Ruminal pH and whole-tract digestibility in dairy cows consuming fresh cut herbage plus concentrates and conserved forage fed either separately or as a partial mixed ration

摘要: The objective of this experiment was to compare ruminal pH and whole-tract digestibility in cows consuming fresh cut herbage plus concentrates silage or hay fed either separately as a partial mixed ration (PMR). Fourteen rumen-fistulated Holstein-Friesian that had calved late winter were housed metabolism stalls for 9-day experiments spring (97 days milk (DIM)) autumn (237 DIM). All offered 8 kg dry matter (DM)/day perennial ryegrass (Lolium perenne L.) herbage, provided two equal portions after each milking. Seven assigned diets: (i) Control: 8.8 DM/cow.day milled wheat grain at milking, 3.2 silage, with all receiving the portion their diet but before afternoon milking; (ii) PMR: 12 PMR containing similar ME Control supplements, comprising maize grain, lucerne (spring) pasture (autumn). Intake faecal output measured on 5 during experiment, every 2 h 24-h period. Degradability using standard sacco techniques. In both experiments, higher fluid than least part day. Apparent digestibilities DM, organic matter, nitrogen, neutral detergent fibre starch greater not different (except starch). Ruminal increased by feeding maize-based associated digestibility. We conclude low enough long compromise digestion, there compensatory post-ruminal digestion.