Comparison of gastrointestinal transit times in stabled Thoroughbred horses fed freshly cut pasture and three conserved forage-based diets

Context The type of forage offered to horses varies in physical form, moisture content and nutrient quality, these variables could affect the intake, passage rate digestibility consumed. Aims To investigate changes digesta through gastrointestinal tract fed four different forage-based diets (diet effect). Methods Thoroughbred mares (n = 6) were stabled loose boxes for 6 weeks. During Weeks 1, 3 5 (washout periods), all freshly cut pasture, either restricted quantities (Week 1) or ad libitum (Weeks 5). Using a × Latin square design during 2, 4 6, each pair was abruptly transitioned one three conserved (chopped ensiled exclusively with oats, perennial ryegrass hay oats) libitum. At beginning week, indigestible polyethylene markers 200) administered via nasogastric tube, followed immediately by transition new diet. Key results There significant diet effect on daily dry-matter intake feed (P < 0.0001), percentage time spent eating 0.001), frequency voiding faeces 0.05) quantity voided 0.0001). horse 0.0001) but no differences faeces. effects recovery first marker 0.01 P respectively) mean retention 0.05 0.001 respectively). Mean negatively correlated (r2 –0.51 r2 –0.64 Conclusions Longer associated greater fibre supply, thus supporting hypothesis that alter basis absorption optimisation model. Implications Feed composition, also offered, may measurement apparent horses.