Comparison of mandibular motion in horses chewing hay and pellets.
Authors: Bonin S J, Clayton H M, Lanovaz J L, Johnston T
Journal: Equine veterinary journal
Summary
# Editorial Summary: Mandibular Motion in Horses Chewing Hay and Pellets Understanding how different feed types influence temporomandibular joint (TMJ) kinematics has important implications for dental health, yet direct measurement of mandibular motion during mastication in horses remained limited until this 2007 investigation. Bonin and colleagues used optical motion capture technology to track skull and mandibular markers in seven horses whilst they chewed both hay and pellets, with a virtual marker positioned at the mandibular midline representing overall jaw movement relative to the skull. Hay chewing produced significantly larger mandibular excursions in all three planes of motion and lower chewing cycle frequency compared to pellets, though mean velocity remained constant between the two feeds; critically, the mediolateral displacement during hay mastication was sufficient to achieve full occlusal contact across the dental arcades, whereas pellet chewing did not generate comparable lateral movement. These findings carry considerable weight for equine practitioners: horses maintained on concentrate-heavy diets experience restricted mandibular motion that may predispose them to dental irregularities, suggesting that animals receiving predominantly pelleted feeds warrant more frequent dental examinations and prophylactic treatment to identify and manage developing malocclusions before they become established problems.
Read the full abstract on PubMed
Practical Takeaways
- •Horses on high-concentrate diets experience reduced mandibular motion during chewing, which may predispose them to dental irregularities; more frequent dental examinations are warranted for these horses
- •Providing adequate forage (hay) rather than relying heavily on pelleted feeds promotes better temporomandibular joint function and more complete occlusal contact
- •Consider feed type when counseling on preventative dental care protocols and scheduling for dental prophylaxis
Key Findings
- •Mandibular excursions were significantly larger in all three directions when chewing hay compared to pellets
- •Chewing frequency was lower for hay than for pellets
- •Mean velocity of mandibular motion was equivalent between hay and pellet chewing
- •Mediolateral mandibular displacement during hay chewing provides full occlusal contact of upper and lower dental arcades, whereas pellet chewing does not