Acacia cyanophylla lindl as supplementary feed/for small stock in Libya*

D. Dumancic ^a and H.N. Le Houérou ^b
a Agronomist, FAO Expert in Fodder Crops, FAO Project TF Lib 10
^b Range Science Consultant, FAO Projects: TF Lib 10 and 11 and Jeffara Plain Authority,
Ministry of Agrarian Reform and Land Reclamation, Tripoli

1. Introduction

2. Material, methods and conditions of the experiment

3. Results

4. Discussion

5. Summary

References

1. Introduction

Some 40,000 hectares of fodder shrubs were planted in Libya in 1976-79. These are essentially Acacia cyanophylla, Atriplex halimus, A. nummularia, A. canescens A. lentiformis and Opuntia ficus-indica, var. inermis. (Le Houérou, 1978, 1979, 1980; Bouchamaoui et Hadri, 1980) A few hundred hectares of other species of fodder shrubs were planted as well in various sites, notably: Acacia liqulata, A. aneura, A. salicina, A. victoria, Calligonum comosum, C. arich, C. azel, Periploca laevigata, Morns alba, Prosopis juliflora, Eucalyptus albens, Medicago arborea, Cassia sturtii, Colutea arborescens.

These plantations were carried out in solid blocks of 5–50 hectares for two main purposes:

1. Reserves for the seasonal feed shortage occurring every year from August to December (last seasonal rains occurring usually in April and the first in October).
2. For buffer feed reserves as part of a drought-evading strategy for "abnormal" periods of prolonged droughts, which may occur at any time of the year, irregularly, one year out of three to five, as an average.

This overall strategy was described by Le Houérou and Froment (1966): 'Definition d'une doctrine pastorale pour la Tunisie steppique' (see References) and, in the case of Libya, by Le Houérou (1965, 1974, 1979, 1980).

2. Material, methods and conditions of the experiment

An experiment of supplementary feeding with Acacia cyanophylla Lindl. was undertaken from 1 October to 18 December 1978, some 20 km southwest of the town of Azizia in an area receiving an average annual rainfall of 225 mm (as measured over a period of some 60 years).

The flock used was composed as follows:

84 breeding (pregnant) ewes Barbary Fat Tail Libyan

sheep

20 yearlings
5 rams
10 adult female-goats Black North African goat
  1 buck
  2 kids

The flock was herded on a rotational basis over 4 fenced paddocks of 29.5 ha each, with a supplementary ungrazed block of 32 ha of shrub plantations (Acacia cyanophylla, Opuntia ficus indica, A. halimus, A. nummularta, A. canescens).

Each of the four paddocks was grazed for one month and rested three months alternatively, all the year round. The total grazed area was thus 29.5 × 4 = 118.0 ha. This grazing system was described and successfully carried out in more or less similar conditions in Tunisia for many years and au same 10 sites. This scheme of 150 ha (118 ha of range – 32 ha of fodder shrubs reserves) is the typical sheep-farm designed for this area by the Jeffara Plain Development Authority. A few hundred of such farms are in the process of being allocated to recipient farmers in 1980. The aim of the experiment was to test the technical and economic feasibility of the scheme (Le Houérou, 1965, Ionesco, 1975). The rainfall distribution (mm) in two nearby sites N and S of the experimental area is shown in Table 1.

Table 1. Rainfall distribution (mm) in 2 sites near the experimental area

The soils of the experimental area are essentially stabilized sands dunes with some local outcrops of calcareous rocks and quaternary lime crust (caliche) and some localized drifting sands. Elevations 125 to 150 m asl.

Range conditions of the area were first described by Le Houérou (1965), the several studies and large scale mappings 1/20000 were undertaken by Gefli (1974) and the FAO team of the TF–Lib. 10 project. Estimation of long-term yearlong carrying capacity was:

1 sheep for 1.5^1/ ha (Le Houérou, 1965)
1 sheep for 2 ha (Gefli, 1974)
1 sheep for 3 ha (FAO Team. 1977)

The main range type in the area is that of Stipagrostis pungens and Lygos raetam.

Further studies by Stephanesco (1977) subdivided it into 52 grazing subtypes of which three are present in the experimental farm under study. The range had been protected from grazing for 2 years before the start of the experimental farm in 1976 and was in good condition.

Plant cover was 75 to 90% (Canopy cover) of which 25 to 50% were annuals and 35 to 50% were perennials. Maximum standing crop was:

Fresh matter Dry matter
Total 2000–4000 kg 600–1200 kg
Perennials 800–1700 kg 350–700 kg
Annuals 1200–2300 kg 250–500 kg

During the 1977-79 period range production was estimated to be around 200 FU/ha/yr, i.e. a carrying capacity of one head of sheep for 1.5 ha or one sheep unit for two hectares.

The main range species (Le Houérou 1965,1974, Ginzburger et al, 1976), were as follows:

1) Perennial grasses: Stipagrostis pungens (deep coarse sand), Stipagrostis plumosa (sandy soils), Hypparhenia hirta, (shallow soils, rocky outcrops), Stipa parviflora (shallow soils).

2) Tall shrubs 50-2.50 cm: Lygos raetam, Genista saharae

3) Dwarf shrubs 20-60 cm: ¹ Artemisia campestris subsp. glutinosa, ² Ononis natrix subsp. falcata Echochilon fruticosum, Rhantherzum suaveolens, Gymnocarpos decander (shallow soils), Atractylis serratuloides (shallow soils), Argyrolobium uniflorum, helianthemum lippii var. sessiliorum, H. kahiricum (shallow soils), Polygonum equisetiforme, Salsola vermiculata var. brevifolia, Teucrium polium, Nolletia chrysocomoides

4) Perennial herbs (forbs), Lotus creticus, Plantago albicans, Salvia verbenaca subsp. clandestina, Rumex tingitanusvar. lacerus, Anthyllis vuneraria, Eremobium aegptiacum, Launaea resedifolia

5) Annuals:

(a) Grasses: Cutandia dichotoma, Schirmus barbatus subsp. calycinus, Stipa capensis, Bromus rubens subsp. fasciculatus Koeleria pubescens subsp. salzmanni.

(b) Legumes: 
Medicago truncatula, Medicago laciniata, Medicago litoralis, Hedysarum spinosissimum, Lotus pusillus, Hippocrepis bicontorta, Ononis serrata

(c) Cruciferae: 
Eruca uncata subsp. aegyceras, Matthiola longipetala, subsp. kralickii, Diplotaxis harra, Brassica tournefortii, Didesmus bipinnatus

(d) Others: Plantago psyllium, Erodium triangulare subsp. laciniatum, Salvia aegyptiaca, Silene colorata, Anacyclus cyrtolepidioides, Anthems pedunculata, Neurada procumbens, Reseda arabica.

¹ It should be noted that the experimental site is at the drier end of the range type mentioned which is found further north under annual rainfalls of 250–350 mm. The experimental site is actually an ecotone between the Artemisia campestris-Ononis falcata association (1 sheep/ha) and the Rhanterium suaveolens-Stipa lagascae association (one sheep/2-3 ha.).

Table 2. Average temperatures in °C in Azizia (59 years) some 20 km N–E of the experiment site are as follows:

^a highest temperature ever officially recorded on earth under standard conditions (3 Sept. 1922).

Supplementation started 1 October 1978 and ended 18 December 1978. It consisted of 58 kg per day of barley grain (i.e. 58/92 = 0.63 kg/day 1 per Ovine Unit equivalent to 58/122 = 0.475 kg per head of stock) and Acacia cyanophylla lopped branches ad libitum. The Acacia branches were lopped, air-dried for 24 h, and handfed in the pen 24 h after having been harvested. The amounts of Acacia fresh and dry wood and leaves (phyllods) offered and refused were weighed; the difference was considered as consumed. Acacia was offered twice daily at noon and in the early evening, when animals were returning from grazing and before resting. Preliminary trials had showed that Acacia was best accepted after 24 h of air-drying than when offered fresh.

3. Results

The consumption of Acacia is shown in tables 3 and 4

Acacia cyanophylla consumption remained remarkably stable during the whole period: 3.26 kg (24h air-dried) per O.U^–1 day^–1 or 1.760 kg Dm O.U^–1 day^–1. This is remarkably high: 3.2 kg/DM per 100 kg of body weight (one ovine unit in the present case = 54 kg). The feed value has been conservatively estimated at 0.30 FU per kg of DM based on the following assumptions:

Apparent digestibility of organic matter: 51%

Net energy value/kg DM according to Breirem's predictive equation:

NE = 2.36 DOM – 1.2 (OM – DOM)
                      1 650

Where NE = Net Energy in F.U. per kg^–1 DM, DOM = Digestible organic matter, OM = Organic matter.

We have thus an energy value of 0.31 FU per kg/DM (El Hamrouni and Sarson, 1974).

It is worth noting that consumption of Atriplex nummularia in similar conditions was found to be 50 to 75% of that figure in Tunisia (Franclet and Le Houérou, 1971).

Table 3. Acacia consumption

Table 4. Analysis of consumption of acacia

4. Discussion

The demonstration sheep farm (experimental area) sustained an average 84 ovine units over 118 ha over the whole year 1978. The carrying capacity of the range with supplementary feeding was 1.4 ha per O.U.; it would have been 2 ha per O.U. without supplementary feeding. Range production consumed was 200 FU per ha, i.e. ~ feed unit or 3 kg DM for each mm of rain actually fallen and per ha or range.

The amount of consumable biomass left on the range at the end of the summer (Sept–Oct) was not measured but was very small by visual estimation and supplementary feeding was deemed necessary. The contribution of range production to the total feed requirement of the ewes was 70%. The supplementation feeding was thus 30% of which 0.5 kg of barley grain per day at the flushing period for 30 days in June and 20 days in September (not taken into account in the present report). The total grain supplementation was thus 70 kg per O.U. for a total of 129 days, instead of the 50 kg planned. The highest bodyweight of ewes was attained in May at the end of the peak of range production, without supplementary feeding. The total lamb liveweight produced from 84 O.U. was 2112 kg or 18.0 kg per ha of range at weaning time. The number of lambs weaned was 88 at 90 days with an average weight of 24 kg. The final weight of lambs at 6 months was 36.4 kg (no supplementary feeding). Including 17 culled ewes total liveweight production' of 26.9 kg per ha when lambs were sold at 6 months, which is a normal practice in the country.

Supplementation with Acacia cyanophylla showed a fairly constant consumption of 3.26 kg fresh weight (24 air-dried) or 1.760 kg DM per O.U. and per day i.e. approximately 3.25 kg DM per 100 kg of liveweight, which is higher than most figures in the literature when browse consumption is concerned. The amount of Acacia cyanophylla consumed corresponded to almost 12% of the feed requirement of the livestock and to most of their protein requirements for the months of October, November and December when needs are high (end of pregnancy, lambing and lactation) and when green forage on the range is scarce or absent.

Acacia cyanophylla, consumed at a rate of 1.760 kg DM per day, having a crude protein content of 12.8%, thus brings an average 225 g crude protein per ovine unit and per day, or about 175 g digestible protein (using Demarquilly and Weiss' regression where DP = 0.929 CP – 35.2). This corresponds to the dietary needs of a ovine unit weighing 54 kg with a growth rate of 0.250 kg per day which is about the case in the experiment. As the animals also received 0.5 kg of barley grain bringing an additional daily ration of 43 gr of digestible protein the total amount of digestible protein in the ration was approximately 218 gr per O.U. which suffices to account for all needs: pregnancy, growth, lactation, at a period where digestible protein in range forages is close to zero.

Table 5. Contribution of various feed resources to the flock diet during the experiment.

^a Lambing period

^b 17.6% and 5910 kg when counting 1500 kg of barley provided at flushing period in June.

Table 6. Sheep performance

Item	1977/78	1978/79
No of ovine units		84
Conception rate, %	95.0	97.6
Lambing, %	103.3	106.0
Twinning, %	8.7	8.5
Lamb sex ratio M/F	38/24	54/46
Abortion %	Nil	1.2
Average birth weight kg	3.8	4.13
Lamb mortality, %	Nil	Nil
Ewe mortality, %	5.0	2.38
Ewe culling, %	8.3	21.43

Additional qualitative trials with Acacia salicina Lindl. and A. ligulata A. Cunn. ex Benth, showed that the former is very readily consumed by small stock, at least as well as A. cyanophylla, while A. ligulata was accepted with some reluctance, at least for the first few days. This fact is in contradiction with a tenacious legend of unpalatability of A. ligulata based on an ill-conceived experiment in Tunisia a few years ago. This, in itself is an encouraging fact as those two species are far more drought resistant than A. cyanophylla.

5. Summary

A flock of 84 breeding ewes, 20 yearlings, 5 rams, 10 breeding goats, 1 buck and 5 kids herded on a fenced, 4-paddock rangeland at a stocking rate of 1.4 ha per ovine unit, near Aziza (200 mm) in Libya, was pen supplemented for 79 days from 1 October to 18 December 1978 with 0.5 kg of barley grain and Acacia cyanophylla ad libitum.

The consumption of Acacia cyanophylla phyllodes was constant throughout the feeding period: 3.26 kg fresh (24 h air dried) or 1.760 kg DM per day per ovine unit or 3.2 kg DM per 100 kg of liveweight. This supplementation was enough to meet the maintenance energy needs, but not the production requirements which were met with an extra daily 0.5 kg of barley grain.

The Acacia consumption was enough, however, to meet the protein requirements. Animal performance was excellent (106% lambing,106% weaning, daily growth at 90 days 0.226 kg (24 kg) and 0.180 kg (36.4 kg) at 180 days).

Table 7. Lamb performance (M + F)

		30 days		60 days		90 days
Year 1977/78	Birth Weight	Weight kg	Growth kg/d	Weight kg	Growth kg/d	Weight kg	Growth kg/d
Male	3.86	11.71	0.261	18.39	0.242	24.67	0.231
Females	3.68	11.41	0.258	17.54	0.231	23.10	0.216
Average	3.79	11.59	0.260	18.05	0.238	24.05	0.225
Year 1978/79
Male	4.07	15.21	0.371	18.65	0.243	25.63	0.239
Females	4.06	11.19	0.238	17.41	0.222	23.35	0.214
Average	4.07	13.20	0.304	18.03	0.232	24.49	0.226

Table 8. Ewes' weight, 1978)

J	F	M	A	M	J	J	A	S	O	N	D	Year
40.6	41.4	44.3	46.6	51.7	49.3	50.3	47.9	47.4	46.8	44.4a	39.0a	45.8

^a Lambing period

Table 9. Chemical composition of Acacia cyanophylla (average of 3 analyses on 3 different sites in Sept /Oct 1978

List of species cited

Acacia aneura F. Muell. ex Benth.
Acacia cyanophylla Lindl
A. ligulata A. Cunn. ex Benth.
A. salicina Lindl.
A. victoriae Benth.
Anacyclus cyrtolepidioides Pomel
Anthemis pedunculata Desf.
Anthyllis vulneraria L.
Argyrolobium uniflorum (D.C.) J. et S.
Artemisia campestris L. subsp. glutinosa (J. Gay) Batt.
Atractylis serratuloides Sieb.
A triplex canescens (Pursh.) Nutt.
A. halimus L.
A. lentiformis S. Watts
A. nummularia Lindl.
Brassica tournefortii Gouan
Bromus rubens L. subsp. fasciculatus (Presl.) Trab.
Calligonum arich Le Houérou
C. azel Maire
C. comosum L'Hérit
Cassia sturtii R. Br.
(= C. nemophila a. Cunn ex Vogel var. codacea (Benth.) Symon = C. eremophila A. Cunn. ex Vogel)
Colutea arborescens L.
Cutandia dichotoma (Forsk.) Trab.
Didesmus bipinnatus (Desf.) D.C.
Diplotaxis harra (Forsk.) Boiss.
D. simplex (Viv.) Spreng.
Echiochilon fruticosum Desf.
Eremobium aegyptiacum (Spreng.) Hochr.
Erodium triangulare (Forsk.) Musch. var. laciniatum (Cav.) M.
Erucaria uncata (Boiss.) Asch. et Schw. subsp. aeuceras (T. Gay) M. et Weill.
Eucalyptus albens Benth.
Genista saharae Coss. et Durieu
Gymnocarpos decander Forsk.
Hedysarum spinosissimum L.
Helianthemum kahiricum Del.
Helianthemum lippii (L.) Pers. var. sessiflorum (Desf) Murb.
Hippocrepis bicontorta Lois.
Hypparrhenia hirta (L.) Stapf
Koeleria pubescens (Lamk) P. de B. subsp. salzmanni (Boiss. et Reut.) Trab.
Launaea residifolia (L.) O. Kuntze
Lotus creticus L.
L. pusillus Medik
Lygos raetam (Forsk.) Heywood
Medicago arborea L.
M. laciniata (L.) Mill.
M. litoralis Rhode
M. truncatula Gaertn.
Matthiola longipetala (Vent.) D.C. subsp. kralickii (Pomel) M.
Neurada procumbens L.
Nolletia chrysocomoides (Desf.) Cass.
Ononis natrix L. subsp. falcata (Viv.) Murb.
O. serrata. Forsk.
Opuntia ficus-indica (L.) Mill. var. inermis Weber
Periploca laevigata Aiton
Plantago albicans L.
P. psyllium L.
Polygonum equisetiforme L.
Reseda arabica Boiss.
Rhantherium suaveolens Desf.
Rumex tingitanus L. var. lacerus Ball
Salvia aegyptiaca L.
S. verbenaca L. subsp. clandestina (L.) Pugsl.
Schismus barbatus (L.) Thell. subsp. calycinus (L.) M. et Weill.
Silene colorata Poir.
Stipa capensis Thunb. (= S. rerorta Cav. = S. tortilis Desf.)
S. lagascae Roem. et Sch.
S. parviflora Desf.
Stipagrostis plumosa (L.) Munro ex Anders.
S. pungens (Desf.) De Winter
Salsola vermiculata L. var. brevifolia (Desf.) M. et Weill.
Teucrium polium L.

References

Breirem, K. (1954). `Die nettoenergie als Grundlage der Bewerkung der Futter-mittel'. In: Nehring. K.100: Jahre Mokern Die Bewertung der Futterstoffe and andere Probleme der Tiernahrung. Berlin, Deutsch Akad. der Land-wirtschafts-Wissenschaften, II, 97–115. Leipzig, Nehring ed. (VEB).

Brierem, K. (1969). In: Handbuch der Tiernahrung, I, 611–691. Hamburg and Berlin, Verlag Paul Parey.

Dumancic, D. and Badawi, S., (1979). `Preliminary results obtained in the Range Management demonstration farm in Bir El Ghanem grazing perimeter'. Mimeo. Tripoli, FAO/TF: LIB 10 Project.

El Hamrouni, A. and Sarson, M. (1974). `Valeur alimentaire de certaines plantes spontanées ou introduites en Tunisie? (Note de Recherche no. 2.)'. Tunis, Inst. Nat. Rech. Forest.

Franclet, A. et Le Houérou, H.N. (1971). 'Les Atriplex en Tunisie et en Afrique du Nord'. Rome, FAO: FO:SF/Tun 11, (Rapp. Techn. no 7).

Gefli, (1974).  'General development of the Gefora and Jabel Nafusa Grazing Land Development'. Tripoli (s.n.).

Ginzburger, G., and Bayoumi, M., (1977).  'Survey of the present situation and production of the Libyan range-lands'. Mimeo. Tripoli, Agr. Res. Centre.

Ginzburger, G., A1 Idrisi, M.S. and El Sudani, H. (1976).  'Range study on Jeffara plain. 1-Sheep project-Bir Eol Ghanem 56'. Tripoli, Agric. Res. Centre.

Ionesco, T., (1975). 'Methodologie utilisée en matiére d'amé lioration dans le centre et le sud Tunisien'. Mimeo, Tunis, INRAT, FAO-Tun/69/00.

Lenkeit, W. and Breirem, K. (1972). Handbuch der tiernahrung, 2, Hamburg and Berlin, Verlag Paul Parey.

Le Houérou, H.N. (1965).  'Report to the Government of Libya on grazing and fodder resources'. Rome, FAO/ EPTA Rep. no. 1979.

Le Houérou, H.N. (1974). 'Ecological foundations of Agriculture and range development in Western Libya'. Rome, FAO, AGP: Misc./23.

Le Houérou, H.N., (1979).  'Consultation mission to Libya' (Jan. 1978) BDPA, Paris.

Le Houérou, H.N. (1979). 'Rangeland potentials in Libya, outline of a strategy for development'. Paris, BDPA.

Le Houérou, H.N. (1980).  'Outline of a master plan for pasture development in Libya'. Rome, AGP/AGSO-FAO.

Le Houérou H.N. (1980). 'Guidelines for a five years (1981-85) range and livestock development plan'. Paris, BDPA.

Le Houérou, H.N. et Froment, D. (1966). 'Definition d'une doctrine pastorale pour la Tunisie steppique'. Bull. Ec. Sup. Agric. Tun. 10–11, 73–152, Tunis.

Le Houérou, H.N., et Ionesco, T. (1973). 'Appetabilité des especes végétales de la Tunisie steppique'. Mimeo. Tunis, FAO/Tun/71/525. et 69/001 INRAT.