Grain legumes for animal feed
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Botany and ecology
Prospects for improvement
Among the grain legumes from the Old World, we may single out two species of the genus Lathyrus (L. sativus L. and L. cicera L.), one species of the genus Trigonella (T. foenum-graecum L.) and three species of the genus Vicia (V. ervilia (L). Willd., V. monanthos (L). Desf. and V. narbonensis L.) on account of their current state of marginalization. In Spanish, L. sativus is called by the popular names almorta, gija, muela and tito and in Latin America by the names alverja and chícharo (in Portuguese it is known as chicharo, in English as chickling vetch and in India as khesari). L. cicera is known as titarro, almorta de monte, chícharo, galgana and cicércula. T. foenum-graecum is known as alhlova and also heno griego or fenogreco (in English, fenugreek). V. ervilia corresponds to the yeros, also known as alcarceña, alverja, alcarraceña, ervilla, lenteja bastarda, etc. (in Portuguese, ervilha de pombo and gero, and in English bitter vetch). V. monanthos is the name of algarroba, garroba and lenteja de Aragón (in English, one flowered or one-leaved vetch, and in Portuguese ervilhaca parda). Finally, V. narbonensis is known as alverjón and haba loca (in Portuguese ervilhaca de Narbona, and in English Narbonne vetch).
This species, along with the garden pea (Pisum sativum L.), broad bean (Vicia faba L.) and chickpea (Cicer arietinum) were the first cultivated legumes, according to archaeological findings of the neolithic period, Bronze Age and Iron Age in Europe, the Near East and the Nile Valley.
Their location has demonstrated the spread of these species from their centre of domestication. Because of their larger size, the seeds that have been found are considered to be cultivated rather than wild forms.
Columela, in Dere rustica (first century), mentions Trigonella foenum-graecum (fenugreek), Vicia ervilia (bitter vetch) and Lathyrus cicera (vetchling or flat pod pea), referring to their use, soil requirements, tillage and sowing dates. He refers specifically to L. cicera as it is cultivated in what is today Andalusia for feeding oxen as a replacement for V. ervilia - in the form of milled grains, moistened with water and mixed with straw - also stating that it is not an unpleasant food for humans. Libro de agricultura by Abu Zacaría (twelfth century) also mentions T. foenum-graecum and V. ervilia referring to their soil requirements, methods and dates of sowing, fertilization and types of use in animal feeding as well as describing their use as a human medicine and other uses. In Agricultura general by Alonso de Herrera (1513), V. ervilia and L. sativus are also mentioned, with different cultivation techniques and methods of use for feeding livestock and treating ailments recommended. L. sativus is used in the human diet in a similar way to chickpeas and is mixed with other grains to make bread.
Table 10 sets out the origin and distribution of the wild or cultivated form of the various species. Because of their marginal character, there are no data on a worldwide basis relating to the cultivated area of this group of legumes. Chickling vetch (L. sativus) is widely grown in India, with an area of 1.6 million ha referred to by Duke (1981). Vetchling (L. cicera) is currently grown only in Spain, although it was formerly grown throughout southwestern Europe. Fenugreek (T. foenum-graecum) is cultivated in the Mediterranean region, the Near East, Ethiopia, India and southern California. In North Africa, it has been grown for fodder around the Saharan oases from very early times. Bitter vetch (V. ervilia) is grown in Asiatic Turkey, central and northern Spain and other countries of the Mediterranean region and western United States; the seed is exported to the United Kingdom and other countries for feed, especially for sheep. There are barely any references to one-leaved vetch (V. monanthos) or Narbonne vetch (V. narbonensis), in spite of the fact that both species, particularly the former, were widely cultivated in the Mediterranean in past times. Figure 34 shows the regressive pattern of cultivation of these legumes in Spain; some of them are practically on the verge of extinction.
Composition and use
Table 11 sets out the seed composition of the species studied. Protein content ranges between 20 and 30 percent and the fat content is generally very low except in the case of fenugreek (T. foenum-graecum). As in the other legumes, lysine is the most favourable amino acid and methionine is the most limiting. Several antinutritional properties are also present in the grain (Table 12). Chickling vetch and vetchling (L. sativus and L. cicera) contain a neurotoxic amino acid called ODAP (b-N-oxalyl-a-b-diaminopropionic acid) which causes neurolathyrism in humans and animals. This disease causes paralysis of the lower joints through neurological lesions brought about by degeneration of the spinal cord, particularly in equine stock, if the seed is eaten continually for months as the main component of the diet. In extreme cases it even causes death. Occasional consumption is not harmful and does not appear to affect sheep, so stockfarmers use these legumes for gestating females, fattening lambs and serving males. Macerating or soaking the seed in water, followed by cooking and treatment at high temperatures, seems to inactivate the lathyrogenic component, preventing its toxicity. Chickling vetch (L. sativus), which has a white flower and seeds, has a lower ODAP content. In some localities of northern Spain, selected white chickling vetch is traditionally eaten because of its lower content of lathyrogenic substances. There is a negative correlation between the total protein content of the Lathyrus and its ODAP content, which is of interest for improving varieties. The ODAP content of chickling vetch grown in Spain is lower than that of Asiatic chickling vetch. It has also been shown that the ODAP content of L. cicera is lower than that of L. sativus (0.146 and 0.205 percent, respectively).
Fenugreek (T. foenum-graecum) has a high content of gums and mucilages (around 28 percent) which makes its direct use in the diet of monogastric species difficult. It contains other substances which give the plant an unpleasant smell, which permeates all its surroundings and is conveyed to the meat and milk of animals that eat it.
The antinutritional factors of the species of the genus Vicia, in addition to affecting the nutritional value of the grain, can cause pathological changes of varying extent in animals that consume them, especially birds.
Figure 32 Grain legumes: A) one-leaved vetch (Vicia monanthos); A1) calyx A2) flower; A3) legume c) Narbonne vetch (V. narbonensis); C1) flower; C2) legume
The seed is the part mainly used in this group of legumes, although they are also grown as green fodder or hay and play an important role as a green manure, which is dug in at the end of the winter to improve soil fertility. The straw of these legumes is of high nutritional value for livestock.
Among the entire group, it is chickling vetch (L. sativus) which is most used for human consumption, in the form of green vegetables; the dry seed especially is soaked in water and boiled or else husked and made into flour for mixing with cereals and making bread or porridges. The latter method of preparation is usual in India (for dhal), and it was a popular recipe during times of scarcity and famine in the Spanish regions of Castilla-La Mancha and Extremadura, where many serious cases of neurolathyrism occurred as a result of it being consumed in the wrong way in the 1940s. The current Spanish Food Code prohibits human consumption of chickling vetch seed and the products obtained from its preparation. Mixtures with oilseed cake are used for sheep although, in Spain, its use in animal nutrition is not very widespread because of the fear of lathyrism.
Vetchling (L. cicera) is used as both a fodder plant and grain producer. The name comuña is given to the mixture of cereal grains, legume grains or both (as well as to their combined cultivation) which provides a complete food for livestock. Its etymological origin is from "común" in its meaning of mixture, referring to the mix of seeds obtained when cleaning the grain and which contaminate the main grain, generally wheat. The combination, which was of very variable content, was first formed from spontaneous plants which the farmer improved by introducing other species with a higher yield or quality. In the Spanish region of Tierra de Campos, vetchling began to dominate in comuña as a consequence of mechanical selection, since its grain was bigger than that of the vetches and tares, the two names used nowadays without distinction. There is therefore an ancestral knowledge of the use of comuña and its lathyrogenic side-effects. The use of L. cicera for sheep does not pose any lathyrism problems if doses do not exceed 50 percent of the ration in concentrates.
Fenugreek (T. foenum-graecum) is primarily grown for the production of its seed. Its strong smell somewhat discourages livestock from eating it. It must be used in low doses, since it imparts an unpleasant flavour to meat and milk and also causes animals to put on weight, which is not suitable for draught animals. Livestock dealers sometimes use it to tone animals up and give them a transient good appearance. It is also grown as a condiment, an essential oil being extracted for flavouring different foods and drinks, such as cheeses, sweetmeats, pickles and liqueurs. It is also used in the pharmaceutical and cosmetics industry because of the vast range of chemical products that it contains. The plant also has insecticidal properties and is used in stored grains as a repellent. Popular medicine attributes tonic and vermifugal properties to its seeds, the mucilaginous components being used to treat stomach ailments. In Hindu medicine, the seed extract is used because of its cardiotonic, diuretic, antiphlogistic, hypoglucemic and antihypertensive properties. It has active ingredients which act on the metabolism of fats and cause weight loss in women. In India, consumption of the seed is believed to stimulate lactation.
The species of the genus Vicia are traditionally used for feeding ruminants, particularly sheep, but they are practically unused for monogastric species in view of the seed's toxicity and its negative effect on growth. Bitter vetch (V. ervilia) must not exceed 25 percent of the ration in sheep and cattle feed. One-leaved vetch (V. monanthos) is more readily eaten by sheep, but refused by other types of livestock because of its slightly bitter taste. Birds, with the exception of pigeons, do not take to it. The seed of V. narbonensis can be used as feed for cattle which accept it more readily than pigs and sheep, provided it is fed to them in ground form. Like common vetch (V. saliva), it has a slightly bitter taste which animals grow accustomed to, but which can be passed on into milk.
Figure 33 Grain legumes: A) chickling (Lathyrus sativus); A1) flower; A2) legume; B) vetchling (Lathyrus cicera); B1) legume; C) fenugreek (Trigonella foenum-graecum); C1) flower; C2) legume
Botany and ecology
Table 13 describes the main botanical characteristics of the various leguminous species studied. Because of their origin, distribution and cultivation, they are suited to Mediterranean ecological conditions. Their cycle takes place in the autumn to spring period and they are resistant to cold and frosts as well as drought, especially in the final phase of cultivation. They are suited to poor soils and frequently to marginal ones (Table 10).
There is very little information on the genetic diversity, infraspecific variability and relations of these species with other related wild species. Few cultivars are known or well defined. Only limited areas of cultivation remain in some areas of the world and, in many of them, the individuals are threatened. The material available in gene banks is scarce. Consequently, there is the risk that important plant material obtained over thousands of years of cultivation might disappear, while only a few isolated works on classification and selection are to be found.
In the species Lathyrus sativus, there are a great number of varieties and types which differ in flower colour, form of growth and colour and shape of the seeds. Two varieties can be distinguished: lesser white chickling vetch and greater white chickling vetch. The first is possibly the original form of the species. Greater white chickling vetch is perhaps a selection of the former, featuring bigger seeds, a lighter colour and a more flattened shape. In India, 56 types have been identified. As in almost all this species group, the types sown are heterogeneous populations of botanical varieties. The centres of diversity are central Asia and the Mediterranean.
L. cicera is considered to be a semi-domesticated plant, with local varieties and spontaneous plants existing in Spanish cultivation regions, especially in the centre and north. There are local, primitive indigenous varieties in Castilla-León made up of very heterogeneous and widely varying material suited to adverse conditions. This material has traditionally been cultivated in combination with other plants (comuña) and its domestication has been rare, in spite of the fact that the plant has been grown for thousands of years. The main changes introduced in these varieties are: a more erect and compact habit of the plant, lesser dehiscence of pods and greater seed size. The wild populations of L. cicera, which are abundant in Spain, have characteristics very close to those of the cultivated plants. Domestication of L. cicera occurred in southern France and Spain when cultivation of chickling vetch (L. sativus) spread to those countries from its area of origin and domestication, which it subsequently replaced. Descriptors have been proposed for L. cicera and three botanical varieties are recognized: pedunculatus, foliolatus and palentinus.
Improvement programmes have been designed for fenugreek (T. foenum-graecum) to increase the yield of diosgenin, a steroid which is present in the seed and which is used in medicine, as well as to study the behaviour of a spontaneous mutant with earlier flowering and bigger sized seed. Twenty-nine different ecotypes have been recognized. The centre of diversity of fenugreek is situated in the western Mediterranean and the Near East.
Figure 34 Changes in the cultivated area of legume species for animal feed in Spain
The cultivated types and varieties of bitter vetch (V. ervilia) are very heterogeneous populations which frequently appear mixed with other cultivated or spontaneous species of Vicia. In Spain, the variety most used is common red bitter vetch but, in recent years, four selected varieties have been recorded. Comparative tests between these varieties and local controls, carried out in central Spain, have demonstrated the higher yield of the selected material. The centre of diversity of the bitter vetches is situated in the western Mediterranean and in the Near East.
Also in the case of one-leaved vetch (V. monanthos), the cultivated varieties are botaniy very heterogeneous populations from which selections, lines and ecotypes adaptable to different environments could be obtained. In Spain, two types of one-leaved vetch can be distinguished: the white seed type and the black seed type, depending on the different shades of the background colours of the seed, the black type being grown in a greater proportion and the white type more rarely. The western Mediterranean, the Near East and the Euro-Siberian regions are quoted as centres of diversity.
Vicia narbonensis is considered to be a species very close to Vicia faba. It was once even thought that this was the original from of broad bean, although cytogenetic studies showed that this theory was without foundation. It is thought that the var serratifolia is the origin of the current forms of V. narbonensis. Since ancient times, attempts have been made to cross V. faba and V. narbonensis to obtain an interspecific hybrid that combines the valuable characteristics of both species. In recent years, these crossings have been possible through genetic manipulation and through the embryo recovery technique, enabling valuable material to be obtained when using the appropriate genotypes as parents. Compared with V. faba, V. narbonensis has a high level of resistance to aphids (Aphis fabae), with intraspecific variations for resistance, hence it shows good agronomic potential. It also seems to have greater resistance to broomrape (Orobanche spp.), which is why farmers have grown it in the past.
Figure 35 Changes in the grain yield of legume species for animal feed in Spain
Table 14 sets out the existing collections of germplasm of the legume species studied, according to the country and institution which keeps them. Probably the most complete collection is to be found in Spain. According to the most recent data, there are 49 lines of L. sativus from Spain and Portugal; 92 lines of L. cicera from Spain; 177 lines of V. ervilia from Spain and Portugal; 76 lines of V. monanthos from Spain; and ten lines of V. narbonensis.
TABLE 10 Origin, distribution of cultivation and ecology of grain legumes
|Lathyrus sativus L. (2n= 14)||Mediterranean, central Asia||Central, southern and eastern Europe, India, Iran, South America||Suited to dry climates, although tolerates an excess of rain. Annual precipitation: 320-1360 mm. Annual mean temperature: 13°C||Suited to poor soils, it tolerates heavy, clayey soils. Sensitive to acid soils|
|Lathyrus cicera L. (2n= 14)||Mediterranean, western Asia||Southern and eastern Europe, Near East, North Africa||Tolerates cold and frosts in the Mediterranean region, with autumn sowing; resistant to drought in the spring||Suited to poor soils, not too damp or saturated. Prefers heavy, well-limed soils with alkaline pH|
|Trigonella foenum- graecum L. (2n=16)||Mediterranean, Near East||Southern Europe, North Africa, Near East, India,Ethiopia, United States||Suited to regions with moderate or light precipitation. Development favourable during the cool, temperate growth season. In a Mediterranean climate, with mild winters, it is sown in winter and ripens in spring. Annual precipitation: 380-1 530 mm. Annual mean temperature: 16°C||Grows well on drained, deep, loamy soils and on gravel and sandy soils. Ill-suited to clayey, acid soils. It is damaged by excessive soil dampness|
|Vicia ervilia (L.) Willd. (2n=14)||Mediterranean, Near East||Mediterranean, Turkey, United States||Very resistant to cold during the growing period because of its sparse habit and branching and slow growth. Very resistant to drought, even in spring. A harvest is obtained even during excessively dry years. In favourable conditions, high yields are obtained. Annual precipitation: 360 1160 mm. Annual mean temperature: 14°C||Suited to neutral or lightly acid soils. Tolerates limy types of soil, provided they are not too clayey|
|Vicia monanthos (L.) Desf. (2n=14)||Mediterranean||Mediterranean||Very resistant to low temperatures during vegetative development and to prolonged drought. Suitable crop for regions with late, dry autumns. Sensitive to drought during the flowering period, which reduces the yield drastically Annual precipitation: 350- 1 230 mm. Annual mean temperature: 11°C||Suited to a wide range of soils provided they are not too damp. Prefers soils that are not very clayey, that are deep and contain little lime. This is one of the legumes which requires the least soil fertility|
|Vicia narbonensis L. (2n=14)||Mediterranean||Central Europe Mediterranean, Near East, Ethiopia, central Asia, India||Temperature requirement greater than the broad bean (Vicia faba) and lesser humidity requirements. Replaces this species advantageously in warm dry areas. It does not tolerate cold, and is damaged by frost||The most suitable soils are loose and sandy, deep and with a good lime content. Tolerates clayey soils that are not too damp|
Sources: Duke. 1981; Mateo Box, 1960; Pascual, 1978: Villax, 1963.
TABLE 11 Composition of gratin legume seeds
|(Percentage of weight)|
|Lathyrus cicera L.||25- 27||-||-||1-1.3||56||6||3|
|Trigonella foenum-graecum L.||23- 30||1.48- 2.3||0.35||6- 8||55||8-10||3.6 -4.3|
|Vicia ervilia(L.) Willd.||17-21||1.53-2.02||0.37||1.3-2||61-64||4-6||2.4-3|
|Vicia monanthos (L.) Desf.||22||1.29||0.25||1.6||60||4.8||3.3|
|Vicia narbonensis L.||23-25||1.44-1.76||0.11-0.18||1-1.5||53||7.5-10||2.7-2.9|
Sources: Duke, 1981; Franco Jubete, 1989; Gómez Cabrera, 1983; Mateo Box, 1960; Villax. 1963.
The cultivation techniques of these legumes are very rudimentary, given their marginal character, the small yields obtained and the little benefit which they bring the grower. Soil preparation is reduced and no type of fertilization is applied, as sowing is carried out in autumn or at the beginning of winter. Nor is any type of herbicide applied. Harvesting is sometimes done manually and threshing is carried out on the threshing floor, although it is frequently done with a motorized reaper, followed by threshing and cleaning and, less often, with a combine harvester.
Table 15 sets out the traditional cultivation techniques for each species. Some tests on new cultivation techniques have been carried out in Spain recently. For L. cicera in addition to a better selection of seed, it has been proposed that 125 kg of seed per hectare be used and herbicides applied (propyzamide + diuron or trifluralin + linuron), while harvesting should be done by reaping and leaving the crop in rows to ripen, or else using a modified cereal harvester. For bitter vetch (V. ervilia) which, among these species, has the biggest cultivated area in Spain and of which selected varieties exist, the use of herbicides (alachlore + linuron, metholachlore + promethrin, cynazine or metazole) is recommended, as is harvesting with a cereal harvester during the first hours of the morning and harvesting only in one direction to avoid the problem of grain loss.
Table 16 shows the grain yields of each species in different regions and countries, both in normal cultivation conditions and in trials.
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