Diet composition influences equine large intestinal motility as measured by transcutaneous ultrasound

To quantify gastrointestinal motility at 3 anatomic locations of the large colon in healthy horses fed 2 diets.

12 American Quarter Horses were enrolled in a prospective crossover study. Horses received either a complete pelleted diet fed at 1.35% body weight (BW) per day or Coastal Bermudagrass hay fed at 2% BW with 0.5% to 0.7% BW of complete pelleted feed. Each diet was fed for 13 days prior to motility assessment. Two ultrasonographers recorded the frequency of contractions at the sternal flexure of the large colon, left ventral colon, and cecum for 4 consecutive, 1-minute periods at 2 hours after the morning and evening feedings. A contraction was defined as movement of the large intestinal wall that exceeded 2 cm. Data were analyzed using the Wilcoxon signed-rank and Kruskal-Wallis tests with Bonferroni correction.

Time of day did not affect the frequency of large colon contractions at any site. At the sternal flexure of the large colon, horses fed the complete pelleted feed exhibited a greater frequency of contractions compared to those receiving hay with supplementation. No significant differences in contraction frequency at the left ventral colon or cecum were observed across diets or time points.

These results suggest that diet may affect the frequency of contractions at specific anatomic locations of the large colon in healthy horses.

Diet can affect large colon motility in healthy horses, emphasizing the need for veterinarians to consider dietary factors when assessing gastrointestinal health and function.