A post at Science of Dogs bemoans a century of dog breeding for its production of too many dogs with genetic defects. Excerpts:
The dogs on the left are from the 1915 book, ‘Breeds of All Nations‘ by W.E. Mason. The examples on the right are modern examples from multiple sources...Other examples at the source include the Basset Hound, the English bulldog, the German Shepherd, the Pug, and the St. Bernard.
[top photo] It seems incredible that at one time the Bull Terrier was a handsome, athletic dog. Somewhere along its journey to a mutated skull and thick abdomen the bull terrier also picked up a number of other maladies like supernumerary teeth and compulsive tail-chasing.
A shorter face means a host of problems. The modern Boxer not only has a shorter face but the muzzle is slightly upturned. The boxer – like all brachycephalic dogs – has difficulty controlling its temperature in hot weather, the inability to shed heat places limits on physical performance. It also has one of the highest cancer rates.
The Dachshund used to have functional legs and necks that made sense for their size. Backs and necks have gotten longer, chest jutted forward and legs have shrunk to such proportions that there is barely any clearance between the chest and floor. The dachschund has the highest risk of any breed for intervertebral disc disease which can result in paralysis; they are also prone to achondroplastic related pathologies, PRA and problems with their legs...