Though Imperata cylindrica pastures may be used profitably in some situations, they must be supplemented with other pasture species and feeds to obtain acceptable animal performance (Falvey, 1981; Holmes et al., 1980). In the Thai Highlands, Imperata cylindrica provides some forage but tends to decline or disappear if continually grazed by cattle (Andrews, 1983).
It has been estimated that the low protein content of Imperata cylindrica forage can support live weight gain in beef cattle only for the first 6 weeks of forage growth (Papua New Guinea) or 20 weeks (Thai Highlands) (Falvey, 1981). Nylon bag digestibility of Imperata cylindrica was found to be 2/3 lower than that of buffel grass (Cenchrus ciliaris), Setaria sphacelata and elephant grass (Pennisetum purpureum) (Holmes et al., 1980). In the Thai Highlands, in vitro digestibility declined with plant age, from 70% when young to 40% at 150 days, and depended on the season: 50-70% for wet season regrowth and lower than 45% in the dry season (Falvey, 1981).
Imperata cylindrica is palatable if cut frequently but the mature leaves are sharp and irritating (see Potential constraints above) (Soerjani, 1970).
Imperata cylindrica pastures can support a viable extensive cattle production system provided that they are supplemented with sources of energy (carbohydrates such as cassava), nitrogen (urea or legumes), and minerals (Falvey, 1981; Holmes et al., 1980; Soewardi et al., 1974). Weight gains of cattle grazing non-supplemented Imperata cylindrica were reported to be lower than those obtained with supplemented Imperata cylindrica pasture, or with other pasture species at higher stocking rates.
Using urea-molasses-mineral blocks and introducing new fodder species (especially legumes) significantly improved production from Imperata cylindrica grasslands in smallholder farming systems. Fodder species for fallow improvement, modified alley cropping or hedgerow systems and plantations integrating livestock production may help to increase sustainability (Calub et al., 1996).
The following table presents several trials involving Imperata cylindrica pastures.
||Average daily gain and stocking rate for Imperata cylindrica
||Average daily gain and stocking rate for other forage species or supplemented Imperata cylindrica
||Papua New Guinea
||0.2-0.25 kg/day, 0.8-1.6 animal/ha
||0.45 kg/day, 1.7-2.2 animals/ha on Guinea grass and legume pastures
||Holmes et al., 1980
||Papua New Guinea
||0.47-0.52-0.63 kg/day when supplemented with palm kernel meal alone, with molasses or with molasses and urea
0.53-0.56-0.54 kg/day when supplemented with palm kernel meal alone, with molasses or with molasses and urea
|Galgal et al., 2000
||0.27 kg/day, 1 animal/ha
||>0.81 kg/day, 2 animal/ha on Brachiaria mutica/centro pasture
||Magadan et al., 1974
||+30% with sodium supplementation
||0.21 kg/day with legume supplementation, 0.24 kg/day with urea-molasses and mineral block
||0.21 kg/day with urea, carbohydrate and mineral supplementation
||Soewardi et al., 1974
Sheep and goats
Supplementing Imperata cylindrica with legumes is a valuable strategy in small ruminants. Dry matter intakes of 2.8 and 3.3 % LW (for goats and sheep respectively) were obtained using alang-alang grass (ad libitum) and Leucaena leucocephala (300 g). These values were higher than those obtained for I. cylindrica or Leucaena alone. Diet digestibility of the low-quality herbage was higher for goats than for sheep (Komolong et al., 1988).