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ear tagPreauricular tag A common minor skin defect, consisting of a rudimentary tag of tissue, often with central cartilage, usually located just in front of the ear
the organ of hearing and of equilibrium. The ear is made up of the outer (external) ear, the middle ear and the inner (internal) ear. The anatomical parts of all three can be found under their specific names. See also auricular, auditory, external ear.
The outer ear consists of the auricle, or pinna, and the external acoustic meatus. The auricle collects sound waves and directs them to the external acoustic meatus which conducts them to the tympanum.
The tympanic membrane (eardrum) separates the outer ear from the middle ear. In the middle ear are the three ossicles, the malleus (hammer), incus (anvil), and stapes (stirrup), so called because of their resemblance to these objects. These three small bones form a chain across the middle ear from the tympanum to the oval window of the inner ear. The middle ear is connected to the nasopharynx by the auditory tube, through which the air pressure on the inner side of the eardrum is equalized with the air pressure on its outside surface. Two muscles attached to the ossicles contract when loud noises strike the tympanic membrane, limiting its vibration and thus protecting it and the inner ear from damage.
In the inner ear (or labyrinth) is the cochlea, containing the nerves that transmit the electrical impulses stimulated by sound to the brain. The inner ear also contains the semicircular canals, which are essential for the sense of balance. When a sound strikes the ear it causes the tympanic membrane to vibrate. The ossicles function as levers, gearing down the motion of the tympanic membrane, and passing the vibrations on to the cochlea. From there the vestibulocochlear (eighth cranial) nerve transmits the vibrations, translated into nerve impulses, to the auditory center in the brain. See also hearing.
see pinnal alopecia.
an erect, broad-based ear in dogs; seen in the French bulldog and Welsh corgi.
one with a very rounded tip.
break in ear
the fold line in the semi-dropped ear of dogs.
deformed or misshapen ears, as a result of injury or congenital defect. Most often of concern in dog breeds that are supposed to have erect or specifically defined ear conformation, e.g. Collie, German shepherd dog, Chihuahua.
in dogs, an ear flap lying close to the head, and pointing toward the eye. Seen in fox terriers.
a squamous cell carcinoma of the ear of sheep. The lesion commences around the free edge and then invades the entire ear.
a lay term applied generally to otitis externa but sometimes specifically to that caused by ear mites.
drooped, erect, alert, all indicative of mental state or state of muscle tone. Also a specified feature of breed standards for dogs.
see auricular cartilage.
a vice of confined pigs due largely to boredom and overcrowding.
a misplaced tooth germ or ear tooth in horses; occur unilaterally at the base of the ear, attached to the temporal bone. Called also heterotopic polyodontia.
an ear that is normally not erect; the end folds over or droops forward. Seen in many dog breeds.
inability of the ear to remain in an upright position in those species in which that is the norm. It may be a congenital abnormality, due to injury that has damaged the cartilage, or a sign of neurological deficit.
see auricular hematoma.
ear margin dermatosis
crusts, scabs and sometimes ulcerations, may occur at the edges of the external ear flap in dogs. Usually a form of seborrhea.
patterned pieces of cartilage punched out as a means of identification. Very popular at one time with intricate codes to identify age and family groups of pigs. Marks nicked out of the edges but also the centers of the ears.
see ear mark (above).
hypertrophic dermatitis appearing as small (0.5 inch diameter) plaques on the inner surface of the ear pinna in horses. They are scaly, slightly papillomatous, painless and alopecic. The cause is unknown.
see auricular points.
alligator forceps with cup-shaped opposing blades up to 1.5 inch diameter. A biopsy instrument for use in the depths of the ear canal.
ear pricked and patient unable to move them; indicative of general skeletal muscle tetany.
result of phlebitis and venous thrombosis occurring in many septicemias. It is most common in pigs where it begins as purple discoloration of the ears and surrounding skin. Also part of the response in peripheral gangrene syndrome caused by ingestion of the fungus clavicepspurpurea.
spinose ear tick
a vice occurring in penned pigs and calves caused by boredom. Has no serious effect unless it leads to cannibalism in pigs.
a technique of animal identification favored in sheep and cattle. Has the disadvantage that tags are often lost. This can be avoided by putting duplicates in each ear. The need to catch the animal to read the tag is overcome by using large placard type tags. For cattle being worked through a chute, tail tags are more convenient. Insecticides can be incorporated into the tag to provide protection against horn fly and head fly. May contain transponders for individual identification or trace back.
clipping off the tip of the external ear so that the animal can be identified from a distance. Limited categories available.
ear tip necrosis
a common problem in individual pig herds; sporadic cases usually related to frostbite, thrombosis after septicemic disease, especially Salmonella dublin in young calves; herd problems may be due to ergot poisoning or endophyte-containing hay, or an ear-sucking habit.
see ear cropping.
a rope twitch is twisted onto an ear instead of the muzzle.