Page 184 - Anatomy and Physiology of Farm Animals, 8th Edition

The Equine Foot and Passive Stay Apparatus / 169

stifle (and hock) that may be intermittent part of sleep most usually associated
VetBooks.ir or persistent. Conservative treatment with dreaming. One of the defining
characteristics of REM sleep is that
involves conditioning exercise to improve
the horse’s ability to control the patella. If
all skeletal muscles are in a state of flac-
this fails, the medial patellar ligament can other than eye and respiratory muscles,
be transected; this prevents the patella cid paralysis. Horses are awake about
from becoming fixed over the ridge. 19 hours of a day and spend about
Can horses sleep standing up? Yes 2 hours each in light and slow‐wave
and no. Sleep is divided into five stages, sleep, during which they can stand with
numbered I through V. Stages I through only the most minimal of muscle tone,
IV are a continuum of increasing depth thanks to the stay apparatus. Horses
of sleep, with I and II indicating light normally have REM sleep for only about
sleep (drowsing) and III and IV indicat- an hour a day, but because REM sleep is
ing deep sleep (“slow wave sleep”). Stage associated with paralysis of voluntary
V is what is described in humans as REM muscles, horses must lie down during
(rapid eye movement) sleep. This is the this time.