PSI-4 - Animal and agronomic performance while grazing winter stockpiled novel endophyte tall fescue established with three pasture renovation strategies

Comparing animal and agronomic performance following renovation of toxic-infected tall fescue (TF) to novel endophyte tall fescue (NE) is fundamental to evaluating economic returns and increasing adoption of NE. In 2018, three NE renovation strategies were implemented in a randomized complete block design in Bahama, NC. Strategies included: 1) control (C), 2) renovation to NE after one season of a single specie cover crop (1-SM), 3) renovation to NE after three seasons of a single specie cover crop (3-SM), and 4) renovation to NE after three seasons of a multi-specie cover crop (3-CM). Sixty-four Angus heifers (initial BW 290 kg ± 88)were randomly assigned to treatments and strip-grazed stockpiled fescue for 56-d, two years after NE establishment. Forage yield and nutritive value was measured every 14-d. Data were analyzed using proc GLIMMIX of SAS v9.4. Average daily gain was greatest (P = 0.0024) for cattle grazing 1-SM (0.67 kg/d), and least for 3-CM (0.54 kg/d) and C (0.44 kg/d), which did not differ. 3-SM (0.57 kg/d) did not differ from other treatments. Within the grazing period, forage yield was greatest (P = 0.0001) in 3-CM, 3-SM, and C compared to 1-SM (3053, 2941, 2856 and 2465 kg/ha, respectively). Prior to the initiation of grazing, crude protein concentration was greater (P = 0.0089) for 3-CM (17.5%) compared to C, 1-SM, and 3-SM (15.8%, 15.8% and 15.3%, respectively). Neutral detergent fiber was greater (P = 0.0135) for 3-SM (57%) than C (55.1%) and 3-CM (54.5%), but did not differ from 1-SM (54.6%). Concentration of total digestible nutrients was greater (P = 0.0187) for 3-CM (73.2%) compared to 1-SM (72.1%) and 3-SM (71.9%), but did not differ from C (72.5%). Data suggest animal and agronomic performance for NE was improved compared to TF during winter stockpile grazing in years following renovation.