Livestock Research for Rural Development 27 (3) 2015 Guide for preparation of papers LRRD Newsletter

Citation of this paper

Seasonal variations in the chemical composition and nutritional characteristics of three pastoral species from Algerian arid rangelands

R Mayouf and F Arbouche1

Department of Agronomy, Faculty of Sciences, Hadj Lakhdar University, Batna 05000, Algeria
1 Laboratory of Agriculture and Ecosystem Functioning, Faculty of Sciences, El-Tarf University, El-Tarf, 36000, Algeria


The main objective of this study was to determine the quality of the pasture in the arid region of Algeria. Three dominant shrubs ( Haloxylon schmittianum, Anabasis articulata and Astragalus armatus) were analyzed to characterize the chemical properties, in vitro organic matter digestibility and nutritional value. Samples were collected during a period of one year (from December 2011 to November 2012) to evaluate the variations in the chemical composition and nutritional characteristics between the dry and wet seasons.

Results showed that the three species differed significantly in their nutrient composition in both seasons except for the Ash and organic matter (OM) which did not differ between seasons. Crude protein (CP) and neutral detergent fiber (NDF) differed significantly between species and among the seasons. The Crude protein (CP) content of the browse species was higher in the wet season compared to dry season, A. Articulata had the highest values (173 and 112 respectively), the lowest forA. armatus (126 and 85 respectively). The NDF values ranged between 417 in H. schmittianum and 446 in A. armatus for the wet season while for the dry season on DM basis, the values ranged from 429 to 491 in H. schmittianum and A. armatus, respectively.In vitro Organic matter digestibility (IVOMD), digestible organic matter (DOM) and estimated net energy (NE) varied significantly between species and seasons, H. shmittianum had the highest values during the both seasons, while A. armatus had the lowest values. Generally, apart from the differences among species within a same season, for each species, there was a significant difference in nutrient composition between the dry and wet season. The present study showed that the three fodder shrubs had a good nutritive value for wet season feed, while A. armatus require a supplementation of nitrogen for dry season. However, further research is needed to assess the changes on the nutritional value of pastoral shrubs at different phenological stages

Key words: in vitro digestibility, nutritive value, season, semiarid, shrubs


In the natural pastures of Algerian steppe, the forages browsed by the livestock can be classified into two main groups; ephemeral annual plants which germinate and growth for only a few weeks after raining, and perennial shrubs and tree fodders. The diversity and relative abundance of fodder plants has allowed the steppe to provide animal food for 15% of the Algerian population, and represents the main source of red meat for the population as a whole (Aidoud 1994). The quality of nutrition is a key factor of any ruminant that wants efficient. They must receive all the essential dietary nutrients in optimal amounts. However, several factors are involved, and largely responsible for situations deficiencies as: intensification of farming, climate instability, fertilization, soil characteristics that influence the bioavailability of these nutrients. In arid and semi-arid regions of eastern Algeria, the food situation is characterized in ruminants by insufficient forage offers both quality and quantity. Field farming is especially extensive. The diet of these animals is formed by a spontaneous annual vegetation of natural pastures, fallow and by residues from agriculture.

Trees and shrubs play an important role in ruminant feeding systems in semiarid areas. Studies on some fodder shrubs from Algerian semiarid regions have shown a positive effect on the performance of animal. Therefore, evaluation of the nutritive value of species, commonly used as feed resources, would be important to intensify their utilization (Haddi et al 2009). However, in Algeria, studies related to the ingestion and digestion in ruminant on semi-arid areas rangelands are relatively recent (Haddi et al 2009; Arhab et al 2009; Boufennara et al 2012; Bouazza et al 2012). Such research should be continued to develop appropriate methods for the estimation of the average intake and digestibility taken vegetation during the year to share periods of complementation for the safeguarding and/or improve the production of this species. In the other hand, this could encourage farmers that are responsible for rational and sustainable management of the rangelands to preserve this threatened area from desertification (Ben Arfa et al 2004). Therefore, the aim of this work was to study the chemical composition, in vitro organic matter digestibility and nutritive value of three important fodder species in a arid area of Algeria. This area was selected in this study as a good model of Algerian steppes because the browse constitutes the major food resource for goats, camels and sheep in this region.

Materials and Methods

Description of the study site

The study site is an arid zone and was located on the southeast of Algeria, region of Tebessa (34°28’59’’ N and 7°31’0’E). The trial was carried out during a period of one year (December 2011 to November 2012). This region is characterized by altitude level of 316 m, with a typical Mediterranean climate. The coldest month is December, with occasional freezing (down to -2°C) in January and February. The period between July and August is the hottest, sometimes extremely hottest, during which temperatures can reach as high as 46°C (in the shade). The rainfall is characterized by low averages, high irregularity and torrential downpours. Generally, the region receives between 100 and 300 mm per year. Samples were collected from the pastures every first week of each month.

Chemical analysis

Before analyses, the samples were dried for 48 h at 60°C and then, the samples were weighed and ground in a hammer mill, provided with a 1 mm pore size screen. The chemical analysis of plants was performed according to the methods of the Association of Official Analytical Chemists (AOAC 1990). The dry matter (DM) content of plants was determined by drying to constant weight at 105°C, and ash after heating at 550°C until a constant weight has been reached. In this analysis, the following contents: organic matter, crude protein (CP = 6.25 × nitrogen), ether extract (EE), nitrogen free extract (NFE) were analyzed according to standard methods (AOAC 1990), neutral detergent fiber (NDF), acid detergent fiber (ADF), acid detergent lignin (ADL) were determined according to (Van Soest et al 1991). Organic matter in vitro digestibilities of samples was determined by the method (Aufrere 1982). Based on digestible organic matter (DOM) content of forages, metabolizable energy (ME, MJ kg−1 DM) content of the shrubs was estimated according to (MAFF 1984) equation (ME = DOM% X 0.015). The net energy for lactation (NE) content was calculated using the ratio NE/ME = 0.60 (Sauvant and Morand-Fehr 1991), where ME is the metabolizable energy content of the feed.

Statistical analysis

Different experimental groups (constituents and parameters) were compared with the Univariate ANOVA followed by Bonferroni’s test for comparisons post hoc. A probability level of P≤0.05 was considered to be statistically significant. The SPSS software package (SPSS Ver. 15.0, SPSS Inc., Chicago, Illinois) was used for all tests.

Results and discussion

Chemical compositions of shrubs samples are shown in Table 1. The dry matter contents ranged from 721.1±1.0 g/kg DM for A. articulata to 834.0±2.5 g/kg DM for A. armatus in wet season. While in the dry season, the DM content was 894.7±3.1 g/kg DM in H. schmittianum and 910.7±2.0 g/kg DM in A. armatus (Table 1). The DM concentrations recorded for the three shrubs in this study were within the ranges reported by Bouazza et al (2012) under similar conditions in Algerian arid and semi-arid areas. All the shrubs contained sufficient DM to support a reasonable amount of DM intake.

The present study showed that the dry matter contents of our shrubs were influenced by seasons and species. This is because dry season values were significantly higher (P<0.05) than those of wet season.

Table 1 . Mean chemical composition (g/kg DM ± SD) of the biomass from the three collected shrub species.

Chemical composition per season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season




The ash content varied from 114 g/kg DM to 198 g/kg DM in the dry season, whereas in the wet season, varied from 108 g/kg DM to 191, this result was compared than the values reported by Arhab et al (2009). Ash concentrations differed (P<0.05) between species; but seasonal effect was not observed. The high value of Ash could be attributed to the climate effect and especially to the high temperatures and the sand accumulation on the aerial part of the plant.

The crude protein (CP) content of the browse species ranged from 85 g/kg DM in A. armatus to 112 g/kg DM in A. articulata during the dry season. Corresponding values for wet season ranged from 126 to 173 g/kg DM in A. armatus and A. articulata, respectively (Table 1). The CP values were similar to those reported for other Mediterranean shrubs (Arhab et al 2009; Ammar et al 2004).

Additionally, the CP content of the three species was higher in the wet season than in the dry season (P<0.05). This was consistent with previous studies that conducted in areas with distinct wet and dry seasons (Safari et al 2010; Yayneshet et al 2009, Hassen et al 2007). The protein content decreased with advancing dry season for the three shrub species. This decline in nutrient contents could be related to the stage of maturity (Rawnsley et al 2002). Mero and Udén (1998) have reported that the levels of protein at young stages of plant growth are usually high; at the end of vegetative stage achieve the maximum values and declining as plants matured.

The CP content of the shrub species studied herein is higher, mainly in the wet season, than the minimum level of 7 to 8% DM required for optimum rumen function and feed intake in ruminant livestock (Van Soest 1994). This suggested that fodder shrubs can support maintenance requirements and certain level of production in ruminants.

The NDF content varied between species and seasons (P<0.05). The highest NDF content was recorded for A. armatus in the dry and wet seasons (491 and 446 g/kg DM, respectively) while H. schmittianum had the lowest values in both seasons (429 and 417 g/kg DM). In the dry season, the lowest ADF content was recorded in A. articulata (258 g/kg DM) while the highest value was recorded in A. armatus (328 g/kg DM) . In the wet season, H. schmittianum had the lowest ADF content (417 g/kg DM) while A armatus had the highest (300 g/kg DM). The values of ADL ranged from 56 g/kg DM in H. schmittianum to 86 g/kg DM in A articulata in the dry season, but in the wet season, ADL ranged from 91 g/kg DM in A articulata to 98 g/kg DM in A armatus (Table 1). A. armatus had relatively higher NDF, ADF, than A. articulata and H. schmittianum. The NDF level of A. armatus was higher than that reported for other browse species during the dry season in eastern Algeria by Bouazza et al (2012), but was lower than reported by Arhab et al (2009). Differences in NDF may be related to proportion of leaf and twigs in samples used for chemical analysis. The ADL levels were within ranges reported for some browse plant species in Algeria (Boufennara et al 2012).

The IVOMD (Table 2), varied significantly between species and seasons. During the wet season, IVOMD varied from 56 % in H. shmittianum to 40 % inA. armatus. During dry season, IVOMD ranged between 48 % in H. shmittianum and 32 % in A. armatus. It is important to note that H. shmittianum had the highest IVOMD in both season followed by A. articulata. For the DOM contents, H. shmittianum had the highest values in the dry and wet season, 422 and 485 g DOMkg-1DM respectively, hawever A. armatus had the lowest values, 261 and 330 g DOMkg-1DM.

Table 2. Mean Organic matter digestibility (% DM± SD), digestible organic matter (g/kg DM± SD) and estimated net energy content (MJ/kg DM± SD) of shrubs.

Parameters per season





Dry Season




Wet Season





Dry Season




Wet Season





Dry Season




Wet Season




IVOMD and DOM content of the three shrubs were lower than those found by Ventura et al (2004) and similar to those found by Kokten et al (2010) for other Mediterranean shrubs. Other researchers (Rogosic et al 2006, Mokoboki et al 2005) have reported values lower than that of H. shmittianum and A. articulata, but higher than that of A. armatus. Considering the estimated net energy content of shrubs (Table 2), values had a significant difference among species and seasons. The lowest content was recorded for A. armatus in the dry and wet seasons (2 and 3 g/kg DM, respectively) while H. schmittianum had the highest values in both seasons (3 and 4 g/kg DM). The NE content (Table 2) of these shrubs was higher than that estimated by Bovolenta et al (2008) and Rogosic et al (2006), with the highest contents in wet season. Between wet and dry season, it was observed increases in Ash, NDF and ADF, while CP and EE declined. This causes a reduction in OMD and a decline in NE.



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Received 10 December 2014; Accepted 19 January 2015; Published 3 March 2015

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