Two experiments were conducted to evaluate effects of corn dry distiller grains plus condensed solubles (DDGS) supplementation level on performance digestion characteristics of steers grazing native range during the forage growing season. In the performance study, 72 (206 ± 23.6 kg; 2008) and 60 (230 ± 11.3 kg; 2009) English crossbred steer calves were used in a randomized complete block design replicated over 2 yr. The grazing periods lasted 56 and 58 d and started on August 11 and 18 for 2008 and 2009, respectively. Each year, steers were blocked by BW (light, medium, and heavy), stratified by BW within blocks, and randomly assigned to 1 of 4 grazing groups. Each grazing group (6 steers in 2008 and 5 in 2009) was assigned to a DDGS supplementation levels (0, 0.2, 0.4, and 0.6% BW). Grazing group served as the experimental unit with 12 groups per year receiving 1 of 4 treatments for 2 yr (n = 6). In the metabolism study, 16 English crossbred steers (360 ± 28.9 kg) fitted with ruminal cannulas grazing native range during the summer growing season were used in a completely randomized design to evaluate treatment effects on forage intake and digestion. The experiment was conducted during the first and second weeks of October 2008. Steers were randomly assigned to supplement level (0, 0.2, 0.4, and 0.6% BW; n = 4) and grazed a single native range pasture with supplements offered individually once daily at 0700 h. In the performance study, ADG (0.64, 0.75, 0.80, and 0.86 ± 0.03 kg/d for 0, 0.2, 0.4, and 0.6% BW, respectively) increased linearly (P = 0.01) with increasing DDGS supplementation level. In the metabolism study, forage OM, NDF, CP, and ether extract (EE) intake decreased (P ≤ 0.05) linearly with increasing DDGS supplementation level. Total CP and EE intake increased (P ≤ 0.002) with increasing DDGS supplementation level. Digestibility of OM, NDF, and EE increased (linear; P ≤ 0.008) whereas the soluble CP fraction of forage masticate sample linearly increased (P = 0.01) and slowly degradable CP fraction linearly decreased (P = 0.05) with increasing DDGS supplementation level. Forage in situ masticate DM and NDF disappearance rate decreased (quadratic; P ≤ 0.05) and DDGS in situ DM disappearance rate increased (linear; P = 0.03) with increasing supplementation levels. These results indicate that DDGS supplementation enhanced grazing performance and total-tract digestion of steers grazing native range during the forage growing season.

In addition to fixing N in the soil, legumes can be a good source of forage for livestock. The objective of this study was to assess the dry matter (DM) yield and nutritive value of two warm‐season annual legumes (WSAL) as potential new forages for the Southern High Plains of the USA. Lablab bean (Lablab purpureus L.) cv Rio Verde (RV) and Rongai (RO) and cowpea [Vigna unguiculata (L.) Walp.] cv Iron and Clay (I&C) and Catjang (CATJ) were sown for two years at NMSU‐Agricultural Science Center at Artesia. Legumes were harvested once in 2008 and twice in 2009 at a maturity stage that ranged from vegetative to 10% green pod. Dry matter yield and nutritive value were analyzed between years, species, and cultivar within species for first cut. Lablab had greater DM yield than cowpea in both years averaging 2.82 Mg/ha for lablab and 1.53 Mg/ha for cowpea at first cut. Among cultivars for first cut, RO had the greatest DM yield of all four cultivars (0.80, 2.26, 2.51, and 3.11 Mg/ha for CATJ, I&C, RV, and RO, respectively; SEM = 0.357). Crude protein (CP) concentration was > 200 g/kg in all legumes, but it was 28.6 g/kg greater in cowpea than lablab. Additionally, NDF and ADF concentrations were lower in cowpea than lablab. Considering the higher DM yield and reasonable nutritive value, lablab has greater potential for forage production than cowpea and could be an additional source of forage for dairy or beef cattle in Southern High Plains of the USA.