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Castor bean (Ricinus communis) forage


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Common names 

Castor plant, castor bean, castor oil plant, castor-oil plant, palma christi [English]; wonderboom [Dutch]; Wunderbaum [German]; ricin, grande épurge; ricin commun [French]; Ρίκινος [Greek]; mamona, mamoneira, mamoeiro, carrapateira, carrapato, ricino [Portuguese]; hierba mora, higuera del diablo, ricino, ricino comun, tartago [Spanish]; Hint yağı bitkisi [Turkish]; קיקיון מצוי [Hebrew]; خرّوب [Arabic]; کرچک [Farsi]; kasterolieboom [Afrikans]; ጉሎ [Amaric]; Zirman [Hausa]; अरंडी [Hindi]; jarak (tumbuhan) [Indonesian]; ആവണക്ക് [Malayalam]; Pokok jarak  [Malaysian]; Lansina [Tagalog]; 英语 [Chinese]; トウゴマ[Japanese]; 피마자 [Korean]; Thầu dầu [Vietnamese]


The castor plant (Ricinus communis L.), also called castor bean plant or castor oil plant, is a shrub or small tree cultivated in tropical and temperate regions for its seeds rich in an oil valued for its many industrial applications. The plant, and particularly its seeds, contain several toxic and even lethal substances. While castor plant foliage is less harmful than the seeds, its utilization as fodder is limited due to its potential toxicity, and it should be used carefully.


Ricinus communis is a very versatile species with different colours, sizes, shapes and seed colours depending on the cultivar, growth conditions and climate (Maroyi, 2007). The castor plant is a glabrous, soft-woody shrub or small tree, up to 7 (-10) m high, grown as an annual in temperate zones and as a perennial in the tropics. It is strongly taprooted with prominent lateral roots. The stem and branches have conspicuous nodes and ring-like scars and glands often present at nodes. The shoots are usually glaucous, green or red in colour. The leaves are spirally arranged, borne on 3.5- 50 cm long petioles. The leafblade is large (up to 50 (-70) cm in diameter), palmately compound with 5-12 acuminate lobes, median one up to 8(–20) cm long. The leaf margins bear glandular teeth. The inflorescence is an up to 40 cm long, erect terminal panicle becoming lateral as the plant develop new branches (due to indeterminate growth habit). The flowers are unisexual, regular, 1–1.5 cm in diameter; the male flowers are borne towards the base of the inflorescence, with many stamens in branched bundles and the female ones, towards the top of the inflorescence, with early caducous sepals, red or green in colour. The fruits are spiny or smooth ellipsoid to globose, slightly 3-lobed capsules, 1.5-2.5 cm long, brown in colour. Ripening of fruits within an infructescence is uneven, the lower fruits maturing before the upper ones. At maturity, the fruit is dehiscing in 3 cocci each opening by a valve and 1-seeded. The seeds are ellipsoid, 9–17 mm long, compressed, with a brittle, mottled, shining seedcoat and with distinct caruncle at the base (Salihu et al., 2014b; Maroyi, 2007).


The mature leaves can be used after seed harvest as fodder for livestock, but in small amounts since they are somewhat toxic (Maroyi, 2007). Leaves are the traditional feed for the eri-silkworm (Philosamia cynthia ricini) (Fukuda et al., 1963). The leaves are be used for textile production and the bark and rods can be turned into ropes and sacks and fibre for paper (Kemayo Farms, 2019).


The origin of Ricinus communis is debated due to its wide distribution since ancient times, and because of the rapidity of its establishment as a native plant. It may have originated in North-East Africa and it was grown for its oil in Egypt about 6000 years ago. It spread through the Mediterranean, the Middle East and India at an early date, and it may have spread to Southern Africa as far back as the Stone Age. The castor plant is cited in the Bible in the Book of Jonah 4: 6-7: "And the LORD God prepared a plant and made it come up over Jonah, that it might be shade for his head to deliver him from his misery. So Jonah was very grateful for the plant. But as morning dawned the next day God prepared a worm, and it so damaged the plant that it withered" (Modzelevich, 2020).

Ricinus communis is found in most drier areas of the tropics and subtropics and in many temperate areas with a hot summer. It is indigenous to north-eastern tropical Africa, especially in Ethiopian areas below 2400 m altitude (Seegeler, 1983). It naturally occurs across the African continent, from the Atlantic coast to the Red sea, from Tunisia to South Africa and in the Indian Ocean. It was introduced to Florida during the 18th century and was naturalized in Hawaii not later than 1819. It is becoming an abundant weed in Florida, California and Hawaii (Rojas-Sandoval et al., 2014).

The castor plant naturalizes easily and can be grown productively on marginal lands that are not suitable for food crops (Salihu et al., 2014b). It thrives in areas where average daily temperatures are 28°C and where annual rainfall are 600-700 mm (Gana et al., 2013; Maroyi, 2007). High moisture and high rainfall encourage prolific vegetative growth but may impair pollination and seed production, and the plant becomes more sensitive to diseases in such conditions (Salihu et al., 2014b). Optimal growth is obtained on fertile (good N supply and organic matter content), well-drained moisture retentive soils like clayey and sandy loam with a pH of 6-7.3 (Gana et al., 2013). Water requirements are lower on light soils than on heavy ones (Seegeler, 1983).

Forage management 

Ricinus communis is propagated through seeds. They should be sown on a flat land that is not subject to erosion since the roots have poor soil binding ability. The castor plant can be sown as a sole crop or in association with annual crops in smallholders farms. The seeds should be placed in holes (2-3 seeds/hole) or in rows situated at 4-5 m distance for regular cultivars and at 1 m distance for dwarf ones, in a well-prepared and moist seedbed where there is no compact layers left. The in-row distances should be 25-30 cm for dwarf cultivars and 30-40 for regular ones. Careful mechanical weeding is necessary in the early stages of growth of the seedlings. The first harvest can be done 5-8 months after plantation (Maroyi, 2007; Seegeler, 1983).

Environmental impact 


Ricinus communis has been referred to as an invasive or weedy species in many countries, particularly in the tropics. Dense thickets of castor plants shade out native flora and may be detrimental to biodiversity. Because of its high invasive potential, its use as a bioenergy crop has been rejected in the USA and Caribbean (Bridgemohan et al., 2014; Gordon et al., 2011).

Land use competition

Ricinus communis is able to grow on marginal land where no other crop can be cultivated and does not compete with food crops for land use (Kemayo Farms, 2019).

Organic soil fertilizer and bioremediation

The castor plant was grown successfully on cadmium-contaminated sites. It could help stabilize 51% Cd in their roots, stems and leaves and was recommended for soil remediation (Bauddh et al., 2015).

Nutritional aspects
Nutritional attributes 

Castor plant forage has a good chemical composition. The protein content of the leaves is quite high, in the 20-30% DM range, though lower values (possibly for older material or material containing stems) have been recorded. In a trial in Mexico, the composition did not change much from 60 days to 180 days (Ramirez et al., 2017).

Potential constraints 

Toxic substances

The castor plant produces several toxic substances, particularly ricin, a lethal and cytotoxic lectin notorious for its potential use as a biological weapon. Other undesirable substances include the alkaloid ricinine and allergen CB-1A (Maroyi, 2007).


The endosperm of castor seeds contains about 1-5% of ricin. Ricin is found only in the endosperm and is no present in the oil as it not oil-soluble (Johnson et al., 2005; Lord et al., 1994). Ricin is a glycoprotein lectin composed of 2 chains, A and B, linked by a disulphide bond (Audi et al., 2005; Akande et al., 2016). The B chain is a lectin and binds to galactose-containing glycoproteins and glycolipids expressed on the surface of cells, facilitating the entry of ricin into the cytosol. The A chain inhibits protein synthesis by irreversibly inactivating ribosomes which prevents chain elongation of polypeptides and leads to cell death (Audi et al., 2005). Ricin structure and its mode of action have been extensively reviewed (Lord et al., 1994). The toxicity of ricin mainly consists in the inhibition of protein synthesis, but other mechanisms like apoptosis pathways, direct cell membrane damage, alteration of membrane structure and function, and inflammatory mediators are also described (Al-Tamimi et al., 2008). Symptoms of ricin poisoning begin within hours after exposure by ingestion or inhalation (Haritha et al., 2019). They may include stomach irritation, vomiting, bloody diarrhea, abdominal pain, increased heart rate, low blood pressure, profuse sweating, collapse, convulsions, and death within a few days (Salihu et al., 2014a). Symptoms and their intensity depends on the animal species. In horses, signs include: sweating, trembling, incoordination, vigorous heart action that shakes the whole body but pulse weak, muscle spams, erection of penis or clitoris, abdominal colic and shallow respiration. In cattle, signs similar to those of horses have been observed as well as elevated temperature, and diarrhoea stained with blood. In swine, vomiting occurs (which often saves their life of animal), and the skin of ears, flanks and hams becomes cyanotic. In poultry, depression is observed; feathers are ruffled, the wings are drooping, comb and wattles are greyish. In hens, egg production is stopped and moulting occurs. Birds that do not quickly die lose weight (Weiss, 1971).


Ricinine is an alkaloid found mainly in the leaves but it exists in all parts of the plant, including the seed pericarp (Severino et al., 2006). Foliage ricinine contents of 1.3% DM (Severino et al., 2006) and 0.13-0.26% fresh weight (Burgess et al., 1988) have been reported. Ricinine content is higher in young tissues, damaged or stressed plants (Azevedo et al., 2007; Tavora, 1987; Moshkin, 1986). While less toxic than ricin, ricinine is still detrimental to animal health (Albuquerque et al., 2014). In cattle and rabbits, cases of ricinine intoxication from leaves or fruit pericarps have been reported to have neurological effects. Symptoms included lack of equilibrium, ataxia, head deviation, muscular tremors, sialorrhea (excessive salivation), and eructation. These signs could be followed by sudden recovery or death. No lesions were found in the central nervous system (Ferraz et al., 1999; Tokarnia et al., 1975). The ricinine LD50 for rabbits is about 3 g/kg LW in a single oral dose (Al-Khafaji et al., 2017). In mice, animals receiving the higher doses of ricinine became exophtalmic, had tremors and clonic seizures, and died in a few minutes of tremors and clonic seizures and died a few minutes after receiving the extract (Ferraz et al., 1999). Ricinine is toxic to some insect species and castor plants can be used as insects traps in horticultural crops and gardens (Burgess et al., 1988).

Allergen CB-1A

Some complexes of protein and polysaccharides have been referred to as allergenic. However, the main concern is with people handling castor bean products and animals were not reported to suffer from allergies (Candido et al., 2008; Anandan et al., 2005).

Castor plant poisoning

Castor plant poisoning occurs when animals ingest broken seeds, chew the seeds or eat high quantities of forage. Unbroken seeds may pass through the digestive tract without releasing ricin. Most of the cases reported in the literature are due to accidental situations where animals consume entire plants containing both foliage and seeds. Growers of ornemental castor plants are advised to remove flower clusters from the plant as they appear so that no seeds are produced, reducing the risk of accidental poisoning (Salihu et al., 2014a). It is recommended to limit the access of animals to areas where castor plants are grown, particularly during periods of forage scarcity, or to cut and eliminate the shrub, preventing any intake of leaves and seeds (Aslani et al., 2007).

Cases of cattle poisoning were reported in Brazil, when animals consumed leaves but also fruits with seeds due to severe scarcity of pasture. The main reason of the death of the animals is probably due to seed consumption (observed into the rumen and omasum) (Albuquerque et al., 2014). Cases of poisoning have also been described with sheep consuming leaves and seeds (Aslani et al., 2007; Bianchi et al., 2018). In California, sheep wandering into an unharvested field of castor plants were poisoned and some died (Weiss, 1971). Poisoning was also reported with goats consuming only leaves from recently cut branches (Brito et al., 2019). The lethal doses of fresh leaves for adult cattle was reported to be 20 g/kg (fresh) body weight (Albuquerque et al., 2014; Armien et al., 1996). In cattle, dry leaves consumed after a 19 weeks storage period lost half of their toxicity (Tokarnia et al., 1975). For sheep the lethal doses of castor plant foliage would be 30 g/kg (fresh) BW and for goats it could be higher than 40 g/kg BW but this needs confirmation (Brito et al., 2019).Rabbits and sheep fed on small dried castor seedlings mixed with alfalfa hay showed no toxicity or difference in growth between treated and control animals (Weiss, 1971). It has been reported that frequent consumption of castor seeds could alleviate castor plant poisoning in cattle but this effect was not observed when cattle ate castor plant foliage (Afonso et al., 2001).


Information about the use of castor plant forage in ruminants is limited. Castor plant forage seems to be palatable to cattle and sheep and to have a good nutritive value. As noted the Potential constraints section, cases of poisoning have been reported in ruminant species after the ingestion of leaves or leaves and seeds. Some experiments with dried castor plant leaves do not report toxicity. Dried castor plant forage with a reduced content in ricinine and devoid of toxic seeds is a good potential forage for ruminants due to its high protein content and high DM degradability (Ramirez et al., 2017). However, the possible presence of toxic compounds makes castor plant forage a risky feed.


Castor plant foliage was reported to be well browsed by ruminants in Brazil (Afonso et al., 2001). In Mexico, dried forage was relished by sheep, and it could represent up to 33% of the diet without causing intoxication (Lara et al., 2016).

Digestibility and degradability

In Mexico, dried plant castor plant forage of good quality (protein 27-32% DM, NDF 19-26 % DM) was found to have a very high in sacco DM degradability in sheep (95-97%) (Ramirez et al., 2017; Lara et al., 2016). In India, dried mature leaves of lower quality (protein 11.5% DM) offered as sole forage to sheep were well consumed (up to 1.24 kg DM/d) and their DM digestibility was high, with no reported toxicity (Behl et al., 1986).

In India, castor plant straw could replace up to 20% sorghum straw in a complete diet based on 40% forages and 60% concentrate, offered to 5-6 months fattening calves without any negative effects while cost of feed per kg live weight gain increased (Reddy et al., 1993).


The presence of toxic compounds, notably ricinine, in the castor plant foliage, makes the plant undesirable for rabbit feeding. Given the ricinine values of fresh leaves and the ricinine LD50 for rabbits stated in the Potential constraints section, the daily ingestion of 300 g of fresh leaves (about 70 g/d DM) would reach the LD50 within 5 days. Castor plant forage must thus be considered as toxic for rabbits and discarded from rabbit feeding. Accordingly, no information is available in the international literature on the use of castor plant leaves as forage for rabbits.

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

Main analysis Unit Avg SD Min Max Nb  
Dry matter % as fed 90.5 1.9 87.7 92.5 5  
Crude protein % DM 24.7 6.6 11.5 32.2 9  
Crude fibre % DM 11.5 2.1 9.7 14.7 5  
Neutral detergent fibre % DM 27.6 6.4 18.5 37.6 7  
Acid detergent fibre % DM 24 4.8 17 30.7 7  
Lignin % DM 2.8       1  
Ether extract % DM 4.3 1.2 3.3 5.8 5  
Ash % DM 11 2.7 6.8 15.4 8  
Insoluble ash % DM 2.5       1  
Gross energy MJ/kg DM 18.4         *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 26   25.3 26.7 2  
Phosphorus g/kg DM 3.7   2.8 4.6 2  
In vitro digestibility and solubility Unit Avg SD Min Max Nb  
In vitro DM digestibility (pepsin) % 69       1  
Ruminants nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 76.2         *
Energy digestibility, ruminants % 72.5         *
DE ruminants MJ/kg DM 13.3         *
ME ruminants MJ/kg DM 10.6         *
Nitrogen digestibility, ruminants % 70.2       1  
Dry matter degradability (effective, k=6%) % 64   47 71 4 *
Dry matter degradability (effective, k=4%) % 70         *
a (DM) % 29   16 34 4  
b (DM) % 65   61 74 4  
c (DM) h-1 0.07   0.045 0.085 4  

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


Behl et al., 1986; Deribe Gemiyo Talore, 2015; Lara et al., 2016; Nsahlai et al., 1996; Ramirez et al., 2017; Sen, 1938

Last updated on 07/10/2020 14:28:21

Datasheet citation 

Heuzé V., Tran G., Hassoun P., Lebas F., 2020. Castor bean (Ricinus communis) forage. Feedipedia, a programme by INRAE, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/103 Last updated on October 8, 2020, 11:17