Management and utilization of browse species as livestock feed in semi-arid district of North Ethiopia

Teferi Aregawi, Solomon Melaku* and Lisanework Nigatu*

Humera Agricultural Research Center, Humera, Ethiopia
*Haramaya University, PO Box 138, Dire Dawa, Ethiopia

solmelay@yahoo.com

Abstract 

The research was conducted in eight representative farmers associations in Abergelle, a semi- arid district of Tigray, Ethiopia. The objectives of the study were to identify the major browse species, their management as well as their utilization by livestock. The information about the browse species were collected using structured questionnaires. Twenty browse species were identified to be most important in the district.

According to the respondents, nearly all the domesticated ruminants in the survey area consumed browse species. Browses were utilized in both wet and dry seasons. Certain browse species are deciduous, while others retained leaves late into the dry season. Leaves, pods, twigs and flowers were the plant parts utilized by livestock. However, leaves were the most preferred plant fraction utilized by livestock. The browse species were found on grazing land, crop land, around homesteads or grown on boundary between farm lands. The mode of utilization of the browse species for livestock feeding did not employ any sort of management for optimum use.

Therefore, more emphasis has to be paid to maintain the biodiversity of the browse species as well as to enhance their role in improving animal productivity in semi-arid conditions similar to the study area.

Key words: Ethiopia; feed resources; ruminants; survey

Introduction

Despite the large livestock population in Ethiopia, the productivity of livestock is low with 8 kg of beef produced annually per head of cattle (ILCA 1993) and with average milk yield of 1.23 liters per cow per day (CSA 2005). The major bottleneck limiting productivity of livestock is poor supply and low quality of feeds. The problem of feed supply and quality is even more aggravated in arid and semi-arid areas with erratic and unreliable rainfall. In such areas, the erratic nature of the rainfall hampers crop production. This in turn affects the quantity of crop residues available for feeding to livestock. Low and erratic rainfall also severely affects the growth of grass and other forages. Thus, animals in these areas have to survive only on range vegetation that have low nutritive value for most part of the year. The crude protein (CP) content of range vegetation is between 8- 12% of dry matter (DM) at the beginning of rainy seasons, but drops to 2- 4% in the four to six month dry season (Amaning-Kwarteng 1991), leading to prolonged period of under nutrition and malnutrition.

In an effort to alleviate the animal feed supply problem, looking for potential feed resources, particularly those which survive during the dry season, deserves due attention. In this regard, the use of browse species has great potential. As mentioned in many studies (Bamualin et al 1980; Ibrahim 1981; Devendra 1990) the importance of these plants in the arid and semi-arid areas is well recognized throughout the world. The major use of foliage of browse species is as a source of CP. This quality of browse species is most useful during the dry season when most of the range grasses and other herbaceous species dry off (Devendra 1990). The ability of most browses to remain green in the dry season is attributed to their deep roots that enable them to extract water and nutrients from deep in the soil profile. Moreover, leguminous browse species fix atmospheric nitrogen, and this increases soil fertility that can be utilized by the companion or subsequent crops grown in the area (Atta-Krah 1990), and also contribute to the increased CP content of the foliage of browse species. Browse species also provide fuel and shelter and are used in soil and water conservation.

Abergelle district, where this study was conducted, has mixed crop-livestock production system, with livestock production, especially small ruminant production being dominant. The district has largely semi- arid to arid climatic conditions, and browse species are the main vegetation types in the district. Livestock mainly depend on foliages of the browse species as feed source. Despite the wide use of the indigenous browse species, little has been documented with regard to the major species found in the district, the traditional management practices as well as extent of their utilization. Thus, the objectives of this study were to identify the major browse species, their management and manners of utilization in Abergelle district.

Materials and methods 

Description of the study site

Abergelle district is found in Tigray Regional State, Ethiopia. It is located at 13^o 14^' 06^" N latitude and 38^o 58^' 50" E longitude. Its area coverage is about 1225 km². The total number of farm households in the district is estimated at 14,194 and the average landholding per household is estimated at 1 hectare (CSA 2000). The district is categorized as a lowland area (less than 1500 masl); the area is situated in the hot to warm sub-moist lowland (SM1-4) sub-agro ecological zone of the region, which is characterized by low and erratic rainfall. A five-year (1999-2003) rainfall recorded in the district indicated that the highest rainfall (756 mm) was received in the year 1999, followed by 2003 (650 mm) and the lowest (130 mm) in 2002. The annual temperature ranges from 24 to 41^oC (Yilma 1999). According to CSA (2000), cultivated land covers 89,550 hectares, natural forest cover about 8,475 hectares, reforested area make up about 121 hectares and miscellaneous land use types (includes bare lands, marginal lands, rock outcrops, roads and very steep slops of unproductive land) cover about 24,354 hectares. Soils in the study area are of diverse types with low OM content. Sandy loam soils (63.73%) are predominant followed by clay and clay loam soils (30.47%) and silt loam (5.8%) (BoANR 2000).

Selection of the study site and sampling methods 

In Abergelle district, 16 farmers associations (FAs) with distinct boundaries are found. Out of the 16 FAs, 8 were selected for the survey study. Purposive sampling technique was used in selecting the 8 FAs with the intention of covering those FAs where indigenous browse species contribute significantly to animal feed resources, and those with different altitudinal ranges, farming systems and fair accessibility. From each FA, 10 farmers were randomly selected (total 80 farmers). Semi-structured questionnaire was developed to collect data on the animal feed situation of the area, the practice of feeding browse species to animals, the type and parts of browse species preferred, problems associated with feeding browse species to animals, and the traditional measures taken by farmers to solve the same. In addition, relevant information for this study was collected from Bureau of Agriculture and Natural Resources and other organizations in the district.   

Methods of identifying of the browse species and data analysis

Specimens of the browse species encountered in the study area were collected, pressed, labeled, dried and taken to the National Herbarium of Addis Ababa University for proper taxonomic identification. Identification of the different browse species followed the Flora of Ethiopia (Hedberg and Edwards 1989) and the Flora of Tropical East Africa (Cufodontis 1953- 1972). Descriptive statistics was used to analyze the data.

Results and discussion 

Browse species in Abergelle district

In a survey conducted in the representative FAs of Abergelle district, 20 indigenous browse species were reported as useful feed resources for cattle, goats, sheep and camels (Table 1).

Nearly all the domesticated ruminants in the survey area consumed browse species at one time or another during the year, depending upon availability (Table 2), availability of alternative feed resources and the preference by the animal species. Moreover, introduced browse species such as Sesbania sesban and Leucaena leucocephala were found scattered in grazing land, croplands and at home compounds in some FAs, although their abundance, distribution and utilization was very limited. 

Distribution of the browse species

Distribution of the browse species was not uniform throughout the district with spatial distribution of the browse species being variable in the different FAs (Table 3). The uneven distribution of browse species throughout the district is in agreement with that reported by Brinkman and de Leeuw (1976). The authors suggested that the existence of different types of browse species between and within localities, and their distribution tendencies with any spatial arrangement could be explained by lack of proper management and by the characteristics of their reproductive structures. The majority of the species produce small fruits with hairs, bristles or scales, which facilitate their dispersion by wind or by attaching themselves to human clothing or to animal hair. The reproduction of these species appeared to be based on the abundant production of seeds for easy dispersion and with a fast vegetative growth and development.

Browse utilization in Abergelle district

The browse species were used as livestock feed both in the wet and dry season. In the wet season, most of the foliages were consumed directly from the live plant and some of them were lopped and sometimes offered as cut and carry feed. Cut and carrying to home was mostly meant to feed sick or young animals. In the dry season, leaves and pods from deciduous trees and shrubs were consumed after they had fallen naturally to the ground. These deciduous parts represented the larger quantity consumed during the first three months of the dry season (December, January and February). These parts consisted of any thing that were previously out of reach of the livestock, but also of whatever were not palatable at the living state to cattle, but may be consumed readily when dropped from the live tree like foliages of Boswellia papyrifera, Sterculia africana and Terminalia brownii. Moreover, herdsmen facilitate improved accessibility of leaves, pods and other edible portions of the browse species to livestock during the dry season by using stick or stones or by shaking the browse plants/ branches or lopping their branches.

Feeding preferences of livestock on the various browse species

Some browses were consumed preferentially by certain livestock species, but not by others. Cattle were much more selective in feeding on browse species than goats. According to the farmers, cattle generally showed a marked preference for browses with soft leaves, short in height and without spine. Species like Acacia asak, Acacia lahai, Acacia oerfota, Acacia  tortilis, Dichrostachys cinerea and Ziziphus spina-christi, due to their thorny nature and Ximenia americana due to its rough leaves, were not highly preferred by cattle, particularly when they had a choice. But, animals like goats and camels showed interest even for thorny browses and rough leaves. Goats were observed to be better than cattle by feeding directly on foliage of the browse species, while they were intact on the plant. On the other hand, cattle were better than goats at consuming many of the deciduous parts of the browse species. The improvement in palatability of the leaves of browse species after leaf shedding was explained by Lowry (1995) who stated that leaves that might be toxic or unpalatable in their living state could be less so after shedding, as adverse secondary metabolites might have translocated from the leaf. He also indicated that for many native browse species, the deciduous foliages could be of higher feed value than the intact mature grasses during the dry season. However, livestock would have to utilize the leaves soon after it fell to avoid deterioration in quality.

Seasonal availability of foliage of browse species

Certain browse species shed leaves early in the dry season, while others retained leaves late into the dry season. Livestock herders in the district preferred those browse species which could retain leaves late into the dry season so that more feed could be supplied at critical times of the year when there is less fresh vegetative biomass available for feeding to livestock. Browse species like Sterculia africana, Boswellia papyrifera and Acacia oerfota shed their leaves relatively early in December (Table 4) and browse species like Dichrostachys cinerea, Ziziphus spina-christi and Acacia  tortilis retain leaves until June. When rain starts falling, Acacia oerfota and Acacia lahai regenerate earlier than the other browses. Some farmers were observed to cut the browse species like Terminalia brownii at the beginning of the wet season so that the plant will coppice and retain leaves into the dry season. The farmers’ practice of cutting the browse species during the wet season to get high dry matter yield during the dry season is in agreement to the study of Acheampong and Muzinga (1994) that reported leaving the browse species uncut for longer than six months resulted in low fodder yields because of leaf senescence. According to their results on Calliandra calothyrsus, the highest quantity of dry season production was obtained from the plants that were cut six months before the driest month.

Pattern of utilization and problems associated with the use of browse species

Parts of the browse species utilized by livestock were leaves, pods, twigs and flowers. In all browses, leaves were the plant parts mostly utilized by livestock. The pods of Acacia  tortilis and Dichrostachys cinerea were important feed resources for goats during the dry season. Dried leaves were found to be more palatable for cattle and goats than wet leaves from broad leaved browse species like Terminalia brownii, Boswellia papyrifera and Sterculia africana. Farmers indicated that some of the browse species such as Acacia oerfota were not palatable to livestock due to possessing a strong disagreeable odor that occurs when the leaves are crushed. Similar observation of strong odor was reported to reduce palatability in other browse species such as Gliricidia sepium (Nochebuena and O’ Donovan 1986). However, the negative palatability factor in Acacia oerfota arising from the bad odor was reduced by wilting it for some hours before offering it to animals, and this was observed to improve its intake. Wilting of the leaves perhaps contributed to the reduction or elimination of some anti-nutrients contained in Acacia oerfota. Farmers in the study area associated digestive problems with feeding of the pods of Acacia amara. Wilted leaves of Acacia asak also caused digestive disorder (diarrhea). Thorniness (Acacia asak, Acacia lahai, Acacia oerfota, Acacia  tortilis, Dichrostachys cinerea and Ziziphus spina-christi) was also mentioned as a problem in the utilization of these browse species for livestock feeding. However, the problem was mentioned to be serious for cattle than goats.

Multiple uses of browse species

Nearly all the browse species were reported to be of multipurpose use (Table 5). Among the 12 most preferred browse species as livestock feed, all except Acacia oerfota and Dichrostachys cinerea were used as fuel wood. With the exception of Acacia lahai and Acacia oerfota, all were used for construction. About 45% of the browse species were used for making farm utilities. Other uses included fruits for human food, traditional medicine, for beekeeping and gum used as frankincense. Similar uses of browse species were reported by Bekele (1993) in Ethiopia and Roothaert and Franzel (2001) in Kenya.

Niches of browses in the farming system, their establishment and management

The niches in the farming system where the local browse species grow were not similar. Some of them were found scattered on grazing lands or croplands. A few species were found around homesteads (Terminalia brownii) or grown on the boundary between adjacent crop fields. Most of the browse species were observed to regenerate and establish naturally, but farmers do not let them grow to maturity. The browse plants in the district were owned communally, except the browses grown around homesteads and on private farmlands. Extensive deforestation and intensification of land use for crop cultivation has undermined the proper handling of browse species in the area. Processing and preservation of browse foliages were non-existent in any of the FAs.

Conclusions 

The results obtained indicted the multipurpose use of browse species and their potential use in animal feeding during periods of feed scarcity in areas with limited precipitation and natural endowment.

References 

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Received 3 December 2007; Accepted 11 March 2008; Published 10 June 2008

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