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Blue lupin (Lupinus angustifolius) forage

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 

Blue lupine, European blue lupine, narrow-leaf lupin, narrow-leaved lupin, New Zealand blue lupin, sweet lupinseed [English]; lupin bleu, lupin à feuilles étroites, lupin petit bleu [French]; blaue Lupine, schmalblättrige Lupine [German]; lupino azzurro [Italian]; tremoçeiro-azul [Portuguese]; lupino azul, altramuz azul, lupino australiano [Spanish]; blålupin, fingerlupin [Swedish]

Synonyms 

Lupinus angustifolius L.; Lupinus angustifolius subsp. angustifolius; Lupinus angustifolius subsp. reticulatus

Feed categories 
Description 

Blue lupin is the main lupin species used for forage. While lupins (Lupinus spp.) seeds are a potential significant alternative to soybean, blue lupin (Lupinus angustifolius) provide valuable source of forage for livestock whether it is grazed green or as stubble or cut and made into hay or silage.

Lupin (Lupinus spp.) is the most important legume crop grown in Australia. There, among other lupin species, blue lupins (Lupinus angustifolius) represent 91% of total lupin cultivation area (Pulse Australia, 2016). The sweet varieties of Lupinus angustifolius with low alkaloid content are known as "narrow-leaf lupin". Their seeds are harvested and fed raw or ensiled to livestock. Their stubbles are used as forage or as pasture (during late winter or early spring) for livestock. The bitter varieties of Lupinus angustifolia that form blue flowers and have high alkaloid content are called "blue lupin". They are used as green manure.

Morphology

Blue lupin (Lupinus angustifolius) is a self-regenerating annual legume that reaches a height of (20-) 60-150 cm (Ecocrop, 2017). Blue lupin is deeply taprooted, the roots reaching a depth of 2.5 m. The stems are robust and hairy, with profuse lateral branching, when sown at low density. The foliage is dark-green in colour. The leaves are digitate and the leaflets are narrower (hence the name "narrow-leaf lupin") than in white lupin (Wolko et al., 2010; Wiley, 2009). The inflorescence is a terminal, 3-30 cm long, false raceme bearing many blue pea-like flowers. The pods are large and shatter readily once mature, making them difficult to direct harvest. Pods are susceptible to bud worm (Heliothis) damage when green. The seeds are hardcoated, and they can remain viable in the soil for up to 20 years. This means that it is almost impossible to eradicate blue lupins from a paddock. Seed weight is about 230 mg (Wiley, 2009). The flowers are usually blue in colour but some new varieties have white flowers (Ecocrop, 2017).

Uses

Blue lupin stubbles are used for forage and silage, and for late winter and early spring grazing. Bitter cultivars are grown mainly for soil improvement. Blue lupin is a good source of honey (Ecocrop, 2017). 

Distribution 

Lupins (Lupinus spp.) are broadly distributed throughout the world. There are two geographically separated groups: New World species and Old Word species among which 4 are cultivated, one from the New World and the 3 others from the Old World. All of them are smooth seeded. Lupins occupy almost all kinds of habitats from sea level to altitudes up to 4000 m (Wolko et al., 2010).

Blue lupins prefer light to medium textured, well-drained soils that are acid or neutral soils (Wolko et al., 2010). Blue lupin does well on low to moderately fertile, well-drained, light or medium textured and mildly acidic to neutral sands and sandy loams (Wolko et al., 2010). Blue lupin does not withstand waterlogged soils but has tolerance of transient waterlogging (Wolko et al., 2010). Under conditions where P is limiting lupins form specialized cluster root structures and/or release P-mobilizing carboxylates that free it from insoluble forms (Lambers et al., 2012). However, blue lupin is less effective than white and yellow lupins for P and Zn uptake (Wolko et al., 2010).

Statistics about lupin production are only about seed production and nest all types of lupins. Main blue lupin forage producer is Australia but no information about forage production is available. 

Forage management 

Yield

In the UK, up to 20 t/ha DM were reported for lupin forage cultivated under irrigation during summer (Burtt et al., 1981). In Poland, fresh matter yield from 15.8 to 30.8 tons/ha corresponding to 2.2 to 8.8 tons DM/ha were reported (Faligowska et al., 2014). In Czech Republic, blue lupin yielded 3.8 tons DM/ha in 2017 (Jancik et al., 2017).

Stubble yields were reported to be between 3.75 and 7.5 (-10) t/ha (Gladstones, 1970). Yields of 7 tons DM/ha for stubbles, and 2 tons DM/ha for seeds from the same crop were reported recently (Graham Centre, 2011).

Pasture

Green feed

Narrow-leaf lupin has been used as a pasture species since a long time. In France, it was grazed by sheep in the early 19th century. Grazing could occur before flowering stage and could be done several times during the season of growth (Koltz, 1864). In England, narrow-leaf lupins were used as a sheep feed and for soil improvement in the late 1850's (Oldershaw, 1920). In Australia, narrow-leaf lupins had been recognized as a forage readily eaten by sheep at the end of the 19th century. It could then be used as a winter green feed or as fattening feedstuff during dry spells (Gardner et al., 1929). It was, nonetheless, also considered a weed in many parts of Australia and some lupinosis outbreaks reduced its use as forage in the middle of the 20th century (Gladstones, 1969). Nowadays, in South Africa, grazing narrow-leaf lupin is not recommended in the early growth stages, since there is little regrowth, and because of high concentrations of alkaloids in the young leaves and growth points. As the plant matures, more parts of the plant are eaten. For the best value as a grazing it is recommended that it be grazed at an advanced growth stage when most of the growth has taken place (Truter et al., 2015). In the USA, where narrow-leaf lupin was first cultivated in the 1930's, it was grazed as a winter forage when feed was scarce (Glasscock et al., 1950). In France, in the early 19th century, narrow-leaf lupin was also used as green chop. It could be cut along winter without losing its nutritive value (Koltz, 1864).

Lupin stubbles

Narrow-leaf lupin was referred to as a valuable grazing option for sheep after harvest of the seeds since it had higher value than cereal stubbles (Gladstones, 1970). It was reported that lupin seed harvest let approximately 150-400 kg seeds/ha on the ground and on stubbles. Lupin has the greatest value during the dry season, when sheep pick up the fallen seeds and graze also the stubble (Truter et al., 2015).   

Stubbles, provided they are not infested by Phomopsis, that is responsible for lupinosis, also have higher protein value than cereal stubbles (Curnow, 2019). In South Africa, sheep could graze on dry lupin lands from November until late summer (February) rains allow green lupin regrowth (Flight, 1956). Mature plants of narrow lupins as well as stubbles after seed harvest could also be grazed (Gladstones, 1970).

In New Zealand, mixed pasture of lupins and cocksfoot (Dactylis glomerata) was sown and compared to alfalfa pasture. The mixed pasture produced 70% of alfalfa but could grow in areas unsuitable for alfalfa and could be grazed earlier than alfalfa (Hamill, 2015)

For a good stubble management the stocking rate should not be too high as overgrazing could expose the soil to rainfall and wind, and result in erosion (Graham Centre, 2011).

Lupin hay

Dry forage of lupin (Lupinus angustifolius) could be pen-fed to livestock provided it was not moist. The bitterness of early varieties of narrow-leaf lupin made it necessary to wait for livestock to get used to it (Koltz, 1864). Lupin plants cut after pod formation and left on swath to dry and make hay were adequately packed in rolls and bales to prevent lupinosis, providing good summer feed to sheep (Allen et al., 1978).

Lupin silage

It was possible to make silage from narrow-leaf lupin. It was used by farmers in the 1950's in South Africa, where it was recommended to cut it at the young succulent stage and wilt it for 4 days, to add sugars in the form of molasses (3-4%). As narrow-leaf lupin could be limited in aminoacids it was also recommended to supplement it with grain or fishmeal. Another option was to ensile narrow-leaf lupin in association with maize or sorghum (Van Zyl, 1973; Van Zyl, 1967; Vosloo et al., 1963). In a more recent experiment in Poland, cutting narrow-leaf lupin at flat pod stage and wilting on the field during 24 hours was found to be effective in reducing fermentation losses and increasing DM content of silage from 20 to 35%. Flat pod stage was suitable because narrow-leaf lupin had higher sugar content and thus fermented better (Faligowska et al., 2014). The addition of lactic acid bacteria improved the quality of narrow-leaf lupin silage (Faligowska et al., 2014). In South Africa, lupin is also used for silage production: its high seed production combined with high green matter yield and high protein content provides a valuable carbohydrates for the silage making process (Truter et al., 2015).

Environmental impact 

N-fixing legume and sustainable P management

Romans used to grow lupins (Lupinus spp.) as a green manuring crop for improving soils (Burtt, 1981). Lupins are N-fixing legumes that are reported to fix 300-400 kg N/ha, in Europe and Australia (Jansen, 2006). Lupins can provide benefit to the following crop (PGRO, 2014). Lupins are valuable legumes for sustainable P management. In soils depleted in available P, lupin plants form specialized cluster root structures and/or release P-mobilizing carboxylates that free it from insoluble forms (Lambers et al., 2012).

Soil improver and phytoremediation

Thanks to its deep taproot, the lupin plant improves soil texture and drainage. Lupins can be used  for phytoremediation. Lupins may extend the phytoremediation period and increase the bioavailability of metals in polluted soils under recovery (Fumagalli et al., 2014). In mixed cultures of bioenergy crops, lupins (Lupinus albus and Lupinus angustifolius) have the ability to mobilize trace elements during and make these elements available for co-cultured species. Lupines mobilize trace elements by carboxylates and enzymes exudation and by lowering the pH value in the rhizosphere. In a comparison between white and blue lupin for trace element mobilization, blue lupin was however less effective than white lupin (Hentschel et al., 2016).

Nutritional aspects
Potential constraints 

Alkaloids

The bitter earlier varieties of lupins (Lupinus spp.) contained a toxic alkaloid and were not recommended for animal feeding unless the alkaloid was removed by soaking in water. The newly obtained sweet alkaloid-free varieties, which can be distinguished by taste and smaller growth, are palatable to stock.

Lupinosis

Lupinosis outbreaks are susceptible to occur in sheep and cattle when lupin is fed as dried forage. Lupinosis is due to phomopsis, a class of toxins produced by fungal infestation of lupin plants by Diaporthe toxica (Jansen, 2006). These toxins cause severe damage to the liver, resulting in loss of appetite, lethargy, jaundice and often death. Sheep are more sensitive to lupinosis than cattle (Clark, 2014; Jansen, 2006). Lupinosis can be prevented by timely harvest and storage of forage or baling before rain falls (Allen et al., 1978).

Ruminants 

Blue lupin can be used as forage for ruminants. It can be grazed either green or as stubble, and could also be used as silage or hay.

Pasture

Green forage

Blue lupin can be grazed as green forage before flowering stage and at several times during the season of growth, but since there is little regrowth, it more recommended at advanced growth stage (Truter et al., 2015).

Lupin has good potential as a high quality summer forage crop for grazing of young lambs (Burtt, 1981). The green pod stage (where total available DM is the highest) is not the ideal stage to graze ; it may be prefered between the preflowering (where the nutrient density is the highest) and the primary flowering stages, were protein and energy values are sufficient to obtain a reasonable lamb growth rate. It would be particularly suitable in situations where grain crops are also grown, since the lupin can also be used in the rotation to restore soil fertility (Burtt et al., 1990b).

Compared with grazing annual pastures only, ewes conducted in a system with 26% of the grazing area cropped to lupins (grazing lupin stubbles in summer and fed lupin grain in late pregnancy and early lactation), have beneficial effects on reproduction results. Ewes lambing in march have heavier lambs that initially grew faster (but same weights at weaning), and ewes lambing in June produce 16% more lambs due to a higher ovulation rate, fewer dry ewes and more twins.

In contrast, lupin feeding does not affect clean wool production (Arnold et al., 1979). The great potential of sweet annual lupin as a source of green feed for grazing lambs in also oberved in area with low summer temperatures (Iceland), with lamb growth rates reaching 450 g/d. Lupin can thus play a role in extending the period of rapid growth by grazing late into the automn before slaughter (Gudmundsson et al., 1988). Lupin can also been associated to cocksfoot in pasture. Cocksfoot-lupin produces forage of comparable quality to lucerne, and can also be grazed earlier in spring. Cocksfoot-lupin appears an alternative forage in areas unsuitable for lucerne (Hamill, 2015). 

Lupin stubbles

After harvest of the seeds, blue lupin stubble can have higher value than cereal stubble. Indeed, fallen lupin seed that remains on the ground after harvest can reach 300-400kg per hectare. It makes lupin stubbles an excellent feed for weaner. Good body weight gain are obtained with stocking rates of 10 weaners/ha for up to two months if there are good levels of grain available. Higher stocking rates (20 weaners/ha) can be applied on a shorter period to allow stubble utilization early in summer before risks of storms. In contrast, when there is less than 50 kg of lupin seed / ha in the stubble, sheep tend to lose weight and develop early signs of lupinosis. Water source should be available at proximity, to allow large paddocks to be grazed more evenly (Curnow, 2019).

Silage

It is also possible to make silage from narrow-leaf lupin. Cutting at flat pod stage – where sugar and protein contents are high and favours fermentation process - and wilting on the field during 1-4 days appears a good way to ensile between 20 to 35% DM and preserve nutritive value (Truter et al., 2015; Faligowska et al., 2014). Fermentation processes are also improved by the addition of lactic acid bacteria (Faligowska et al., 2014).

Hay

Lupin can also be conserved as hay in fodder rolls and bales. This reduces the risk of lupinosis compared to lupin stubble. No additional advantage was gained by spraying cut lupins with formalin before rolling or bailing (Allen et al., 1978). In vivo references on animal responses with blue lupin used as preserved forages are still lacking.

 

Pigs 

Association of lupin (Lupinus angustifolius) forage with other forage legumes (Triflorum decorum, Lablab purpureum, Desmodium uncinatum, desmanthus virgatus, trifolium tembense desmodium intortum, Vicia villosa and Stylosanthes hermata) have been suggested to provide forage to pigs on smallholders farms in Uganda (Lukuyu et al., 2017).

Rabbits 

Whole plant forage

International literature on the use of blue lupin (Lupinus angustifolius) forage in rabbit feeding is very scarce. However it should be noticed that in a study conducted in Portugal on 7 cultivar of lupin (among witch 4 blue lupins) it has been necessary to protect the experiment against rabbits, with a fence (Campos Andrada et al., 2008). It means that fresh plants of lupin in general, and blue lupin in particular, are palatable for rabbits.

Dried blue lupin forage used as the main source of fibre in rabbit diets induces growth rate and feed efficiency close to those obtained with white lupin forage or alfalfa meal used as control (Harries et al., 1999). Thus blue lupin forage can be a potential source of proteins (12-16% DM at minimum) and fibre (39-44% NDF in DM) (Bruno-Soares et al., 1999); but before unrestricted recommendation for rabbits feeding, some additional experiments would be welcome.

Nutritional tables
Tables of chemical composition and nutritional value 
References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. https://www.feedipedia.org/node/24503 Last updated on April 29, 2019, 11:32

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