The effects of bit chewing on borborygmi, duodenal motility, and gastrointestinal transit time in clinically normal horses.

Abstract

To determine the influence of bit chewing on gastrointestinal transit in clinically normal horses. Prospective crossover designed study. Six healthy adult horses. Horses were assigned randomly to treatment (apple flavored bit) and control (no-bit) groups and studied for 2 × 1-week trial periods with a 2-week washout period between trials. Horses were fasted for 24 h and slowly refed over 3 days. The bit was placed for 20 min every 6h. Duodenal contractions and borborygmi auscultations were evaluated every 12 h, approximately 5min following bit placement. Gastrointestinal total transit time (GI TTT) was measured by administering 200 colored beads via stomach tube and then collected in the manure until 50% and 80% were recovered. Measured variables were compared using an ANOVA or Wilcoxon signed-rank test and the P value was noted. The GI TTT was shortened in the bit chewing group (median: 106.37 h, range: 70-171 h) compared to the no-bit group (median: 170.1h, range: 149-186 h) (P=.0156) at 80% bead passage (only 4/6 horses passed 80%). Borborygmi (P=.8193), duodenal contractions (P=.2605), and 50% bead passage (P=.0781) showed no differences. Bit chewing was safe, inexpensive, and well tolerated. Bit chewing shortened GI TTT and might be an adjunct therapy to augment GI TTT. Further clinical studies are warranted. Ileus is a common complication following equine abdominal surgery with no current consistently successful treatment. Bit chewing may be a simple and inexpensive way to augment progressive GI motility.