Cutting frequency and cutting height effects on forage quality of rough fescue and Parry oat grass

Abstract

An experiment was conducted to determine the qualitative response of rough fescue (Festuca scabrella var. campestris) and Parry oat grass (Danthonia parryi) to five cutting frequencies and three cutting heights Beginning in mid-May, the same plants were cut every 1, 2, 4, 8, or 16 wk. during a 16-wk period, at heights of either 5, 10, or 15 cm above ground level. The treatments were repeated in 3 consecutive years on the same plants. Crude protein (CP), lignin, and calcium (Ca) were significantly greater for Parry oat grass than for rough fescue, which had greater acid detergent fiber (ADF) and phosphorus (P) concentrations. Increasing cutting frequency in the first year reduced acid detergent-insoluble nitrogen (ADIN), ADF, and lignin but increased CP and in vitro digestibility of dry matter (IVD) in both forages. Repeated treatment over 3 yr tended lo increase ADF and Ca but reduce CP, P, and IVD. In the first year of treatment, CP yields in rough fescue and Parry oat grass were greatest with 2 or 4 cuts during the growing season. However, in the second year of treatment, CP yield was greatest with one or two cuts in rough fescue and with four cuts in Parry oat grass. The data confirm the benefits of repeated grazing within a year to maintain high quality forage but demonstrate the need to limit the frequency of repeated grazing to avoid deterioration and maximize nutrient yield. Nutrient yields and, presumably, benefits to livestock would be greater at a lower grazing frequency on rough fescue than on Parry oat grass. Key words: Festuca scabrella var. campestris, Danthonia parryi, crude protein, acid detergent fiber, in vitro digestibility, forage quality