This 30+ year old mare is "sleep crashing" from lack of necessary REM sleep. It went on for many weeks, but became increasingly worse.
What's Wrong With My Horse?
There was nothing physically wrong with this horse and she was not in pain, except she'd either refuse, or not feel comfortable enough to lie down to sleep. I tried to come up with some ideas that might help her, but none of the changes I tried, such as additional stall bedding, pasture turn out and open stall door to see the horse in the adjacent paddock still did not encourage her to lie down, though she had no trouble rolling. Perhaps her biggest handicap was that SHE was the one that always felt she had to stand and watch over the other horses and offer them comfort in her perceived role of being the alpha-mare. The following video was taken a few days before the decision was made to humanely put her down.
Sleep crashing is NOT the same as equine narcolepsy (or cataplexy), but rather it is a direct consequence of recumbent sleep deprivation necessary to facilitate the so-called rapid eye movement (REM) sleep phase. Horses can only get REM sleep by lying down and they need at least 20-40 minutes of it a day. If they don't get this type of sleep then they may sleep extra deep when standing up. Possible causes include:
- inability to lie down which may be environment-related (eg stall size)
- pain or restricted movement (eg an older horse with arthritis)
- feeling insecure to lie down (eg no herd mate on guard, stressful environment)
You will notice a typical nod where the head slowly sinks to the ground, then their legs buckle followed by the crash. Once this happens repeatedly several times a day it seriously affects the horse's well being and quality of life. Not only is it worrisome and dangerous, but these poor horses walk around all day miserable and exhausted.