Changes in facial expression are caused by the action of facial muscles. These changes are an important form of non verbal communication in animals (and humans) and can convey a large variety of emotional states.

A cranialnerve (nerve that originates from the brain rather than the spinal cord) that provides sensory and motor innervation to a large part of the facial muscles and skin.

A farrier is the person who carries out farriery. Farriers are required not only to be competent metal workers, but also to be knowledgeable in all aspects of equine hoof care. A farrier may apply horseshoes or any other form of hoof protection he/she finds suitable, and is also responsible for the professional care of horses which do not have shoes.

A tool with jaws and handles joined by a rivet. Pincers come in a great variety of sizes depending on the job they are required to do. Heavy pincers with large jaws are used to remove shoes (also known as shoe pullers), slightly lighter versions are used to turn over, wring-off and tighten the ends of the nails (clenches).  

The person responsible for holding the limb of the horse during 'french style' shoeing (ferrer à la française).

A profession which involves all aspects of hoof care. Whereas historically it was considered a predominantly metal working profession (hence blacksmith), these days, farriery is regarded as an equine health care profession.

A layer of fibrous connective tissue that surrounds muscles or groups of muscles and their associated blood vessels and nerves, binding some structures together, while permitting others to slide smoothly over each other.

The long hair in the pastern and sometimes cannon region of the horse. Feathers are a distinctive trait of most cold blooded breeds. Their purpose is to protect the lower limb from injury and moisture.

The bone between the hip joint and the stifle. It is a long bone with a relatively large circumference and with several tuberosities onto which the large muscles of the thigh insert.

With regard to digestion, fermentation generally refers to an anaerobic (= without oxygen) biological process that occurs in the digestive tract of an animal. In the horse, the main site of fermentation is the large intestine or hind gut. During fermentation, microbes secrete enzymes which break down ingested food (and fibre the horse cannot digest itself), which results in gas production and the formation of other molecules, some of which can be absorbed by the animal and provide energy (e.g. fatty acids). The exact products of fermentation depend on the conditions and the substance being fermented.
Easily fermentable food (e.g. grains with easily accessible, high contents of starch or sugar) result in a fast fermentation and large amounts of CO2, which is acidic when disolved. Constant exposure of the digestive tract to high acid levels can cause irritation. Fibrous foods generally result in a slow fermentation, which can be considered more beneficial for the horse.