Effect of rostrocaudal mobility of the mandible on feed digestibility and fecal particle size in horses.
OBJECTIVE
To evaluate the effect of rostrocaudal mobility (RCM) of the mandible during extension and flexion of the atlanto-occipital joint on weight gain, feed digestibility, and fecal particle size in horses.


METHODS
Randomized controlled trial.


METHODS
34 pregnant mares housed in 1 barn.


METHODS
Horses were randomized into a treatment (n = 17) or control (17) group. All horses were sedated, and the distance between the rostral portions of the upper and lower incisor arcades was determined during extension and flexion of the atlanto-occipital joint; mandibular RCM was calculated as the difference between these values. In the treatment group, measurements were made after dental floating. Body weight was recorded 1 day before dental floating and at intervals after mandibular RCM determination for a period of 24 weeks. Feces were collected from each horse during two 5-day periods. Samples of feed and feces were analyzed to determine feed digestibility; particle size analysis was performed on dried fecal samples.


RESULTS
Data obtained from each group of horses revealed that RCM of the mandible did not affect weight gain, feed digestibility, or particle size in feces; there were no differences among breeds. Controlling for age and number of dental lesions did not significantly affect results.


CONCLUSIONS
In horses, RCM of the mandible did not appear to affect weight gain, feed digestibility, or fecal particle size. On the basis of these and other published data, the assumption that dental abnormalities affect digestion detrimentally in horses needs to be reevaluated.
Carmalt
James L
JL
Department of Large Animal Clinical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK S7N 5B4, Canada.
Allen
Andrew L
AL
D000818:Animals; D003813:Dentistry / Q000379:methods / Q000662:veterinary; D004063:Digestion; D005243:Feces / Q000737:chemistry*; D005260:Female; D006736:Horses / Q000502:physiology*; D008334:Mandible / Q000473:pathology*; D008409:Mastication / Q000502:physiology*; D010316:Particle Size; D011247:Pregnancy; D015430:Weight Gain / Q000502:physiology*