Neurological Disorders

Over the years there has always been one type of horse I find fascinating more than any other.  And since you are reading this page, you have probably guessed by now it is in fact the Neurological Horse.  Not sure how or when I first got interested, I feel a lot of it comes from my desire to always root for the underdog.  And that is what a neurological horse is, is an underdog in the Equine world.  An underdog in that they are not well understood (by scientists and owners alike).  An underdog in that their functionality as a performance horse is limited.  An underdog in that many people give up on them via euthanasia, selling them, or placing them in a rescue/sanctuary setting. Very few are willing to take on the task that is caring for a neurological horse for life.  So below we will discuss the three most common causes of neurological disorders, and then will go into further information how we care for our neurological horses.  Our sanctuary is currently home to 5 horses of varying neurologic grades. 

As previously stated there are 3 common Neurological dysfunctions in the horse.  EPM (Equine Protozoal Myeloencephalitis) is from consuming contaminated feed.  Wobbler's is from a compression in their spinal cord either in the neck or back.  The final and most devastating one is known as EDM (Equine Degenerative Myeloencephalopathy also known as eNAD-Equine Neuroaxonal Dystrophy, commonly referred to  eNAD/EDM) which has a genetic component but is triggered by a lack of Vitamin E in utero.  

EPM is way more prevalent in the Eastern US than Western, but since horses are constantly shipped all over the US it is important to understand.  It is more prevalent in Eastern US as there are more opossum's there which their feces that contains the protozoal parasite Sarcocystis neurona, which then gets deposited into the grain they rummage through. Once in the equine, it spreads from the GI tract into the blood and attacks the central nervous system.  Although it is estimated 50 percent of Equines have been exposed to EPM, only about 1 percent show the neurological symptoms.  To confirm EPM, a vet needs either a blood or more definitive a spinal fluid tap (CSF tap) to confirm EPM.  There are treatments available such as Marquis and Rebalance which helps the horse recover from the neurological symptoms. If treated early, most horses can make a full or mostly full recovery.  There are currently no EPM neurological horses here :).

Wobbler's is from a compression on the spinal cord either in the neck or back. There is believed to be a genetic component and they are finding a link between spinal cord compression in between C3-4 in their neck as a genetic/hereditary compression. I tend to agree since Rampage and Cassie are both Wobbler's and they are full brother and sister (I have not done X-Rays to determine where their compression is).  Cassie was already in utero when Rampage was diagnosed.  Wobbler's is a tough one as there is a surgery (known as Basket Surgery) which can improve the neurological grade by at least a grade or two, but there is also a lot of risk putting a neurological horse in surgery and recovery.  Vitamin E is highly recommended since there is a compression to the spinal cord, the spinal tissues/nerves are also affected so the Vitamin E helps stabilize the tissue/nerves. 

eNAD/EDM is probably the most devastating of the three, as by the time it is "diagnosed" the damage has been done and the only thing to prevent it would have been done while the horse was in-utero. Once they are born, they are what they are, there is no fixing the neurological condition/no ways to improve the neurologic tendencies.  The only way to truly diagnose eNAD/EDM is on necropsy to see the damage done to the brain stem.  So a diagnosis is only done by excluding other neurological causes, UC Davis has a new test that they are hoping in the future may help support a diagnosis pre-mortem.  Horses with this condition are usually neurologic in all four limbs but the hind limbs are more affected than the fronts. Usually by the time they turn 2-3 years old, you will know what you are dealing with as they usually don't get any worse at that point.  Vitamin E is still recommended for these horses, but it does not improve the deficits as since they lacked Vit E in-utero, they don't know how to absorb it and use it.  Aurora is our resident eNAD/EDM horse.  When she first arrived, she was quite thin.  We pulled a blood sample to test for Vitamin E and her level was 155, this isn't even an acceptable number for a newborn foal! Normal vitamin E levels in horses should be greater than 300, with a desire of a level greater than 400.  So we immediately started her on Kentucky Performance Products Elevate W.S., along with starting on Santa Cruz's Vitamin E pellets.  After 2 months on Elevate, and a month following of just being on the Vitamin E pellets it was time to retest her Vit E level.  She was on maintenance level of Vit E (2 scoops per day which equates to 8,000iu Vit E per day). and upon retest she is at 249, which is still well below where she needs to be.  So she is still a battle of finding out what she needs to maintain a normal level for her.  She has gained a lot of weight and looks like a normal horse now, just with a weird gait!