As a result of the owners survey we decided to use x-rays of the skeletal anatomy to determine phenotypes.  These have the advantage that the anatomical measurements can be made very exact and that there are a very large number of phenotypes that can be determined from a few x-rays.  As x-rays are received they are digitally photographed and filed in the computer.  This makes them easy to find and readily available to several persons who may be measuring anatomical data.  Owners have submitted approximately 200 sets of x-rays.
 

From these five x-rays we can determine more than 70 different quantitative phenotypes many of which are of great interest to the owners and breeders with whom we collaborate.

For example, a standard OFA view of the pelvis yields many measurements of which a few are noted here:

Another advantage of the computer is that it can change an image making it easier to analyze.  In the x-ray below, a lateral view of the skull has been changed to make the various boundaries of the skull bones more easily visible.

This dog has a bad bite, which can be caused by the length of the upper and lower jaws or by the angle of the lower teeth.  Although her lower teeth protrude at a very flat angle, other dogs have teeth which are even closer to the horizontal, yet their bite is good.  Genes for the angle of the tooth as well as other genes for the relative lengths of the upper and lower jaw will determine bite.  It will not always be true that mating a bad with a good bite will result in a correction.  It will depend on the number and kinds of genes involved.  Such x-rays will provide clues as to which breedings will be most appropriate in order to produce the desired puppies.

The hind leg bones shown below are taken from three females all of which weigh about 50 pounds.  Each pair contains the main bone of the lower (tibia) and upper (femur) portion of the leg.

The two bones are about the same length in the two dogs on the right and left, although one dog has a much longer pair (rear end high).  The dog in the middle has a hind leg about the same length as the one on the left, but the two bones are not of equal length.  This comparison is an example of the kinds of genetic variation which can occur in the breed.  It also demonstrates the facility of the computer to isolate parts of  x-ray images for comparison.

The anatomical phenotypes which are seen also will help to explain the performance of dogs.  This is illustrated by comparing the feet of two the dogs.  In this image the heel of the foot is on the left.

A contracting muscle pulling on the heel and rotating both feet through the same angle, will push the upper dog through a greater distance because of the longer foot (distance between the hock and the paw).  This dog will run faster, once up to speed.  However, because of the better leverage, the lower dog with the shorter foot can generate more force and get off to a faster standing start.  Such information should help us to understand the anatomical constraints on performance and enhance our ability to breed for performance.