Energy and Degradable Intake Protein Supplementation for Spring-Calving Beef Cows Grazing Stockpiled Bermudagrass Pasture in Winter
2002
Johnson, C.R. | Lalman, D.L. | Steele, J.D. | O'Neil, A.D.
Two experiments were conducted to evaluate the effects of supplemental energy source and degradable intake protein (DIP) concentration on 1) performance of cows (n = 63) grazing stockpiled bermudagrass pastures and 2) on forage utilization by steers fed hay harvested from the pastures during early winter. For both experiments, supplements were fed at the rate of 0.17% BW and formulated using 1) soybean hulls (SH); 2) corn and soybean meal (SBM) to achieve similar DIP to SH (LDC); or 3) corn and SBM to achieve twice the DIP of SH (HDC). A fourth treatment group did not receive supplementation (control). Pastures were grazed to approximately 10 cm in late August and fertilized with 56 kg N/ha. In Experiment 1, grazing was deferred until November 15, when treatments were initiated and continued for 70 d. Supplement treatment did not influence (P>0.1) cow BW change or forage intake. Supplementation resulted in a slight improvement (P<0.05) in body condition score compared with non-supplemented animals. In Experiment 2, four steers were used in a Latin square design and received the same supplementation regimes as described in Exp. 1. Supplement treatment did not affect forage organic matter intake (OMI), total OMI, or fiber digestibility. Supplemented steers had greater (P<0.01) apparent CP digestibility. Steers that received the corn supplements (LDC and HDC) had greater apparent CP digestibility than did those that received SH. The forage DIP concentration was not limiting in these experiments, and supplementation did not significantly alter animal performance, forage intake, or apparent digestibility of forage.
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