Preference of Cattle Grazing Birdsfoot Trefoil in Binary Mixtures with Meadow Bromegrass, Orchard Grass, Perennial Ryegrass and Tall Fescue.

Cattle often preferentially graze one forage species in mixed cool season pastures typical of the Intermountain Western USA. Our objective was to determine cattle grazing preference in mixed birdsfoot trefoil-grass pastures. Birdsfoot trefoil (Lotus corniculatus L.; BFTF) was established in binary mixtures with tall fescue (Festuca arundinacea Schreb.; TF), perennial ryegrass (Lolium perenne L.; PRG), orchard grass (Dactylis glomerata L.; OG) and meadow bromegrass (Bromus biebersteinii Roem. & Schult.; MB). Each grass was established in mixed rows and alternating rows with the BFTF. Jersey heifers were rotationally grazed in each treatment for 7 day grazing bouts on a 35 day rotation starting 21 June 2016. Percent utilization of each species was visually determined on day 3 and 7 of each grazing bout. Overall on day 3 BFTF utilization averaged 24% and grass utilization 18, 21, 23 and 27 % for OG, TF, MB and PRG, respectively. Overall on day 7 BFTF utilization averaged 66% while grass utilization was 51, 56, 59, and 64% for OG, TF, MB, and PRG, respectively. In the first rotation, early-summer, BFTF utilization was 14% less than PRG but averaged 12% greater than all other grasses. In the second rotation, mid-summer, there was no difference in utilization between BFTF, MB and PRG; however, BFTF averaged 20% greater utilization than OG and TF. In the third rotation, late-summer, BFTF utilization average 6% more than OG, PRG, and MB with a much larger 30% greater utilization than TF. When compared to TF, BFTF is always preferentially grazed while in all comparisons with MB there is no difference in grazing preference. Early in the rotation there was no grazing preference between OG and BFTF, but late in the rotation (day 7) BFTF was preferentially grazed over OG. During early growth PRG was preferentially grazed over BFTF, but this reversed during later growth.