The relationship between cheek tooth occlusal morphology, apparent digestibility, and ingesta particle size reduction in horses.

OBJECTIVE

To investigate potential relationships between cheek tooth occlusal morphology, apparent feed digestibility, and the reduction in feed particle size that occurs during digestion in horses.

DESIGN

Cross-sectional study.

ANIMALS

17 horses of various ages and breeds and either sex.

PROCEDURES

Horses were fed 1 of 3 hay-based diets ad libitum for 14 days prior to euthanasia; nutrient analysis was performed on samples of each of the 3 diets. At the time of postmortem examination, the head was disarticulated, photographs were taken of the occlusal surfaces of the maxillary and mandibular cheek tooth arcades, and samples of stomach and small colon or rectum contents were collected for determination of apparent feed digestibility and particle size determination. An overall oral pathology score was assigned, and morphologic features of the occlusal surfaces of the cheek tooth arcades were determined.

RESULTS

Results of nutrient analyses did not differ among the 3 hay diets, and there was no significant difference in apparent feed digestibility among diets. Feed particle size differed significantly among the 3 diets, but stomach content and fecal particle sizes did not differ among diet groups. No significant correlations were identified between cheek tooth morphologic variables and feed digestibility, and fecal particle size was not significantly associated with oral pathology score.

CONCLUSIONS AND CLINICAL RELEVANCE

Results did not provide any evidence of associations between cheek tooth morphologic variables, fecal particle size, and apparent digestibility in horses.