Yield and Forage Quality of Coastal and Tifton 85 Bermudagrass

Summary

Tifton 85 bermudagrass was released in 1992, and where it is adapted across the Southeast, it has proved to be a superior forage in terms of hay and pasture yield, hay and forage quality, and in supporting higher growing cattle stocking rates and gains compared with other bermudagrasses. In a small plot study in 2004, DM yield at the 8-wk harvest was higher(6114 vs 4778 kg DM/ha; P < 0.01) for Tifton 85 (T85) than for Coastal (C). A forage × sampling date interaction (P < 0.05) occurred for IVDMD, and the IVDMD was higher (P < 0.05) for T85 than C forage samples at both 4-wk (68.57 vs. 61.15 %) and 6-wk (65.24 vs. 55.55 %) maturity harvests. Both T85 and C had lower IVDMD at 6-wk compared with 4-wk maturity. Plot data results supported improved calf gains for T85 compared with C pastures in a related 2-yr study involving 96 cow-calf pairs/year.

Situation

Beef cattle production in Georgia has benefitted from higher prices in recent years, and from utilization of improved production practices. Tifton 85 bermudagrass was released in 1992, and where it is adapted across the Southeast, it has proved to be a superior forage in terms of hay and pasture yield, hay and forage quality, and in supporting higher growing cattle stocking rates and gains than other bermudagrasses (Coastal, Alicia, Tifton 44, Russell). A small-plot experiment was conducted to determine yield and nutritive value of Coastal (C) and Tifton 85 (T85) bermudagrass, to support larger cow-calf continuous grazing studies.

Response

Three replicated small plots (5 m × 7 m plot area) of Tifton 85 and Coastal bermudagrass (Cynodon dactylon, L.) were established on Tifton sandy loam soils in 2001, at Tifton, GA. On August 26, 2004, plots were mowed to stubble heights of 5 cm, to initiate a new yield and quality trial. Four harvests were made at 2-wk intervals beginning September 10, 2004. Fertilizer was applied on August 26, 2004 (224 kg/ha, 24-6-12 ratio of N: P2O5: K2O). Four quadrats (0.1 m2) were clipped to ground level in each plot, and clipped samples were dried at 60° C for 72 h. Plot DM yields were determined, and IVDMD of the 4- and 6-wk samples were determined using the DAISY incubator procedure.

Impact

In the experiment, DM yield at 8-wk harvest was higher (6114 vs 4778 kg DM/ha; P < 0.01) for T85 than for C, and CP at 2-week harvest was higher (24.8 vs 18%) for C than for T85. The DM yield increased with maturity (P < 0.01), but CP decreased with maturity (P < 0.01) for both C and T85 over time. There was a forage × sampling date interaction (P < 0.05) for NDF increasing more for T85 than C after the 4-wk harvest. A forage × sampling date interaction (P < 0.05) occurred for IVDMD, and the IVDMD was higher (P < 0.05) for T85 than C samples at both the 4-wk (68.57 vs. 61.15 %) and 6-wk (65.24 vs. 55.55 %) maturity. Both T85 and C had lower IVDMD at 6-wk compared with 4-wk maturity. The T85 IVDMD was only slightly depressed at 6-wk compared with 4-wk samples, but C plots had 9.5% lower IVDMD at 6-wk compared with 4-wk samples. Even more dramatic was the 17% higher (P < 0.05) IVDMD of T85 compared with C at 6-wk maturity. Despite high NDF concentrations in T85 forage samples the relatively high IVDMD values suggest that fiber was highly digestible for T85 compared with C. The small-plot data verified quality and yield characteristics of C and T85, and supported the increased cow and calf performance on T85 pastures in a recent 2-yr study. In that study, calves grazing T85 had 19% higher average daily gains compared with calves grazing C bermudagrass (2.07 vs. 1.74 lb, or 0.94 vs 0.79 kg; P < 0.01) . Calf adjusted weaning weights were higher for calves produced on T 85 than on C (558 vs.530 lb, or 253 vs 240 kg; P < 0.01 ). Using these results, a producer could expect to earn $3300.00 more for calves produced on T85 compared with C pastures, if calves were sold at $115/cwt. Since bermudagrass stands may last more than a decade, economic returns could be substantial over time. Results suggest higher gains from calves grazing Tifton 85 bermudagrass during the summer could improve production efficiency in cow-calf operations across much of the Southeastern United States.

State Issue

Agricultural Profitability and Sustainability

Details

• Year: 2007
• Geographic Scope: Multi-State/Regional
• County: Tift
• Program Areas:
  • Agriculture & Natural Resources