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PRODUCTION AND USE OF OPUNTIA AS FORAGE IN NORTHERN MEXICO

Juan José LÓPEZ-GARCÍA, Jesús Manuel FUENTES-RODRÍGUEZ and R.A. RODRÍGUEZ

Juan José LÓPEZ-GARCíA, Jesús Manuel FUENTES-RODRíGUEZ and R.A. RODRíGUEZ

Universidad Autónoma Agraria Antonio Narro
Coahuila
México.

OPUNTIA IN NORTHERN MEXICO

Environmental conditions and physiographic variables have resulted in a wide range of semi-arid ecosystems with a diverse flora and fauna in northern Mexico, where Opuntia is abundant and widely distributed in large thickets called nopaleras. It is represented by 104 species, 60% located in the Chihuahuan desert. The most important species for forage use are: Opuntia leucotricha, O. streptacantha, O. robusta, O. cantabrigiensis, O. rastrera, O. lindheimeri and O. phaeacantha (Bravo, 1978; Elizondo et al., 1987).

GEOGRAPHICAL DISTRIBUTION OF NOPALERAS

Marroquin et al. (1964) recognized three large regions covered with opuntias in northern Mexico alone. A wider approach, including the whole country, was proposed by López and Elizondo (1990), who recognized four regions occupied by opuntiaeras exploited for forage or fruit, or both.

A. Central-southern zone. This includes parts of the states of Puebla, Querétaro and Oaxaca, and is characterized by tree types cultivated in nopaleras and producing tender pads (nopalitos), fruits (tunas) and forage. Species are mainly O. ficus-indica (nopal de Castilla), O. amyclaea (nopal alfajayucan), with several cultivated varieties (Barrientos, 1972), O. megacantha (tuna amarilla) and O. tomentosa.

B. High plateau zone. This lies mainly in the states of Zacatecas and San Luis Potosí, but includes also parts of Aguascalientes, Durango, Guanajuato and Jalisco. It includes tree-type vegetation of O. leucotricha (nopal duraznillo) and O. streptacantha (nopal cardón), as well as shrubby plants of O. robusta (nopal tapón), O. cantabrigiensis (nopal cuijo), O. rastrera (nopal rastrero), O. lindheimeri (nopal cacanapo) and O. leptocaulis (nopal tasajillo).

C. North zone in the Chihuahuan desert is the largest region, and includes the states of Chihuahua, Durango, Zacatecas and Coahuila. It is represented by shrub vegetation of O. cantabrigiensis, O. phaeacantha (nopal rastrero), O. lindheimeri and O. rastrera.

D. Coastal zone of the Gulf of Mexico. This covers parts of the states of Coahuila, northern Nuevo Leon and Tamaulipas. Shrubby plants of O. lindheimeri are found associated with other forage species: O. leptocaulis, O. microdasys (nopal cegador), O. imbricata and O. rastrera to a lesser extent.

DISTRIBUTION OF THE MAIN FORAGE SPECIES

O. leucotricha (nopal duraznillo). The most widely distributed species across region B at altitudes between 1500 and 2500 m with an annual rainfall ranging from 220 to 450 mm. These wild populations have been seriously affected by the continuous increase in the cultivated area of maize and dry beans.

O. streptacantha (nopal cardón) is present in large areas of the states of Zacatecas and San Luis Potosí, and to a lesser extent over Aguascalientes, Durango, Jalisco and Guanajuato. This area is threatened by serious desertification.

O. robusta (nopal tapón) grows in association with O. leucotricha and O. streptacantha. It is widely distributed over the states of Zacatecas, San Luis Potosí, Guanajuato, Aguascalientes and Jalisco. The tender cladodes are large and succulent, appreciated for human consumption both fresh and pickled.

O. cantabrigiensis (nopal cuijo) is a shrub with a well-defined stem and abundant spines, used mainly to feed goats. It has a wide distribution at altitudes from 1500 to 2200 m with relatively low densities on calcareous soils over the states of Nuevo León, Coahuila, Zacatecas, San Luis Potosí, Hidalgo, Aguascalientes, Durango, Jalisco, Querétaro and Guanajuato.

O. rastrera is a shrub with creeping habit, less than 1 m tall, widely used to feed dairy cattle in the states of Coahuila, Nuevo León, Zacatecas, San Luis Potosí, Durango and Aguascalientes. It grows well in a wide range of soils, from deep to shallow, rocky and calcareous. It is sometimes found in dense thickets.

O. lindheimeri (nopal cacanapo) extends over the states of Coahuila, Nuevo León and Tamaulipas at altitudes around 1000 m with an average annual rainfall of 400 mm. The species has four important varieties, all widely appreciated for forage: aciculata, lindheimeri, subarmata and tricolor.

O. phaeacantha grows wild in Coahuila and the southern parts of Chihuahua and Durango with only 200 mm of annual rainfall at altitudes between 1500 and 1700 m. Five distinct forage varieties have been described: major, phaeacantha, diskette, spinosibaca and Nigerians. All of them have good forage quality.

O. engelmannii is found in NE Zacatecas and SW Coahuila at altitudes between 1700 and 2200 m in shallow, calcareous soils. It is used mainly to feed goats and sheep.

O. imbricata (nopals coyonoxtle, xoconoxtle, cardenche or cholla) exhibits great variability and is widely distributed in the states of Coahuila, Zacatecas, San Luis Potosí, Chihuahua, Aguascalientes, Durango, Jalisco and Guanajuato. It grows well in relatively poor soils and is a typical invader plant in poorly managed grasslands. Used to feed goats and sheep after burning off the spines in situ.

O. microdasys is a short shrub without true spines but loaded with short bristles or ahuates, which are blown by wind and can easily blind animals. It grows on calcareous soils, and is used to feed animals under extreme drought conditions in southern parts of Coahuila, north of San Luis Potosí and Zacatecas.

O. violacea (morado) is recognized by its purple-coloured cladodes. A short shrub (< 1 m) that grows on deep clay soils of Chihuahua, NW Coahuila and east Durango - areas with only 200 mm of annual rain, hot summers (up to 45°C) and cold winters (-8°C). Its forage quality is poor.

O. rufida (blinding opuntia) is a shrub growing to about 2 m that grows in calcareous clay soils, in the slopes or in the deep valleys. Its cladodes are larger than O. microdasys, and its quality as forage is also poor. It is used only as an emergency feedstuff (Elizondo et al., 1987).

PRODUCTION

Wild stands

Forage availability from Opuntia in northern Mexico relies mainly on wild populations, formed by the species described above, which are distributed on 283 000 km2. Unfortunately, these areas have been subjected to heavy use and poor management (Marroquin et al., 1964). Recurrent periods of drought associated with scarcity of other feedstuffs have also increased the demand for opuntia forage. The productivity of such ecosystems is relatively low and unstable, strongly dependant upon climate and management conditions.

Yield ranges from 25 to 125 t/ha, depending upon the species, plant vigour, climate, soil fertility and management system. The yield value assumes that 75-80% of aboveground biomass is usually harvested. The recovery period is strongly dependent on rainfall and intensity of usage.

Cultivated nopaleras

There are several production systems, ranging from replanting wild stands to intensive production systems based on high densities and irrigation. Federal programmes aimed to recuperate highly deteriorated nopaleras have failed due to a lack of understanding of the complexity of the production systems involved. Plantations were usually established on marginal lands and under poor management practices, which contributed to the failure of programmes. However, these federal projects should continue putting emphasis on more efficient use of natural resources, to improve the ecological and socio-economic conditions of the semi-arid regions in northern Mexico (López, 1977; Medina et al., 1990).

Well-tended nopaleras planted with 2500 plants per hectare can produce above 100 t/ha after the fifth year of planting. Recorded yield for the seventh year is 160 t/ha. Sustainable production is accomplished by harvesting every other row annually. However, in general, plantations are poorly managed and average yield varies from 5 to 15 t/ha after the fifth year of planting.

Factors important in improving yield include:

* Site selection. For intensive production, it is advisable to select the best part of the land in terms of soil conditions. The plantation should be at high density. Extensive plantations are suggested as an aid to recover natural grassland. Planting under these conditions involves a low density of opuntia plants. Extensive plantings are conducted in any type of soil.

* Variety selection. A wide range of adaptation to local conditions is needed, expressed as good vigour, health and productivity. They should be suitable for animal feeding either spineless or with a minimum density of spines, palatable with no side effects, of high nutritive value, and have quick recovery after harvest. Tolerance to pests and diseases is also desirable.

* Propagation. The source for planting material should be 1-4 years old, collected from healthy and vigorous plants. Cladodes are cut at the joint with a sharp knife, the base disinfected with Bordeaux mixture (1 kg of copper sulphate, 1 kg calcium hydroxide and 100 litre of water) and allowed to air-dry in the shade for a week. Cladode bruising should be avoided. These practices increase transplanting success.

Soil preparation For extensive plantings, cladodes are deposited directly in shallow holes dug in the field without disturbing natural vegetation. Depending upon the slope, it might be necessary to build terraces or individual micro-catchments. Once the plants are well established, surrounding vegetation shading the plants could be eliminated or pruned back. Under intensive planting systems, regular soil preparation practices (ploughing and contour furrowing) should be performed before transplanting the cladodes.

Transplanting Under dry conditions during the spring in the Chihuahuan desert, it is highly recommended to transplant after the first summer rain. However, if additional water for irrigation is available, planting could be performed any time, but late fall seems to be the best time of year to allow plant rooting previous to budbreak.

The best planting material is a cutting with two cladodes, burying 50 to 75% of the basal cladode. If planting material is in short supply, then single-cladode cuttings can be used. Based on the authors’ experience, row orientation has not proved to be important for initial plant development in the field.

Planting density Using 2 500 plants/ha it is possible to produce 100 t/ha in the fifth and 160 t/ha in the seventh year of transplanting. If densities are increased up to 40 000 plants/ha under fertile soils and intensive management practices, such as irrigation and fertilization, yields may reach 400 t/ha (Barrientos, 1972). However, actual yields in the arid regions of Coahuila are very low, ranging from 5 to 15 t/ha.

Management practices Care during the first two years involves only the elimination of cladodes growing too close together, which can be used for human consumption (while still tender) or for animal feeding. Although it is not common, in some nopaleras fruit production is allowed to satisfy family needs or demand from local markets. Under these circumstances, a more conservative pruning method is practised, leaving a few more one-year-old cladodes where some fruits will develop during the following season.

HARVESTING SYSTEMS

The use of Opuntia as a source of forage to feed cattle, sheep and goats is an old tradition in northern Mexico. Cladode harvesting ranges from direct animal consumption in the field, to various types of harvest systems practised by ranchers.

The variants observed among extensive livestock operations are:

* Direct feeding. Opuntia plants are consumed whole including spines, by cattle, sheep and goats. This practice is inefficient, resulting in serious damage to the animals or even death.

* Removal of cladode edge. The upper portion of the cladodes, where the largest number of thorns is present is removed with a knife, allowing animals to feed on the plant. Its main disadvantage is waste of cladodes.

* Singeing-off of spines of whole plants. The plant is flamed completely, with a propane or kerosene burner, and the animals allowed to consume it down to the base. Usually leading to the complete destruction of the plant. It is combined with grazing in the case of sheep and goats.

* Singeing and chopping in situ. The cladodes are harvested and spines burned with firewood or gas torch. Then they are chopped and offered to animals.

A specific case is opuntia harvesting for suburban dairy operations. The plants are harvested whole and transported to stables, where they are burned and chopped. Depending on the size of the operation, chopping is performed manually or with adapted machinery.

Unfortunately, all of these systems are destructive to some degree, as they rely only on wild stands, and should be limited because none of them involve replanting, leading to depletion of the natural resource.

A sound practice consists of extensive cladode cutting and superficial burning to eliminate spines to allow animals to either feed directly in the field, as whole cladodes, or cut into small pieces to facilitate their consumption. Alternative - and more efficient - harvest practices include cladode harvesting from dense stands, which are then transported to the farms, spines burned off, and cut into small pieces to feed the animals.

CONSUMPTION BY ANIMALS

It has been estimated that cattle can consume from 15 to 40 kg of fresh cladodes/day/beast, but under drier conditions they might consume up to 90 kg if cladodes are abundant, while sheep and goats consume between 3 and 9 kg/day. During the rainy season, daily consumption may decrease if other sources of food, such as grasses, are available.

For housed cattle and sheep, opuntia consumption ranges widely (from 15 to 95 kg/day), depending upon the availability of other sources of food. The most common other feed sources include alfalfa (green or as hay), sorghum stover, and cornmeal or cotton meal. Common hay sources are maize or dry bean stover, wheat and oat straw, used to complement opuntia feeding, due to their relatively low nutritive value compared with opuntia. However, due to the high costs of hay, opuntia demand is increasing every year, particularly during periods of drought.

NUTRITIONAL VALUE

The use of Opuntia as a source of food for humans, domestic animals and wildlife has been very important in the arid and semi-arid regions of northern Mexico for centuries. Although it has been considered poor in terms of nutrients and fibre, it constitutes the main source of water in traditional production systems, particularly during the dry winter-spring season. Opuntia is a key ingredient to supplement the diet of domestic animals due to its:

* Water content. Opuntia is one of the main water sources for animals in the semi-arid north. However, the total amount of water stored depends upon species and varieties (Table 1). Water content is strongly influenced by environmental conditions.

* Dry matter content. Several factors strongly influence DM, both endogenous (species, geno-type and cultivar) and environmental, such as soil, climate and season (Table 2).

* Bromatological analysis. There are significant differences among reported data on tissue analysis, associated with variation in species, physiological factors, soil fertility, climate, etc. (Table 2).

Table 1. Water content among species and varieties of Opuntia used as forage in Saltillo, Coah., Mexico.

Species

Minimum

Maximum

O. ficus-indica

88

93

O. cantabrigiensis

68

84

O. lindheimeri var. tricolor

72

86

O. lindheimeri var. subarmata

76

87

O. imbricata

70

84

Source: J.J. López-González, unpublished data

Minerals There are few reports on studies aimed to quantify mineral content of opuntia in Mexico. According to Bravo (1978), the main mineral components in opuntia ashes are calcium, potassium, magnesium and sodium, usually found as salts and silica. Iron and aluminium are found in traces.

Digestibility The rate of feed intake by the animal is influenced by species, variety and season (Table 3), cladode age (Table 4), and their corresponding interactions (Revuelta, 1963; Flores and Aguirre, 1992).

Morrison (1956) reported digestibility values as fibre, 40%; crude fat, 72%; protein, 44%; and nitrogen-free extract (NFE), 78%, while Murillo et al. (1994) studied the influence on opuntia digestibility of yeast supplemented with two sources of nitrogen. When yeast is added to Opuntia, digestibility was 61.6%; if ammonium sulphate was combined with yeast, digestibility increased to 93.9%. Adding yeast and urea, digestibility reached 76.8%.

Table 2. Nutritional values of Opuntia species on a DM basis.

Species

DM

OM

CP

Fat

Fibre

Ash

NFE

Source

Nopalea spp.

10.69

73.79

8.92

1.51

17.21

26.21

50.7

Griffiths and Hare, 1906

O. chrysacantha

15.52

73.45

3.54

1.11

4.32

26.55

64.33

Palomo, 1963

O. tenuispina

12.45

70.21

4.42

1.04

5.14

29.80

59.52

O. megancantha

10.12

74.51

7.71

1.38

3.75

25.44

68.87

O. rastera

14.41

59.89

2.78

0.76

6.18

40.11

43.23

O. azurea

12.55

68.88

4.54

1.35

3.98

30.12

59.84

O. cantabrigiensis

11.86

68.46

4.79

1.09

3.71

31.54

58.87

O. engelmannii

15.07

68.41

3.32

1.19

3.58

31.59

60.32

O. lucens

17.45

69.59

3.67

0.57

2.58

30.43

62.75

O. lindheimeri

11.57

74.51

4.15

1.03

3.02

25.50

66.25

O. robusta

10.38

81.41

4.43

1.73

17.63

18.59

57.61

O. streptacantha

16.01

79.38

3.17

1.99

18.88

20.62

55.34

Griffiths and Hare, 1906

O. leucotricha

14.01

74.01

7.56

2.66

14.01

26.00

49.78

O. imbricata

17.71

84.25

7.11

1.75

11.51

15.75

63.86

O. cacanapo

16.95

72.51

5.19

2.06

11.21

27.49

54.04

O. stenopetala

13.24

77.87

8.84

1.74

9.14

22.13

58.16

O. duranguensi

10.34

82.94

4.51

1.29

8.23

17.06

68.91

Bauer and Flores, 1969

O. ficus-indica

11.29

86.93

3.81

1.38

7.62

13.07

74.13

cv. Amarillo oro








O. ficus-indica

13.36

81.55

3.66

1.76

9.18

18.45

69.95

O. spp.

10.01

----

5.71

3.01

8.11

12.01

55.01

Lastra and Pérez, 1978

O. ficus-indica

8.01

----

6.81

1.01

----

8.88

81.25

O. ficus-indica

7.96

----

4.04

1.43

8.94

19.92

65.67

O. imbricata

10.41

----

5.01

1.81

7.81

17.30

68.11

Key: DM = dry matter. OM = organic matter. CP = crude protein. NFE = nitrogen-free extract

Table 3. Variability in nutrient digestibility of spineless Opuntia.

Season

Crude protein

Fat

NFE

Cellulose

Winter-Spring

0.2-0.3

0.08-0.12

3.0-5.5

0.4-1.0

Summer-Autumn

0.3-0.4

0.15-0.16

6.5-11.0

0.8-2.0

Source: Revuelta, 1963.

Table 4. Digestible nutrients of Opuntia as influenced by variety and cladode age.

Source

Crude protein

Crude fat

Fibre

NFE

Spiny variety

1st yr. cladodes

0.24

0.14

5.22

5.22

2nd yr. cladodes

0.21

0.17

0.51

4.73

Spineless variety

1st yr. cladodes

0.22

0.17

0.49

4.81

2nd yr. cladodes

0.18

0.19

0.63

4.39

OPUNTIA AND ANIMAL PRODUCTION

The information available on use of Opuntia to feed livestock in extensive as well as intensive meat and dairy operations supports the importance of Opuntia (Fuentes, 1966).

Meat production

Griffiths (1905) reported the first results, stressing the importance of Opuntia as a source of food for domestic animals. These preliminary findings, derived from feeding bovines for meat production, were based on a 15-week study, were that:

* cornmeal + opuntia is better than corn [maize] grain + opuntia mixture,
* daily mean consumption per animal was 48.0 kg,
* daily animal gain was 0.85 kg, and
* 55 kg of opuntia combined with 2.5 kg of cornmeal were required to produce 1.0 kg of meat.

Experiences reported from Brazil concluded that 60% of the total energy requirements could be supplied by opuntia. Increasing the protein provision (from cotton meal and mamona (Melicoccus bijugatus)) or providing molasses did not improve liveweight gain of animals of Zebu, Indobrasil and Guzerat breeds (Viana et al., 1965). Diarrhoea caused by excess opuntia fodder was successfully controlled by providing sorghum stover at the rate of 0.75 to 1.3 kg/animal/day.

In a study conducted by Fuentes (1991) on seven sites in Coahuila, 685 animals grazing freely and supplemented with maize stover, molasses and urea were also fed with 10 to 20 kg/day of burned-chopped opuntia. Daily animal gain ranged from 0.1 to 0.6 kg. Opuntia provided 7.8% of total maintenance energy, 20.6% of the protein, 50% of phosphorous and 100% of the calcium requirements recommended by the NRC (1984).

These results support the importance of including Opuntia in the diet of domestic animals, based on experiments combining species, varieties, local conditions and their corresponding interactions.

Milk production

Since the early 1900s, most suburban areas in Northern Mexico provide milk to large cities, and cows are fed with opuntia as a supplement to the regular diet. The belief is that opuntia-based supplement increases not only milk production, but also improves quality of butter in terms of consistency and storage life, as well as adding an attractive “golden” colour to the finished product (Griffiths, 1905; Cottier, 1934; D’Arces, 1941; Aguilar, 1946; Blanco, 1958; Calvino, 1952; González et al., 1998).

However, Gonzalez et al. (1998) reported that milk production in Holstein cows decreased with the rate of Opuntia in the diet. Therefore, they recommend using only 20 to 30% (on a dry matter basis) and supplementation with alfalfa hay, oats and sorghum to obtain a good balance between production costs and returns.

Daily Opuntia consumption in southern Coahuila (Fuentes, 1991) and Nuevo Leòn (Fuentes, 1992), ranges between 20-30 and 25-40 kg/cow, respectively. It was estimated that in such conditions Opuntia provided 4.5% of the total energy required for suckling, 12.2% of the proteins, 46% of crude fibre, 15% of phosphorous and 100% of calcium compared to the recommended requirements (NRC, 1984).

Sheep

Under a free pasture consumption system in the field, sheep consume less opuntia than goats, but when fed with burned-chopped Opuntia, their consumption reaches about 3-5 kg/day.

Other studies abroad report bovines being fed for 400 days exclusively on an opuntia diet without watering, without serious side effects (Rossouw, 1961). While in South Africa, reports indicate up to 525 days (Havard, 1969; Terblanche et al., 1971). Although there is not a real increase in weight, animals are saved from starvation.

The consumption of opuntia by sheep is associated with an improvement in the quality of the wool, attributed to an increase in the lanolin content, as reported by Ríos (1954) and Revuelta (1963). The effect was observed with a daily consumption of 7 kg/animal in Tamaulipas and Nuevo Leòn (Rios, 1954) and up to 9 to 10 kg in other regions (De Klerk, 1960).

Table 5. Influence of Opuntia cladode dry matter content on body weight loss of “Merino” sheep

Cladode treatment

Dry matter intake
(g/animal/day)

Weight loss
(kg/animal/week)

Fresh

345.7

0.620

Intermediate

396.1

0.510

Dehydrated

507.1

0.230

Source: Terblanche et al., 1971

Using a linear regression model, Flores (1977) predicted a 2- to 3-fold increase in body weight for sheep fed with opuntia supplemented with alfalfa hay, sugar beet and corn silage, for 32-kg sheep.

Terblanche et al. (1971) studied the influence of a diet based exclusively on opuntia on the weight loss of Merino sheep using fresh (10% dry matter), dried (27% dry matter) and dehydrated cladodes (87.9% dry matter). The last treatment represented the best option (Table 5).

Other animals

In northern Mexico, goats browse freely and feed on Opuntia all year round, but rely more on the cactus from late autumn to late spring. Daily consumption ranges from 3 to 9 kg/day in the open field, and up to 11 kg when they are housed.

Open browsing, singeing in situ, and cladode collection are the methods of opuntia utilization, as for cattle.

The most commonly used species to feed goats in northern Mexico include O. leucotricha, O. streptacantha, O. robusta, O. cantabrigiensis, O. rastrera, O. lindheimeri, O. imbricata, O. microdasys and O. leptocaulis. All of these species used as forage sources have abundant spines, which are hard, large and have abundant glochids (ahuates), which can cause serious problems to eyes and mouth of domestic animals feeding on them.

Opuntia is extremely important for wildlife, probably even more than for domestic animals, supporting the rich fauna of the Chihuahua desert.

PROBLEMS AND PERSPECTIVES

The recent droughts in northern Mexico have resulted in the loss of more than 200 000 animals, and consequently the demand for opuntia is rapidly increasing. A few decades ago, opuntia was collected at distances up to 20 km away from urban areas, while now it is necessary to transport plants from distances exceeding 100 km (Marroquine et al., 1964).

Production systems practised today destroy vegetation and accelerate the desertification process, representing a serious danger to the native flora and fauna of northern Mexico. Therefore, it is very important to implement re-vegetation projects that include several important native species, such as Opuntia, Agave, Prosopis, Acacia, Mimosa and others.


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