Episode 103: Guest Dr. Sharon May-Davis — Grading ECVM (Equine Complex Vertebral Malformation)
Summarised Transcript:
In this episode, Dr. Raquel Butler and Sophie Vandenberg are joined by Dr. Sharon May-Davis to explore the development and grading of Equine Complex Vertebral Malformation (ECVM).
Sharon shares how her investigation into ECVM began after discovering unusual changes in the C6, C7 and first sternal ribs of Thoroughbred skeletons, and how years of dissection, anatomical research and collaboration led to a clearer understanding of the condition.
The conversation explores the prevalence of ECVM across different breeds, the development of a grading system based on changes to C6, and why higher-grade presentations—particularly Grade 4—may warrant further investigation of C7, the first ribs and surrounding anatomical structures.
They also discuss how ECVM may influence muscular and postural support through the lower cervical and cervicothoracic regions, alongside possible clinical signs including tripping, toe dragging, hypersensitivity, neurological changes and unpredictable behaviour.
Throughout the episode, the discussion emphasises the importance of early observation, appropriate veterinary investigation, understanding the individual horse and considering how breeding decisions may influence the future health of the equine population.
Chapters:
00:00 — Introduction to Dr. Sharon May-Davis and ECVM
02:04 — History and discovery of ECVM in horses
03:59 — Prevalence and distribution of ECVM across breeds and species
06:50 — How ECVM research and classification developed
11:49 — Genetic, domestication and paleontological perspectives
14:56 — Possible clinical relevance and ECVM in young horses
17:23 — Introduction to the ECVM grading system
19:59 — Understanding the C6 grading system and anatomical changes
23:47 — Using radiographs to identify and grade ECVM
25:01 — Why Grade 4 may warrant further investigation of C7 and the ribs
27:08 — Grade 4 ECVM, clinical signs and quality-of-life considerations
31:08 — Behavioural and neurological observations associated with ECVM
32:50 — Early signs: tripping, falling, toe dragging and hypersensitivity
35:06 — Unilateral versus bilateral ECVM
37:55 — Longus colli changes, symmetry and postural support
40:01 — Cervical movement, balance and vestibular function
42:25 — Domestication, movement and changes in the equine skeleton
44:44 — Tendons, muscles and implications for structural support
47:48 — Recognising subtle signs and investigating horses earlier
49:13 — Caudal cervical pain and the importance of observation
51:41 — Industry responsibility, breeding and future research
55:34 — Key takeaways: prevalence, grading and supporting affected horses
57:57 — Observing posture, movement and behaviour in everyday life
1:01:06 — Final takeaways and closing discussion
Key Takeaways:
* ECVM involves anatomical variations that can affect C6, C7, the first ribs and potentially other structures within the horse.
* The ECVM grading system helps describe the degree of change at C6, with Grade 4 horses more likely in the discussed research to have additional changes involving C7.
* ECVM can occur unilaterally or bilaterally, and the degree of change may differ between the left and right sides.
* Changes to the longus colli muscle and tendon attachments may influence cervical stability, symmetry and postural support.
* Possible signs worth investigating include tripping, toe dragging, difficulty travelling downhill, hypersensitivity, neurological changes and unusual or unpredictable behaviour.
* A diagnosis does not automatically determine a horse’s future, but it can help owners and professionals make more informed decisions about management, posture, workload and welfare.
* Continued research, responsible breeding practices and earlier recognition are important for understanding the wider implications of ECVM.
Notable Quotes:
* “The bones never lie and they tell a story.”
* “Grade four — we better look at C7.”
* “You want to kind of know what you’re riding.”
* “Just switching on your observation skills.”
* “Ask questions about your horse’s posture and movement.”
