**5. Spinelles Cactus as forage and desertification mitigation**

The semiarid in the world land structure is almost entirely characterized by a large number of small and medium sized family-owned establishments. In Brazil, 70% of the consumed food is produced by small producers [63]. Although family farming is economically in these regions crucial, producers in the semi-arid region are most vulnerable to the impacts of climate change. The combination of an adverse environment and economic activity that is dependent on nature leads to extreme vulnerability of the production systems, represented by virtual collapses under climatic conditions that are unfavorable to production. This, in part, results in economic fragility.

In dry areas around the world, periodic droughts have a major impact on rural properties, leading to serious socio-economic losses [29]. In these regions, biomass production is typically low (<5 tons of DM per ha per year), with low forage potential (<1 ton of DM per ha per year), leading to a low support capacity (12–15 ha to sustain an adult cow; Dubeux et al., 2015). However, producers should make efforts to identify and implement strategies to deal with these adversities, which can reward them with long-term resilience [64]. For this reason, [65] suggested corn crop for silage production. [66] evaluated five short cycle corn cultivars, recommended for silage production in semi-arid regions, and observed a productivity of 8.04 tons of DM/ha (6.12 to 9.68 tons of DM/ha).

However, the use of cactus, notably cactus cladodes (*Opuntia* and *Nopalea*), for ruminant feeding in dry areas has been increasing, as, for example, in North Africa [67] and northeast Brazil [68, 69]. Cactus is chosen for its high efficiency of water use, rapid dissemination, high water and energy content, and high biomass yield [70]. Recently, [71] suggested cactus *Opuntia stricta* (Haw.) Haw. cladodes as a new option for milk production in smallholder systems in semi-arid regions. In addition, [58] published productivity data of this cactus cladodes' clone in different semi-arid areas in Brazil and reported a minimum production of 40 tons of DM/ha and a maximum production of 60 tons of DM/ha, achieved every two years.

In general, energy is the most limiting "nutrient" for animal production. [72] showed that *O. ficus-indica and N. cochenillifera* has an average ME content of 2.34 Mcal/kg DM. In **Table 8** presents the estimates of DM productivity/ha of various forages that are commonly recommended for semiarid regions. Thus, they are equal


#### **Table 8.**

*Metabolizable Energy (ME) content and productivity expectation of different forages.*

to the potential for ME production/ha of forage cactus, which was 55,434 Mcal/ha (23,690 kg DM; 2.34 Mcal/kg DM). The average productivity of the forage cactus species was considered in the paper of [43]. The ME values of the various forages were taken from the Brazilian Tables of Feed Composition for Cattle [73].

It is impossible to achieve the productivity of the selected forages in semiarid conditions (**Table 8**) under low rainfall without irrigation. However, they should not be discarded, because they could be used, to a lesser extent in the diet, as a source of fiber.

Some other advantages justify spineless forage cactus use; for example, cows producing 15 kg of milk/day, fed with a diet contenting 50% of forage cactus, practically do not need water via a drinking fountain [74]. Spineless forage cactus is a perennial crop that allows for a reduction in implantation costs over time.

Due to its crude protein content (5.4%), CNF content (54.3%), and NDF content (24.8%), cactus cladodes combined with a cheap source of fiber (sugarcane bagasse, wheat straw) and NPN (urea), as a feeding strategy for ruminants, show very satisfactory results, including a reduction in the required amount of concentrated feed. [75] evaluated diets for crossbred lactating cows, with 61% forage cactus, 34.2% roughage, 1.7% urea, and only 3.1% soybean meal. They reported an average production of 11 kg milk/day. In another study, Holstein heifers, with an average weight of 243 kg, received a basal diet consisting of spineless forage cactus (69.8%), sugarcane bagasse (27.6%), and urea (2.6%), supplemented with 1 kg wheat bran per day. They showed an average gain of 0.71 kg/day [76]. Spineless forage cactus is an excellent feed for small ruminants. [77, 78] reported a positive performance for sheep with an average daily gain of 251 g/day, and lactating goats with average milk production of 2.97 L/day, respectively, when the animals were fed with spineless cactus.

A major issue that affects the global society is desertification, which is the process of land degradation in arid, semiarid, and sub-humid areas stemming from factors such as climatic variations and human activities [79]. Due to climatic conditions, soil characteristics, the inadequate exploitation of natural resources, and overgrazing, the Caatinga, a specific biome in Northeast Brazil, has become fragile and vulnerable [80]. In general, the causes of desertification in Northeast Brazil are not different from those typically found in other areas around the world. They are related to the exploitation of natural resources, to improper practices of land use (overgrazing and over-cultivation), and above all, to models of immediatism regional development [80].

It is necessary to consider the notorious contribution of livestock activity to the acceleration of the desertification process, along with the aforementioned climatic factor. According to [81], the use of semi-extensive or extensive livestock in semiarid areas becomes a factor in environmental changes due to the excessive stocking of animals in limits above the ecosystem's support. In the medium term, it exerts strong pressure on the floristic composition of the native vegetation due to the high palatability that is causing the extinction of species. It also exerts pressure on the soil due to the excessive trampling that causes compaction (in the rainy season)

*Spinless Forage Cactus: The Queen of Forage Crops in Semi Arid Regions DOI: http://dx.doi.org/10.5772/intechopen.100104*


#### **Table 9.**

*Caatinga management and biomass production vs. forage cactus.\**

and disintegration (in the dry season), which has negative effects on soil physical, chemical, and biological properties. In the long term, it contributes to the irreversible degradation of soils and vegetation, thus generating areas that are susceptible to the process of desertification.

The use of spineless forage cactus in areas where it can develop normally and may become the basis for ruminants' feed would increase the support capacity production systems. This would avoid the indiscriminate use of natural vegetation, mitigate desertification, and improve coexistence with the adverse conditions of the semiarid region. Taking Caatinga as an example that is an exclusive Brazilian biome with semiarid weather, vegetation with a few leaves and adapted to dry season, presents great biodiversities, but it is quite degraded by man.

According to [82], there are techniques for handling the Caatinga that can significantly increase the forage supply in that biome and contribute to its preservation. The main techniques used are thinning, lowering, and enrichment of the caatinga, with possible combinations between them. The thinning consists of making selective cuts in species of little forage and timber value, reducing the density of these plants in the area, thus allowing other species to develop and serve as a source of feed for the animals. Lowering is cutting the highest part of trees and shrubs to increase the forage supply for grazing animals. This practice makes forage in the pasture accessible, but it is not easily available because it has two meters high, becoming indicated for use in goat production systems or that combine goats and cattle. On the other hand, enrichment is a technique to improve forage production conditions by introducing perennial species. In addition to the benefits for herds, these management techniques help to regenerate native vegetation and optimize the use of forage resources (**Table 9**). There is a considerable increase in forage availability, from 400 (native caatinga) to 3600 kg of dry matter/ha/year (enriched caatinga).

Despite the increase verified with the manipulation of the Caatinga, it could be preserved using more productive species such as *Opuntia* and *Nopalea*, which would will produce much more in less area used fill less space. A comparison was made between the amount of dry matter in a hectare of native Caatinga or different management systems can make available to the animal and how much this would represent if forage cactus were used (**Table 9**). According to the simulation carried out, it can be seen that thousands of hectares of Caatinga could be preserved with the use of forage cactus. We must not forget that the forage cactus must be supplemented with fiber and nitrogen sources according to animal requirements.

### **6. Conclusion**

*Opuntia* spp. and *Nopalea* spp. are cultivated and have been income sources for farmers as fruit, nutrition, medicine and forage use. Cultural treatments such as weeding control, irrigation and fertilization; stand and spacing are extremely important factors to consider in the planting of forage cactus in order to increase productivity.

Specifically for Brazil's semiarid region these species can make the difference as forage for animal feeding, cultivated as monoculture or intercropped, for soil conservation and desertification mitigation, source of water for animals, preservation of the Caatinga biome and be a potential source of income for producers if cultivated as vegetable for nutritional properties and medicinal derivative of fruits and cladodes for exports.
