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Molasses grass (Melinis minutiflora)

Datasheet

Description
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Common names 

Molasses grass, brazilian stink grass, afwatakala grass [English]; herbe à miel, herbe de mélasse [French]; chopin, pasto de gordura, capin melao, calinguero [Spanish]; capim-gordura [Portuguese]; 糖蜜草 [Chinese]

Synonyms 

Melinis tenuinervis Stapf, Panicum melinis Trin., Panicum minutiflorum (P. Beauv.) Raspail

Related feed(s) 
Description 

Molasses grass (Melinis minutiflora P. Beauv.) is a sticky, tufted, stoloniferous, perennial grass up to 180 cm high. It has a strong characteristic odour of molasses, or cumin, due to the secretion of a volatile oil through the leaf hairs (FAO, 2011; Partridge, 2003). The culms are usually decumbent, rooting at the lower nodes, and form purple to red-brown, loose tussocks (Partridge, 2003; Duke, 1983). The leaves are 5-17.5 cm long x 4-13 mm broad, minutely to densely hairy. The inflorescence is a pale pink to purple, 10-30 cm long panicle, open at flowering and closing at maturity (Duke, 1983). Molasses grass varieties vary widely in vigour, leafiness, hairiness and growth habit (Göhl, 1982).

Molasses grass is used as fodder and can be grazed or cut for hay or silage (FAO, 2011). Oil obtained from molasses grass has been used as insect and parasite (ticks) repellent in several parts of the world (FAO, 2011; Mwangi et al., 1995; Göhl, 1982). In Mexico, the anti-tick effect of Melinis minutiflora grass against Boophilus microplus has been demonstrated experimentally by infesting fields with Boophilus microplus larvae over several years (Fernandez-Ruvalcaba et al., 2004). Molasses grass was recently found to be a potent biological controller of maize stemborer moths (see Environmental impact below) (Parrott, 2005).

Distribution 

Molasses grass is native to tropical and Southern Africa and has been introduced to South America and India (Duke, 1983). It is now widely naturalized in many tropical countries (FAO, 2011) and is considered a weed in Brazil, Colombia, Hawaii and Venezuela (Duke, 1983). It is found within 16 and 30.5°N and S, from sea level up to an altitude of 2500 m (Ecocrop, 2011). It favours bush, shady places, forest edges and open ground or grassland, as well as steep, rocky slopes and disturbed places (Ecocrop, 2011; Quattrocchi, 2006).

Molasses grass thrives in areas with 960-1700 mm annual rainfall though it tolerates 750-2500 mm. Molasses grass is relatively drought hardy and can be found in areas with a 4 or 5 month dry season. It is sensitive to waterlogging (Ecocrop, 2011; FAO, 2011; Göhl, 1982). Average annual temperature can range from 18 to 21°C. Day-temperatures about 30°C result in higher growth rate than 20°C and, because molasses grass is sensitive to frost, the average temperatures of the coldest month should be between 6°C and 15°C. Molasses grass grows on low fertile, well-drained, sandy to clayish soils and even on ashes left after a scrub fire (FAO, 2011). Nevertheless, higher soil fertility results in positive response (Ecocrop, 2011). Molasses grass can grow on a wide range of soil pH (4.5 to 8.4). It is tolerant of aluminium but cannot grow in saline soils. Molasses grass is tolerant of partial shade (Ecocrop, 2011; FAO, 2011).

Forage management 

Melinis minutiflora does not withstand heavy grazing and the stand should not be grazed before being well established or below 15 cm (FAO, 2011).

Molasses grass is a fast growing grass that spreads readily because of its rooting habit. It forms a fairly dense sward that smothers other plants (Partridge, 2003). Though, molasses grass should not be sown alone, and legumes such as centro (Centrosema molle), Neonotonia wightii, siratro (Macroptilium atropurpureum); or Desmodium spp. are suitable companions. The grass may be harvested as early as 50 days after sowing (Ecocrop, 2011).

Molasses grass yields are about 5-10 t/ha, but the yield can vary from 2 to 20 t/ha depending on moisture and soil fertility status. It reacts positively to the addition of N fertilizer (FAO, 2011).

Environmental impact 

Pioneer grass and soil erosion control

Molasses grass is a remarkable pioneer grass in areas that have been burnt or in very rocky places. It thrives on ashes and out-competes weeds that may develop after fire (FAO, 2011). Its vigorous growth also prevents erosion of recently burnt soils (mainly ashes) (Ecocrop, 2011; FAO, 2011).

Weed and biodiversity reduction

Melinis minutiflora is considered a weed in several places because of its outstanding ability to grow and out-compete other species in harsh conditions (Ecocrop, 2011; Partridge, 2003). Its seed dormancy and high seed viability contribute to the dispersal of its seeds in wildlife protection areas (Carmona et al., 2010). It is one of the biggest threats to biodiversity in the Brazilian Cerrado (Martins et al., 2004). This fast growing grass invades degraded areas and is often found at forest edges (Williams et al., 2000). It is prone to fire and increases fire intensity: this may hamper forest regeneration and prevent other pioneer plants from developing (Hoffmann et al., 2004; Shrestha, 2004). In Brazil, several experiments have been carried out in order to test control methods. Burning was not an effective control method (Martins et al., 2004) and adverse factors such as shade, inter and intraspecific competition, low soil fertility and water stress did not completely eliminate all of the recently established individuals of the last rainy season (Martins et al., 2009)

Biological control agent

Molasses grass, in association with Napier grass (Pennisetum purpureum) may be a valuable biological agent to control maize stemborer moth species (Busseola fusca and Chilo partellus). When it is sown between maize rows, the molasses grass emits two chemical signals: one chemical has a repellent effect on the stemborers, and the other chemical attracts the wasp Cotesia sesamiae, a stemborer parasite. The stemborer moths repelled from the maize plot go to hatch on Napier grass. The Napier grass leaves bored by the larvae release a sticky liquid that kills almost all larvae while the surviving ones are attacked by Cotesia sesamiae (Parrott, 2005).

Nutritional aspects
Nutritional attributes 

Melinis minutiflora has a rather low protein content, usually in the 4-10% DM range, though mature grass can be as low as 2-3% and young grass can reach 18% (Feedipedia, 2011; Cook et al., 2005). Crude fibre content is quite high, in the 35-45% DM range (Feedipedia, 2011), with NDF values up to 69% DM (Bauer et al., 2008).

Potential constraints 

The characteristic odour of Melinis minutiflora is caused by an exudate from glandular leaf hairs that contains fatty acids, esters, and probably a phenolic substance (Cook et al., 2005). 

Crystals of calcium oxalate have been found in leaves of Melinis minutiflora (1.1-1.7%) but have not caused problems (Lersten, 1983; Cook et al., 2005).

Ruminants 

Palatability

Melinis minutiflora is palatable to cattle once they become used to the smell (Göhl, 1982). In Minas Gerais, Brazil, Melinis minutiflora was the principal component of the diet of grazing cattle and was preferred during the rainy season. In the dry season, Andropogon bicornis and Imperata brasiliensis were preferred to molasses grass (Bauer et al., 1998).

Nutritional value

Molasses grass has a low to acceptable nutritive value. An in vivo OM digestibility of 54% was reported (Axtmayer et al., 1938; Göhl, 1982). In vitro OM digestibility values between 45 and 66% have been observed (Coser et al., 1997; Lebdosoekojo, 1978). In a digestibility trial on penned sheep, Melinis minutiflora grass was found to be of very low quality during the dry season, well below maintenance requirements for sheep and calves: ME values were between 5.9 and 8.6 MJ/kg DM and digestible crude protein was 0.58-2.18% DM (Costa et al., 1981).

Beef cattle

In tropical savannahs in Colombia, steers grazing Melinis minutiflora pastures during the rainy and the dry seasons produced 111 and 68 kg live weight/ha/year respectively. Stocking rates were 0.88 and 0.44 head/ha (Paladines et al., 1974). On the plains of Eastern Colombia, beef cows grazed native grasses in the dry season and Melinis minutiflora during the rainy season, with either salt or a complete mineral supplementation. The live-weight gains of cows and the weights of calves at weaning were significantly higher (330 kg/head and 172 kg/head) with a complete mineral supplement than with salt alone (302 kg/head and 132 kg/head) (Lebdosoekojo, 1978).

In Minas Gerais, improved natural pasture sowed with Melinis minutiflora and Stylosanthes guyanensis was grazed by Zebus steers, resulting in live-weight gain/ha almost 4 times higher and an average daily gain twice that of the unimproved pasture (Vilela et al., 1978). In the same region, a comparison was made between Melinis minutiflora and Brachiaria decumbens pastures grazed by dairy calves. Daily live-weight gain was higher for Melinis minutiflora pastures (178 and 467 g during the dry and rainy seasons respectively, vs. 39 and 333 g for Brachiaria) but annual live-weight gain/ha was higher for Bracharia decumbens pastures (Coser et al., 1997). Stocking rates were 0.4 AU/ha for Melinis minutiflora and 1.2 AU/ha for Brachiaria decumbens. Also in Minas Gerais, Melinis minutiflora was the principal component of the diet and was preferred in the rainy season, but Andropogon bicornis and Imperata brasiliensis were preferred in the dry season (Bauer et al., 1998).

Dairy cattle

In Brazil, dairy cows grazing Melinis minutiflora pasture were supplemented with soybean meal, with maize grain with husks or with both soybean meal and maize grain with husks, but supplementation was not found to be economically viable as it failed to increase milk yield, DM intake and crude protein intake (Vilela et al., 1980).

Sheep and goats

Very few studies have been published on the use of Melinis by small ruminants. In Cameroon, the performance of sheep and goats grazing natural pasture (Melinis minutiflora, Pennisetum purpureum, Imperata cylindrica) was maximum at the beginning of the rainy season. The animals started losing weight at the peak of heavy rains and the greatest weight losses were at the end of the dry season. As stocking rates increased from 40 to 100 heads/ha, sheep and goats increasingly lost weight. However, these results would be similar with other grass species in the same conditions (Fai et al., 2000).

Rabbits 

No information found (2011).

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 30.5 7.6 17.2 45.6 249
Crude protein % DM 6.5 2.2 3.0 12.0 259
Crude fibre % DM 39.3 2.7 33.5 44.4 259
NDF % DM 74.2 *
ADF % DM 45.6 *
Lignin % DM 6.6 *
Ether extract % DM 2.8 0.7 1.3 4.2 254
Ash % DM 8.8 2.0 5.9 14.8 259
Gross energy MJ/kg DM 18.4 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 3.3 0.7 2.1 4.9 257
Phosphorus g/kg DM 1.7 0.6 0.9 3.1 256
Potassium g/kg DM 14.1 5.5 5.9 25.6 225
Sodium g/kg DM 0.3 1
Magnesium g/kg DM 2.2 0.5 1.4 3.5 219
Manganese mg/kg DM 152 35 85 236 24
Zinc mg/kg DM 36 10 20 55 24
Copper mg/kg DM 5 2 3 8 24
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 57.3 *
Energy digestibility, ruminants % 54.8 *
DE ruminants MJ/kg DM 10.1 *
ME ruminants MJ/kg DM 8.1 *
Nitrogen digestibility, ruminants % 42.0 1

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

References

Axtmayer et al., 1938; CIRAD, 1991; Pozy et al., 1996

Last updated on 24/10/2012 00:44:36

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 90.3 1.0 88.9 91.3 5
Crude protein % DM 7.8 4.2 4.2 13.8 5
Crude fibre % DM 34.6 2.6 32.3 37.8 5
NDF % DM 69.8 *
ADF % DM 40.4 *
Lignin % DM 5.5 *
Ether extract % DM 2.2 1.4 1.0 4.1 5
Ash % DM 9.0 1.2 7.4 10.2 5
Gross energy MJ/kg DM 18.1 *
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 59.2 6.5 48.5 61.1 3 *
Energy digestibility, ruminants % 55.7 *
DE ruminants MJ/kg DM 10.1 *
ME ruminants MJ/kg DM 8.2 *
Nitrogen digestibility, ruminants % 37.9 7.3 31.0 45.6 3

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

References

Chavancy, 1951; Sen, 1938; Todd, 1956

Last updated on 24/10/2012 00:44:36

References
References 
Datasheet citation 

Heuzé V., Tran G., Boval M., 2015. Molasses grass (Melinis minutiflora). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://feedipedia.org/node/414 Last updated on May 11, 2015, 14:30

English correction by Tim Smith (Animal Science consultant) and Hélène Thiollet (AFZ)