Ruminal bacterial community shifts in grain-, sugar-, and histidine-challenged dairy heifers

Abstract

Ruminal bacterial community composition (BCC) and its associations with ruminal fermentation measures were studied in dairy heifers challenged with combinations of grain, fructose, and histidine in a partial factorial study. Holstein-Friesian heifers (n = 30) were randomly allocated to 5 triticale grain-based treatment groups: (1) control (no grain), (2) grain [fed at a dry matter intake (DMI) of 1.2% of body weight (BW)], (3) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI), (4) grain (1.2% of BW DMI) + histidine (6. g/head), and (5) grain (0.8% of BW DMI) + fructose (0.4% of BW DMI) + histidine (6. g/head). Ruminal fluid was collected using a stomach tube 5, 115, and 215. min after consu..