PSI-A-12 Evaluation of Novel and Traditional Cover Crops Utilizing Cattle in High-Density, Short-Duration Grazing

Abstract

Abstract The objective was to evaluate yield, nutritive value, and neutral detergent fiber digestibility (NDFD) of traditional and non-traditional cover crops utilizing short-duration, high-density grazing. This experiment was conducted at Western Illinois University Kerr Farm, Macomb, Il. Cow-calf pairs (n = 58) grazed 0.4046 hectare plots in spring 2021. Dry cows (n = 58) grazed 0.4046 hectare plots in the fall 2021. Grazing duration was 24 hours per plot. In the spring, five plots of rye were grazed. In the fall, two plots of kernza, two plots of cover crop mix (CMIX), and one plot of red clover were grazed. The cover crop mix contained 12 varieties including brassicas, legumes, cereal grains, and grasses. Kernza is a novel perennial crop harvested for grain in the summer and used for grazing in the fall and winter. Plots were randomly sampled four times pre and post grazing using a 0.4047 square meter forage ring. All grass within the ring was clipped leaving 10.16-15.24 cm of material to mimic grazing. Forage height was recorded using a tape measure. Samples were collected and dried prior to combining and averaging data. Data pre- and post-grazing included DM, forage height, and DM yield. Cattle intake was calculated using pre- and post-grazing DM yields. Samples were analyzed at Rock River Laboratories (Watertown, WI) for CP, aNDF, ADF, and NDFD at 12, 30, and 48 hours. Data were analyzed using the Mixed procedure of SAS 9.4. Means were determined using LSMeans and separated using the p-diff function. Pre-grazing height of rye was 141 cm, CMIX was 87.6 cm, while kernza and red clover were both 26.7 cm (P < 0.01). Rye was most abundant in kg/ha of DM pre-graze and post-graze (P < 0.01). Cows consumed over 50% of kernza and CMIX, but only 29% of rye (P < 0.01). Forage dry matter percentages did not differ. Kernza had a lower CP (6.36%) than rye (8.91%; P = 0.02). Kernza CP did not differ from CMIX at 7.78% (P = 0.19). Kernza had a 7.18% greater aNDF than rye (P = 0.04). The aNDF of CMIX (55.56%) was greater compared with red clover at 44.75% (P = 0.04). Kernza ADF was 49.22% compared with rye at 43.8% (P = 0.02). The CMIX had the most desirable NDFD at 12, 24, and 48 hours (P < 0.01). Data indicated that rye, kernza, red clover, and cover crop mixtures offer value in high-intensity, short-duration cover crop grazing in terms of nutritive value and NDFD for cattle. Rye had the greatest DM yield values but less consumption by cattle due to forage maturity.