Risk factors for bit-related lesions in Finnish trotting horses.
Authors: Tuomola Kati, Mäki-Kihniä Nina, Valros Anna, Mykkänen Anna, Kujala-Wirth Minna
Journal: Equine veterinary journal
Summary
# Bit-Related Lesions in Finnish Trotters: What the Evidence Shows Oral lesions are recognised consequences of competition in harness racing, yet their underlying causes remain poorly understood. Finnish researchers examined the mouths of 261 harness racehorses (predominantly Standardbreds and Finnhorses) immediately post-race, correlating lesion severity with bit type, equipment use, and performance variables. Unjointed bits—particularly mullen mouth regulators (odds ratio 9.9), straight plastic bits (13.7) and Crescendo bits (3.6)—showed significantly higher associations with moderate-to-severe lesions than conventional single-jointed snaffle trotting bits, with bar lesions being notably more prevalent in unjointed designs. Interestingly, tongue-ties, overchecks, galloping episodes and race success showed no protective or aggravating effect on lesion risk, suggesting that bit mechanics rather than auxiliary equipment or performance intensity drive tissue trauma. For practitioners selecting bits or advising on harness-racing tack, these findings support a preference for jointed bits, though the authors acknowledge that absolute causation cannot be proven without controlling for rein tension—a critical variable that likely mediates the relationship between bit design and oral damage.
Read the full abstract on PubMed
Practical Takeaways
- •Avoid Crescendo, mullen mouth regulator, and straight plastic bits in trotters; use single-jointed snaffle trotting bits to reduce moderate/severe oral lesion risk by up to 13-fold
- •Select jointed bits over unjointed designs to minimize bar lesions in harness racing horses
- •Investigate rein tension and bit-rein interaction as critical variables, since lesions occur even with safer bit types and equipment factors like tongue-ties show no protective effect
Key Findings
- •Crescendo bits (OR 3.6), mullen mouth regulator bits (OR 9.9), and straight plastic bits (OR 13.7) were associated with significantly higher risk of moderate/severe oral lesions compared to snaffle trotting bits in 261 harness racing horses
- •Bar lesions were significantly more common with unjointed bits than jointed bits (P<0.001)
- •Tongue-ties, overchecks, race performance, and galloping were not associated with oral lesion risk
- •Moderate to severe lesions were observed across all bit types, suggesting bit type alone does not fully explain lesion etiology