Assessment of Eragrostis Tef (Zucc.) As a Forage Base for Growing Beef Steers

A two year-study of animal gain performance and forage dynamics were evaluated over the course of a 63-d backgrounding period in which beef steers were supplemented while grazing Eragrostis tef (Zucc.). Paddocks (n = 4; 2.66 ha; experimental units) equipped with subsurface drip irrigation were seeded in ‘Tiffany teff’ grass (3.72 kg/ha) in both years and each paddock stocked with crossbred beef steers (n = 4, initial shrunk BW = 289 ± 30 kg year 1; n = 5, 286 ± 22 kg year 2) using a randomized complete block design. Supplements were randomly assigned to paddock: cottonseed meal (CSM; 0.45 kg/hd daily) or dried distillers’ grains (DDGS; 0.5% shrunk BW/hd daily). Steers were weighted on d 20, 41, and 62 (12-h fast). Weekly samples of whole plant (WP) and canopy (CNY) structures were obtained for DM, OM, and fiber concentrations. Biweekly, samples were analyzed for CP and IVTDMD. Data were analyzed with supplement, day, and their interactions as fixed effects. Gain did not differ by supplement from d 0-21 (P = 0.13). Observed ADG from d 0-42 and cumulative ADG was higher (P ≤ 0.03) among steers offered DDGS. Across the period, forage allowance was not affected by supplement or day (P ≤ 0.43), and no supplement × day interaction (P = 0.83) was detected. Numerically, forage allowance was lowest on d 0 and greatest on d 28. A day × structure interaction resulted in measures of NDF greater (P < 0.01) in WP relative to CNY on d 35 and 49. A similar interaction in ADF concentration resulted in greater values (P < 0.01) in WP relative to CNY on d 49. Neither IVTDMD (P = 0.63) nor CP (P = 0.54) of forage were affected by cattle supplementation. A numerical 1.29% increase (P = 0.18) in IVTDMD was observed for CNY whereas CP of CNY was greater (1.59%; P < 0.01) than WP. Concentration of CP tended to be greater at d 56 relative to d 28 (P = 0.08). Soil moisture was not affected by cattle supplementation (P = 0.40), with expected differences among soil depth (P < 0.01) and days through grazing period (P < 0.01) being observed. Supplementation with DDGS increased weight assimilation in growing beef steers without negatively affecting pasture production or canopy structure. Teff grass may be well suited for backgrounding beef cattle with supplementation.