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Chilean mesquite (Prosopis chilensis)


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Common names 

Chilean mesquite, chilean algarrobo [English]; algarrobo, algarrobo blanco, algarrobo de Chile, algarrobo chileno [Spanish]


Acacia siliquastrum Lag., Ceratonia chilensis Molina, Prosopis siliquastrum (Lag.) DC.

Taxonomic information 

In several areas, Prosopis trees once believed to be Prosopis chilensis are now considered to belong to other species. As a result, scientific literature written before the confusion was resolved, or written by authors unaware of the issue, may erroneously refer to Prosopis chilensis. This is the case with Prosopis chilensis trees brought to Sudan in the early 20th century that are now found in African and Middle Eastern countries: they are considered to be Prosopis juliflora even though the seeds are occasionally marketed as Prosopis chilensis. A similar taxonomical problem exists in Peru and in Hawaii, where Prosopis chilensis trees are now identified as Prosopis juliflora or Prosopis pallida (or hybrids) (Gabar, 1988; Pasiecznik et al., 2001).

Feed categories 

The Chilean mesquite (Prosopis chilensis (Molina) Stuntz) is a small to medium-sized legume tree up to 12 m in height and 1 m in diameter. It has a shallow and spreading root system. It branches freely and its wood is hard and reddish, with brown and fissured bark. Its leaves are 4-7.5 cm long, compound, each with several pairs of pinnate leaflets. The flowers are greenish-white to yellow, about 5 mm long, abundant and occur in spike-like 5-10 cm long racemes. The pods are slender, slightly curved or straight, flat at maturity, 10-20 cm long, yellow when ripe, borne in drooping clusters. Seeds are bean-shaped, oblong, 6-7 mm, light brown, each in 4-angled case (Hosaka et al., 1944; Orwa et al., 2009). Prosopis chilensis flowers regularly in spring and sometimes sporadically again in late summer (Orwa et al., 2009).

Prosopis chilensis wood gives good charcoal, fibre, and a relatively dense timber valued for furniture and floors. The ground pods are eaten by rural people in Northern Argentina. The leaves are not very palatable to animals but the sugary pods are eaten by livestock and the seeds are sometimes ground and added to a concentrate feed (Orwa et al., 2009).

Disclaimer: As noted above, knowledge regarding Prosopis chilensis is ambiguous due to long-standing taxonomic confusions with Prosopis juliflora and Prosopis pallida. Many animal and agronomic trials are wrongly attributed to Prosopis chilensis, but actually refer to other Prosopis species. This is always the case with the work done in Hawaii. For South America and Africa, however, the situation is less clear and this datasheet will use references obtained in these areas, even though there is some uncertainty about the proper taxonomic attribution of the results.


Native to Central America, Prosopis chilensis is common in Peru, Chile, Argentina and Uruguay. It is naturalized in many African countries as well as in the USA. Prosopis chilensis is found in arid and semi-arid regions with ground water of between 3 and 10 m below the surface, for example drainage channels along ground water sinks. It grows at an altitude between 340-1230 m, in mean annual temperatures of 12-45°C, under average annual rainfall of 350-400 mm (Orwa et al., 2009). It is found in sandy, alkaline soils and has been observed to grow in sea water (Göhl, 1982, Orwa et al., 2009).

It is a common ruderal weed, either growing singly or in groups along roadsides, round habitations, on refuse dumps and in other disturbed habitats (Orwa et al., 2009).

Forage management 

Large trees may produce 40 kg of pods under optimal conditions (Orwa et al., 2009). Pod productivity studies conducted in North America, Hawaii and Sudan showed production varying over a wide range, between 1 and 20 t/ha/year. Pod production starts in December, steadily increasing until it peaks in March. It then decreases to a minimum in June, after which time the trees cease production (Gabar, 1988). In Chile (Pampa del Tamarugal), the forage production of the largest trees ranged from 31 to 117 kg per tree (Zelada, 1986). As noted above, such studies (notably those in Hawaii and Sudan) could actually refer to other Prosopis species due to taxonomical errors.

Environmental impact 

Prosopis chilensis offers several environmental benefits. Like other legumes, Prosopis chilensis fixes atmospheric nitrogen in its root nodules. When planted as a hedgerow it provides shade for fruit trees, field crops, to the homesteads and to livestock. Due to its deep rooting habit, it is a candidate for erosion control and soil stabilization in arid lands. It could be used as a barrier plant to form stock-proof hedgerows able to provide a perennial source of pods and firewood. Grasses and other plants have been said to grow better in association with Prosopis chilensis, benefiting from shelter, humus and nitrogen enrichment of the soil. Its use in intercropping and in agroforestry systems could be valuable (Orwa et al., 2009).

Nutritional aspects
Nutritional attributes 

The main feed product provided by Prosopis chilensis are its pods. The pods are low in protein (9-13% DM) and rich in fibre (crude fibre, 20-26% DM) (Feedipedia, 2011; Gabar, 1988). Like other Prosopis pods, the ripe pods are rich in sugars and can be a valuable source of energy (Göhl, 1982). The seeds are particularly rich in protein (32.5% DM). Leaves are also reported to be protein-rich, CP ranging from to 14.8 (Gabar, 1988) to 18.3% DM (for fresh loppings in India, Khirwar et al., 2003) and 22.5% DM (Fraps et al., 1940).

Potential constraints 

The usefulness of Prosopis chilensis may be limited by its relatively high content of phenolic compounds and other toxic components. Mice fed on mesquite leaf meal as the sole source of protein could not survive (Lyon et al., 1988). Fresh leaves and flat-green immature pods of Prosopis chilensis can be toxic to goats and sheep. A daily intake of 10 g/kg body weight will cause death to sheep and goats within a period of 4-5 weeks for leaves and 5-8 weeks for the flat green immature pods. Generally the symptoms included inappetence, weight loss, weakness, loss of fitness, visible pallor, mucuous membrane, loss of eye reflex, alopecia, lack of coordination, foul watery diarrhea, severe dehydration and recumbency followed by death. The symptoms are identical for the pods and the leaves (Ibrahim, unpublished data, cited by Gabar, 1988).



Unripe green pods are bitter, of little value and potentially toxic to sheep and goats. The ripe pods or beans drop between June and November and are an excellent feed rich in sugar. In some countries the seeds are ground into meal for use in concentrate rations for all classes of livestock. Kiln-dried pods ground into a meal are far superior to air-dried chopped pods (Göhl, 1982).

In the desert conditions of the Pampa del Tamarugal in Northern Chile, sheep, goats and cattle are fed with the leaves and pods of planted and natural stands of Prosopis tamarugo and Prosopis chilensis. This forage alone cannot support growth and reproduction and must be supplemented with protein and energy feeds such as alfalfa hay and wheat bran, with added vitamins (Zelada, 1986).

In Sudan, Prosopis chilensis pods can be an adequate maintenance ration for goats and sheep, particularly during the long dry season when feed is scarce. It is not advisable to feed sheep exclusively on Prosopis chilensis pods beyond a period of 13 weeks. It is usual for loss in weight to occur in the dry season (March-July) and although feeding solely on P. chilensis for a period shorter than 13 weeks will result in some weight loss, it can sustain the animals during this period. For livestock fattening, pods should be supplemented with a source of energy and protein (Gabar, 1988).


The relatively high protein content of the seeds suggests that they may be useful as a protein supplement to poor grass, especially if crushed (Gabar, 1988).


The leaves are grazed to some extent, but are a less important fodder than the pods (Göhl, 1982). The green leaves are unpalatable to all domestic animals except camels and they can be toxic to sheep and goats (Gabar, 1988).

The 48 h in situ degradability of Prosopis chilensis leaves is low (34%) (Rossi et al., 2005). The digestibility of fresh Prosopis chilensis loppings was lower than that of Prosopis cineraria and a Prosopis cinerara x Prosopis juliflora hybrid (Khirwar et al., 2003).


No information found (2011).


No information found (2011).


There is scarce information about the use of Prosopis chilensis products for rabbits. The replacement of part of the wheat bran by Chilean mesquite pods (28.4% of the diet) in growing rabbit diets led to slightly lower final live and carcass weights when the feeds were mixed mechanically, and to much lower weights when the feed was mixed manually (Caro et al., 1992). When the pods replaced wheat bran and rapeseed meal and provided 30 and 60% of dietary crude protein (8.4 and 29.4% of the diet DM respectively), the final live weight at 76 days was significantly lower for the pod-based meal (Caro et al., 1991).

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
Crude protein % DM 22.5 1
Crude fibre % DM 24.7 1
Ether extract % DM 2.9 1
Ash % DM 4.7 1
Gross energy MJ/kg DM 19.4 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 8.6 1
Phosphorus g/kg DM 2.5 1
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 70.6 *
Energy digestibility, ruminants % 67.5 *
DE ruminants MJ/kg DM 13.1 *
ME ruminants MJ/kg DM 10.4 *

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


Fraps et al., 1940

Last updated on 24/10/2012 00:43:35

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 90.0 4.0 84.3 94.4 7
Crude protein % DM 10.5 1.4 8.7 12.7 7
Crude fibre % DM 22.3 5.1 11.9 26.9 7
NDF % DM 37.8 1
ADF % DM 28.0 1
Lignin % DM 7.0 1
Ether extract % DM 1.6 0.7 0.6 2.6 7
Ash % DM 5.5 2.1 3.2 7.9 7
Gross energy MJ/kg DM 18.2 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 2.9 1.4 1.6 4.4 4
Phosphorus g/kg DM 1.5 0.2 1.3 1.6 4
Potassium g/kg DM 11.6 11.0 12.1 2
Magnesium g/kg DM 0.9 0.8 1.1 2
Manganese mg/kg DM 16 14 19 2
Zinc mg/kg DM 23 23 23 2
Copper mg/kg DM 5 3 7 2
Iron mg/kg DM 117 1
Amino acids Unit Avg SD Min Max Nb
Leucine % protein 6.6 1
Lysine % protein 3.3 1
Threonine % protein 3.1 1
Tryptophan % protein 0.8 1
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 87.0 *
Energy digestibility, ruminants % 83.9 *
DE ruminants MJ/kg DM 15.2 *
ME ruminants MJ/kg DM 12.5 *
Nitrogen digestibility, ruminants % 70.0 1
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 55.1 *
DE growing pig MJ/kg DM 10.0 *
Nitrogen digestibility, growing pig % 58.1 1

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


Anon., 1937; CIRAD, 1991; Cowie, 1947; Fialho et al., 1995; Ibrahim, 1984; Vargas et al., 1965

Last updated on 24/10/2012 00:43:36

Main analysis Unit Avg SD Min Max Nb
Crude protein % DM 5.6 1
Crude fibre % DM 27.3 1
Ether extract % DM 0.2 1
Ash % DM 3.8 1
Gross energy MJ/kg DM 18.1 *
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 85.4 *
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 47.2 *
DE growing pig MJ/kg DM 8.5 *

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


Johnson et al., 1918

Last updated on 24/10/2012 00:43:36

Main analysis Unit Avg SD Min Max Nb
Crude protein % DM 35.2 1
Crude fibre % DM 9.1 1
Ether extract % DM 5.2 1
Ash % DM 5.1 1
Gross energy MJ/kg DM 20.0 *
Amino acids Unit Avg SD Min Max Nb
Arginine % protein 6.3 1
Glycine % protein 2.5 1
Histidine % protein 2.2 1
Isoleucine % protein 1.2 1
Leucine % protein 6.3 1
Lysine % protein 6.1 1
Methionine % protein 1.2 1
Phenylalanine % protein 2.6 1
Threonine % protein 2.3 1
Tyrosine % protein 1.4 1
Valine % protein 2.9 1
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 91.1 *
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 75.8 *
DE growing pig MJ/kg DM 15.2 *

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


Johnson et al., 1918; Ronda Lain et al., 1963

Last updated on 24/10/2012 00:43:36

Datasheet citation 

Tran G., 2016. Chilean mesquite (Prosopis chilensis). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. http://www.feedipedia.org/node/553 Last updated on April 12, 2016, 15:29

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