Development of sheep and goat production system based on the use of salt-tolerant plants and marginal resources in the United Arab Emirates

Small Ruminant Research 91 (2010) 39–46

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Review

Development of sheep and goat production system based on the use of salt-tolerant plants and marginal resources in the United Arab Emirates夽 S.A. Al-Shorepy ∗ , G.A. Alhadrami, A.I. El Awad Department of Arid land Agriculture, College of Food and Agriculture, United Arab Emirates University, P.O. Box 17555, Al Ain, United Arab Emirates

a r t i c l e

i n f o

Article history: Available online 24 February 2010 Keywords: Salt-tolerant plants Sporobolus virginicus Distichlis spicata Atriplex spp. United Arab Emirates Sheep Goats

a b s t r a c t In the United Arab Emirates (UAE), several programs and centers have been established to study and evaluate halophytic and salt-tolerant plant communities. A large number of halophytic species, acquired from various parts of the world, have been evaluated and field-tested under salt and seawater irrigation regimes at UAE University and International Center for Biosaline Agriculture (ICBA). Among these species, Sporobolus virginicus and Distichlis spicata were thoroughly evaluated and showed consistent yield potential and forage quality under high levels of salinity. Currently, these grasses are grown as irrigated crops on a large scale and mechanically handled and harvested at UAE University and ICBA. Several experiments were carried out at the UAE University on sheep and goats to investigate the effect of feeding Sporobolus and Distichlis grasses as well as a mixture of Atriplex shrubs on growth performance and carcass composition. In this paper, results of five experiments aimed to evaluate the performance of sheep and goats fed these plants were presented. Animals were allocated to several dietary treatment groups to have either Sporobolus and Distichlis grass hay or a mixture of Atriplex shrubs as a source of forage in a replacement series with the conventional forage Rhodes grass commonly used in the region. Two breeds of sheep (local and Awassi breeds) and one local breed of goats were used. The result data indicated that the productive performance or carcass characteristics of sheep were not influenced by the inclusion of different levels of Sporobolus grass hay in the diets. Similarly, the inclusion of Distichlis grass hay as the only source of forage up to 100% in the diet did not have any adverse effect on growth performance or carcass composition of growing local goat kids. These studies also showed that, incorporating Atriplex spp. shrubs and Sporobolus grass hay into mixed diets enhanced growth performance of local goats. It can be concluded that when managed properly, S. virginicus and D. spicata, have the economic and environmental potential to be used in an integrated forage-sheep and goats system particularly in marginal environments with low quality soil and water resources. © 2010 Elsevier B.V. All rights reserved.

1. Introduction

夽 This article is part of the special issue entitled “Potential use of halophytes and other salt-tolerant plants in sheep and goat feeding” guest edited by H. Ben Salem and P. Morand-Fehr. ∗ Corresponding author. Tel.: +971 3 7133442; fax: +971 3 7632384. E-mail address: [email protected] (S.A. Al-Shorepy). 0921-4488/$ – see front matter © 2010 Elsevier B.V. All rights reserved. doi:10.1016/j.smallrumres.2009.11.017

Demands of agricultural products, particularly in developing countries, are increasing rapidly. Consequently, land and water resources are unable to sustain such demands. In most developing countries, prime farmland and fresh water are already fully utilized. Maximizing the efficiency of resource utilization and identification of alternative

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resources to support agricultural production are becoming a priority in many developing countries. In arid environments resources are very limited, therefore marginal land and water resources have been used extensively. However, the extensive use of these resources has led in most cases to degradation and depletion of such resources. One of the main reasons for failure is the adoption of conventional production systems on marginal environments. Many arid and semi-arid regions in the world have soils and water resources that are too saline for most of the common conventional crop systems (Pitman and Lauchli, 2002). An alternative approach to the use of saline water and soil resources is the use of non-conventional plant production systems. However, the challenge in this case is the identification of economic and sustainable methods for the use of such plants. Salt-tolerant plants and halophytes can utilize land and water unsuitable for conventional systems for the economic production of fodder and other products (Masters et al., 2007). Arid environments are also characterized by extensive coastal deserts where only seawater or highly saline water and sandy soils are available. Halophytes grown in such desert environments have been shown to produce levels of biomass and seed production comparable to conventional crops (Lieth, 1994; Galvani, 2007). Therefore, the use of such marginal resources for the development of salt-tolerant plant-livestock production systems can provide a feasible and economic option (Glenn and Watson, 1993; Gihad and El Shaer, 1994; Swingle et al., 1996; Kraidees et al., 1998; Al-Dakheel et al., 2006, 2008). In the United Arab Emirates (UAE) a large number of halophytic plants acquired from various parts of the world, have been evaluated and field-tested under salt affected soil and seawater irrigation. Among these species, Sporobolus virginicus and Distichlis spicata were thoroughly tested for survival when irrigated with highly saline water ranging from 25,000 ppm up to seawater salinity levels (Lieth, 1994; Alhadrami et al., 1998). In this review, we present results of studies on the effects of inclusion of different levels of Sporobolus and Distichlis grass hay as well as a mixture of Atriplex shrubs in the diets on sheep and goat performance in the UAE. Large scale utilization of halophytes in the UAE is presented. 2. Overview of studies on halophyte in the UAE The history and importance of research and development on halophytic and salt-tolerant plant communities in the UAE have been reported (Boer and Lieth, 1999; Abdullah and Hasbini, 2004). Several programs and centers have been established in the UAE to evaluate such plants. The UAE University established the Zayed International Agricultural and Environmental Research Program in 1992 to study various salt-tolerant and halophytic plants. A large number of halophyte plants have been collected and evaluated and field-tested under salt and seawater irrigation. Currently, 28 plant species (native and exotic) are growing in UAE. Among these species, S. virginicus and D. spicata were thoroughly evaluated for survival when irrigated with high saline water ranging from 25,000 ppm up to seawater

salinity levels (Lieth, 1994). ICBA’s objective is to develop and promote the use of sustainable agricultural systems that use saline water to grow forages, field crops, vegetable, fruits and trees (Taha and Al-Attar, 2004). The experimental area consists of 14 blocks with a combined area of 35 ha. Each block is supplied with water of 3 salinity concentrations: low-salinity (2000–6000 ppm), medium-salinity (6000–15,000 ppm) and high-salinity (above 15,000 ppm) (Taha and Al-Attar, 2004). Research on mangroves and rehabilitation of coastal areas is conducted at the Marine Resources Research Center (MRRC) at Umm Al Quwain. The MRRC activities have been focused on the development of sowing and cultivation techniques to increase mangrove populations along the coast line of the UAE (Abdullah and Hasbini, 2004). Numerous large-scale projects on the ecology, distribution and germination of halophytes were carried out, and are being planned by the Environment Agency—Abu Dhabi since its establishment in 1995 (Boer, 2004). 3. Importance of sheep and goats in the UAE Sheep and goats are important meat producing animals in the UAE. In 2005, there were 2.6 millions sheep and goats out of 2.95 millions livestock in UAE (Ministry of Environment and Water, 2005) which represent more than 86% of the total livestock population. The indigenous sheep and goats constitute about 20–30% of the total number of the sheep and goat populations (Al-Shorepy, 2001; Al-Shoropy et al., 2002). The most common indigenous breed of sheep is called Mahali (local), which is characterized by a small to medium body size with average mature body weight of 35 kg, a thin tail with a slightly thick base, and is predominantly black (Alhadrami et al., 1997; Mansour, 1998). The popular indigenous goat breed (Emirati goats) is characterized by smooth glossy hair and its color/pattern is black with a brown or white belly and brown or white markings on the face and legs. Both males and females are horned. Adult males weigh on average 26 kg at 3 years of age while females attain a similar body weight at about 4 years (Al-Shoropy et al., 2002). Indigenous sheep and goat breeds are well adapted to a wide range of farming systems and their meats are preferred by the local population. Two types of production systems are practiced: traditional production system and semi-intensive production system. Under the traditional production system, sheep and goats make the best use of marginal grazing and browsing land, which covers most of the UAE. While under semi-intensive production systems, sheep and goat production depends primarily on feeding Rhodes grass, other grass hays and commercial concentrate. 4. Salt-tolerant plants under evaluation for fodder potential Description and chemical and mineral compositions of Sporobolus grass (S. virginicus), Distichlis grass (D. spicata) and Saltbush (Atriplex spp.) are reviewed in this section.

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4.1. Description of plant material 4.1.1. Sporobolus grass (S. virginicus (L.) Kunth) Sporobolus grass is a halophytic, perennial grass with buried rhizomes and erect branches to 25–30 cm tall. The grass is well adapted to a variety of different soils from clays to sands. S. virginicus produces seeds in which few of it is viable. However, the practical method of propagation is by vegetative rhizomatous slips. The grass is highly salt and wind tolerant. 4.1.2. Distichlis grass (D. spicata (L.) Greene) Distichlis grass is a halophytic, perennial, warm-season grass commonly found throughout the world. Above ground, the grass exhibits a pattern of paired blades which grow off opposite sides of the stem in the shape of a “V”. Below the ground, Distichlis grows and spreads through a network of rhizomes, a horizontal subterranean stem that sends out both roots and the shoots that eventually form the above-ground stems and blades. The roots system is generally dense but shallow. 4.1.3. Atriplex spp. Various species belong to Atriplex family and are distinguishable by their different morphology, biological cycle and ecological adaptations (Le Houerou, 1992). Because of their high crude protein content, and tolerance to drought and salinity, many species of Atriplex are excellent livestock fodder in arid and semi-arid areas. Atriplex halimus, Atriplex lentiformis and Atriplex nummularia are among the species of Atriplex introduced to UAE. These halophytes are considered a valuable source of forage in addition to positive effect on the environment. 4.2. Chemical composition The chemical and mineral composition of Sporobolus and Distichlis grasses and Atriplex shrubs are presented in Table 1. The chemical analysis of Rhodes grass was also conducted and is reported for comparison. Halophyte grasses (Sporobolus and Distichlis) contained lower crude protein (CP) than the conventional feed (Rhodes grass). However, NDF, ADF and ash contents of these two grasses are comparable with those of Rhodes grass. Atriplex shrubs contained higher level of CP and ash than the other grasses. Both halophyte grasses and Rhodes grass varied moderately in some minerals. Halophyte grasses had higher Na, P and Fe contents than Rhodes grass whereas the Rhodes grass had higher Ca and K (Table 1). Concentrations of other minerals in the halophyte grasses are similar to those in Rhodes grass (Table 1). Atriplex shrubs contained higher Ca, Na, K, Mg, Fe and Al and lower P than other grasses. Variation in chemical composition within Sporobolus and Distichlis grasses was detected. Al-Dakheel et al. (2008) reported the CP content of these grasses ranges between 6.3 and 9% DM and between 6.8 and 8.9% DM, respectively. Alhadrami (2003) reported a higher CP content (11.2% DM) of Sporobolus grass, this was attributed to the effect of fertilizing with urea few weeks prior to harvesting. Studies related to mineral composition of Sporobolus and Distichlis grasses are scarce. Bell and O’Leary (2003) studied the

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effects of salinity on cation accumulation of S. virginicus and concluded that this species is a euhalophytic grass that does not accumulate Na+ in response to salinity. Kazuto et al. (1989) found that S. virginicus could maintain a salt concentration at a lower level in the tissue against the external saline condition by a suppressive function to salt uptake and the exclusion of salt through salt glands of the leaves. Both grasses (Sporobolus and Distichlis) and the mixture of 3 Atriplex species (A. halimus, A. lentiformis and A. nummularia) varied greatly in mineral composition. The Atriplex mixture contained higher Ca, Na, Mg, Fe, and Al but lower P content than halophyte grasses. A wide variation in the mineral content of Atriplex spp. has been reported in the literature. This variation attributes to the difference in species, geographical regions, seasons and soil type (Valle and Rosell, 2000; Alazzeh and Abu-Zanat, 2004). Na content of Atriplex spp. found in our study (5.3%) is similar to that reported by Norman et al. (2008) in A. nummularia. Concentrations of some minerals in Atriplex spp. are higher than those recommended for ruminants and seem to reduce voluntary feed intake (Norman et al., 2004, 2008; National Research Council, 2005; Masters et al., 2007). 5. Research studies and main findings on fodder potential of halophytes 5.1. Experiment 1: growth performance of indigenous sheep fed S. virginicus grass hay grown in saline desert lands and irrigated with high salt content ground water (Alhadrami et al., 2005) This study aimed to evaluate the productive performance of local sheep fed a diet containing Sporobolus grass hay as the only forage source. Twenty-eight indigenous (local) ewe lambs were used in this study. Animals were randomly allocated to 2 treatment groups, with 14 ewe lambs each. Lambs in treatment 1 received Sporobolus grass hay (SGH), while lambs in treatment 2 received Rhodes grass hay (RGH) as the only source of forage. The following measurements were recorded or calculated: average daily gain (ADG, g/day); dry matter intake (DMI, g/day); feed conversion ratio (FCR) was calculated by dividing DMI by weight gain; total water intake (TWI); water consumption per unit feed intake (L/kg) was calculated as (TWI/DMI). Two stages were considered for statistical analysis: between 6 and 11 months of age, and gestation period. Feed and water intakes and growth performance for the local sheep are presented in Table 2. The average daily dry matter intake was higher (P < 0.05) for the animals fed Sporobolus grass hay (SGH) than those fed Rhodes grass hay (RGH). Animals in the SGH group consumed 689 g DM/day of Sporobolus grass hay while animals in the RGH group consumed 557 g DM/day of Rhodes grass hay at all stages. The SGH animals consumed about 23% more of water than the RGH animals did. Average water intake per day was higher during both stages in SGH group than in RGH group (P < 0.05). Body weight gains did not differ significantly (P > 0.05) between treatments at either stage. Nevertheless, a high growth rate was observed in the animals fed RGH at stage one. Animals fed SGH exhibited higher growth and

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Table 1 Chemical composition of Rhodes grass, Atriplex mixture, Sporobolus grass and Distichlis grass.

Crude protein (g/kg DM) Acid detergent fiber (g/kg DM) Neutral detergent fiber (g/kg DM) Ash (g/kg DM) Ca (g/kg DM) Na (g/kg DM) P (g/kg DM) K (g/kg DM) Mg (g/kg DM) Cu (mg/kg DM) Mo (mg/kg DM) Fe (mg/kg DM) Al (mg/kg DM) Zn (mg/kg DM) Mn (mg/kg DM) a

Rhodes grass

Atriplexa

Sporobolus grass

Distichlis grass

88.7 322.3 647.6 115.5 5.4 10.5 3.9 14.3 3.6 4 1 105 62 23 20

131.6 163.7 262.5 353.0 22.3 53.2 0.5 33.8 9.5 4 1 878 736 22 38

86.7 341.8 720.0 125.8 8.1 14.5 1.2 7.3 3.0 2 1 138 96 22 18

98.0 327.6 740.8 115.3 6.4 13.3 1.3 10.0 3.1 4 1 134 62 37 17

Atriplex mixture is a combination of three Atriplex species (A. halimus, A. lentiformis and A. nummularia).

recovered their growth rate even faster than animals fed Rhodes grass hay during the gestation period, which may be attributed to the increase in concentrate in diet from 200 to 300 g/day. Hence, the animals which received Sporobolus grass hay gained 16% more than those animals fed Rhodes grass hay during the first 3 months of gestation. The average daily gain for SGH and RGH, respectively, were 45 and 55 g during the first stage, and 78 and 73 g during the gestation period (Table 2). Feed conversion ratios were lower for animals in the RGH group than for animals in the SGH group at stage 1 (P < 0.05). However, the difference in feed conversion ratio was not significant at stage 2 (P > 0.05). The animals in this study were able to increase their feed intake to compensate for the lower organic matter content of the Sporobolus grass hay compared with Rhodes grass hay. Thus, it is possible that Sporobolus grass hay had laxative effects on the animals which resulted in increased feed intake and higher gain. 5.2. Experiment 2: effect of feeding long term S. virginicus grass hay on growth performance of Awassi sheep (Alhadrami et al., 2005) The objective of this study was to determine the feed and water intakes and productive performance of Awassi Table 2 Least square means of feed and water intakes and growth performance in indigenous ewe lambs fed either Sporobolus or Rhodes grass hay (Alhadrami et al., 2005). Item

Stage 1* SGH**

Daily forage intake (kg DM) Feed conversion ratio Daily water intake (liter) Water intake/feed (liter/kg DM) Initial body weight (kg) Final body weight (kg) Average daily gain (g) a,b

a

0.60 18.88a 3.17a 3.98a 16.98 21.02 44.9

Stage 2* RGH** b

0.52 13.99 b 2.43b 3.42b 17.61 22.8 55.2

SGH

RGH a

0.81 14.72 5.15a 4.62a 22.57 32.94 78.7

0.64b 12.82 4.63b 4.9b 24.60 34.38 67.8

Means in the same line with different superscripts are significantly different (P < 0.05). * Stage 1: 6–11 months of age; stage 2: gestation period. ** SGH: Sporobolus grass hay; RGH: Rhodes grass hay.

sheep fed a diet containing different levels of Sporobolus grass hay. Thirty-six Awassi 3-month-old ewe lambs were used in this study. The ewe lambs were randomly and equally assigned to 4 dietary treatments, which were initially formulated to have 100, 66.6, 33.4 or 0% Sporobolus grass hay, as a source of forage in a replacement with the conventional Rhodes grass commonly used in the region. Commercial concentrate was offered equally to all groups to meet animal requirements. Sporobolus grass was grown at the International Center for Biosaline Agriculture, UAE, and irrigated with ground water of high salt content (20,000 ppm). The amount of hay and water offered each time to the sheep was recorded daily. Refusals and wastage were weighed on the following morning. Three stages were considered: between 3 and 9 months of age, between 9 and 14 months of age and gestation period. The ewes fed 0% Sporobolus grass hay (100% Rhodes grass hay) served as the control. Feed and water intakes for the experimental ewe lambs are presented in Table 3 for the 3 stages. The average daily dry matter intake was higher for the animals fed the diet with Sporobolus grass hay than those fed Rhodes grass hay (P < 0.05). Water intakes varied among stages. Water intake for stage one was similar for animals fed diet containing 0, 66.6 or 100% Sporobolus grass hay. While in stage 2, animals fed the diet with 66.6% Sporobolus grass hay consumed the highest volume of water (P < 0.05). In stages 1 and 2, animals fed 33.4% Sporobolus grass hay consumed less water compared with the other 3 groups (P < 0.05). In stage 3, the animals that did not receive any Sporobolus grass hay (0%) consumed less water compared with the other 3 groups (P < 0.05). Body weight gains did not differ significantly between the 4 treatment groups in stages 1 and 3 (P < 0.05). However, animals fed 70% Sporobolus grass hay tended to gain more weight compared with those in the control groups in stage 2 (P < 0.05). In general, live-weight growth of Awassi sheep in the current study was comparable with Awassi and other tropical breeds at similar age; given a traditional forage (Gatenby, 1986; Galal et al., 2008). Kraidees et al. (1998) reported that Najdi lambs fed with diets containing Salicornia stems tended to gain weight faster than those

S.A. Al-Shorepy et al. / Small Ruminant Research 91 (2010) 39–46 Table 3 Least square means of feed and water intakes and growth rate in Awassi sheep fed different levels of Sporobolus grass hay (Alhadrami et al., 2005). Item

Proportions of Sporobolus grass hay in the diet 0%

30%

70%

0.54c 3.44a 6.58a 14.14 28.06 76.03

0.54c 3.08b 6.08b 14.54 27.43 70.42

Stage 2* Daily forage intake (kg DM) Daily water intake (liter) Water intake/feed (liter/kg) Initial body weight (kg) Final body weight (kg) Average daily gain (g)

0.69d 3.55b 5.11a 28.06 36.50b 49.35b

0.77c 0.89b 3.34d 3.70a 4.43b 4.13c 27.43 29.39 38.36ab 41.89a 67.88b 77.64a

0.96a 3.53bc 3.71d 28.17 38.22ab 62.46ab

Stage 3* Daily forage intake (kg DM) Daily water intake (liter) Water intake/feed (liter/kg) Initial body weight (kg) Final body weight (kg) Average daily gain (g)

0.93c 4.92b 5.28a 36.50b 46.88 65.58

1.05b 1.13a 5.17a 5.39a 4.86b 4.74b 38.36ab 41.89a 45.9 53.17 54.09 55.55

1.04b 5.26a 4.82b 38.22ab 48.17 51.00

0.64b 3.43a 5.55c 14.29 29.39 82.53

Table 4 Least square means of feed and water intakes in indigenous sheep lambs fed different levels of Sporobolus grass hay (Al-Shoropy et al., in press). Item

100%

Stage 1* Daily forage intake (kg DM) Daily water intake (liter) Water intake/feed (liter/kg DM) Initial body weight (kg) Final body weight (kg) Average daily gain (g)

0.71a 3.42a 5.28c 14.29 28.17 75.85

a,b,c

Means in the same row with different superscripts are significantly different (P < 0.05). * Stage 1: age between 3 and 9 months; stage 2: age between 9 and 14 months; stage 3: gestation period.

fed diets containing Rhodes grass hay. It was assumed that the body weight gain improvement might be related to increased body-water retention and accumulation of sodium (Kraidees et al., 1998; Masters et al., 2005). 5.3. Experiment 3: growth performances and carcass characteristics of indigenous lambs fed halophyte S. virginicus grass hay (Al-Shoropy et al., in press) This experiment aimed to assess the effects of the inclusion of Sporobolus grass hay as a source of forage into whole-mixed diets on growth, feed and voluntary water intake and carcass composition of indigenous lambs. Twenty male and 20 female indigenous lambs were used. Lambs from each sex were randomly and equally allotted to one of the 4 dietary treatment groups, which were initially formulated to have 100, 70, 30 or 0% Sporobolus grass hay, as a source of forage, with 5 lambs of the same sex per treatment. The group receiving no Sporobolus grass hay (100% Rhodes grass hay) served as control. The diet was formulated using chopped Sporobolus grass hay and/or Rhodes grass hay and commercial concentrate to provide a ratio of 40:60 forage and concentrate, respectively. At the end of a 63-day period, the male lambs were slaughtered. Lambs were fasted for at least 12 h and body weight (BW) was recorded before slaughter. After slaughtering, head, skin, feet and offal were removed and weighed. The reticulo-rumens were weighed full and empty and the weight of the gut content was calculated as the difference between full and empty weights. The 9th, 10th and 11th ribs were cut laterally to the vertebral column and

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Daily feed intake (kg DM) Daily water intake (liter) Initial body weight (kg) Final body weight (kg) Average daily gain (g) Feed conversion ratio Slaughter weight (kg) Empty body weight (kg) Hot carcass weight (kg) Hot dressing percentage (%) Digestive tract content (kg)

Proportions of Sporobolus grass hay in the diet 0%

30%

70%

0.83c 2.17d 14.05 21.7 121.43 6.9 24.9 20.32 10.6 42.16 4.58a

0.88b 3.007b 14.50 22.6 128.57 6.9 25.2 21.0 10.6 41.88 4.20ac

0.91ab 0.94a 3.24a 2.64c 14.25 14.30 22.95 22.35 138.09 127.78 6.6 7.5 27.3 25.2 22.62 21.28 11.51 10.68 42.0 41.92 4.68a 3.92bc

100%

a,b,c,d

Means in the same line with different superscripts are significantly different (P < 0.05).

parallel to the rib and subcutaneous fat thickness over M. longissimus dorsi (LD) muscle was measured with a caliper. The average daily feed intake per animal for both males and females was higher (P < 0.05) for the animals fed the diet containing 100% Sporobolus grass hay than those fed either 30 or 0.0% Sporobolus grass hay (Table 4). Daily water consumption per animal was higher (P < 0.05) for the animals receiving the diet containing 70% Sporobolus grass hay compared to the control animals. The volume of water intakes per unit of feed was higher (P < 0.05) for animals fed diet containing 70% Sporobolus grass hay than animals in the other groups. Both initial and final weights and average daily gains of animals were not significantly different between groups. Overall feed conversion ratio (FCR; kg feed/kg BW) was similar for all treatment groups. Ram lambs fed various levels of Sporobolus grass hay and slaughtered at the end of the experiment at approximately 145 days of age had similar weights of slaughter and hot carcass, and empty body weight. Lambs fed 100% Sporobolus grass hay had lower (P < 0.05) digestive tract content than those fed either 0 or 30% Sporobolus grass hay. Both physical and chemical compositions of ribs were not influenced by the inclusion of different levels of Sporobolus grass hay in the diets. Findings of this study suggest that inclusion of Sporobolus grass hay up to 100% in the diet did not have an adverse effect on growth performance or carcass characteristics of growing indigenous lambs. Therefore, Sporobolus grass could become important forage resources for sustaining small ruminant production in the saline coastal and subcoastal areas of the world. Although the water requirement of the animals is higher when feeding this grass, the net saving of fresh water is substantial. 5.4. Experiment 4: effect of dietary inclusion of halophyte D. spicata grass hay on growth performance and body composition of Emirati goats (Al-Shorepy and Alhadrami, 2009) This experiment was performed to study the effect of inclusion of Distichlis grass hay as a source of forage

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Table 5 Least square means of growth rate in Emirati goat kids fed different levels of Distichlis grass hay (Al-Shorepy and Alhadrami, 2009). Item

Total feed intake (kg DM) Daily feed intake (kg DM) Daily water intake (liters) Initial body weight (kg) Final body weight (kg) Average daily gain (g) Feed conversion ratio Slaughter weight (kg) Empty body weight (kg) Hot carcass weight (kg) Hot dressing (%) Intestine contents

Proportions of Distichlis grass hay in the diet 0%

33.4%

66.6%

100%

70.44bd 0.51bc 1.24c 11.81 15.63 55.33b 9.36a 17.80 15.31 8.61b 47.81b 4.71a

69.04cd 0.50b 1.57a 11.35 15.85 65.21a 7.78c 16.37 14.23 8.80ab 49.25ab 3.09c

72.20b 0.53ac 1.01d 11.18 16.18 72.46a 7.38d 18.45 16.16 8.60b 48.20 2.56cd

75.29a 0.55a 1.46b 11.40 15.90 65.30a 8.47b 18.50 15.98 9.00a 50.20a 3.91b

a,b,c,d

Means in with different superscripts are significantly different (P < 0.05).

into whole-mixed diets on growth, feed and voluntary water intake and carcass composition of Emirati goat kids. Eighteen male and 22 female local goat kids were used in this study. The kids were randomly assigned to 4 dietary treatments of the same sex, which were formulated to have 100, 66.7, 33.3 or 0% Distichlis grass hay as the forage in a replacement with the conventional Rhodes grass commonly used in the region. Commercial concentrate was offered equally to all groups to meet animal requirements. The kids were fed in groups of the same sex. The amount of feed offered each time to the goats was recorded daily. Refusals and wastage were weighed on the following morning. The kids had free access to water and the volume of water offered each time was recorded daily and the remaining was recorded on the following morning. The kids were weighed individually on a weekly basis before feeding. At the end of a 70-day feeding period, the male goats were slaughtered after being fasted for at least 12 h and weighed. The average daily feed intake per animal for both males and females was higher (P < 0.05) for the animals fed the diet containing 100% Distichlis grass hay than those fed diets containing either 33.3 or 0.0% Distichlis grass hay (Table 5). Also, the animals fed diets containing 66.7% Distichlis grass hay consumed more daily feed compared with those fed diets containing 33.3% Distichlis grass hay. Daily water intake differed significantly (P < 0.05) between the animals receiving diet containing 100% Distichlis grass hay compared to the control animals. These animals consumed on average 15% more water than the control animals did. The initial, final weights and average daily gains of goats were not affected (P > 0.05) by the diets (Table 5). However, goats fed diets containing Distichlis grass hay tended to gain weight faster than those fed on the control diet (100% Rhodes grass hay), but the difference was not significant (P > 0.05). Goats fed diets containing Distichlis grass hay had better (P < 0.05) feed conversion ratio (FCR) than the control goats (0% Distichlis grass hay). Among the diets containing Distichlis grass hay, the goats fed 66.7% Distichlis grass hay had the lowest FCR (P < 0.05).

The male goat kids fed various levels of Distichlis grass hay and slaughtered at the end of the experiment had similar (P > 0.05) slaughter weights and empty body weights (EBW) (Table 5). However, hot carcass weights and dressing percentage for the animals fed diets containing 100% Distichlis grass hay were significantly (P < 0.05) heavier than for the control animals. The goats fed diets containing Distichlis grass hay had lower (P < 0.05) intestine contents compared with those fed the control diet. It appears that the rate of passage of digesta might have accelerated in the lambs fed diets containing different levels of Distichlis grass hay. This implied reduction of digesta-residue time in the rumen which might have increased the dietary protein and soluble nutrients flow to the small intestine and resulted in increased absorption of nutrients of dietary origin and accounted for the lower feed conversion efficiency and higher gain. This is consistent with the findings of Kraidees et al. (1998) who reported a higher gain for lambs fed Salicornia stems than those in the control treatment. They further concluded that the changes in gain being presumably a direct consequence of the higher mineral intake on the Salicornia diets. 5.5. Experiment 5: effect of feeding saltbush (Atriplex spp.) and S. virginicus grass hay on growth performance of Emirati goats (Al-Shorepy et al., 2006) The objective of this study was to determine the effect of feeding a diet containing Atriplex plants and Sporobolus grass hay on growth, feed and water intakes in indigenous goats. Atriplex and Sporobolus grass were grown at the International Center for Biosaline Agriculture Twenty female Emirati goat kids were used in this study. They were randomly and equally allocated to 4 groups. Animals in the first group were fed a mixture (1:1) of fresh cut Atriplex spp. (A. halimus, A. lentiformis and A. nummularia) and Sporobolus grass hay. Animals in groups 2, 3 and 4 (control) were fed Atriplex and Sporobolus and Rhodes grass hay, respectively. The feed was provided free of choice and a mineral block was placed for each group. Feed and water intakes and growth rate are reported in Table 6. The total feed intake was higher (P < 0.05) for the animals fed the diet containing both Atriplex and Sporobolus grasses hay than animals in the other treatment groups. On average, animals fed both Atriplex and Sporobolus grass hay consumed 45% more feed than those fed either Atriplex or Rhodes grass hay. Similarly, animals fed the diet containing 100% Sporobolus grass hay consumed more feed (P < 0.05) compared with those fed either Atriplex or Rhodes grass hay. Daily water intake differed (P < 0.05) between the animals fed the diet containing both Atriplex plants and Sporobolus grass hay compared with the other treatment groups. Water intake did not differ (P > 0.05) between animals fed either Sporobolus grass hay or Rhodes grass hay (control animals), while animals fed the diet containing 100% Atriplex had the lowest (P < 0.05) final body weights. Animals fed both Atriplex and Sporobolus grass hay had better (P < 0.05) feed conversion ratio compared with those fed either Sporobolus hay or Atriplex plants. Results of hematology and serum biochemistry on

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Table 6 Least square means of feed and water intakes and growth performance of indigenous goat fed different levels of Atriplex and Sporobolus grass hay (Al-Shorepy et al., 2006). Item

Daily feed intake (kg DM) Daily water intake (liter) Initial body weight (kg) Final body weight (kg) Average daily gain (g) Feed conversion ratio a,b,c *

Dietary treatments* Atriplex:Sporobolus (50:50%)

Atriplex (100%)

Sporobolus (100%)

Rhodes (100%)

0.53a 2.9a 10.3 16.7a 42.70a 12.37

0.27b 2.4b 9.1 11.8b 18.00b 20.01

0.35ac 2.7c 10.4 15.8a 36.00a 9.29

0.27bd 2.6cd 9.4 16.2a 45.33a 6.80

Means in the same line with different superscripts are significantly different (P < 0.05). Atriplex: a combination of three Atriplex species (A. halimus, A. lentiformis and A. nummularia).

day 0 and at the end of the experimental periods showed that animals fed Atriplex had lower blood urea nitrogen (BUN) compared to the other treatment groups. Results of this study suggest that mixing both Atriplex shrubs and Sporobolus grass in sheep and goat diets resulted in better performances compared with other diets containing either 100% Sporobolus grass or Atriplex shrub. 6. Large scale utilization of halophytes in UAE The three plant species, S. virginicus, D. spicata and Atriplex spp. are grown at a large scale at UAE University and ICBA. Around 1.8 and 0.6 ha of salt affected lands are grown with S. virginicus and D. spicata at Zayed International Agricultural and Environmental Research Program and Atriplex spp. is grown on 0.3 ha. Plantations are irrigated with saline water with an average salinity level 25,000 ppm. The source of saline water is from 50 to 60 m deep wells. The system of irrigation is run automatically and care is taken to ensure that the system is kept free of debris and contamination to ensure the operation is controlled consistently. The two grass species, S. virginicus and D. spicata are irrigated through micro-sprayers whereas Atriplex shrubs are irrigated through drip irrigation. The grasses are cut between 3 and 4 times per year. The average annual yield of each grass is around 35 t of dry matter/ha/year. Atriplex shrubs are cut weekly but there is no recording of dry matter production. Two flocks of sheep and goats consisting of 77 and 36 head, respectively are kept in the farm. These animals were fed with Sporobolus and Distichlis grasses as well as Atriplex shrubs as the only source of forage. They were provided with an average of 1.2 kg DM/head/day. The growth and reproductive performances of these flocks are recorded and monitored. No health problems related to the feed have been noticed. Preliminary analysis of the collected data indicated that reproductive efficiency and early weights are similar to those fed conventional feed (Rhodes grass). ICBA has established two fields’ sites each with 0.6 ha for S. virginicus and D. spicata (Al-Dakheel et al., 2008; Al-Dakheel, ICBA, personal communication). Different combinations of management inputs were applied to determine optimum production packages. They included 3 salinity levels, 3 irrigation levels and 4 fertilizer levels. The grasses were mechanically harvested and baled. Average dry matter production ranged from 30 to 40 t/ha in D. spicata and 30–36 t/ha in S. virginicus. Seasonal variations in yield were observed for both species. Highest yields were

obtained during summer and fall harvest and lower yields during winter harvest. 7. Conclusions The long-term field evaluation of the productivity of 2 non-conventional highly salt-tolerant species, S. virginicus and D. spicata, showed that when managed properly, the 2 species have the economic and environmental potential of using them in an integrated forage-livestock system particularly in marginal environments with low quality soil and water resources. Results of the feeding experiments suggest that inclusion of Sporobolus or Distichlis grass hay up to 100% of the forge component in the diet did not have any adverse effect on growth performance or carcass characteristics of both sheep and goats. Moreover, animals fed a diet composed of 2/3 either Sporobolus grass or Distichlis grass hay performed the best and the performance was similar and sometimes better than animals fed a conventional feed (Rhodes grass). Also, it was found that mixing both Atriplex shrubs and Sporobolus grass in sheep and goat diets resulted in better performances compared with other diets containing either 100% Sporobolus grass or Atriplex shrub. In addition, raising sheep and goats fed on 3 salttolerant plants as the only source of forage resulted in normal reproduction and growth. Acknowledgement This work was financially supported by the Research Affairs at the UAE University under a contract no. 07-612/02. References Abdullah, M., Hasbini, B.A., 2004. Prospects of biosaline agriculture in the United Arab Emirates. In: Taha, F.K., Ismail, S., Jaradat, A. (Eds.), Prospects of Biosaline Agriculture in the Arabian Peninsula. Amherst Scientific Publisher, Amherst, MA, USA, pp. 15–25. Alazzeh, A.Y., Abu-Zanat, M.M., 2004. Impact of feeding saltbush (Atriplex sp.) on some mineral concentration in the blood serum of lactating Awassi ewes. Small Rumin. Res. 54, 81–88. Al-Dakheel, A.J., Alhadrami, G.S., Al-Shorepy, S.A., AbuRummani, G., 2006. Optimizing management practices for maximum production of two salt-tolerant grasses: Sporobolus virginicus and Distichlis spicata. In: Proc. 7th Annual UAE University Res. Conf., vol. 2, pp. 44–50. Al-Dakheel, A.J., Alhadrami, G.S., Al-Shorepy, S.A., Shabbir, G., 2008. The potential of salt-tolerant plants and marginal resources in developing an integrated forage-livestock production system. In: 2nd International Salinity Forum Salinity, Water and Society–Global Issues, Local Action, Adelaide, South Australia, Australia, pp. 1–7.

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