Feedipedia
Animal feed resources information system
Feedipedia
Feedipedia

Salsola (Salsola glabrescens)

Datasheet

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

Salsola, rivierganna, brakbos; brakbossi; brakganna, gewoneganna, grootganna, kortbeenganna, regterooiganna, rooibeenganna, rooilootrivierganna, Rroibeenrivierganna [Afrikaaner]

Synonyms 

Caroxylon glabrescens (Burtt Davy) Akhani & Roalson

Description 

Salsola glabrescens Burtt Davy is an indigenous shrub native of the Nama Karoo, a dry shrubland ecoregion located on the central plateau of South Africa and Namibia, where it is a valuable source of fodder relished by sheep and goats (Vorster, 1986; Hobson et al., 1975; Henrici, 1945).

Morphology

Salsola glabrescens is a variable shrub growing to 1-1.5 m in height and 1.5 m in diameter. It has scattered woody branches bearing leafy shoots and buds. Young shoots are hairless and red in colour (Le Roux et al., 1994). The shoots are very fine and glaucous (Ludlow, 1950).The leaves are alternate,oblong, often pointed in shape, bluish-green in colour, sessile, and densely packed on the shoots. The flowers are borne on scattered spikes, grouped in panicles on the shoots (Le Roux et al., 1994). The fruits are spherical and have a crown of translucent wings (Wilcock, 2009).

Uses

Salsola glabrescens is a palatable species readily browsed by sheep and goats when fresh (Henrici, 1945; Hobson et al., 1975; Vorster, 1986; Klopper, 2000).

Distribution 

Salsola glabrescens is indigenous to South Africa and is typical of the Nama Karoo, a dry ecosystem important for agriculture and more particularly for small ruminants (Klopper, 2000). It occurs in conspicuous stands in depressions, riparian rangelands and, in some cases, on plains, hence its vernacular name "Rivierganna" (Le Roux et al., 1994; Ludlow, 1950). Salsola glabrescens is a drought-tolerant species (Klopper, 2000; Vorster, 1986; Hobson et al., 1975) that is often the only green remaining species in times of drought (Le Roux et al., 1994 cited by Wilcock, 2009). Unlike other species in the Karoo region, Salsola is not considered to be endangered in the South Africa national assessment of the IUCN Red List (Foden et al., 2005).

Environmental impact 

Veld reclamation

Salsola glabrescens was listed among other native species as a candidate for rehabilitation in the arid rangeland situated in the transition area between Succulent Karoo and Nama Karoo, It was recommended to protect the plant from herbivores during fructification as the seeds do not remain viable after a passage through the digestive tract. It was suggested to make pure stands - that are less prone to overgrazing - from seeds to subsequently re-establish Salsola glabrescens in rangeland (Wilcock, 2009).

Saline wetlands

Salsola glabrescens is a typical species of the Eastern saltwort wetlands in South Africa: it grows on brakish pans and valley bottoms (Sieben et al., 2016).

Nutritional aspects
Nutritional attributes 

Even though Salsola glabrescens is a common browse in its native range, nutritional information about it remains scarce: what is known is mostly based on the work of South African plant physiologist Marguerite Henrici in the 1930-1950s. The protein content of Salsola glabrescens browse is moderate to high and variable, ranging from 12% to more than 25% DM (Henrici, 1932). It is high compared to that of other Karoo shrubs. While the non-protein nitrogen content may be high, the nitrate content of Salsola glabrescens is very low, between 0.08 and 0.11 % (Henrici, 1952). It seems to have a moderate amount of fibre (crude fibre 25% DM).

Salsola glabrescens has a high ash content (13% DM) (Henrici, 1945) and is one of the Karoo shrubs that accumulates most of sodium chloride or sulphates. Like other Salsola species (for instance Salsola soda, which used to be a source of sodium carbonate), Salsola glabrescens has a very high sulphate and sodium contents, especially on brak soil on which the ash content of such plants may be as high as 30-40% (Henrici, 1945; Henrici, 1952).

Potential constraints 

Salsola species are known to accumulate sodium sulphate, which may affect their palatability (Van der Heyden et al., 1999).

Ruminants 

A typical plant of the Karoo ecosystem, Salsola glabrescens is widely browsed by small ruminants. It has a good nutritional value but it cannot be fed alone and must be mixed with poor quality forages.

Palatability

Fresh Salsola glabrescens is known be palatable and readily eaten by sheep and goats, but only when fresh (du Toit et al., 1995; Le Roux et al., 1994; Davies et al., 1986; Hobson et al., 1975; Henrici, 1952; Henrici, 1945). It was not eaten by sheep and goats when the leaves were dried, so it is no use to conserve it in dry form (Henrici, 1952; Henrici, 1945). Fresh Salsola glabrescens was specially selected by rams during drought in Karoo (Davies et al., 1986), which is due to the fact that this very drought-tolerant species is often the only remaining green foliage during those periods (Le Roux et al., 1994; Hobson et al., 1975). Thoughout the year, sheep and goats grazed Salsola glabrescens in proportion to its availability in winter, spring and autumn and in a lower proportion in autumn (du Toit et al., 1995). Salsola glabrescens was less grazed when it occured in homogenous stands (Le Roux et al., 1994).

Digestibility and nutritive value

Salsola glabrescens foliage fed fresh to sheep during winter and early spring had an OM digestibility of 71%, which can be considered high in comparison to other Karoo shrubs (Henrici, 1945). When leaves of Salsola glabrescens are fed dried, the digestibility of fibre and protein became very low (Henrici, 1945, Henrici, 1952).

Salsola glabrescens should not be offered as the only pasture due to the risk of diarrhea (Botha, 1939 cited by Henrici, 1952). It must be treated as a concentrate and poor quality grass should be given to balance the diet (Henrici, 1945, Henrici, 1952). In Henrici's digestibility trials, sheep were fed two parts of fresh Themeda triandra for one part of Salsola glabrescens on a fresh basis (Henrici, 1945).

Sheep are fond of Salsola glabrescens, probably because of its high chloride (potassium and sodium) content, and they do not require need salt in their licks or supplemental feeding. However, the salty character of the shrub may be a constraint. If it is fed alone, sheep will not favour it too much as it is too salty. If it is fed in association with others shrubs it can be heavily grazed but the high level of calcium and magnesium and the unbalanced Ca/P ratio in Salsola decreases phosphorus availability and can be detrimental to sheep.

The high level of magnesium sulphate in Salsola glabrescens has laxative effect on sheep, and sheep sheep fed on small or large quantitities of Salsola glabrescens can only maintain their bodyweight but not fatten. However, these laxative properties have been reported to keep worms down (Buttner, 2012).

Meat quality

Sheep fed in the Karoo were known for the high fat content of their meat, and Salsola glabrescens was known to have positive effect on body weight gain. Henrici attributed this to the relatively higher fat content of Karoo shrubs, which was also, in the case of Salsola glabrescens, highly digestible (Henrici, 1952). More recent observations have shown that Salsola glabrescens could contribute, with other Karoo Salsola species, to the specific sensory profile of Karoo lambs, likely because of the high content in secondary metabolites, such as mono- and sesquiterpenes (Erasmus et al., 2016). Descriptors related to this plant in sensory panels were : dusty, dandy, soapy, woody, damp/musty Cayenne pepper, sheep wool, tobacco, Ceylon tea (Erasmus et al., 2016).

Rabbits 

As of August 2019, no information seems available in the international literature on the use of Salsola glabrescens for rabbit feeding. However, field observations made in South Africa identified this species as one of the plants grazed by the riverine rabbit (Bunolagus monticularis)(Hughes et al., 2008).

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 39.4          
Crude protein % DM 18 4.1 12.4 25.5 17  
Crude fibre % DM 25.2       1  
Neutral detergent fibre % DM 37.5         *
Acid detergent fibre % DM 25.1         *
Lignin % DM 7.2          
Ether extract % DM 2.1       1  
Ash % DM 13.3       1  
Gross energy MJ/kg DM 17.6         *
               
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 19.5       1  
Phosphorus g/kg DM 1.5       1  
Selenium mg/kg DM 0.01 0.01 0 0.02 5  
               
Ruminants nutritive values Unit Avg SD Min Max Nb  
OM digestibility, ruminants % 70.5       1  
Energy digestibility, ruminants % 67.4         *
DE ruminants MJ/kg DM 11.9         *
ME ruminants MJ/kg DM 9.4         *
Nitrogen digestibility, ruminants % 69.8       1  
               
Rabbit nutritive values Unit Avg SD Min Max Nb  
DE rabbit MJ/kg DM 8.9         *
MEn rabbit MJ/kg DM 8.2         *
Energy digestibility, rabbit % 50.5         *

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

References

Brown et al., 1967; Henrici, 1932; Henrici, 1945

Last updated on 08/11/2019 12:34:57

References
References 
Datasheet citation 

Heuzé V., Tran G., Boudon A., Lebas F., 2019. Salsola (Salsola glabrescens). Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. https://www.feedipedia.org/node/99 Last updated on November 8, 2019, 17:52

Image credits