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Signal grass (Brachiaria decumbens)

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Datasheet

Description
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Common names 

Signal grass, signalgrass, sheep grass, Kenya sheep grass, Suriname grass [English]; braquiaria, decumbens, pasto alambre, pasto braquiaria, pasto chontalpo, pasto de la palizada, pasto de las orillas, pasto peludo, pasto prodigio, zacate prodigio [Spanish]; Australiano, braquiária, braquiária comum, braquiária de alho, capim braquiária, decumbens [Portuguese]; Thai: Ya siknaentonnon, ya surinam [Thai] (Miles et al., 1996)

Synonyms 

Brachiaria bequaertii Robyns, Brachiaria brizantha sensu Senaratna, Brachiaria eminii (Mez) Robyns, Panicum eminii Mez, Urochloa decumbens (Stapf) R.D. Webster, Urochloa eminii (Mez) Davidse (Quattrocchi, 2006).

Brachiaria brizantha (Hochst. ex A. Rich.) Stapf and Brachiaria decumbens (Stapf) are very similar morphologically, which has led to incorrect identifications (Miles et al., 1996).

Description 

Morphological description

Brachiaria decumbens is a high-yielding, vigorous trailing perennial grass.  It has a dense root-system with many bunched, quickly growing roots that go as deep as 2 m in the soil layers (Husson et al., 2008). Signal grass has a prostrate or decumbent habit, up to 60 cm high. Its flowering stems can however be up to 100-150 cm in height (Cook et al., 2005; Loch, 1977). Signal grass roots from the nodes of the stolons. The leaves are short, 4-14 (-25) cm long x 8-12 mm wide, hairy and dark green in colour (Cook et al., 2005; Bogdan , 1977). The inflorescence is a panicle with 2-7 slightly curved, 2-5 cm long racemes.  The racemes are almost at right-angles to the axis (Cook et al., 2005). The spikelets are hairy, 4-5 mm long and borne in 2 rows along the rachis (Cook et al., 2005; Loch, 1977. The weight of 1000 seeds is 3.57 g (Cook et al., 2005).

Brachiaria decumbens is closely related and intergrades with B. brizantha (Cook et al., 2005). It mainly differs in its habit which is more decumbent and form a denser cover (Cook et al., 2005).

Utilization

Brachiaria decumbens is the most cultivated species of the genus Brachiaria. Unlike Congo grass, it has no or very few diseases (Loch, 1977). It is a high-yielding forage that forms low leafy herbage and is mainly used as permanent pasture. It is palatable to cattle and withstands heavy grazing (Cook et al., 2005; Loch, 1977). Signal grass can be grazed, cut to be fed fresh or to be made into hay. Signal grass is also used as a cover crop and in the control of weeds (Cook et al., 2005).

Nutritional aspects
Potential constraints 

A widespread sporadic toxicity syndrome associated with Brachiaria species is hepatogenous photosensitization. Sheep, goats and cattle develop skin lesions, facial edema, liver damage and ruminal stasis that result in severe drops in weight gain (down to 40%) and even in death if the animals are not removed from the pasture. This syndrome has been reported with ruminants grazing Brachiaria decumbens in Africa, Southeast Asia and South America (FAO, 2010; Lascano et al., 1996). The cause of toxicity appears to be the presence in bile ducts and hepatocytes of crystals of insoluble salts of sapogenin glucuronides originating from steroidal saponins present in the plant. Sapogenins content can vary in the same Brachiaria species due to environmental stress, plant age and developmental stage. Outbreaks of Brachiaria spp. poisoning in central western Brazil are frequently observed in pastures that had been more than 30 days without animals grazing. They also occur during the growing stage of the pastures at the start of the rainy season (Brum, 2009).

Ruminants 

Readily grazed.

Nutritional tables
Tables of chemical composition and nutritional value 

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 25.7 5.3 19.5 39.6 29
Crude protein % DM 8.2 3.5 1.9 14.1 53
Crude fibre % DM 31.2 5.4 22.6 39.7 40
NDF % DM 68.3 5.9 57.8 75.8 11 *
ADF % DM 36.9 4.6 30.1 45.7 22 *
Lignin % DM 5.0 1.2 3.6 7.8 13 *
Ether extract % DM 2.3 0.6 1.4 2.9 8
Ash % DM 8.7 1.8 5.4 12.2 52
Gross energy MJ/kg DM 18.1 2.8 15.4 20.5 3 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 3.9 1.1 1.9 6.1 36
Phosphorus g/kg DM 2.3 1.2 0.6 4.4 36
Potassium g/kg DM 17.8 8.5 2.4 29.8 32
Sodium g/kg DM 0.5 0.4 0.6 2
Magnesium g/kg DM 2.1 0.6 1.4 3.8 36
Manganese mg/kg DM 148 65 83 281 9
Zinc mg/kg DM 30 17 10 76 11
Copper mg/kg DM 4 3 2 11 11
Iron mg/kg DM 707 140 1273 2
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 54.0 3.8 54.0 68.0 8 *
Energy digestibility, ruminants % 51.6 51.6 62.9 2 *
DE ruminants MJ/kg DM 9.3 9.3 12.9 2 *
ME ruminants MJ/kg DM 7.6 *
ME ruminants (gas production) MJ/kg DM 6.6 0.2 6.3 6.8 4
Nitrogen digestibility, ruminants % 58.9 13.2 33.5 71.0 8

The asterisk * indicates that the average value was obtained by an equation.

References

Abaunza et al., 1991; Aregheore et al., 2006; Aumont et al., 1991; Butterworth, 1963; CGIAR, 2009; CIRAD, 1991; Dougall et al., 1958; Evitayani et al., 2004; Evitayani et al., 2004; Gowda et al., 2004; Nasrullah et al., 2003; Xandé et al., 1989

Last updated on 27/11/2012 14:27:53

References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. http://www.feedipedia.org/node/489 Last updated on April 27, 2015, 18:16

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