Differentiating Affects of Effective Fiber Sources on Performance of Lactating Dairy Cows

The aim for this research was to determine if corn stover and straw can be efficiently added to lactating dairy cow diets as physically effective fiber sources. A 5x5 Latin square design was used with 5 multiparous rumen cannulated Holstein cows. The treatments were: 1) CS; corn silage as sole forage source (44.1% forage), 2) ALF; corn silage and 11.5% alfalfa hay (45.5% forage), 3) STW-5; corn silage and 5% wheat straw (39% forage), 4) STW-10; corn silage and 10% straw (46.2% forage), and 5) STV; corn silage and 5.5% corn stover (39.5% forage). The dry matter intake (DMI) was lowest for STW-10 (P < 0.05). The body weight (734 kg) and BCS (3.18) were similar among treatments. Milk (35.6 kg/d), milk fat (3.56%), milk protein (2.87%), and MUN (17.4 mg/dl) also were similar among treatments. The different forage sources resulted in similar total tract digestibilities of dry matter (75.7%), organic matter (76.9%) and NDF (63.5%). Rumen pH (6.12), acetate:propionate (3.10), and ruminal concentrations of total VFA, acetate, propionate, butyrate, and valerate were similar among treatments. Concentrations of isovalerate (P < 0.05) and isobutyrate (P < 0.10) were highest for STW-10 compared to the other diets, and isovalerate was also lower (P < 0.10) for ALF than for STW-5 and STV. Feeding the higher level of straw may have caused more rumen fill and thus reduced DMI, which would likely lower milk yield in a longer term study. Feeding similar forage NDF concentrations with corn silage based diets using corn stover, alfalfa hay, and wheat straw can result in similar animal performance and ruminal fermentation with adequate formulation of dietary non-fiber carbohydrates and total NDF.No embarg