The tactile sensitivity of the horse, which varies according to the part of the body is especially strong around the lips, nostrils, and eyes, given both the high concentration of receptors and the presence of vibrissae, which are rooted in many nerve endings. Among other advantages, these vibrissae provide a horse with a "second view", which enables him to precisely analyze, by touch, what is in front of him in the blind spot of his visual field and to calculate how far he is from it. Mc Greevy (2004) reports that, in addition, "horses are said to test electric fences with these whiskers before touching them".
Consider, too, the presence of many filiform papillae with a tactile function within the buccal mucosa of the horse, which enhance its capacity for discrimination by allowing it to finely sort what it ongests, which explains the rarity of foreign bodies in horse intestines, compared with, say, cows (Mc Greevy 2004). This buccal sensitivity also comes into play in the different effects of the bits used on horses.
The sensitivity of the equine body is especially evident in its response to very light stimulation produced by the presence of flies, which causes a reflex twitch of the skin, the cutaneus trunci muscle reflex (Theriault and Diamond 1988), named for the broad, thick subcutaneous muscle that extends under the skin of the back and flanks. Saslow (2002) carried out a study of the tactile sensitivity of the horse that unfortunately remains unpublished. She measured the variation of the tactile sensitivity tresholds of different parts of the trunk, using the same methods as those used to test human tactile sensitivity. A propos of this subject, she notes: "We were surprised to find that horse sensitivity on the parts of the body which would be in contact with the rider's legs is greater than what has been found for the adult human calf or even the more sensitive human fingertip.
Horses can react to pressures that are too light for the human to feel. This might, she continues, explain the negative consequences (failed training, "dead-sided" horses) of human instability in the saddle, and the rider unconsciously giving his horse irrelevant cues, as well as a trained animal's apparent "extrasensory perception" of the intentions of its rider, which may simply be a response to light movements or muscle contractions that the rider makes unawares.
In addition there are also mechanoreceptors, thermoreceptors, and nociceptors in the hooves, with Ruffini and Pacini corpuscles, as well as free nerve endings (Bowker et al 1993; Floyd and Mansmann 2007)
Fm The Mind of the Horse-An introduction to equine cognition- by Michel-Antoine Leblanc
I thought that this extract from The Mind of the Horse about the tactile sensitivity of the horse could be of great benefit for many riders and horse people and I strongly recommend to read this very interesting book to understand better our horses,
Cristina Libardi De Marchi
Instructor at the Horse Classical Riding centre Il Paretaio, Italy
The tactile sensitivity of the horse
NewsStaff Il Paretaio 2016-01-19