It is a truism that anatomical structure is the most important and least variable component determining how a dog, or any other animal, moves. Other factors are temperament, speed, terrain and general vitality.
Since the Kerry Blue Terrier was bred as a working terrier in Ireland, he obviously had to be sturdy and display great stamina as he went about his many duties. In order to conserve his energy, an economy and freedom of motion are essential. This economy of available energy can only be obtained if the animal is properly structured and properly conditioned. Any structural faults which result in a labored gait will waste energy, causing the dog to fatigue quickly and eventually lead to physical breakdown.
What is the desired anatomical structure for the Kerry Blue Terrier, and how do we evaluate the individual dog to see how closely he approaches the ideal in structure and function? Structure and fuctionare directly related and best correlated in the show ring by an observation of how the dog moves at various speeds. The most useful gait for evaluation is the trot, which may vary somewhat in speed. if the dog is gaited too slowly, it may lapse into a walk or unsightly amble. If gaited too fast, the dog may canter or gallop.
There is very little in the official American Standard of the Kerry Blue Terrier to help us in the evaluation of gait, although it is fairly specific in defining structure. We must first understand the anatomical structure, and then study it's effect on movement. Improper structure will inevitably be reflecteed by improper movement.
Some knowledge of anatomical terms is necessary for the understanding of desired structure according to The Standard. The reader is referred to "the Kerry Blue Terrier Illustrated Standard" to gain this knowledge. From this basis, hopefully, we can develop further understanding of what anatomical structure means as applied to the dog.
one of the often poorly understood questions is that of measurement for height and length. Height is a vertical measurement from the surface on which the dog stands to the top of the withers. Withers as applied to anatomy is defined by Webster's Third New International Dictionary as "a. the ridge between the shoulder bones of the horse and b. the part between the shoulder bones at the base of the neck in various animals." This corresponds to the prominent spinous process of the first thoracic vertebra. It can be felt between the tops of the scapulae, or shoulder blades, just back of a depression at the base of the neck. To get an accurate measurement the dog must be positioned with the forelegs straight under the shoulder blades, and the head and neck elevated in a natural stance. The head and neck must not be depressed to attemept to make the dog measure shorter, or pulled up to make the dog measure taller. Length is measured from the forward tip of the sternum, or breast bone, to the most distant prominences of the pelvis, below and to each side of the tail.
The dog should be approximately as high as it is long. If he is too short in length the hind feet and forefeet are apt to get in each others way when moving in the trot. Also rf too short in length, the dog is apt to have a "tight coupling" from withers to pelvis, meaning he will lack flexibility thru the loin and pelvis creating a stilted, bouncy rear end, and he will not turn easily to the side.
The next consideration is the concept of "layback". Layback is the angle at which the scapula, or shoulder blade, lies on the thorax, or upper body. A proper layback is important to allow freedom of motion and good forward reach of the foreleg. Proper shoulder layback approaches 45º, although few specimens achieve this. Rachel Page Elliot has demonstrated the average layback in most trotting dogs to be 28-30º. A 45º layback means that the angle formed from the more forward and lower part of the scapula, at the shoulder joint, to the upper prominences of the scapulae at the withers, measures 45º from the vertical and from the horizontal. This can be judged by laying the index finger along the ridge formed by the spine of the scapula, in which case it should be a line half way between vertical and horizontal. Another approximation can be gained by observing the relation of the prominences of the scapulae at the withers to the forward prominences of the shoulder joint.
The scapula should lie flat against the thorax and glide easily over the thorax on motion, without any "winging" or displacement from a close co-aption to the thorax. The upper bone of the foreleg joins the scapula at a backward angle equal to the scapular layback angle, thus balancing the two bones and placing the rest of the foreleg straight under the tip of the scapula at the withers. This creates a flexible coupling of the front leg assembly to the body. This whole assembly is attached to the body solely by muscles and ligaments. Excess stresses will lead to either "loaded shoulders" with heavy muscular development or overstretching and weakening the musculature accompanied by "winging" of the scapula. The major cause of excess stress on the foreassembly is the straight or "streep" shoulder, meaning that the scapular layback is too vertical. This leads to limited forward reach and pounding of the forefoot. The straight shoulder also diminishes apparent length of the neck.
It is important to watch the foreassembly in motion. Along with proper layback the chest must not be too narrow or too wide. If too narrow, the shoulders will be pinched and a paddling type gait in which the foreleg swings in a somewhat lateral motion results. If the chest is too wide, the dog will be apt to move the elbow outward in a partially circular manner which is wasteful of energy, uncoordinated and clumsy. As a working terrier, a wide chest also makes it difficult to "go to ground" for burrowing animals.
A dog with proper structure will lift and reach straight forward with the foreleg, the foot swinging fairly close to the ground. This covers the maximum amount of ground with the least effort. As the foot strikes the pastern flexes to absorb the shock and the toes grasp the surface to break what in reality is a forward, falling motion provided by the propulsion of the rear. Good feet are important and often overlooked. This forward propulsion continues with the reaching foreleg drawing back and "pulling in the ground".
This action in front is coordinated with the rear which is our next consideration. In order to provide proper drive, once again proper structure of bone, joint and muscle is necessary. The pelvis should be slightly flexed and joined to the body by a flexible loin. With a properly flexed pelvis, the ischial tuberosities or "pin bones" will be prominent in the dog's rear end. The upper thigh bone is somewhat flexed forward and an angle is formed at the stifle by the backward flexed "second thigh" leading to the "well let down" back and rear pastern where another angle is formed. This combination of angles places the weight borne by the rear directly over the hind foot in natural stance. A straight stifle limits motion and flexibility. The usual "stacked" show stance places the rear weight slightly ahead of the rear foot.
Motion in the rear must be straight forward and back, the hocks turned neither in nor out. Forward reach in the rear must equal forward reach in front. If reach is greater in the rear than a straight fronted dog can accomplish in front, a delaying tactic to achieve coordination between front and rear is a "hacking" gait in front. This is stylistic, but not proper, and wastes considerable energy, as well as limiting forward reach.
There is widespread misconception about the amount of backward push or drive which is desirable The drive must be sufficient to propel the dog forward in a smooth: level manner, with sufficient momentum to vault the body over the forward reaching foreleg. The strike of the rear foot at the end of forward reach is followed by a strong push off in which the foot is only momentarily on the ground. Any overextension of backward motion once the rear foot has left the ground is wasted motion. It usually accompanies limited forward reach of the rear leg and places the strike point of the foot too far back, which limits the ability of the dog to readily change direction since his weight is not well centered over the foot. This results in extra strain on rear musculature and early fatigue. Also a lowering of the dog's body is noticeable as he moves forward at speed.
An appreciation of the foregoing is necessary to evaluate a specimen of our breed. It is all too easy for an exhibitor or handler to hide many of a dog's structural faults by a skillful trim of the coat. However, the knowledgeable and observant ringsider, who can't put his hands on the dog, will not be fooled once he sees the dog move.