What is IVDD?

Please watch this informative session presented by Dr. Natasha Olby from NCState at our Spring Social on 5/10/25

Here is a PDF of Dr, Olby's Slides for the Presentation 

Boykins and IVDD Slide Deck
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File Type:	pdf

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Frequently Asked Questions about IVDD

 Over the last several years IVDD (intervertebral disc disease) has become a topic of concern with Boykin Spaniel Owners. In order to prevent any misinformation or misdirection regarding this disease and the injuries that are emotionally and financially devastating for the owners, the Boykin Spaniel Health Organization would like to answer some of the Questions that frequently are asked on social media posts.

• What is IVDD?

• How do I know if my dog has IVDD or can a test be run for IVDD?
• How do I know if my dog is having issues because of IVDD?
• Do ALL Boykins have IVDD? Can we still breed this disease out of the breed without ruining the characteristics of the breed?
•  Not all back injuries are IVDD

 
We would like to address these questions with answers from our advisors with links to further information. We hope this will be informative and helpful to help dog owners and potential dog owners understand that IVDD can be tested for and to be financially prepared with options such as Pet Insurance to help offset costs of treatment and help you make the best decisions possible for your companions.
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• What is IVDD?

 Chondrodystrophy (IVDD) changes the character of all of the intervertebral discs at a young age. The discs have abnormal degeneration of the nucleus pulposus, which is the center of the intervertebral disc that normally provides cushion and flexibility to the back. The end of the degeneration process is a mineralized or calcified disc. The change in the cellular structure of the disc is what predisposes it to herniate (move into the spinal canal impinging on the spinal cord). The chondrodystrophic degenerative phenotype is evident in all the intervertebral discs as early as 10 weeks of age in dogs homozygous for CDDY but is absent in breed matched dogs lacking the mutation (Murphy et al., 2019). https://vgl.ucdavis.edu/news/managing-genetics-chondrodystrophy
What does this mean?
In Chondrodystrophic breeds, premature calcification of the nucleus pulposus at early age (from birth to 1 year of age) results in degeneration of all discs in young dogs. These abnormal discs are predisposed to herniation into the spinal canal where the inflammation, and hemorrhage can cause severe pain and neurological dysfunction (myelopathy) termed Intervertebral Disc Disease or IVDD. IVDD has high mortality rate and high cost of surgical and medical veterinary care.
Here, we report that 12-FGF4RG is both associated with intervertebral disc calcification and with age at time of surgery for IVDD across all affected breeds. The presence of 12-FGF4RG increases the risk for disc herniation 5.5–15.1-fold over the background risk in segregating and mixed breeds.

•  How do I know if my dog has IVDD or can a test be run for IVDD?  

Per UCDavis/Veterinary Genetics Laboratory (The developer and provider of guidelines for interpretation and breeding recommendations): Our tests assay for the causal variants, not for linked markers, therefore the genotypes are accurate and not inferred. CDDY and CDPA occur in many breeds. Testing for these mutations can help breeders determine if CDDY is present among breeding stock and to identify dogs at risk for IVDD. In breeds where both mutations are present, breeders can benefit from test results to implement breeding strategies to reduce incidence of CDDY, while retaining the short-legged phenotype conferred by CDPA.
https://vgl.ucdavis.edu/test/cddy-cdpa {Click for Coupon}
 
We recommend using the Veterinary Genetics Laboratory UCDavis for testing, or any company that CLEARLY uses the UCDavis guidelines, such as Orivet/PawPrint Genetics https://caninehealthcheck.com/ {Click for Coupon}

{We do NOT recommend Embarq for testing for CDDY. Embarq uses MARKERS per their website “There are different ways we do this, and in the case of IVDD, it’s through a linkage test. DNA sequences that are close together on a chromosome tend to be inherited together, so we’re able to infer the presence or absence of a variant of interest by examining the genetic variation surrounding it. Because linkage tests don’t directly look at a variant of interest, they may not be perfectly predictive of your dog’s true genotype.” https://embarkvet.com/resources/type-i-ivdd-slipped-disc/}

• How do I know if my dog is having issues because of IVDD?

There are different levels of injury that are caused by IVDD that neurologists use.
Grade 1: PAIN ONLY

• Able to walk normally

• Exhibiting signs of back pain such as not wanting to jump or move, shivering, walking slowly or gingerly, crying, shivering, muscle spasms, arching the back, or a tense belly

Grade 2: Ambulatory Paraparesis

• Still able to walk, but weak and wobbly in rear limbs
• May cross, splay out, or stumble over back legs or walk with back paws knuckled under

Grade 3:Non-Ambulatory Paraparesis

• Too weak in rear limbs to stand or walk
• Still able to move limbs and wag tail

Grade 4: Paraplegia (Still has deep pain Sensation)

• Cannot stand or walk
• Cannot move rear limbs
• Still able to feel toes

Grade 5: Paraplegia with Absent Nociception (no deep pain sensation)

• Cannot stand or walk
• Cannot move rear limbs
• Cannot feel rear limbs at all

  
“Without timely treatment, IVDD can progress quickly and cause irreversible damage. Therefore, your pet should be evaluated by our team as soon as you notice any signs of back pain and difficulty walking. There are two basic ways to treat IVDD in dogs:
Non-Surgical: For patients with first-time back pain or mild weakness, we can try a medical approach that includes pain medication and strict crate rest for at least four weeks. We also use this approach if the patient cannot undergo MRI due either to owner preference or concurrent medical conditions.
Your pet can come out of the cage for urination, defecation, and physical rehabilitation, but should otherwise be crate rested.
For dogs with grades 1-4 IVDD that are managed non-surgically, the chances of making a fully functional recovery are about 50-70%, depending on the degree of neurological symptoms. They may take longer to improve, have a higher risk for recurrence, and are at greater risk for worsening when compared to those that are treated with surgery.
Grade 5 is a surgical emergency.
Surgical: If the patient is experiencing difficulty walking or has recurrent or persistent back pain that will not respond to rest or medication, surgery may be the best option. The goal is to remove the disc material that is pressing on the spinal cord. We can also do a preventative procedure at this time to reduce the likelihood of recurrence.
For dogs with grades 1-4 IVDD that are managed surgically, the chances of making a fully functional recovery are about 95% in the hands of an experienced neurosurgeon at SEVN.
For grade 5 dogs, the chances of recovery are significantly lower at about 50%. Surgery should be performed as soon as possible for the best chance of recovery, no more than 48 hours after losing the ability to feel the legs.
Unfortunately, with or without surgery, dogs with grade 5 IVDD are at risk for myelomalacia, an extremely serious condition that is typically progressive and fatal.
(https://sevneurology.com/conditions-we-treat/intervertebral-disc-disease?fbclid=IwY2xjawFNZehleHRuA2FlbQIxMAABHbMMtxJhwxFm-t1_qJN-aPd3cBnoB-XHhsDZt5H7zieVruIa9ikxz1clFg_aem_0SvdOTvHbk3yp6GhfH2NTw)

• Do ALL Boykins have IVDD? Can we still breed this disease out of the breed without ruining the characteristics of the breed?

 “CDDY is a dominant mutation, current research from genetic testing shows the estimated allele frequency for CDDY in the Boykin Spaniel to be  0.57.  Periodic updates the breed allele frequencies can be found on the VGL’s website.  Using the estimated allele frequency tells us that approximately 82% of the dogs in the Boykin Spaniel population have one or two copies of CDDY.   Therefore selection against CDDY should be done cautiously to maintain diversity in the breed.   Recommendations on breeding can also be found on our website but in short, with a greater than 50% allele frequency we  recommend that breeders select away from this mutation over multiple generations and to mate dogs with CDDY to dogs with two copies of the normal allele (N) to reduce the allele frequency slowly without a dramatic effect on breed diversity” -Dr. Rebecca Bellone, Director UC Davis VGL https://vgl.ucdavis.edu/news/managing-genetics-chondrodystrophy)
“Our findings suggest that breeding priorities should be for dogs with fewer copies of 12-FGF4RG, so that the allele frequency can be reduced. In breeds with lower allele frequencies of 12-FGF4RG, selection against the allele should reduce the incidence of disc disease. Even among breeds with high allele frequencies, genetic screening may be desirable to identify dogs with only one copy of 12-FGF4RG o that dogs with zero copies may eventually be bred, significantly improving the overall health of affected breeds.” (page 15/17 Phenotypic Effects of FGF4 Retrogenes on Intervertebral Disc Disease in Dogs https://www.boykinivdd.com/uploads/1/3/4/4/134455252/genes-10-00435.pdf)
For your convenience Our website has the current frequency of the gene statistics from both UCDavis and Neogen/Paw Print Genetics. https://www.boykinivdd.com/dna-testing-statistics.html   

Provided by Dr. Natasha Olby, NCState (in presentation above)

Provided by Dr. Casey Carl, DVM Paw Print Genetics

•  Not all back injuries are IVDD
  

"If we just look at the FGF4 form - 64% were type I IVDD. Of course that is across many breeds of dog and in the chondrodystrophic breeds as a whole, Hansen type 1 IVDD accounted for 85% of all cases. Given Boykin’s are fitting into the chondrodystrophic category, it give you a sense of the risk of that mutation.
 Yes it is correct to say not all back injuries are due to FGF4 associated IVDD but that doesn’t lessen the importance of those dogs that do suffer from this condition, which could potentially be dramatically reduced in the breed through genetic testing and breeding away. - breeds with a closer to 100% prevalence of the FGF4 CFA 12 variant have high rates of IVDD – Boykin Spaniels are already at 80%.
you don’t want the Boykin spaniel to end up at 100%"
Natasha Olby Vet MB, PhD, DACVIM (Neurology) Professor (Neurology and Neurosurgery NC State)) (N Neurosurgery)
 

For more information please visit our website dedicated to
IVDD in Boykin Spaniels 
   And PLEASE consider getting pet insurance

Our thanks to the following for their input on this article:

• Natasha Olby Vet MB, PhD, DACVIM (Neurology) Professor (Neurology and Neurosurgery NC State)) (N Neurosurgery)
• Dr. Rebecca Bellone, Director UC Davis VGL
  
• Michael Wong, DVM, DACVIM (Neurology)