should not be lost.

As we look back, we keep our memories of our friends close to our hearts. The friends we have made during our lifetime with the ApHC give us the reasons we stay. Through those friendships we have built a family across the United States and feel honored to be a part of breeding programs across the country and the world.

As the holidays approach, take time to make that phone call and tell your friends how much you miss them. The gift of time is priceless.

If we haven’t told you lately, “Thank you for including us in your breeding decisions. We are blessed to be a part of such a wonderful family.”


Wishing you a successful 2012.

Mark & Gail Smith

Science, DNA, and Breeding

Why do we do what we do?
I think there are many breeders that ask themselves the question why are we doing this? When a shipment is delayed when blizzards cause canceled flights, an occurrence that happened in Texas this spring. Our mares and customer's mares refusing to cycle for the early baby. The baby is born and everything is put in perspective. At that moment, there is a hush in the stall, that you feel you are intruding.
The friends you meet when the foals are placed, the excitement to watch them show, the thrill of competing and accelerated when watching a foal from your stallion winning the trophy, a World or National Title or a Futurity, but the best feeling comes when we get a letter from a happy horse owner that has found their forever horse.
I lose track of time watching the mares graze and the foals play. I enjoy watching the stallions showing their macho side trying to attract the mares to their harem, as the mares continue to graze in teh pasture with no interest in the boys. The foals develop their own traits as the grow playing with the others and disciplined by their mothers when they get a bit out of hand or don't listen.

Our horses are breeding animals, but they are so much more.
Our mares and studs are a part of a program it has taken years to develop through selective choices of proven bloodlines. We choose mares to complement our stallions and if one or two mares are retained from our stallions, we choose outside stallions to complement our mares, considering conformation and production records. As DNA is further studied, Science will be a part of the equation, as well.

Breeding is so much more than Science and DNA.
A breeding program is choosing mares and stallions that work together and have the ability to produce a once in a lifetime foal that will give you the thrill of competition and the incomparable feeling of success. Science finds the newest genetic marker. Folks on the sideline start discussing which horses should be bred and which ones not. Many feel if you can see the faults, i.e.; crooked legs, poor heads, short necks, long backs, bad hocks, and nasty dispositions maybe okay to breed forward, yet they are not traits that can be corrected or managed with a healthy feeding program and lifestyle. What you see is what you get. Some mare and stallion owners may actually give those visible qualities a pass to breed forward without thought of consequences.

The recent genetic discovery identifies the gene that has been around for thousands of years.
The latest genetic marker presented to the equine industry is the PSSM marker. It is related to the syndrome that has been in the equine industry since before registration associations were formed. This test identifies the gene that may cause a case of "tying up". The old timers referred to tying up as "Monday Morning" sickness. When horses were worked hard all week and given a day off. The following Monday morning, the farmers would find their resource of power would be stiff and unable to return to the workforce for the day or maybe longer. I'm not sure how much time was allotted to these workhorses when it was time to plant or plow.

PSSM is a condition that may go undetected for the life of the horse, until you overdo or cause stress to your equine partner. Most often it is manmade; either through over work, over supplements, or just the wrong feed. Whenever, something new is discovered, there is a learning curve and we have to adjust our programs to make educated decisions.

We have just completed testing our entire herd and are waiting for the results. We tested our studs in the spring of 2011; NOT because there were problems or symptoms of tying up; because a mare owner had tested his mares and found his mares were carriers of the PSSM marker. Believing one marker is manageable, but rather not take the 25% chance for two PSSM genes, which could be tougher to manage, we tested our stallions and found both carry the PSSM marker. A decision was made to have the mare owner find another stallion. We have had no problem with one PSSM gene. We have and will share our information with mare owners after we learned the results of our stallions and before they breed their mares in 2012. This is the type of information we need to share. Responsible mare owners will need to test, even without the symptoms. This gene is not confined to one bloodline or family of horses. It is theorized PSSM has been around prior to the discovery of the New Worlds.

We take all of the information available to us and genetic testing is part of our equation. When we choose breeding animals we consider all aspects of the" what ifs". Our breeding program includes decisions from conformation to color. Homozygous color producers are night-blind, themselves, but management of their condition is a possibility. It runs on the color gene and can only be passed on if you breed color to color. We breed solid mares to the colored studs. Rat tailed horses or lack of hair is another inherited trait than can show up when you least expect it. These poor horses that live outside with the flies are tortured. There are so many things to consider when choosing the perfect cross. Poor conformation in general may cause a lifetime of problems, some can be managed with farriers and corrective shoeing.
Just when we get the perfect horse after a lifetime of breeding…along comes another genetic marker. The good news; because one horse is a carrier, it does not mean they will pass it on. Statistically there is a 50% chance of inheriting the gene if half of your breeding equation (stallion or mare) includes one of the hidden genes.

We encourage responsible breeding
We will continue to test and educate ourselves and mare owners. PSSM in particular is a genetic condition that is not precluded to one specific bloodline. We believe testing and sharing as much information available to us at the time gives the mare owner another decision to weigh when comparing to other genetic factors that may not be as manageable; in reference to visible conformation faults.

We encourage good equine management. Breeders need to look at the entire picture and decide which flaws they can live with and which ones they can live without. Early farmers learned to manage the tying up syndrome. Now, we have a test that will give us a headstart with the proper management and will prevent of an occurrence of tying up. Some genetic traits are quite manageable, others can be fatal. I believe PSSM is similar to a predisposition in humans and the animal world to Diabetes2. We know what we must do to prevent the disease as we enter middle age. It is a condition that can be controlled with proper diet years before we see signs of the disease. With the knowledge Science has provided us, as horse owners, we can be more responsible in our care.
There will be new discoveries, and better ways to feed and manage our equine friends that have learned to adapt to a manmade environment. If you are planning to breed, test your mares for the genetic markers available. From this point forward, we have made the commitment that foals from our breeding program will be tested before they go to their new homes. We understand that Science has new discoveries from color factors to hidden genetic markers. We will try to keep up as tests are available and pass them on to you.