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Olive forage


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Common names 

Olive, olive tree [English]; olivera, olivo, aceituno [Spanish]; olivier [French]; oliveira [Portuguese]; olyf, olyfboom [Afrikaans]; olijfboom [Dutch]; Olivenbaum, Echter Ölbaum [German]; zaitun [Indonesian, Javanese, Malay]; olivo, ulivo [Italian]; oliwka europejska [Polish]; puno ng olibo, oliba [Tagalog]; zeytin [Turkish]; maslina [Croatian]; Маслина [Serbian]; ô liu [Vietnamese]; الزيتون [Arabic]; ελιά, ελαιόδενδρο, λιόδεντρο [Greek]; 올리브, 올리브나무 [Korean]; ज़ैतून,  ज़ैतून के वृक्ष [Hindi]; זית אירופי [Hebrew]; オリーブの樹 [Japanese]; ഒലിവ്, ഒലിവ് മരം [Malayalam]; ऑलिव्ह [Marathi]; ਜੈਤੂਨ ਦਾ ਰੁੱਖ [Punjabi]; Оли́ва европе́йская, Оли́вковое де́рево [Russian]; சைத்தூன் [Tamil]; มะกอกออลิฟ [Thai]; زیتون [Persian, Urdu]; 橄欖 [Chinese]

Products: olive tree forage, olive tree leaves, olive leaves, olive branches, olive browse


Olea africana Mill., Olea chrysophylla Lam., Olea cuspidata Wall. ex G. Don, Olea europaea subsp. africana (Mill.) P. S. Green, Olea europaea var. cerasiformis Webb & Berthel., nom. illeg., Olea europaea var. maderensis Lowe, Olea ferruginea Royle, Olea laperrinei Batt. & Trab., Olea maroccana Greuter & Burdet, Olea sativa var. verrucosa (Willd.) Roem. & Schult., Olea verrucosa (Willd.) (USDA, 2010)


The olive tree (Olea europaea L.) is a slow growing evergreen tree that reaches a height of 5-10 m. It is an emblematic tree of the Mediterranean basin. It has a rather shallow root system. The trunk is erect, deeply fissured and distorted. The leaves are simple, lanceolate, 3-9 cm × 0.5-3 cm, leathery, dark grey-green and glabrous on the upper side, and densely covered with silvery scales underneath. They are covered by a cuticle that prevents dehydration. The tree shed its leaves once every three years. The inflorescences are 3-8 cm long, many-flowered, borne on the leaf axils. Only 1-5% of the flowers develop into fruits. The fruit is a drupe containing a fleshy mesocarp (pulp) and a woody endocarp (stone or pit). The pulp contains some 20% oil and is highly bitter due to its high tannin content. The tree starts producing fruits between 4 and 7 years after propagation, through cuttings or suckers. It remains productive for up to 50 years and its life-span may reach 500 years (Ecocrop, 2010; Ecoport, 2010; van der Vossen et al., 2007).

Olive trees are mostly cultivated for their edible fruits from which olive oil can be extracted. There are about 2000 cultivars that can be divided into 3 groups: cultivars for oil extraction, cultivars for table olive production and dual-purpose cultivars (Ecocrop, 2010; Ecoport, 2010; van der Vossen et al., 2007). Olive fruits can also be eaten after soaking. Fruits yields vary from 1 to 10 t/ha depending on cultivation conditions (traditional olive groves or irrigated well-managed commercial plantings). However, there is always considerable year-to-year variation in productivity. One hectare produces 350-400 kg olive oil. Olive oil has recently received renewed interest because of its potential health benefits, as it contains unsaturated fatty acids and small amounts of polyphenols, tocopherols and sterols (Ecocrop, 2010).

In 2009, the world production of olive oil was almost twice (2.91 million tons) that of 1995 (1.65 million tons). The Mediterranean countries account for 98% of total olive oil production. Spain, Italy and Greece are the main producers: 75% of the total production (FAO, 2010). Spain, the USA and Greece are the top producers of olive fruit. World table olive production is 1.1 million tons and represents 8% of total olive fruit production. Main table olive producers are Spain, the USA, Turkey, Morocco, Syria, Greece and Italy (van der Vossen et al., 2007).

Olive by-products are commonly fed to livestock. For further information about by-products of olive oil processing, see the datasheet Olive oil cake and by-products. Olive forage is relished by cattle, sheep, goats and camels (Le Houérou, 1980). It can be browsed by livestock or cut and brought fresh to livestock after pruning.


Olive is a native and characteristic fruit tree of the Mediterranean Basin. The wild Mediterranean olive (Olea europaea europaea var. sylvestris (Mill.) Lehr) was domesticated in about 4000 BC in the Eastern Mediterranean and Middle East. The cultivated form, Olea europaea europaea var. europaea, was spread by the Phoenicians and the Greeks throughout the Mediterranean Basin and eastwards to North-Western India and the Caucasus (van der Vossen et al., 2007). The Spanish introduced olive cultivation to the New World (Peru, Chile, Argentina, Mexico and the United States (California)) in the 16-18th centuries. In the 19th century, it was introduced in China, Japan, Australia and South Africa. However, about 97% of the world’s 850 million olive trees are still grown in the Mediterranean region.

The olive tree is typical of relatively dry Mediterranean climates. It is found between 30° and 45° in both hemispheres and from sea-level to an altitude of 900 m (1200 m in Argentina). Olive trees are winter-hardy and tolerate temperatures between -8°C and -12°C. Optimal growth conditions are average day-temperatures ranging from 18°C to 22°C, a 6 to 9 week period of vernalization below 9°C, and an annual rainfall down to 300 mm on light well-drained soils. Olive trees can survive drier conditions but for commercial purposes irrigation is advisable during dry periods so that the total amount of water reaches 500-800 mm/year. Olive trees do well on poor soils provided they are not waterlogged, saline or too alkaline (pH higher than 8.5) (van der Vossen et al., 2007; Duke, 1983).

In tropical Africa a small production of table olives is developing in Namibia. The wild African olive (Olea europaea cuspidata (Will. ex G.Don) Cif.) grows in Central, East and Southern Africa and the Indian Ocean Islands, in mountain woodland, rainforest and wooded grassland at elevations between 1000 and 3150 m. It is also found in Arabia and from South-Western Asia to China (van der Vossen et al., 2007).

Forage management 

Direct browsing

Browsing of olive forage is used in integrated systems combining livestock and olive oil production. The trees are browsed after olive harvest, and only during winter and spring. Ruminants (mainly sheep) are allowed to enter the olive tree fields and browse freely.

In traditional "Iberico" pig production, pigs enter the olive fields but only graze the understorey grass and eat the fallen fruits without browsing olive forage (Gomez Cabrera, 2010, personal communication).

Cut-and-carry systems

Pruning is of utmost importance in olive tree management as it maintains the balance between tree growth and fruit production. The products of pruning are mainly woody stems and suckers that are used for fuel or charcoal. The stems bearing leaves (50% of the total biomass; Parellada Vilella et al., 1984) can be hand-cut, dried and winnowed. In the 1980s, mechanical chopping experiments were done without positive effects (Parellada Vilella et al., 1984). Later, various baling systems have been developed. Chopped olive forage may be packed with high pressure balers, either alone or mixed with cereal straw or hay (Delgado Pertiñez et al., 1994).

Olive foliage may also be ensiled provided the conditions are anaerobic (Gomez Cabrera, 2010, personal communication).

Nutritional aspects
Nutritional attributes 

The chemical composition and nutritive value of olive leaves depend on their process of obtention (cleaning or pruning) and on the amount of woody material they contain. Olive leaves are characterised by a high level of fibre (NDF of 40-60% DM) and lignin (15-28% DM). This large range is caused by the variable amounts of twigs and branches present in the leaf material. Crude protein content is rather low (about 9.5% DM). High values (over 16% DM) could be associated to the use of foliar fertilizers, which could also affect nitrate content (Delgado Pertíñez et al., 2000). Between 30% and 56% of the protein is bound to ADF (Delgado Pertíñez et al., 2000; Garrido Varo et al., 1989). Along with the high content of polyphenols, this could explain the low digestibility of the protein (Molina Alcaide et al., 2008). Leaves resulting from the cleaning process contain higher amounts of ash due to soil contamination, and a higher oil content due to the contact with the fruits.

The moisture level of green leaves starts at about 45-50% and decreases rapidly when the leaves are left to dry and are protected from the rain. The main limitation to the use of olive leaves is that they need to be carried off the olive fields in order to avoid damaging the fruits. Transportation systems should be designed so that they minimize water loss and conserve their nutritional value.

Potential constraints 

The use of copper-rich fungicides to treat diseases such as the peacock spot (Cycloconium oleaginum or Spilocea oleaginea) can result in amounts of copper that can be toxic to sheep.

In dairy cattle, olive woody material in the forage was reported to cause a very low DM intake (25 g/kgW0.75) and serious digestive problems due to the accumulation of splinters in the omasum (Parellada Vilella et al., 1982).


Olive leaves and twigs are a suitable forage for ruminants as a bulky feed in maintenance and low-production systems. They are rich in long fibre and require nitrogen and phosphorus supplementation. Leaves treated with copper-based fungicides should not be given to sheep.

Cattle or sheep accept 1-1.5 kg/d of green leaves and 0.8-1 kg/d of dried leaves per 100 kg of live weight. Olive leaves should be fed green whenever possible (Göhl, 1982). Their nutritive value decreases with drying: reported OM digestibility of fresh leaves (in sheep) is about 55-60% while OMD of leaves dried on the branches or baled is about 40-50%. The OMD of leaves from chopped branches is in the 15-40% range, even when protected from rain (Delgado Pertíñez et al., 2000). Alkaline treatments (NaOH and NH3) have not been shown to improve significantly the nutritive value of olive leaves (Parellada Vilella et al., 1984).

The low protein digestibility, particularly in the dried leaves, requires nitrogen supplementation with protein or non-protein sources, which results in higher feed intake (Parellada Vilella et al., 1984).


Old dry leaves are palatable to cattle if they are soaked overnight in 2.5 times the volume of water containing 0.2% salt (Göhl, 1982). In dairy cattle, ensiling and partial drying decreased bitterness and improved palatability, but total dehydration resulted in a decrease of palatability (Nigh, 1977).

In dairy cattle, wood splinters were reported to cause low DM intake and serious digestive problems (Parellada Vilella et al., 1982).

Sheep and goats

Significative differences in the digestibility of mixtures of olive leaves and twigs have been observed between sheep and goats, and between different breeds of sheep (Merina and Manchega), as certain animals are better at selecting the less woody parts (Gómez Cabrera et al., 1982).

In sheep, the dry matter and organic matter digestibility of dried olive leaves can be predicted from fibre content using the following equations (Delgado Pertíñez et al., 2000):

  • DM digestibility (%) = 98.21 - 1.31 NDF (% DM) (r = - 0.92; RSD = 3.97)
  • OM digestibility (%) = 105.65 - 1.39 NDF (% DM) (r = - 0.91; RSD = 4.32)
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 89.8 5.9 75.0 94.3 9  
Crude protein % DM 7.8 2.3 4.1 11.0 11  
Crude fibre % DM 25.1 7.1 19.2 43.4 10  
NDF % DM 52.5 11.3 41.9 79.3 10  
ADF % DM 38.7 7.2 31.7 53.6 10  
Lignin % DM 17.9 6.6 10.5 26.2 4  
Ether extract % DM 4.6 3.4 1.5 8.2 3  
Ash % DM 7.2 1.7 3.9 8.7 9  
Gross energy MJ/kg DM 18.5         *
Minerals Unit Avg SD Min Max Nb  
Calcium g/kg DM 24.0       1  
Phosphorus g/kg DM 1.1       1  
Secondary metabolites Unit Avg SD Min Max Nb  
Tannins, condensed (eq. catechin) g/kg DM 7.0       1  
Ruminant nutritive values Unit Avg SD Min Max Nb  
OM digestibility, Ruminant % 32.7 6.7 32.0 51.6 6 *
Energy digestibility, ruminants % 29.7         *
DE ruminants MJ/kg DM 5.5         *
ME ruminants MJ/kg DM 4.5         *
Nitrogen digestibility, ruminants % 22.2 8.1 13.5 29.4 3  
Rabbit nutritive values Unit Avg SD Min Max Nb  
Energy digestibility, rabbit % 37.5         *
DE rabbit MJ/kg DM 6.9   6.2 7.7 2  
MEn rabbit MJ/kg DM 6.9         *
Nitrogen digestibility, rabbit % 10.0       1  

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


AFZ, 2011; Alibes et al., 1990; Fernandez Carmona et al., 1996; Garcia et al., 1996; Gomez Cabrera, 2009; Maymone et al., 1947

Last updated on 31/10/2012 10:36:53

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 50.1 12.2 33.4 68.5 6
Crude protein % DM 9.8 1.6 7.7 13.1 9
Crude fibre % DM 17.9 3.9 14.0 24.5 5
NDF % DM 46.1 5.5 41.3 54.9 7
ADF % DM 34.1 5.6 28.1 44.1 7
Lignin % DM 20.1 4.0 16.2 25.0 5
Ether extract % DM 6.3 1.1 4.7 7.3 5
Ash % DM 9.0 3.1 6.1 15.8 8
Gross energy MJ/kg DM 18.3 *
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 21.5 7.4 11.8 29.7 4
Phosphorus g/kg DM 0.9 0.1 0.8 0.9 4
Secondary metabolites Unit Avg SD Min Max Nb
Tannins, condensed (eq. catechin) g/kg DM 15.0 1
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 56.9 52.6 61.1 2
Energy digestibility, ruminants % 53.7 *
DE ruminants MJ/kg DM 9.8 *
ME ruminants MJ/kg DM 8.1 *
Nitrogen digestibility, ruminants % 44.3 44.3 44.3 2
a (N) % 10.1 10.0 10.2 2
b (N) % 75.2 72.7 77.6 2
c (N) h-1 0.145 0.120 0.170 2
Nitrogen degradability (effective, k=4%) % 69 *
Nitrogen degradability (effective, k=6%) % 63 62 64 2 *

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


Alibes et al., 1990; CIRAD, 1991; Gomez Cabrera, 2009; Maymone et al., 1947

Last updated on 24/10/2012 00:44:43

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 77.1 77.0 77.1 2
Crude protein % DM 12.2 12.2 12.2 2
Crude fibre % DM 20.2 20.2 20.2 2
Ether extract % DM 7.9 1
Ash % DM 8.4 8.4 8.4 2
Gross energy MJ/kg DM 19.2 *
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 47.5 47.4 47.6 2
ME ruminants (FAO, 1982) MJ/kg DM 7.2 1
Nitrogen digestibility, ruminants % 16.8 16.8 16.8 2

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


Alibes et al., 1990; Maymone et al., 1947

Last updated on 24/10/2012 00:44:43

Datasheet citation 

Heuzé V., Tran G., Gomez Cabrera A., 2015. Olive forage. Feedipedia, a programme by INRA, CIRAD, AFZ and FAO. http://www.feedipedia.org/node/121 Last updated on May 11, 2015, 14:32

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