Comparative Value of Kentucky Bluegrass, Kentucky 31 Fescue, Orchard Grass, and Bromegrass as Pasture for Milk Cows. II. Effect of Kind of Grass on the Dry Matter and Crude Protein Content and Digestibility and Intake of Dry Matter

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Abstract
Data are reported concerning a 3-year study to determine the nutritive value of 4 grasses -Lincoln bromegrass, orchard grass, Kentucky 31 fescue and Kentucky bluegrass for lactating dairy cows. The dry matter content of bluegrass was significantly higher than that of the other grasses, but the protein content was significantly lower than that of orchard grass or brome grass, with brome grass ranking highest of all the grasses in this respect. The protein content of the grasses averaged 25.6, 22.7, 21.4 and 19.2%, for brome grass, orchard grass, fescue and blue grass, respectively. The dry matter digestibility of orchard grass tended to be slightly higher than any of the other grasses. Crude protein digestibility of brome grass was considerably higher and the digestibility of blue grass lower than for the other grasses. Daily intake of dry matter per cow grazing brome grass, orchard grass and blue grass was essentially the same, averaging 22.5, 24.3, and 23.3 lb./1OOO lb. body weight. The intake of fescue was somewhat below the other 3 grasses, only averaging 20.0 lb./day. These differences were approaching significance at the 5% level of probability. The seasonal trend was similar for all grasses with the dry matter content being low in the early spring and fall and the crude protein content high during these same periods. Dry matter digestibility was high when the content of the grasses was lower and protein digestibility was high when the protein content of the grass was high. The intake of dry matter remained at a high level from March through July, but decreased to the sub-optimum level during August and September.