Animal feed resources information system

Castor (Ricinus communis) 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).


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Common names 

Castor plant, castor oil, castor oil plant, castor-oil plant, palma christi [English]; ricin, grande épurge; ricin commun [French]; mamoeiro [Portuguese]; hierba mora, higuera del diablo, ricino, ricino comun, tartago [Spanish]; קיקיון מצוי [Hebrew]; خرّوب [Arabic]


Castor (Ricinus communis) plant is a soft-woody shrub or small tree grown as an annual in temperate zones and as a perennial in the tropics, where it can reach 10 m in height. The foliage is seldom used as fodder because it has some toxicity: it should be used carefully. The fruits hulls, could be used more safely but they have only restricted nutritive value.The castor plant is mainly cultivated for its oilseeds and also for ornamental purposes.


Castor plant is a glabrous, soft-woody shrub or small tree, often grown as an annual, up to 7 (-10) m high. 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 (a characteristic of the members of the Euphorbiaceae family), 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., 2014; Maroyi, 2007). 

Castor (Ricinus communis) plant is the only member of the genus Ricinus. It is a very versatile species with different colours, sizes, shapes and seed colours depending on growth conditions and climate (Maroyi, 2007).


The mature leaves and the hulls (also referred to as husks) can be used after seed harvest as fodder for livestock in small amount since they are somewhat toxic (Maroyi, 2007). Leaves are also the traditional feed for the eri-silkworm ((Philosamia cynthia ricini) (Fukuda et al., 1963). The leaves may also be used for textile production while the bark and rods can be turned into ropes and sacks and fibre for paper (Kemayo Farms, 2019). The hulls could be used as organic fertilizer in combination with castor oilmeal to balance N content(Lima et al., 2011).


The origin of castor (Ricinus communis) plant is debated because of its wide distribution since ancient times, and the ease and rapidity of its establishment as a native plant. Countries of the North-East Africa like Ethiopia and Egypt could have been the center of origin of castor plant. It was already grown for its oil in Egypt some 6000 years ago and spread through the Mediterranean, the Middle East and India at an early date. Castor plant was also cited in the Bible (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" (Mozdelevich, 2020).

Castor (Ricinus communis) plant is indigenous to north-eastern tropical Africa, especially the Ethiopian areas below 2400 m altitude (Seegeler, 1983). It could have spread to South-Africa as far back as the Stone Age. Castor plant naturally occurs across the African continent, from the Atlantic coast to the Red sea and from Tunisia to South Africa and in the Indian Ocean islands. It is found in tropical and warm temperate regions throughout the world. 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 in the United States.

Castor plant is also widely cultivated in most drier areas of the tropics and subtropics and in many temperate areas with a hot summer. It naturalizes easily and can be grown productively on marginal lands that are not suitable for food crops (Salihu et al., 2014). Castor plant thrives in places where average daily temperatures are 28°C and where annual rainfall are 600 - 700 mm. High moisture and high rainfall may impair pollination and seed production while it encourages prolific vegetative growth. However, the plant becomes more sensitive to diseases in such conditions (Salihu et al., 2014). Though it can be found on marginal lands, 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). It has been reported that water requirements were lower on light soils than on heavy ones (Seegeler et al., 1983).

Forage management 

Castor plants are propagated through seeds. They should be sown on flat land that are not subject to erosion since the roots have only poor soil binding ability.  Castor plant can be sown as a sole crop or in association with annual crops in small holders 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 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 


Castor plant 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 thus been rejected in the USA and Caribbean (Bridgemohan et al., 2014; Gordon et al., 2011).

No food competition

Able to grow on marginal land where no other crop can be cultivated, castor plant does not compete with food crops for land use (Kemaya Farms, 2019).

Organic soil fertilizer

Castor hulls could be used as organic fertilizer but must be blend with a N-rich organic material like castor oilmeal to provide a better nutrient balance for plant growth (Lima, et. al., 2011).

Nutritional aspects
Potential constraints 


Ricin is the most notorious and deadly constituent found in the seed and in smaller amounts throughout the rest of the plant. As the castor plant is mostly accidentally consumed, it can cause both seed and forage poisoning. Most of the cases reported in the literature are due to accidental situations. Consequently, growers of castor ornamental plants may adopt removal of flower clusters from the plant as they appear so that no seeds will be produced, and the risk of accidental poisoning can be minimized (Salihu et al., 2014). It is also recommended to limit the access of the 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., 2006).

Poisoning due to ricin occurs when animals ingest broken seeds, chew the seeds or eat high quantities of forage. If the seeds are ingested without being broken, they may pass through the digestive tract without releasing ricin. Commercially available cold-pressed castor oil is not toxic to humans in normal doses, either internal or externally.

Mechanisms of ricin toxicity

Toxicity 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 (Tamimi et al., 2008).


Symptoms of ricin poisoning begin within hours after exposure by ingestion or inhalation they are not the same if they are due to seed ingestion or forage ingestion (Haritha et al., 2019).

The symptoms due to seed ingestion 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.

The leaves are reported to cause neuro muscular signs (Torkania et al., 1975).


Cases of cattle poisoning were reported in Brazil (Albuquerque et al., 2014), 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) more than leaves because the ricin contained in the seeds is more toxic than the ricinine contained in the leaves and pericarp of the plant (Albuquerque et al., 2014).

Cases of poisoning are described with sheep (Aslani et al., 2007; Bianchi et al., 2018) consuming leaves and seed and with goats consuming only leaves from branches recently cut (Brito et al., 2019).

Lethal doses of seeds

In cattle, the lethal dose of ground seeds is 2 g/ kg BW for adults and 0.5 g/kg BW for calves (Albuquerque et al., 2014). Other

Experimental poisoning by seeds of sheep (Armien et al., 1996) showed that 5g/kg BW of intact seeds cause slight or no effect but 7.5 and 10 g/kg BW causes the death of the animals. When the seeds are smashed the lethal dose is 2.5 g/ kg BW (Armien et al., 1996).

Lethal doses of forage

According these authors, the lethal dose of fresh leaves for adult cattle is 20 g fresh/kg body weight. Dry leaves consumed after a 19 weeks’ storage period lost half of their toxicity (Torkania et al., 1975). For sheep the lethal dose of castor plant foliage would be 30 g fresh/ kg BW and for goats it could be higher than 40 g/kg BW but needs confirmation (Brito et al., 2019).


Ricinine is a small alkaloid found in castor plant foliage. It is toxic to insects and it has been shown that castor plants may be used as insects traps in horticultural crops and gardens (Burgess et al., 1988).



In a recent Mexican trial, it has been shown that dried leaves of castor (Ricinus communis)  plants of different ages had high crude protein content (31-32 %) and low neutral detergent fibre (NDF) content (18.5 to 26 %) and could thus be a potential good source of forage for ruminants (Ramirez et al., 2017). Their potential ruminal in vivo DM degradability measured in sheep (50 kg BW ewe) was found to be high (94.5 to 97 %) (Ramirez et al., 2017). It was suggested to plan further trials in order to confirm that castor dried leaves could be safely fed to ruminants (see Potential constraints above).

In an earlier experiment, mature wilted leaves were reported to contain 11.46 % crude protein and 14.66% crude fibre. Offered as sole forage to sheep (29.5 kg BW ), they were well consumed up to 1.24 kg DM/d and their DM digestibility was high (Behl et al., 1986). No toxicity problem was observed.

While the chemical composition of castor plant leaves appears to be good, it has not been possible to find results about their utilization in animal feeding. Several cases of poisoning of sheep or cattle due to castor plant leaves or leaves+seeds ingestion have been reported (see Potential constraints). It is thus not recommended to feed animals with castor plant leaves.


Castor bean hulls have recently been used as forage, but their nutritive value is low with 50.7 g/kg DM of CP and 843 g/kg DM of NDF (de Andrade et al., 2013).

Sheep and goat

In Brazil, castor bean hulls were used to replace (33, 66 and 100 %) Tifton hay in a low quality diet based on cactus forage in a fattening lamb diet (de Andrade et al., 2013; Urbano et al., 2013a; Urbano et al., 2013b). The diet provided 400g DM/d cactus forage, 300 g DM/d Tifton hay, 285 g DM/d concentrate, and 15 g DM/d, minerals (de Andrade et al., 2013). Up to 66% replacement, no differences were found in dry matter intake (1.02 to 0.95 kg DM/d), DM digestibility of the diet (75 to 72%), daily weight gain (200 to 170 g/d) or carcass composition (de Andrade et al., 2013). When castor hulls replaced 100% of cactus hay, all parameters significantly decreased (de Andrade et al., 2013).

In the same situation, Urbano et al., (2013a; 2013b) observed a decrease of the carcass composition and body weight at slaughter but no changes in term of meat quality and sensory attribute. In similar conditions, Urbano et al. (2012) find no difference in the diet  DMI (0.95 to 0.86 kg/d), but the carcass composition decreases. All studies do not recommend to replace hay with Castor hulls except if economic situation is favourable. In dairy goat, Castor bean hulls can replace hay up to 33 % into a complete diet offered to 45 kg dairy goats without any significant changes in milk yield (1.05 or 0.93 g/d/g) or milk composition except for fat content which increases (Santos et al., 2011). With higher substitution levels (67 or 100%) milk yield significantly decreases (0.74- 0.77 g/d/g), fat content still increases and fatty acid profile is modified (Santos et al., 2011).


Castor straw can replace sorghum straw up to 20% 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 /kg live weight gain increased (Reddy et al., 1993).



Straw or hulls can be used safely but their low nutritive value does not support any utilization as forage in place of low nutritive value hay for growing animals. They can be used as forage when there is forage scarcity or when hay price is high.  


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

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).

Main analysis Unit Avg SD Min Max Nb
Crude protein % DM 23.7 22.5 24.8 2
Crude fibre % DM 10.3 1
NDF % DM 24.0 1
ADF % DM 22.1 1
Lignin % DM 2.8 1
Ether extract % DM 5.4 1
Ash % DM 12.2 11.9 12.4 2
Gross energy MJ/kg DM 18.1 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 26.7 1
Phosphorus g/kg DM 4.6 1

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


Nsahlai et al., 1996; Sen, 1938

Last updated on 24/10/2012 00:43:56

Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. https://www.feedipedia.org/node/103 Last updated on September 23, 2020, 11:49