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Lethargic and Grumpy Horse

January 21, 2013

What could be the cause of your horse’s grumpiness?


This past summer, I took my 6-year-old gelding, Mater, to a big horse show. Waiting to go into my western pleasure class, a woman nearby sprayed her horse with Raid as a bug spray. By the time I smelled the spray, Mater had clearly inhaled it. Prior to this incident, I have had no medical problems of any kind with him. After my class, I took him back to his stall, and he was covered in hives.

To the touch, he felt like he was burning up, however he was not running a temperature. I cold hosed him for a while with no luck in cooling his skin. We turned his fan on, offered him water and kept a close eye on him. He later came off his grain and water and would not eat or drink anything. We attempted Gatorade, beer, wet grain and hay, but he would not touch anything.

The same night, he became colicky. I had the veterinarian examine him and he ran three separate blood tests. The only one coming back with a concern was his Vitamin E level. He was put on IV fluids and treated for the hives and given a pain killer. We trailered him home, stopping to give him IV fluids. Upon getting home, I took him to my veterinarian. They did a neurological exam, where he failed. They again tested his Vitamin E levels, which came back at 293.

Mater was still not eating or drinking. They put him on 8,000 IUs of Vitamin E, and two weeks later he tested at 710. He started drinking and eating again, but he was very weak. About three weeks later, after putting him back to light work, my vet instructed he go into hard work, such as training. My trainer has been working him diligently, and after a month the veterinarian has had my trainer reduce the Vitamin E to 4,000 IUs.

Mater is now testing at 215.

Mater wants to do nothing but stand in his stall and sleep. He is grumpy, tries kicking and biting people and has no work ethic at all. This is opposite of his normal behavior. Our vet is running out of ideas, and I can’t seem to find any answers anywhere. I was wondering if you had any ideas about what could be causing this?

For the answer to this question, we consulted Dr. Holly Bedman with the American Association of Equine Practitioners.


Without examining Mater, it is difficult to determine what could be causing his sudden change in attitude. There may be several issues at hand given his episode of hives, colic, deficient Vitamin E status and abnormal neurological exam. Sometimes chronic pain can cause a horse to have a poor work ethic or poor attitude in general. Muscle weakness from a muscle disorder can also cause poor performance, which may translate into a poor work ethic and attitude.

Pinpointing a source of pain may be challenging, but starting with a thorough physical and lameness exam to rule out signs of musculoskeletal pain, such as lameness or back pain, etc., would be a good place to start. Repeating the neurological exam to compare pre- and post-Vitamin E treatment might provide further insight. In some horses that are Vitamin E deficient, muscle wasting occurs, especially over the hindquarters, resulting in muscle weakness and poor performance. A muscle biopsy can identify a Vitamin E deficient muscle disorder. Lastly, with a history of colic and possible stress from competition and strenuous training, ruling out gastric ulcers may also be warranted. Please consult with your veterinarian for further evaluation and appropriate diagnostic recommendations for Mater.

— Dr. Holly Bedman, member of the American Association of Equine Practitioners