ABSTRACT Bermudagrass (Cynodon dactylon) has been the most popular warm-season perennial grass for hay production and pastures in the southern United States for several decades. It persists on sandy, acidic soils, and N fertilization increases yields. Many new cultivars thrive in the United States and are being established in South America and other tropical environments. Hybrid bermudagrasses, including `Coastal,' released in 1943, are sterile and require establishment from roots and rhizomes, which may increase establishment costs. Vigorous hybrid cultivars may be established using spring top-growth cut at advanced maturity and planted in moist soils. Seeded bermudagrasses have been developed, but few compare with hybrid cultivars, including `Tifton 44,' `Tifton 78,' `Midland,' and `Tifton 85,' for yield, persistence, or quality. Tifton 85 offers hay production potential in the establishment year, whereas most cultivars do not produce enough forage for hay production or heavy grazing until the 2nd yr. After 8 yr, Tifton 85 has increased acceptance and popularity among hay and cattle producers in the United States, and more than 1 × 106 ha have been planted in Brazil. Dry matter yield and forage digestibility have been consistently higher for Tifton 85 than for Coastal and other cultivars, which allows increased stocking rates and greater gain/hectare. Tifton 85 hays have consistently had higher in vitro and in vivo digestibility than Coastal or Tifton 78 hays, even when NDF of the Tifton 85 hay was above 70%. Recent experiments confirmed lower concentrations of ether-linked ferulic acid in Tifton 85 than in Coastal forage, which explains the higher digestibility of Tifton 85 than of Coastal hays. Dairy research indicated that during cool weather, comparable milk yields occurred when Tifton 85 hay was substituted for alfalfa hay in a total mixed ration. In tropical countries `Coastcross-1' and Tifton 85 have been rotationally grazed by dairy cows. Bermudagrasses will continue to be primary perennial grasses for much of the southern United States, and research efforts may provide cultivars with more digestible fiber, greater cold tolerance, and wider adaptability for hay production and grazing for beef and dairy cattle.
Implications
Improved hybrid bermudagrasses have been primary forages for beef and dairy cattle for more than 50 yr in the southern United States. They are persistent and productive over a wide range of soils, nitrogen applications, and grazing and climatic conditions. Most hybrids offer better yields, persistence, and quality than unselected ecotypes. Tifton 85 forages may be used in total mixed rations for lactating dairy cows and in grazing systems for milking herds. New nutritional challenges are presented by Tifton 85, because its neutral detergent fiber might be a less important quality indicator than are digestion coefficients and ether ferulic acid concentrations. Goals for future bermudagrass cultivars include lower neutral detergent fiber concentrations with advancing maturity, lower ether ferulic acid concentrations, and increased cold tolerance. Bermudagrasses will continue to be the primary perennial warm-season grass used in the southern United States and other countries.
Key Words: Cattle, Cynodon dactylon, Forage, Grazing, Hay
© 2001, by the American Society of Animal Science. All rights reserved.
J. Anim. Sci. 2001. 79:E48-E58
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