Grazing management of tall fescue to maintain nutritive quality is different for the vegetative and for the heading (i.e., reproductive) phases. During the vegetative phase, plants are producing only leaves. In the southern hemisphere, this occurs from early summer in December to early spring in late September. To maintain high quality, tall fescue should be grazed before it reaches 15 cm in height, that is, the 2- to 2.5-leaf stage (Fig. 7-2).

When rotationally grazed during the vegetative phase, tall fescue may be grazed very closely. Continual grazing to below 3 cm, however, will reduce pasture growth, that is, dry matter (DM) in winter and early spring. A residual (stubble) of at least 3 to 5 cm will result in maximum regrowth.

Proper management during the reproductive phase (from mid spring to summer) is essential to achieve high animal performance (Milne, 2001b). The beginning of the heading phase varies by up to 4 wk among cultivars. Some early heading cultivars, such as Demeter, Dovey, and Quantum, begin heading in late August, but later cultivars, like Advance, head in early October. Grazing before seadheads emerge and plants flower is important to stimulate summer tiller density and persistence. Daughter tillers formed in spring will survive into summer only if reproductive tillers are grazed before flowering. Although the heading phase in tall fescue is not as long as that of perennial ryegrass, tall fescue plants can develop stems (tillers and seadheads) rapidly from September to November, producing more than 100 kg DM/ha/d and growing 5 cm/wk. To reduce this shift from vegetative to heading phases, the higher grazing pressure needed can be obtained with a flexible stocking rate and a pasture height of 5 cm, increasing stocking rates two to three times those used in paddocks of other species. The recommended grazing heights for rotational and set stock grazing are illustrated in Fig. 7-3.


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Fig. 7-2. This tall fescue-clover pasture will be ready to be grazed again after a 10-d regrowth period (note that the ruler is marked in cm only).


Fig. 7-3. Recommended grazing heights for rotational grazing of continental tall fescue types.


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