| Abstrakt: |
This experiment was conducted at the Marvin Klemme Research Station near Bessie, OK in the summers of 2021 and 2022 to test the effects of increased supplementation rates with extruded DDGS cubes on animal performance and supplemental efficiency of steers grazing mixed grass prairie in Western Oklahoma. Steers (n = 133 BW = 247 ± 24 kg and n = 96 BW = 264 ± 16 kg) in 2021 and 2022, respectively, were allocated to 3 supplementation treatments; 1) Negative Control (NC), ad lib free choice mineral only, 2) Low Supplement (LS), 0.91 kg of supplemental DDGS cubes animal-1·d-1, and 3) Medium Supplement (MS), 1.81 kg of supplemental DDGS cubes/animal/d. Pastures were stocked at 2.02 ha/steer in 2021 but the stocking density in 2022 was decreased to 2.83 ha/steer due to drought causing poor range condition and limited forage biomass availability. Data were analyzed as a randomized complete block design using PROC MIXED in SAS 9.4. In 2021, early season ADG of LS and MS were 0.43 and 0.58 ± 0.033 kg greater (P< 0.0001) than NC, respectively. Late season ADG was increased by 0.21 and 0.29 ± 0.033 kg (P< 0.0001) by LS and MS, respectively. Overall, ADG was 0.34 and 0.46 ± 0.29 kg greater (P< 0.0001) than NC for LS and MS, respectively. Supplemental efficiency in the early summer was 0.16 ± 0.03 kg of added gain/kg of supplement greater (P< 0.0001) for LS than MS. Late season efficiency was 0.07 ± 0.02 greater (P< 0.0001) for LS than MS. Season long supplemental efficiency was 0.12 ± 0.02 greater (P< 0.0001) for LS than MS. Gain per hectare was greatest for MS, 30.5 and 8.0 ± 1.92 kg greater (P≤ 0.0003) than NC and LS, respectively. In 2022, early season ADG was increased by 0.2 ± 0.054 kg (P≤ 0.0003) for both LS and MS. Late season ADG was 0.27 and 0.52 ± 0.043 kg greater (P< 0.0001) than NC for LS and MS, respectively, while overall ADG was 0.24 and 0.37 ± 0.04 kg greater (P< 0.0001) for LS and MS, respectively. Early season supplemental efficiency was 0.11 ± 0.04 greater (P≤ 0.005) for LS than MS, late season efficiency did not differ (P≥ 0.89). Overall efficiency was 0.05 ± 0.03 greater (P≤ 0.05) for LS than MS. Gain per hectare of MS was 17.8 and 6.5 ± 1.92 kg greater (P≤ 0.001) than NC and LS, respectively. These data suggest that increased supplementation rates with extruded DDGS cube is a viable option to increase performance of steers grazing mixed grass prairie, especially when forage quality is deficient in nutritive value or availability, but, in most cases the efficiency of the supplement decreases. |
