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African sheepbush (Pentzia incana)


Click on the "Nutritional aspects" tab for recommendations for ruminants, pigs, poultry, rabbits, horses, fish and crustaceans
Common names 

African sheepbush, Australian sheepbush, anchor karoo, common karro, good karoo, karroo bush, sheep bush [English]; ankerkaro, ankerkaroo, bitter karroobossie, gansie, goedkaro, grootgansie, karobos, karoobos, karoobossie, kleingansie, rooikarobos, skaapbos, skaapbossie, soetkaroo, vaalkaro, witkarobos [Afrikans]


African sheepbush (Pentzia incana (Thunb.) Kuntze) is an aromatic rounded subshrub that is one of the most important species of the Karroo complex in South Africa. It is considered an important fodder plant for sheep in semi-arid and arid areas, hence the Afrikaans name skapbossie (sheepbush). In South Africa, it is thought to provide the distinctive flavour of Karoo lamb (a registered geographical indication) (Hulley et al., 2018).


Pentzia incana is a perennial shrublet that grows up to 30- 60 cm in height and forms dense bushy rounded cover. It has woody creepers that root where they touch the soil and then turn upright to erect. The leaves are small, fascicled, looking like pine needles, 1-2 cm long. The younger stems and leaves are white- to grey-tomentose, so the leaves are greyish. The yellow flower heads are almost spherical and about 0.5 cm in diameter. The flowers are borne at the apex of long flowering stalks. Because this plant is heavily browsed, it is sometimes difficult to recognize it (SDF, 2021).


Pentzia incana is a important natural pasture component of the Karoo that is grazed by sheep and is thought to provide the particular flavour to Karoo lamb meat. As a forage, it is valuable in arid and semi-arid areas (Parsons, 2012; Pienaar et al., 2004). Leafy twigs are traditionally chewed by people for relief of stomach ache (Hulley et al., 2018).


Pentzia incana is native to tropical southern Africa (Botswana, Namibia, and Cape Provinces, Free State, Northern Provinces in South Africa). It was probably introduced to Zimbabwe and then to Arizona, New Mexico, and South Australia. In the 1930s, African sheepbush was introduced to South Australia in a project of revegetation after the native species had been destroyed by stock overgrazing (Ratcliffe, 1936).

Pentzia incana is found at elevation between 900-1700 m. It does well on sandy soil in arid and semi-arid areas where annual rainfall can be as low as 203.5 mm and average minimum temperature is 7.9°C and average maximum temperature is 26.5°C (du Toit, 2011).

Environmental impact 

Erosion control

African sheepbush plays an important role in preventing erosion thanks to its stoloniferous habit which anchors it on the soil and binds sandy soil. One of its Afrikaans name is "ankerkaroo" (anchor karoo) (Hulley et al., 2018)

Indicator of overgrazing, encroachment

In South Africa, overgrazing by stock results in the devlopment of Pentzia incana and other karoo shrubs, replacing native grassland over wide areas (Darkoh, 2001).

Nutritional aspects
Nutritional attributes 

Pentzia incana has a relatively low nutritional value, with a protein content ranging from 7 to 14% (or 16%) DM. In the Karoo, the highest protein content is found from February to May in certain years. The phosphorus content is the highest during the same months. The plant is notable for its low magnesium content, which may cause deficiency in horses, but it is also low in potassium and sodium, unlike other Karoo shrubs, which makes it valuable for sheep suffering from alkalosis in brak (salt-rich) soils (Buttner, 1963).

Potential constraints 

The low magnesium content was reported to cause paralysis in horses (Buttner, 1963).



African sheepbush has a variable and, on average, a relative low palatability for livestock depending on the place where it is grown (Le Roux et al., 1994 cited by Hulley et al., 2018). In 3 different types of Karoo veld, African sheepbush was not listed among the preferred species of Merino and Dorper sheep (du Toit, 2011). Despite this low palatability, the development of Pentzia incana (volume and flowering capacity) was impaired by heavy grazing in the Nama karoo (Todd et al., 1999). However, it was found to persist even in case of overgrazing (Hulley et al., 2018).


In vitro and in vivo digestibility in wethers were found to be quite low (respectively 42% for in vitro DMD and 46% for in vivo DMD) (Zeeman et al., 1981). Earlier results reported higher values: 67 % OMD and 75 % protein digestibility although the crude protein content was of medium value with 79 g/kg DM (Henrici, 1945).


In South Africa, early trials fond that sheep consuming Pentzia incana had good growth but were too fat. This could be due to the unbalanced protein/energy ratio (too low protein content compared to the energy) which can be related to the digestibility results (Henrici, 1945). It has a negative effect on wool production due to its low protein content. However, though it makes fleece greasy, the low potassium content of the shrub results in less suint and in a better quality wool (Buttner, 1963).

It was suggested that the lipophilic volatiles content of African sheepbush could contribute to the meat flavor of the lamb due to bioaccumulation in the adipose tissue (Hulley et al., 2018). Because of its magnesium deficiency, it was recommended to supplement animals fed on Pentzia incana (Buttner, 1963).


As of 2021, no information seemed available in the international literature on the use of Pentzia incana in domestic rabbit feeding. However, African sheepbush was reported to be consumed in South Africa by the endangered Riverine rabbit (Brunolagus monticularis) when available, during the winter from May to December (Duthie, 1989). Riverine rabbits prefered consuming succulents such as African sheepbush instead of grasses more represented in the local flora. African sheepbush is considered as unpalatable to grazing sheep but highly preferred by Riverine rabbit (Duthie 1989). For the time being, the feeding behaviour of domestic rabbit in front of this plant remains completely unknown.

Horses and donkeys 

African sheepbush was reported to cause paralysis (bewerasie) in horses because of its deficiency in magnesium (Buttner, 1963).

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  
Crude protein % DM 10.5 2.4 6.6 13.9 15  
Crude fibre % DM 31.8   25.5 38 2  
Neutral detergent fibre % DM 65.2         *
Acid detergent fibre % DM 42.5       1  
Ether extract % DM 3.6   2.6 4.4 3  
Ash % DM 10   8.4 12.9 3  
Gross energy MJ/kg DM 18.3         *
In vitro digestibility and solubility Unit Avg SD Min Max Nb  
In vitro DM digestibility (pepsin) % 42       1  
Ruminants nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 49.9         *
Energy digestibility, ruminants % 47.7         *
DE ruminants MJ/kg DM 8.7         *
ME ruminants MJ/kg DM 7         *
Nitrogen digestibility, ruminants % 74.7   74.3 75 2  
Rabbit nutritive values Unit Avg SD Min Max Nb  
DE rabbit MJ/kg DM 6.8         *
Energy digestibility, rabbit % 37         *

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


Botha, 1938; Henrici, 1932; Henrici, 1945; Zeeman et al., 1981

Last updated on 26/08/2021 12:35:19

Datasheet citation 

Heuzé V., Tran G., Hassoun P., Lebas F., 2021. African sheepbush (Pentzia incana). Feedipedia, a programme by INRAE, CIRAD, AFZ and FAO. https://feedipedia.org/node/118 Last updated on August 26, 2021, 12:58