On the other hand, chondrodystrophic breeds of dogs are prone to the development of IVD herniation early in life. In these breeds (including dachshunds, beagles, pekinese, miniature poodles, cocker spaniels, pomeranians and basset hounds), there is a metaplasia of the nucleus pulposus whereby the normal collagen fibers of the nucleus are replaced by hyaline fibers. The hyaline fibers are less elastic than collagen fibers leading to degeneration of the annulus fibrosis. The hyaline fibers during this degenerative process calcify, creating further inelasticity. Due to the fact that the annulus fibrosis is thinnest dorsally toward the spinal cord, the least line of resistance for the degeneration and breakdown of the annulus is toward the spinal cord. Ultimately, the annulus ruptures allowing the herniation of the degenerative nucleus into the neural canal, compressing the spinal cord. Not only does the IVD material compress the spinal cord, but the degenerative material is irritative in nature. The presence of the herniated material in the epidural space causes inflammation, furthering the swelling associated with the herniation.
Almost all chondrodystrophic dogs will show some degree of IVD degeneration within a year of age. The earliest I have seen clinical IVD herniation is these dogs is at 7 months. Usually the onset is between 2-3 years of age with the peak incidence being between 4-6 years of age
...Medical management of IVD disease consists of absolute rest for a minimum of 30 days or 3 weeks beyond return to clinical normalcy. This confinement must be in a cage no more than 2.5 x 1.5 times the animal's body length. An airline carrier is ideal. Many patients will benefit from corticosteroid management during the initiation of treatment. I think this should only be done under direct veterinary supervision. If the patient feels better and then becomes active before healing has occurred, they are at great risk to get worse. We see this outcome commonly. It could be prevented in many cases, with absolute confinement of the patient.