Intake, digestibility and ruminal fermentation of ground and whole maize bran fed to American Alpine goats

A study was conducted to determine the effect of quantity and physical form of maize bran (CB) in diets of goats, on intake, digestibility and rumen fermentation. Sixteen male American Alpine goats weighing ca. 24 kg, were randomly assigned to four groups in a completely random design with a 2 x 2 factorial arrangement of treatments (two levels of CB, 15 and 30%; and two physical forms, whole and ground). Quantity and physical form of CB did not affect DM intake or digestibility. DM intake was 96.6 and 87.2 g/kg0.75 for goats on the 15 and 30% CB diets, respectively. For treatments with whole and ground CB, intake was 93.4 and 90.4 g/kg0.75, respectively. DM digestibility was 72.4 and 71.9% for 15 and 30% CB in the diet. Grinding CB did not improve digestibility (71.9% and 72.4%) for whole and ground CB, respectively. Time spent eating (min/day) was not affected by quantity or physical form of CB. Time spent ruminating was significantly greater for goats fed the 15% CB diets (397 min/day) than for those fed diets with 30% CB (338 min/day). Grinding of CB did not significantly change the time goats spent ruminating. Whereas total time spent masticating was significantly lower for 30% CB diets, no effect of grinding of CB was observed. As CB increased from 15 to 30%, total VFA production increased significantly from 85.5 to 112.1 mmoles/L. Increasing CB from 15 to 30% in the diet increased concentrations (mmoles/L) of acetate (from 55.7 to 72.6), propionate (from 19.9 to 26.1) and butyrate (from 85.5 to 112.1). Grinding CB had no effect on total volatile fatty acid production (101.7 vs. 95.9 for whole and ground, respectively). Molar percent propionate increased from 19.9 to 26.1 when CB increased from 15 to 30%. Molar percent of other VFA (acetate, 65.1 vs. 64.8; butyrate, 11.7 vs. 11.8) did not change. Grinding CB had no effect on VFA molar percent.