Proceedings of the Second NAHWOA Workshop
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The Dehesa: an extensive livestock system in the Iberian Peninsula
R. García Trujillo1 and C. Mata2
1Institute of Sociology and Peasant Studies
2 Faculty of Veterinary Medicine, University of Cordoba, Spain
Extensive livestock production in Spain consists of a group of agroforestry and pasture systems that have been managed and refined throughout centuries of continuous practice. These systems have a great complementary relationship between their components, with high efficiency in the use of natural resources, a great ecological sense in the management of resources and an important interaction with different natural ecosystems. These extensive livestock systems have been decisive in the creation and maintenance of a rich biodiversity of wild and domesticated fauna and flora in the Peninsula.
Under the current conditions of generalized environmental deterioration, aggravated in the last years by the intense managing practices applied in agriculture and livestock production, the characteristics shown by the Spanish extensive and traditional livestock systems emphasise the importance that these systems have in the development of sustainable livestock production. Furthermore, these systems offer us important ecological logic, practices and principles to be applied on the systems management design, making it possible in the short, medium or long term to apply them also in the rescue of many deteriorated zones with high levels of biological, economic and social instability.
This paper also evaluates the productive potentials of these systems at present. It is interesting to note that these systems were often considered to be non-productive in comparison with intensive and simplified systems.
Dehesa history and geography
Dehesa can be defined as an agroforestry and pasture agroecosystem. It has been created during thousands of years of selective pruning and clearing of the primitive Mediterranean forest shrubs and also by livestock pressure on the shrubs, grasses and trees. The system extends itself over the west, south-west and central parts of the Iberian Peninsula. In Spain, it can be found from southern Zamora Province to western parts of Andalucia. Within this territory, it has a significant presence in Salamanca, Ávila, Extremadura, Toledo, Huelva and Córdoba Provinces, being less important and more isolated in Castilla-La Mancha, Castilla-León and Madrid.
The general characteristic that defines a Dehesa is the presence of trees such as Quercus, especially Quercus ilex (Encina) and Quercus suber (Alcornoque). They are capable of producing fruits (acorn) and are present in such density that they can accomplish their multiple functions (Martín Bolaños, 1943 and Gómez-Gutiérrez 1987).
The area occupied by the system is controversial due to different classifications applied to Dehesa (wooded Dehesa and open Dehesa). Thus, for example, Olea and Viguera (1998) say that there are 9 million ha of wooded and open Dehesa in the peninsula. Of this total amount, 6-7 million ha are located in the southwestern peninsula, including 1.5 million ha belonging to Portugal. Daza (1998) refers to the existence of 3.3 million ha covered by encina and alcornoque trees, 2.3 million ha of these being situated in the Dehesa ecosystem. Fifty percent of that area belongs to Extremadura. Ceresuela (1998) reports between 2 and 2.5 million ha of Dehesa, of which 75% is found in the Spanish territory.
In terms of an agroforestry system, ecological, historical and economic aspects have conditioned the origin and development of Dehesa. According to Ceresuela (1983: 46), the evolution of the Dehesa components and landscapes should be understood within the whole context of transhumance. Large parts of the Dehesa that have reached our day come from communal mountains, private or church possessions that have been utilized for livestock production. The extensive migrating livestock system, as well as the property change that occurred in the Middle Ages during the long reconquest and the depopulation of the region, favoured the creation of large extensive farms under the military, clergy and nobility (Naredo 1978; Cabo Alonso 1998).
The physical environment, including climatic, lithologic and geomorphologic characteristics, was decisive in the Dehesa formation. The Dehesa systems emerged in a difficult environment. The climate is very variable and dry and the soils are generally poor, especially in phosphorus and calcium, containing low levels of organic matter. These characteristics limit the systems productive potential and make it unsuitable for an intensive agriculture practice (Granda et al 1991; Cabo 1998; Hernández 1998).
The Dehesa climate varies between the benign oceanic Mediterranean and the continental, dry and cold one. Rainfall varies between 300 to 800 mm annually, concentrated mainly in spring and autumn. There is a great annual variation and significant variation between months of the same year. Summer is dry and warm with maximum temperatures over 40oC, preventing grass growth. The winter is mild (10oC), and although frosts are not frequent, it is sufficiently cold to limit grass growth (Granda et al. 1991; Hernández, 1998).
The Dehesa vegetation comprises three main components: trees, shrubs and grass. The arboreal component is formed mainly by Encina trees (Quercus ilex) and Alcornoque trees (Quercus suber). The shrub stratum is formed by species such as "acebuche" (Olea Europea), "madroño" (Arbutus unedo) and "coscoja" (Quercus cocifera).
The grass stratum, principal feed source for livestock in the Dehesa, is composed of a wide variety of gramineous species, such as lolium, bromus and hordeum, and also of papilonaceas as clovers, medicagos, serradela (Ornitophus ssp.), geraneaceas and crucíferas (Rivas and Rivas 1963; Granda et al. 1991).
Types of soil, characteristics of the terrain, accessibility by the cattle, managing and history of the Dehesa, all determine the relative abundance of the three components, which vary greatly between Dehesas of different zones and within zones. The quantity of encina and alcornoque trees can vary from a few specimens up to more than 80 trees/ha, but the average number of trees is about 45 trees/ha. A good Dehesa is considered to have between 30 and 60 trees/ha (Roselló et al. 1987; Ceresuela 1998), permitting good growth of grass. Scrubs prevail on the grass in the hilly zones, less pastured by cattle. Their predominance over grasses can also indicate improper management of the Dehesa or a deterioration of the soil.
Different trees, shrubs, grass, other small plants and wild and domesticated animals compose the biodiversity of the dehesa. The diversity can be as high as in a forest or a natural environment under similar conditions (Hernández 1998).
The Dehesa ecosystem
A well-established Dehesa can assume different functions for the ecosystem, such as optimization of available energy through biomass production, soil preservation, nutrients circulation, water conservation and bioregulation of climate or microclimate stability.
Trees have different functions in solar radiation interception and water evaporation, reducing the ambient and ground temperature. They take nutrients from the subsoil and deposit them on the surface through their products (acorns, leaves, and stems). These products are used by grass and other vegetation avoiding or reducing losses by leaching. Trees also increase the level of organic matter in the soil as well as improving its physical-chemical properties and the retention of moisture. All these factors favour grass growth and improve its composition. The physical improvement of soil, together with root system improvement, enhances the breakthrough of the water in the soil and its storage, reducing the superficial leaching and erosion. Trees modify the wind, reducing its speed within woods and decreasing water loss.
According to Hernández (1998), when tree density is between 10-50 trees/ha, the effects mentioned are local or in the form of islands, but when the density is greater than 50 trees/ha there is a homogenization of the effects across the area.
Shrubs and grasses, in addition to optimizing the use of energy and space and taking nutrients and water from the less deep soil, have a soil-protecting function. Some grasses and shrubs recycle nutrients, as, for example, is seen in the nitrogen fixation by the leguminous components.
When the trees are pruned approprietly, the surface covered by the trees can be more than 40%, but still allow grass stratum to cover 96% of the soil surface. The same compatibility does not exist between grass and scrub, since the former does not grow under the latter.
The animals consume and transform the biomass produced by the system, redistributing it through manure production over the whole area. By selective use of the different resources available, animals interfere in the balance between the vegetable components.
All these functions favour ecological sustainability of the Dehesa. However, the system has been subject to management intensification, affecting the regeneration of the tree component. It has been suggested that this puts the survival of the Spanish Dehesa in danger (Montoya, 1998).
Dehesas role in agricultural production
Dehesa originated as a diversified agroforestry system of multiple use, with strong agroecological bases. Its productivity has been based on the optimization of the systems components more than on maximizing one or several of these components. The Dehesa development is based mainly on the use of indigenous animal breeds such as the Iberian Swine, Retinto, Morucha and Avileña bovines and the Merino. These species are all adapted to the environment and generate products of exceptional quality.
The traditional Dehesa (Campos Paladin, 1984) makes maximum use of natural resources and integrated production of livestock. The indigenous and wild animal breeds are adjusted well to the system. The Iberian Swine makes an efficient use of acorns; cows and sheep consume grass and pruned leaves; horses and donkeys consume the coarsest grasses; goats and greater wild animals use the less accessible zones and bees use the abundant spring flowering. Cereals (approximately 9% of the total area) are sown in rotations of 4 to 8 years, in order to produce a supplementary feed for the animals and to control the shrubs (figure 6). Kitchen gardens and domestic poultry for family nourishment are frequently seen on a Dehesa farm.
As is observed in Table 1, the production is very varied. Similarly, the productivity of the system varies. Campos Palacín (1984), in his study of Extremadura Province Dehesa, estimated that the stocking density of a well-established traditional Dehesa is about 2.1 UGL (pregnant ewe equivalent units /ha). The productivity in energy terms was estimated at 147,000 kcal/ha, which would be equivalent to 53 kg of channel /ha and 81 kg of live weight /ha. Furthermore, 387,000 kcal /ha of non-consuming products in the form of coal and cork were produced.
The energy analysis of the traditional Dehesa accomplished by Campos Palacín found that the system is characterised by a sustainable and efficient energy utilization. Acosta (1999) showed that the management of the traditional Dehesa requires adequate and efficient management of natural resources, applied by local people based on local knowledge.
After the 1960s, the traditional Dehesa suffered substantial changes due to the "modernization" undertaken in the country. Farms suffering from financial crisis sought their survival by substituting labour with technology, increasing the stocking densities and reducing the systems diversity and or abandoning tasks that were no longer profitable.
Transhumance was reduced and the displacement to the field disappeared. The "majadeo" (certain designated paddocks where the animals spend the nights fertilizing it with manure to be sown next season) has been abandoned. The indigenous breeds have been replaced with imported ones. The goat and poultry population has reduced, and draft cattle, especially in larger properties, have disappeared almost totally. The load applied to the system has increased, stimulated, in part, by subsidies and, on the other hand, by increased dependency on concentrate and forage from outside the farm. The high stocking densities have stopped the regeneration process of the trees in many zones. Fenced paddocks have substituted for the manual work of handling the herds; and a decrease in the labour applied to tree care has led, in some cases, to reduced acorn and coal production. Cultivation has been concentrated in the better zones of the properties, reducing the rotating and resting practices of the cultivated plots. Increase in the hunt estates has transformed the synergistic activity of the inhabitants economy into a sport (Campos Palacín, 1984; Ceresuela, 1998; Acosta, 1999).
Figure 1. General diagram of a traditional Dehesa
Click here to see diagram.
Assessment of productivity in Dehesa
The Iberian Swine has evolved in a semi-extensive system, with different nourishment systems. For example, of the 1 million existing Iberian swine and their crosses fed in 1990, 60% were fed with concentrates and 40% in Montanera-Dehesa systems (AECERIBER, 1992). The latter 40% also received important quantities of concentrate after they were out of the Montanera to reach the desired weight (gravel pigs). Cabeza de Vaca et al. (1992), doing a survey of 51 pig units in Dehesa systems, reported that the cost of concentrate measured as a percentage of the total cost was smaller for pigs eating acorns (26%) than for gravel pigs (41%) and concentrate pigs (55%). Dieguez (1992) reports that in the Montanera swines gain 56-66 kg (84-103 days) of live weight/swine. If we assume a stocking capacity of 0.68 swines/ha, we would have a rate of 38-45 kg of live weight/ha at that period, compared with an acorn production of 522 kg/ha (Cabeza de Vaca et al. 1992).
In the Dehesa we find today 36% of all the bovine cattle of the country. Among them there is an important group of indigenous breeds, such as the Retinta, Avileña and Morucha. They have been crossed with foreign breed bulls, especially Limousine and Charolais, obtaining greater yielding calves, better feed conversion and better results in intensive fattening systems. In specialized beef cattle exploitations of the Dehesa, Espárrago (1991) reported that 28-36% of 40 exploitations surveyed had changed to other livestock activities during the 1980s and 1990s.
A description of these systems is offered by Baréa et al. (1980), who surveyed 134 properties of the Andalucian Dehesa and also of the Extremadura Dehesa devoted to Retinto production. The average size of the studied exploitations was 876 ha. 59% of them were occupied by Dehesa, 21% by grass and 19% by crops, with an irrigated area of 4.4%. Of the crop area, 72% was devoted to cereals and legumes, and the rest (28%) to industrial cultivation for cash crops. The average number of breeding cows was 155 for a stocking density of 0.24-0.34 heads/ha. The properties were selling directly as calves or as steers, aged 14-16 months, and at weaning time, aged 6-8 months. In the best cases (80% sold as steer weighing 400 kg of live weight) the estimated productivity of the system was 48 kg of live weight/ha/year.
An estimate of the benefits of the exploitations analyzed by Espárragos and Baréa (1988 and 1991), considering the prices and subsidies of 1998, suggests that subsidies in 1988 and 1991 were about 36% of the benefits. This means an increase of 14,00018,300 ptas/ha, decreasing the enterprises' minimal area to 182-237 ha (Table 1).
Some 29% of the total Spanish sheep herd (5,237,054 breeding animals) is found in Dehesa areas. According to MAPA (1997), 4.7% of those (247,821 ewes) are milked, meat being the principal product in the Dehesa suystem with sheep. The main breeds used are the Merino, Churra and Merino "entrefina".
An interesting participatory rural appraisal conducted by Contreras et al. (1999) with cattlemen belonging to CORPEDROCHES co-operative shows data concerning sheep production systems applied in these zones. The most common enterprises are 100-400 ha in size. Some 25% (0-40%) of these are devoted to production of different crops (cereals, legumes, textile linen, trees and forage). Sheep production constitutes the main economic activity of these enterprises, selling lambs weighing 23-25 kg. Many of the farms raise some swine for sale or self-consumption (approximately 60%). Some farms also raise cattle. The herd sizes of these enterprises vary between 250 and 800 ewes. The average stocking density is around 1.9 ewes/ha and the lamb production varies between 0.86 and 1.25 lambs/ewe, demonstrating different reproductive strategies. In order to improve lamb characteristics for meat production they cross Merino ewes with precocious Merino, Ille de France and others. Average productivity rates from eight farms analysed were 36 kg of liveweight/ha, 89% of it from sheep, 10% from swine and the rest from cattle production. In addition, the farms produced 2.5 kg of wool/ha and 157 kg/ha of cereals, legumes and olives.
Table 1. Estimates of the economic benefits of beef cattle enterprises at the dehesa (Pesetas/ha).
Source Espárrago (1991) Baréa et al. (1980) Year analysed 1988 1991 Calculated for 1998 Exploitation area expressed in ha 280 ± 113 874 No. of females in reproduction 72 155 Income/livestock production 15.720 14.550 13.672 14.084 Other income 2.380 3.900 5.420 4.967 Subsidies 1.050 2.340 11.216 10.492 Total income (ptas/ha) 19.150 20.790 30.308 29.543 Costs (ptas./ha) 11.280 13.790 16.300 11.241 Benefits (ptas./ha) 7.870 7.400 14.008 18.302
The analysis offered by the workshop attendees at CORPEDROCHES equals an economic benefit of 6,785 ptas./ewe (3,600-11,000) and of 14,309 ptas./ha (5,500 25,500), which includes the sale of other agricultural and livestock products and also the subsidies. The expenses on the purchase of concentrate on these enterprises is high, representing an average of 32.6% (14-50% of the total expenses). This reflects the high dependency on outside inputs of these systems. Since about 75% of the enterprises' land was rented, the rents comprised another important element in the costs (9-19% of the expenses). Approximately 52% of the income came from subsidies (64% of it destined for the sheep production and 36% for the agricultural activities), while the products generated by the sheep production represented 40% of the income. This situation caused the producers to believe that, without subsidies, sheep production would not be profitable.
The workshop data also reflects different strategies followed by the producers in the search for an economic viability (increased stocking densities, incorporation of other subsidized crops, diversification of the livestock production, increase in the units size by leasing more lands, land abandonment with subsidies, etc.), though some of the alternatives were against the ecological viability of the system.
In an economic analysis of a typical sheep enterprise (1.4 lambs/ewe/year and stocking density of 2 sheep/ha), Daza (1998-a) found that an enterprise would be economically viable, providing livelihood with dignity to a farming family, if it had 300 ewes and 150 ha of cultivable land (S.A.U.).
Table 2 was elaborated based on experimental data obtained by López Gallegos et al. (1992 and 1997), Cañeque (1996) and Daza (1998-a) to show the potential of raising sheep in a Dehesa system.
Table 2. Estimate of some sheep dehesa systems' efficiency
System Production/ewe (kg) Intake of concentrate Stocking rate Production/ha (1) Live
Wool Milk (kg/ewe) (ewes/ ha) Carcass equiv. (kg) Energ. (x1000 kcal.) 1 birth/year, lamb raised in whole lactation period + pasture until 105 days old (30 kg of live weight). 27 1.5 0 25 2 27.8 67.6 1 birth/year, weaning at 45 days old + stable fattening until 105 days old (30 kg) + ewes being milked 25.6 1.5 33 91 1.85 40.3 97.9 1.5 births/year + lamb raised with whole lactacion peiod + pasture until 105 days 42 1.5 0 60 2 41.9 101.8 1.5 births/year,weaning 45 days old + stable fattening on until 105 days old + ewes being milked 41 1.5 43 150 1.66 52.5 127.5 CORPEDROCHE system, lambs being sold weighing 23-25 kg. (2) 20.0 1.5 0.65 126 1.9 20.1 50.1 (3)
- The carcass equivalent production refers to converting all livestock production into carcass energy equivalent according to each energy equivalent, which is unusual for meat production because it is directly calculated.
- Includes all the enterprises.
- The agricultural production was 521 Mcal/ha, not including linen.
Data that we have obtained or calculated from existing information shows that the general productivity by area unit is not as low as has been argued (Table 3). Some of these systems are characterized by high productivity, considering that they have been developed under relatively poor resource conditions. On the other hand, the high efficiency of some intensive systems is acheived by transference of nutrients (cereals, legumes, forage) brought from other areas to these systems to feed animals, and also by using fossil energy indirectly or directly (Table 3).
Table 3. Productive efficiency of different systems of Spanish extensive livestock in comparison with intensive systems
Carcass equivalent prod.1)
Energy production (Mcal./ha)
Diversified Dehesa (Palacín, 1984)
Bovine Dehesa (Baréa et al., 1980)
Very intensive Sheep Dehesa - Lamb production (Cabeza de Vaca et al., 1992)
Very intensive Sheep dehesa - lamb and milk production (Cabeza de Vaca et al., 1992)
Monte Gallego (Díez y Sineiro, 1979)
Traditional Mountain diversified with agriculture. (Echevarria,1975)
Extensive Montaña Bovine production (calves sold between 150-200kg) (Echevarria et al., 1999)
Residue livestock (sheep) ( estimated from Vera, 1986)
Semi-intensive meat production at the Pirineos (G-Trujillo, 1998)
Intensive milk production in North Valley(7)
(1) The carcass equivalent is estimated converting all livestock production into its energetic equivalent and transforming this value into an energetic equivalent of an average carcass (2800-2400 kcal./kg).
(2) It refers to the livestock production for the market or to be consumed by the families, and it does not include the manure.
(3) Sold agricultural productions or used for family consumption.
(4) Fuelwood, coal, cork.
(5) Not estimated.
(6) Estimated based on the growth curves calculated by Buxadé Carbó (1983) for the Iberian Swine in a dehesa and the load calculated by Cabeza de Vaca et al. (1992).
(7)Production systems with 3 cows/ha, producing 25 kg of milk/cow/day during 320 days and with 60% of concentrate in the total ration, of which 94% comes from outside the unit, for a general animal load of 0,64 cows/ha, as well as a high fertilized forage production in valleys.
Dehesa is a complex agroforestry system with a high ecological component. It has been developed in zones of climatic and soil restrictions and its productivity is dependent on its resource optimization. The studies gathered in this paper show the importance of this optimization from the point of view of ecology as much as productivity. They also demonstrate the productive potential of the diversified traditional Dehesa that can have a high degree of self-sufficiency when compared with specialized systems. The risks arising from the detention of the tree renovation, the system's high outside dependency, the loss of the production value and the rupture of the traditional Dehesa management systems are also demonstrated.
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