The effects of organic grass and grass-birdsfoot trefoil pastures on Jersey heifer development: Herbage characteristics affecting intake

Low dietary energy and decreased intake of herbage have been attributed to the reduced performance grazing dairy cattle. We hypothesized that grasses with inherently greater would interact in a complementary way condensed tannins (CT) birdsfoot trefoil increase by heifers. Eight pasture treatments comprising high-sugar perennial ryegrass (Lolium perenne L.), orchardgrass (Dactylis glomerata meadow bromegrass (Bromus riparius Rehmann), tall fescue [Schendonorus arundinaceus (Schreb.) Dumort] were established Lewiston, Utah as monocultures binary mixtures (Lotus corniculatus L.; BFT). Pasture rotationally stocked Jersey heifers for 105 d 2017 2018, samples collected pre- postgrazing each 7-d period analyzed mass, nutritive value, apparent intake. observed differences among quantity well On average, grass-BFT had than grass monocultures, every treatment individually their respective monocultures. Using multivariate analyses, we determined approximately 50% variation was due physical characteristics, most explanatory being characteristics related fiber energy, followed those percent BFT herbage. Grass exhibited range inherent but there indication an imbalance crude protein (e.g., deficient) Moreover, some evidence effect between increased CT; however, low CT levels made it impossible determine on per se. This study confirmed chemical different species large Pastures planted nutritious temperate pastures