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German grass (Echinochloa polystachya)

Datasheet

Description
Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 

Aleman, german grass, carib grass (Australia, Panama) creeping river grass, river grass (North America), African wonder cockspur, mudflat millet, Habetz grass, perennial barnyard grass, water bermuda [English]; yerba de rio, zacate aleman, pasto alemin, pasto chiguirera, paja pelu [Spanish]; pasto alemain, pardegrao, prasi-grasi, capim-mandante, canarana verdadeira, canarana fluvial, canarana de pico [Portuguese]

Synonyms 

Echinochloa spectabilis (Nees ex Trin.) Link, Panicum spectabile Nees ex Trin

Related feed(s) 
Description 

German grass (Echinochloa polystachya (Kunth) Hitchc.) is an aquatic or semi-aquatic grass used for forage in tropical and subtropical wetlands. 

Morphological description

Echinochloa polystachya is a perennial aquatic or semi-aquatic grass that forms extensive monospecific and highly productive stands (Hannan-Jones et al., 2008Cook et al., 2005). It can grow in water as deep as 2 m and does not float. It develops coarse stems from a creeping root base anchored in the soil. The stems may be as long as 2 m. They are unbranched and rigid, and long enough to withstand the flowing and rising water (El Bassam, 2010). The internodes are of equal length, and equal diameter. The nodes are densely hairy (Hannan-Jones et al., 2008; Cook et al., 2005). The leaves are linear, 20-60 cm long x 10-25 mm wide (Hannan-Jones et al., 2008). When leaves are submerged in turbid water, they cannot photosynthesize and only the emerged crown (that may be as high as 2 m) is productive (El Bassam, 2010). Their life-span is about 34 days. The inflorescence is a dense panicle made out of dense, short and thick ascending racemes which bear almost sessile spikelets. The spikelets are awned, lanceolate and about 5-7 mm long. 

Uses

Echinochloa polystachya is an aquatic forage species that provides high yields of palatable fodder in natural wetlands and ponded pastures (Hannan-Jones et al., 2008; Cook et al., 2005). In Australia, it was introduced to improve the productivity of ponded pasture in combination with Para grass (Brachiaria mutica) (Cook et al., 2005). Such ponded pastures are protein banks in periods of scarcity (droughts) and prevent weight losses in livestock (Hannan-Jones et al., 2008).

Distribution 

Echinochloa polystachya originated from tropical and subtropical America, from Southern USA to Argentina. It is commonly found in Mexico, the West Indies and in South America. It is widespread in the Amazonian Basin where it covers 5000 km² of floodplains (Piedade et al., 1997). In its native range, it forms dense highly productive stands. The Amity cultivar  was introduced into Australia in the 1970s to improve the productivity of pounded pastures. In 2005, a survey among beef producers revealed that approximately 10% of respondents had planted German grass during pasture improvement programmes (Hannan-Jones et al., 2008). Echinochloa polystachya can be found between 30°S and 30°N preferably in tropical and subtropical lowlands (FAO, 2015). It grows on seasonnally flooded wetlands or under very high rainfall conditions (> 1900 mm) (Hannan-Jones et al., 2008). It can grow in water up to 2 m deep and can keep surviving up to 3 m during short periods. It cannot withstand droughts and will die from dry conditions. However, it can regrow from stolons during subsequent flooding (Hannan-Jones et al., 2008). German grass can grow on a wide range of soils with medium to high fertility provided they are very wet and not well-drained. German grass is tolerant of sodicity and salinity (Lukacs et al., 1992). It is a summer growing species and it does not withstand frost. It is generally protected from overnight frost by its aquatic habit (Hannan-Jones et al., 2008). Echinochloa polystachya growth is closely linked to the annual rise and fall of water level over the floodplain surface (Piedade et al., 1994).

Forage management 

German grass is a high yielding species with average DM yields of 8-12 t/ha in South America and 10-20 t/ha in Australia (Cook et al., 2005). It was reported to yield as much as 99 tons DM/ha in Brazil (Piedade et al., 1991). In Australia, it has been introduced to enhance productivity of Para grass stands (Hannan-Jones et al., 2008). In India it was reported to yield much higher green biomass, dry matter and crude protein than Para grass (Brachiaria mutica) (Hannan-Jones et al., 2008).

Because it grows in deeper water, German grass planting is recommended in mixed stands of aquatic grasses such a Para grass (Brachiaria mutica) or hymenachne (Hymenachne amplexicaulis) which do well in shallower water, respectively 30 cm and 1 m depth) (Cook et al., 2005). German grass seeds are generally sterile and it is recommended to propagate German grass by stem or stolons cuttings (2-3 nodes long, with at least one emerging node). Stems density should be about 1-2 t/ha. Stems should be manually planted into wet mud or mechanically into shallow water thanks to light weight tractor (Hannan-Jones et al., 2008).

Environmental impact 

Weed potential and threat to biodiversity

Like other ponded pasture grasses, Echinochloa polystachya may be a threat for open waters outside its native range (Hannan-Jones et al., 2008). It spreads easily and, once established, it is impossible for native species to establish again. German grass has colonized banks, shallow margins of rivers, lagoons and swamps as well as non-target areas (Holm et al., 1991). In Australia, German grass was found to threaten the habitat of water birds such as waterfowl, magpie goose and pygmy-goose, by displacing native plant species on which the birds feed or by closing open waters where birds feed (Garnett et al., 2000). Echinochloa polystachya is considered a weed in many countries. in Mexico, Argentina, India, DR Congo and Chad (Holm et al., 1991). In Australia, it must undergo weed management plan (Hannan-Jones et al., 2008), its establishment not recommended  and its import forbidden and (US Forest Service, 2013). It is considered a weed in rice fields in Louisiana (affecting 5000 - 6000 ha) and Java (Griffin, 2006; Michael, 1989). 

Fire potential

During the dry season the high amounts of dry matter of Echinochloa polystachya  may increase susceptibility to fire and fire intensity (Hannan-Jones et al., 2008).

Nutritional aspects
Nutritional attributes 

German grass has a relatively low protein content (8-14% DM). Its protein and ash contents decrease with age. Its fibre content is always quite high: from 55 to 65% of DM (Camarao et al., 2004; Campos et al., 2010). The aquatic form of Echinochloa polystachya has lower DM concentration (17 %) than the terrestrial one (23 %) (Camarao et al., 2004). 

Potential constraints 

Nitrate and nitrite poisoning

German grass may cause nitrate and nitrite poisoning in cattle. In some cases, the nitrate + nitrite content of this forage can reach up to 20-25% of total nitrogen. Several outbreaks resulting in cattle mortality have been reported in Paraiba and Rio Grande do Norte in Brazil (Silva et al., 2006; Riet-Correa et al., 2005; Medeiros et al., 2003). Clinical signs of nitrate poisoning include anorexia, respiratory distress, teeth grinding, depression or hyperexcitability, tremors, abdominal contractions, salivation, nasal discharge, uncoordinated gait, cyanosis and recumbency. Nitrate accumulation in the plant is thought to occur after prolonged draught followed by rain, which is what happened for instance in 2001 in Paraiba, where nitrate poisoning caused the deaths of 5 out 11 animals after they were fed German grass regrowth (Medeiros et al., 2003). 

Ruminants 

Nutritive value

The DM digestibility of German grass with protein content varying from 8.2 to 10.3 % and NDF from 66.4 to 61.8% ranged from 59 to 63%. Corresponding intake for sheep increased from 64.3 to 71.2 g/kg metabolic weight as digestibility decreased (Combellas et al., 1973).

Palatability

German grass (Echinochloa polystachya) is more palatable to stock than para grass (Hannan-Jones et al., 2008)

Beef cattle and buffaloes

In Venezuala, in Criollo Limonero steers grazing Echinochloa polystachya pastures, supplementation with of 1 kg concentrate or Leucaena leucocephala did not modify dressing percentage, carcass traits, cut yield, cooking traits and Warner-Bratzler shear force (Rodas-Gonzalez et al., 2007Rodas-Gonzalez et al., 2006). Animal supplementd with leucaena had a lesser proportion of white viscera compared to the control. All animals exhibited low levels of total lipids and cholesterol, which indicated that this meat could be sold as light meat or low fat meat which is interesting from a nutritional point of view for the consumer, especially as steaks had a good consumer acceptability and were considered as tender meats (Rodas-Gonzalez et al., 2007; Uzcategui-Bracho et al., 2008). Buffaloes have higher liveweight gains than cattle when fed on flooded pastures containing Echinochloa polystachya (Camarao et al., 2004Sheikh et al., 2002). Buffaloes are better adapted to live in foodplain habitats and their rumen microflora has lower N requirements than microflora in cattle which excreted more N through urine (Moran, 1983). Gains differ around the year: they are higher in the dry period (up to 678 g/head/day in August) than at the end of the wet period (333 g/head/day in June) (Camarao et al., 2004).

In the Brazilian Amazon, buffaloes are not used intensively for commercial milk production even if some farmers have obtained high yields (Camarao et al., 2004). The nutritive value of a mixture of Echinochloa polystachia and Brachiaria arrecta can be improved by the allowance of multi-nutritional blocks ad libitum to female buffaloes (Lopez-Maduro et al., 2001).

Rabbits 

International literature on German grass utilisation in rabbit feeding is very scarce. Only early paper mentioned such use in Peru (Pinedo Ruiz, 1982). Because this plant is largely used as pasture for cattle in tropical America (Sanchez-Villalobos et al., 2009; Piedade et al., 2010) or normally grazed by capybara, a rodent with a digestive system identical to that of rabbit (Borges et al., 2007), Echinochloa polystachya could be considered as a potential fibrous and low protein forage for rabbits, with a low protein content. However, as nitrate poisoning have been reported in rabbits fed Bermuda grass or Para grass containing high levels of nitrate (Adegbola et al., 1965; Singh et al., 1983), this risk also exists for Echinochloa polystachya (see Potential constraints) and it is recommended to pay attention to the nature of its nitrogen content before using it in rabbit feeding.

Nutritional tables

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

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 16.7 4.1 10.2 24.0 10
Crude protein % DM 10.6 2.8 5.4 16.0 18
Crude fibre % DM 33.4 2.1 31.0 37.5 11
NDF % DM 68.7 7.8 49.4 74.0 10
ADF % DM 39.1 4.2 36.5 46.5 4
Lignin % DM 5.2 *
Ether extract % DM 3.1 1.3 1.0 5.3 17
Ash % DM 11.8 2.0 8.0 13.9 15
Gross energy MJ/kg DM 18.0 16.4 18.5 2 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 3.5 1
Phosphorus g/kg DM 2.2 1
Magnesium g/kg DM 1.8 1
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, ruminants % 64.1 *
Energy digestibility, ruminants % 61.3 *
DE ruminants MJ/kg DM 11.0 *
ME ruminants MJ/kg DM 8.8 *

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

References

Camarao et al., 2004; Campos et al., 2010; INFIC, 1978; Lopez-Maduro et al., 2001; McDowell et al., 1974

Last updated on 18/09/2016 20:21:54

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 85.2   83.9 86.4 2  
Crude protein % DM 10.4   7.9 12.9 2  
Crude fibre % DM 33.9   32.2 35.5 2  
NDF % DM 69.1         *
ADF % DM 39.6         *
Lignin % DM 5.3         *
Ether extract % DM 2.7   2.1 3.3 2  
Ash % DM 11.6   10.5 12.6 2  
Gross energy MJ/kg DM 17.9         *
               
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 60.6         *
Energy digestibility, ruminants % 57.1         *
DE ruminants MJ/kg DM 10.2         *
ME ruminants MJ/kg DM 8.2         *

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

References

INFIC, 1978

Last updated on 18/09/2016 20:26:45

References
References 
Datasheet citation 

Heuzé V., Tran G., Giger-Reverdin S., Lebas F., 2016. German grass (Echinochloa polystachya). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. http://www.feedipedia.org/node/449 Last updated on September 18, 2016, 20:27

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