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Setting the Record Straight: Do Horse Bits Cause Calcification?
Posted by Charmae Bell on Mar 19, 2025
At Bit Bank Australia, we’re committed to equine welfare and education. Recently, we’ve seen claims that using a particular type of bit will always cause periosteal reactions - more commonly referred to as calcification/bony changes of the lower jaw. Let’s take a moment to separate fact from fiction.
The Truth About Bits & Bone Changes
✅ Can bits cause calcification? – Only in extreme cases.
Bits rest on the bars of the lower jaw, an area of bone covered by a thin layer of gum tissue. If a bit is used correctly, fits well, and is paired with soft rein contact, there is no evidence to suggest it will automatically cause calcification.
❌ Is calcification common? – No.
- Horses experiencing prolonged excessive pressure from an ill-fitting or harsh bit could develop bony changes over months to years—but this is rare when the bit is fitted correctly.
- Some horses may show minor bony remodeling over time, but this does not mean pain or dysfunction.
- In contrast, bad hands, tight nosebands, and constant rein pressure are bigger factors in discomfort than the actual bit style itself.
What does research say?
- Skull studies show some older horses may develop bony reactions on the bars, but this varies based on bit type, rider skill, and training methods.
- Horses in bitless bridles or gentle snaffles can show similar bone changes, proving it’s not just about the bit but overall pressure and training techniques.
- References cited at the end of this blog if you'd like to read further.
What Really Prevents Issues?
✔ Correct Bit Fit – A well-fitted bit distributes pressure evenly, avoiding unnecessary discomfort.
✔ Soft Hands & Proper Contact – Harsh, constant rein pressure causes more damage than the bit itself.
✔ Regular Dental & Bit Fit Checks – A vet or bit specialist can identify early signs of irritation and changes.
✔ Variety in Training – Alternating between bits and bitless options can give the jaw relief.
Misinformation Hurts Horses
Spreading fear-based claims about bits can do more harm than good, leading riders to make choices based on misconceptions rather than science. The best approach? Education, expert guidance, and listening to the individual horse.
Want expert bit fitting advice? Our team at Bit Bank Australia is always here to help! Get in touch to chat with a professional, or book a Bit Fitting with your local Accredited Bit Fitter.
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References
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Oral Dimensions Related to Bit Size in Adult Horses and Ponies
- Summary: This study highlights the importance of proper bit fitting, noting that ill-fitting bits can cause discomfort and potential oral trauma.
- Link:
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Bit-Related Lesions in Event Horses After a Cross-Country Test
- Summary: This research found that bit-related oral lesions are common in event horses, emphasizing the need for appropriate bit selection and usage to prevent such injuries.
- Link:
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Bit-Related Lesions in Icelandic Competition Horses
- Summary: The study concluded that certain types of bits, especially curb bits with a port, are associated with severe lesions on the bars of the mandible, underscoring the impact of bit choice on oral health.
- Link:
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Radiographic Study of Bit Position Within the Horse's Oral Cavity
- Summary: This research examined how different bits position within the horse's mouth and their movements in response to rein tension, providing insights into how bit mechanics can affect oral structures.
- Link:
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Equine Mandibular Growths
- Summary: This article discusses calcified growths in the horse's mandible, providing context on how chronic irritation or trauma, potentially from bit use, can lead to such conditions.
- Link: