| Abstrak/Abstract |
Teff (Erogrostis tef [Zucc.], Poaceae) is a warm-season annual grass and has attracted much interest among hay growers in the United States due to its rapid growth, palatability, and high quality and yield. The objective of this study was to assess growth performance and ruminal fermentation of growing beef steers and dairy heifers when fed teff hay-based diets. Twelve growing beef steers and 12 dairy heifers were used in a completely randomized design to test 2 dietary treatments: alfalfa hay-based TMR (AHT) and teff hay-based TMR (THT). In beef steer diets, the AHT contained 20.5% alfalfa hay and 43.0% corn silage, whereas the THT had 44.0% teff hay and 20.7% corn silage. In dairy heifer diets, the AHT contained 54.1% alfalfa hay and 24.8% corn silage, while the THT had 8.5% alfalfa hay, 42.0% teff hay, and 11.3% corn silage. All animals were placed in individual pens, and the experiment lasted 12 wk. Intake of DM increased by feeding the THT to beef steers and dairy heifers (P = 0.01). Dietary treatments did not affect ADG of beef steers; however, feeding the THT to dairy heifers increased (P = 0.02) ADG. Dietary treatments did not affect G:F in both beef steer and heifer diets. Ruminal pH averaged 6.54 or 6.51 in beef steer or dairy heifer diets, respectively, and did not differ between diets. Feeding the THT decreased total VFA concentration by beef steers and dairy heifers (P < 0.02). Feeding the THT to beef steers increased acetate proportion (P = 0.02), but the THT decreased propionate proportion (P < 0.01), resulting in increased acetate-to-propionate ratio due to feeding the THT (P < 0.01). In contrast, feeding the THT to dairy heifers tended to decrease acetate proportion (P = 0.10), but the THT increased propionate proportion (P = 0.05). Although feeding the THT decreased ruminal fermentation by beef steers and dairy heifers evidenced by decreased VFA concentration, the THT increased DMI of beef steers and dairy heifers, leading to no negative effects on growth performance. Teff can be a viable lower-cost alternative to feeding alfalfa in growing beef steers and dairy heifer diets.
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