Intervertebral Disk Disease - Why It Is Common in Short-Legged Dogs

Intervertebral disk disease (IVDD) is a common spine condition in dogs where the intervertebral discs located between each vertebra bulge or rupture, resulting in pain, nerve damage, and if severe, paralysis. Medical studies have found that IVDD is most common in short-legged dog breeds such as Dachshunds, Poodles and Beagles. 

This article is a simplified introduction to IVDD in dogs. 

(Top) Image of a Dachshund 

The intervertebral disk is a jelly-like fibrocartilage that acts as a cushion between two vertebrates of the spinal column. The intervertebral disks help protect the spinal cord and nerves from impacts that may result from body movements or shocks.

Type I IVDD

Occurs when the inner contents of the intervertebral disk calcify and harden. Due to sudden movements, the disks may rupture and extrude out of their fibrous shell, pushing against the spinal cord and surrounding nerve cells. Dogs diagnosed with Type I IVDD may experience sharp pain and nerve damage mostly in the hip or neck area.

Type II IVDD

Involves a slower process where the disk slowly pushes against the spinal cord over time, causing the counterpart of the disk to bulge. Type II IVDD is more common in larger dog breeds such as German Shepherds and causes long-term pain in the spinal cord.

IVDD in short-legged dog breeds

Type I IVDD has the highest occurrence in Dachshunds and other similar dog breeds with the same body structure - short legs and long torso. It is found that the occurrence of Type I IVDD is a likely result of chondrodystrophy (CDDY) in dog breeds with short-legged phenotypes like Dachshunds. The mutation that causes CDDY is the insertion of an extra copy of a gene to a new location on another chromosome. This copy of the gene is referred to as Fibroblast growth factor 4 (FGF4) retrogene. FGF4 is first expressed in the embryo at the developing notochord and limb tissues, which would develop into the spinal cord and intervertebral disks. As a result, dogs with CDDY would experience the degeneration of the intervertebral disks at an early age leading to higher susceptibility to IVDD. 

The case of IVDD in dogs demonstrates the challenges and implications of selective breeding. Selectively breeding dogs for their short-limbed features has likely driven the selection of dogs possessing the FGF4 retrogene, which later on contributes to their likelihood for them to be diagnosed with IVDD.  

Works Cited

Barri (2022). IVDD (Intervertebral Disc Disease) in Dogs. [online] Petmd.com. Available at: https://www.petmd.com/dog/conditions/neurological/c_dg_intervertebral_disc_disease [Accessed 2 Feb. 2025].

Dickinson, P.J. and Bannasch, D.L. (2020). Current Understanding of the Genetics of Intervertebral Disc Degeneration. Frontiers in Veterinary Science, [online] 7. doi:https://doi.org/10.3389/fvets.2020.00431.

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Purinaproclub. (2018). Dachshunds’ Short-Leg Phenotype Linked To IVDD | Purina Pro Club. [online] Available at: https://www.purinaproclub.com/pro-resources/learning-hub/breeding/dachshunds-short-leg-phenotype-linked-to-ivdd [Accessed 2 Feb. 2025].

Ucdavis.edu. (2019). Managing the Genetics of Chondrodystrophy (CDDY) | Veterinary Genetics Laboratory. [online] Available at: https://vgl.ucdavis.edu/news/managing-genetics-chondrodystrophy [Accessed 2 Feb. 2025].