FEEDS AND FORAGES IN PACIFIC ISLANDS
2. Livestock numbers and distribution in the Pacific Islands
3. Production systems
4. Some cattle production systems in six countries
Village beef production
Large-farm production system
Papua New Guinea
Intermediate communal sub-sector
Large scale commercial sub-sector
Estate plantation sector
5. Feeding systems
Cut and carry
Rotational or paddock grazing
Cattle grazing open pastures
Integrated animal and tree cropping systems
Cattle under coconuts
Role of forage and feed in the systems
Crop residues and agro-industrial by- products
Legumes and trees
6. Descriptive and analytical data on some
forages (grasses and browses)
| Some common browse plants of the region
Gliricidia (Gliricidia sepium)
Leucaena (Leucaena leucocephala)
Cassava leaves (Manihot esculenta)
Sweet Potato leaves (Ipomoea batatas)
Vi or Vie plant (Spondias mombin)
Mulberry (Morus alba)
Legumes as feed
7. Descriptive and analytical data of some feed resources
Cocoa by-products (Theobroma cacao)
Noni juice extract waste (Morinda citrifolia)
Coffee pulp meal (Coffea arabica)
Copra cake/meal (Cocos nucifera)
Palm kernel meal
Rice bran, pollard and polishing
8. Impact of the use of the feeds/forages
Some economic data
Feeds and forages likely to increase in use and why
There are many grazing systems in the Pacific Island countries (PICs) – see map; for a target level of animal performance from forage, daily ingested young forage leaf and stem dry matter should possess specified levels of protein (nitrogen), metabolisable energy, phosphorus, calcium, potassium, magnesium, sulphur, sodium and trace elements. The quantity and quality of pasture available to different classes of ruminants in the region varies considerably. Besides environmental factors, others such as inherent nutritive (and sometimes anti-nutritive) characteristics of selected pasture plants, quality of management, weeds and grazing systems and animals contribute to affect pasture quantity and quality.
Ruminant livestock can subsist on forage alone but, to achieve this, available forage for year round feeding should be of good quality to meet the nutritional requirements of grazing animals so as to attain their genetic potential. With good management quality forage could be available year-round, where this is lacking alternative feed should be provided.
Ruminant livestock rely mostly on native and some introduced grasses along with crop residues in the PICs (Macfarlane, 1998). Maximum animal production from an environment or farming system is based on a mix of the best-adapted legumes and one or more grasses while the primary factors which maximize digestible nutrient intake and hence, animal performance (growth, lactation, reproduction and work) are: (i) the quantity of feed; (ii) its nutrient content, and (iii) digestibility.
Most pastures in the PICs are characterized by large fluctuations in quantity and quality of herbage available to free-ranging ruminants. Such fluctuations influence intake and production, thus animal performance in terms of reproduction, growth, traction, milk and meat in the region is generally less than half their genetic potential due to poor quality forage.
The Pacific island countries have no long history of grazing livestock management and production. Despite this, there are now substantial numbers of ruminants (Table 1) in the region. Ruminant production is promoted by all governments for import substitution, self-sufficiency in meat and a source of income for farmers. Ruminant livestock form an integral part of the rural life of the PICs because, at village level, raising cattle, goats and sheep provide many benefits. They are assets that are readily saleable and relied on for income and for meeting large payments such as school fees. In countries which have suffered cyclone disasters, such as Samoa and Vanuatu, smallholders increasingly view cattle as more important than tree crops and relatively cyclone-proof. Smallholders are involved with several species (Macfarlane, 1998).
Ruminant livestock are numerically less significant than non-ruminants but they have the potential to increase smallholder incomes. The countries in the region currently graze 664,900 beef cattle, 30,100 dairy cattle, 24,900 sheep, 258,000 goats, 12,000 farmed deer and 110,000 feral deer (in New Caledonia) (Macfarlane, 1998). Beef cattle, the predominant ruminants, are raised mainly for meat and secondarily for draught, especially by the Indo-Fijians in Fiji. There are dairies in Fiji, Tonga and Papua New Guinea; sheep in Fiji and Papua New Guinea and an important goat industry in Fiji and Vanuatu (Macfarlane, 1998). Vanuatu has the highest number of cattle per person amongst countries in the Pacific Islands.
Land mass, pressure on land for other activities; culture and tradition, size and number of livestock and feed availability determine the type of production system (Aregheore, 2004a). Ruminant livestock in greater or lesser numbers are associated with production systems which differ from one country to another. The smallholder unit (tethering and free range) is common in all countries, always relying on pasture. Foliage of shrubs is used to supplement low quality forage to meet requirements for maintenance, fattening and other physiological processes. Livestock production systems can be classified as free range, tethering, fenced and penned.
Free range – The simplest system where animals roam freely finding their feed and are thought of having no production cost because they exist and reproduce without contribution or inputs from the owner. This system requires little or no skill and involves minimal labour (Ramsay, 1999). Animals are very hardy and are products of their own environment (Aregheore, 2002a).
Tethering – Animals are tied to a tree or stake but have to be moved often to ensure that they can reach feed. This system requires more input than free range but does not guarantee a greater output; it is very common among the Indo-Fijians and in the Cook Islands (Figure 1). It has advantages and disadvantages (Ramsey, 1999). The advantages are:
The disadvantages are:
Fencing - Fences such as permanent post, wire or electric are used to control stock. Fenced animals require a regular supply of clean, fresh water and sufficient feed of good quality. When animals are kept in paddocks, their entire feed requirement should be met by the development and maintenance of available pasture or through supplementation.
Penning or confinement - Animals are confined at all times so this system requires much higher levels of husbandry than the other systems, since all inputs must be provided; this increases production costs. This system is not very common in the PICs. Farmers prefer a semi-intensive system where animals graze during the day and are housed at night or during adverse weather.
Figure 2 shows a make-shift housing or shelter for goats under semi-intensive system at Siusega, Samoa.
These are the general production systems, however countries have modified them to suit conditions peculiar to their environment.
Production systems for cattle in some Pacific Island countries (Aregheore, 2004a) are described below.
Beef production systems in Fiji can be classified as: -
Small arable farms - under 10 ha. These own up to 75 % of the beef cattle. Beef is a sideline to sugar cane or rice production. Most cattle are in the sugar and rice areas of Viti Levu and Vanua Levu. Farmers tether animals along roadsides and field fringes. Bullocks are kept for draught. Fencing is not used and in some situations animals are allowed to roam and fend for themselves.
Commercial farms of 10 – 50 ha. This involves the breeding and/or fattening of animals under extensive grazing. Owners and family members manage the farms, but contract labour is hired from time to time for fencing and daily routine tasks.
Ranching operations of 50 – 2000 ha or more. These are based on intensive cattle systems for breeding and provision of stock to smallholders. Ranches in Fiji are found in Uluisaivou and Yaqara and also in Cakauudrove and Taveuni and are large estates with full time managers, stockmen and labourers. The Yaqara Pastoral Company, Fiji's largest single operation, covers over 4,000 hectares and maintains 7,000 head of cattle. This includes the recent acquisition of the famous French Limousin breed, purchased from New Caledonia.
Cattle under coconuts. This is concentrated in Northern and Eastern Fiji. Cattle are kept to control weeds and provide income. Grazing is continuous. This system requires large areas. Sixty percent of beef farmers in the northern division produce under coconuts and of these 40 % are indigenous Fijians. This system is also found in some bigger outer islands including Rotuma (Vulaono, 2004).
Cattle under pines. This system which is mainly used in the dry, western part of Fiji, involves a small herd maintained by the Fiji Pine Commission. Cattle graze under pine plantations and are used as weeders; grazing is continuous on an extensive area of land.
There are 1,825 beef producers with 30.5 animals per farm and three large properties with more than 1,000 cattle each. The commercial beef herd is distributed by region as 27 % Central, 56.9 % Western, 14.1 % Northern and 2 % Eastern Division. Commercial beef farmers have about 1,100 work oxen (Macfarlane, 2000a). Poor nutrition leads to low weaning percentages and daily liveweight gains. The Ministry of Agriculture, Fisheries and Forests assists farmers in access to beef cattle in Fiji through a breeding programme that aims at improving the genetic composition of local beef herds and involves the importation of high quality semen.
Fiji is well endowed with pasture resources. The potential role of pastures as cheap and available feed has been well documented by Macfarlane (1998) and Kumar et al., (2001). Beef production systems rely on tethering and enclosed grazing with some cut-and-carry feeding. Natural and improved pastures are used. The national cattle herd grazes 125,000 hectares of unimproved Mission grass (Pennisetum polystachyon), 43,000 hectares of naturalized/native pastures including Nadi blue grass (Dichanthium caricosum); Batiki grass (Ischaemum aristatum var. indicum); carpet grass (Axonopous compressus) T-grass (Paspalum conjugatum) and an unquantified area of roadsides and harvested cane fields (Macfarlane, 2000a).
Mission grass (Pennisetum polystachyon) is extensive low cost feeding. But limitations to its use are low productivity, low digestibility and inadequate protein and mineral levels; its quality and quantity can be improved by adding legumes with appropriate fertilization. Improvement of Mission grass by sowing Siratro (Macroptilium atropurpurenum) or Stylo (Stylosanthes guianensis) and broadcasting single-superphosphate at 440 kg/ha into burnt grassland resulted in a three-fold increase in dry matter from 6.0 tons/ha/yr to 18.0 tons/ha/yr. Maximum liveweight gain of 520 kg/ha was recorded from improved Mission grass leading to reduced gains in later years when Mission grass and legumes rapidly disappeared. There is a need for more stable grasses and legumes. Nadi blue (Dichanthium caricosum) and Hetero (Desmodiun heterophyllum) have these attributes and were actively promoted.
In 1995 the cattle population of Samoa was split among sectors in the following proportions:- Government (3 %), Western Samoa Trust Estates Corporation (WSTEC) (12 %), NGOs (17 %), and private (68 %) (Lee, 1999a), thus breaking the early monopoly of WSTEC. At present beef cattle are raised in Samoa under two systems: village production, and large-farm production (Tevita (2001), personal communication).
(a) Village beef cattle production is divided into two types:
Village beef production
The subsistence system is a very significant in Samoa’s beef industry and plays an important role in increasing the number of animals in the country. There are 46 registered cattle farmers’ association or village groups. The formation of the Village Cattle Farmers’ Association, a self-help group activity to improve and draw more farmers to develop interest in beef cattle production, has motivated farmers’ interest in the keeping of cattle. Cattle ownership by small farmers is increasing and development of the beef industry has received government support through importation of cattle, development of breeding farms, distribution of cattle to farmers at subsidized prices and training in pasture development and maintenance (Ramsay, 1999).
Smallholders cum commercial systems. Farmers in this group usually have five – fifty cattle on properties where both subsistence and commercial production are carried out. A farmer will produce livestock, root crops, coconut and bananas for home use. Today, the strength and growth in the beef cattle industry is in the emerging commercial smallholders sector.
Large-farm production system
Government/WSTEC Estates. Two government farms at Togitogiga, Le Mafa and Tanumalala were established under Asian Development Bank funding during 1972 – 1979 to provide demonstration and training, conduct research and provide improved breeding stock for distribution to WSTEC estates and to farmers. WSTEC estates is government owned and has about 3,000 cattle grazing 2,400 ha under coconuts at Mulifanua. WSTEC once controlled most of the cattle in Samoa, but the number of animals and the land area of WSTEC properties have fallen drastically. Government farms sell some of their breeding animals to the other sectors under the village level beef system. Samoa has identified cattle development as an important strategy for import substitution. Beef stock is based on Braham-Hereford mix which seems adapted to the environment. In 1989, Droughtmaster cattle were introduced from Australia with additional shipments in 1993 and 1995. The beef farms at Togitogiga, Lamefa and Tanumalala breed and distribute calves at subsidized rate. Bulls are imported periodically to prevent inbreeding. Droughtmaster cattle have adapted very well to Samoan conditions and have become a breed of choice (Tevita, 1995).
Samoa’s climate favours the growth of forage all year round. Batiki grass (Ischaemum aristatum var. indicum) is the predominant pasture grass, either under coconuts or in open fields. Other grasses such as signal (Brachiaria decumbens), Guinea (Panicum maximum), carpet (Axonopous compressus) and elephant (Pennisetum purpureum) grasses contribute to the nutrition of ruminants. Signal, Guinea and elephant grasses are mostly used in cut-and-carry feeding. Browse plants including Leucaena leucocephala, Gliricidia sepium, Erythrina spp., Spondias mombin, Calliandra calothyrsus, Morus alba and Sesbania grandiflora are available to supplement batiki grass during the dry season (Aregheore, 2003).
Some agro-industrial by-products, especially brewer's grains, noni (Morinda citrifolia) juice extract waste, desiccated coconut waste meal and copra cake are available year-round and are used to supplement grazing animals during adverse weather. The use of brewer's grains is widespread.
The cattle industry expanded rapidly from the early nineteen-sixties and numbers peaked in 1976 at around 153,000 head (although current estimates suggest a national herd of only 82,000 cattle). Numbers have declined sharply in both large and smallholder sectors.
Two production systems are identified (Benjamin, 2001) and these are:
Smallholder projects. Based on earlier data over 1,000 smallholder projects run a total of 50,000 cattle. The remainder is on 550 smallholder farms on 78,000 hectares of grazing land. Cattle graze native, semi-improved or fully improved pastures. Tethering is growing rapidly in mid-altitude zones and areas of high land pressure where smallholders use forage along roadsides and around tree crops. This system is associated with cut-and-carry (Macfarlane, 2000b). Improvements in smallholder projects are limited (Benjamin, 2001, Personal communication).
Large properties/commercial/ranching. Based on earlier data there were 30 ranches with 103,000 head. About 80% of the cattle are on large properties that occupy 113,000 hectares. This system is integrated with about 100 km2 of coconuts. Ramu Beef’s feedlot bales green cane tops and helps Ramu sugar by reducing the wastage of crop residues during ploughing. There are 203,000 ha of extensive natural grasslands in PNG most of which are maintained by regular burning. These grasslands have been recognized as an important resource (Falvey, 1981, Smith and Whiteman, 1985) and have been successfully improved, usually by over-sowing with Stylosanthes spp. following burning and application of appropriate fertilizer (Partridge, 1977). Shelton et al., (2002) stressed the importance of pasture as a cheap feed in PNG. All beef production systems in PNG rely on natural or improved pasture.
The beef industry has developed the supplementary paddock feeding systems with locally-produced by-products. Copra meal, palm kernel meal and molasses are used to supplement pasture (Bubar, 2000). This is a major step through improved growth rates and animal handling. Smallholders can benefit from technologies developed and introduced by ranches. Besides the above mentioned, a number of crop residues such as sugar cane tops, rice straw and bran, cocoa husk, coffee hulls and pulp, palm fibre press and oil palm sludge are available as possible supplementary feed for grazing beef cattle (Moat, 2002).
Beef cattle in Tonga are held under two systems (Lee, 1999b); these are:- smallholders, and large commercial properties:
Smallholders. Beef animals are raised in small numbers. Crop production is the farmers’ priority and livestock are integrated into this system. Their purpose is to supply animals for traditional and social obligations such as funerals, wedding and church functions. Animals are tethered and graze along roadsides, fallow land or under-utilized bushland. Forty percent of beef herds of 10 or fewer animals are under the smallholder system.
Large commercial style properties. Nobles, entrepreneurs who sub-lease land and the churches operate commercial properties involving beef cattle. These properties are now few, but they are very important because of their ability to produce surplus meat for local markets and breeding stock for the beef industry. They specialize in both milk and beef, often with separate herds. They have some developed, fenced long-term pastures and land is generally cropped only during pasture renewal (Lee, 1999b).
In the Solomon Islands over 56 % of the cattle are in the Central district, 20 % in Western district, 16 % in Malaita and 8 % in the Eastern district, (Wahananiu et al., 1993). However, the 1998-2000 civil war or disturbance in the Solomon Islands affected commercial beef production and it declined to less than 78 % of the previous level. Three beef production systems are recognized (Kama, 1994):- small holder; intermediate communal, and large-scale commercial-government.
Intermediate communal sub-sector:
Large scale commercial sub-sector:
A national cattle development plan was initiated some years ago for the rehabilitation of the beef cattle industry. The Solomon Islands government is keen to rebuild the cattle industry in commercially viable areas that have access to established markets. Government policy goals and objectives are to sustain self-sufficiency in all livestock sectors with exports where possible (Wate, 1995). The cattle development strategies of the Solomon Islands included the continued provision of breeding animals for smallholder expansion and restocking. In 1996 the impact of genetic improvement from imported bulls and semen came to fruition. There was a strong interest on Malita and Santa Cruz for breeding stock. The Mamara breeding unit set up by the Livestock Development Authority (LDA) provided vigorous replace ment stock to farmers.
Beef cattle have access to both natural and improved pastures. Grazing areas range from open pastures under extensive grazing under plantations to those in the smallholder sector (Wahananiu et al., 1993). The Livestock Development Authority (LDA) operated five farms on Guadalcanal and four in the Western Province and owned most of the large open pasture. It has been estimated that only 4,000 ha of pasture might be left for grazing. As a consequence of the different holding systems, land for pasture development was allocated in the sixth Development Plan (1970 – 1984) as follows; smallholder (6,441 hectares); LUD projects (3,943 hectares); holding grounds (442 hectares); LDA fattening (760 hectares) and Government (2,060 hectares). By 1991, it was estimated that 9,000 hectares would revert to bush while in some areas pastures will be under-grazed. There is still scope for targeted pasture development in Gizo, Kolombangara, North New Georgia, Rendova areas of western Province, Santa Isabel, Makira; and accessible and adequately fertile areas on Maliata and Guadalcanal (Wate, 1995).
Commercial pasture development in the Solomon Islands was based on the replacement of Themeda australis/Pennisetum polystachyon natural grassland with a minor contribution of Gleichenia linearis and Cyperus spp. by cultivation and planting of grasses such as Para (Brachiaria mutica); signal (Brachiaria decumbens cv. Basilisk); green panic (Panicum maximum var. trichoglume cv. Petrie); batiki grass (Ischaemum aristatum); koronivia (Brahciaria humidicola) and Nadi blue (Steel and Whiteman, 1980; Watson and Whiteman, 1981). The nutrient content and palatability of the grasses would be improved by legumes as mixtures. Legumes used in the Solomon Islands are Centrosema pubescens cv. Common (Centro); Pueraria phaseoloides (Puero), Stylosanthes guianensis cv. Endeavour (Stylo); Vigna luteola (Vigna); Desmodium uncinatum (Silverleaf); D. heterophyllum (Hetero); Macroptilium atropurpureum cv. Sirato (Sirato) and Glycine wightii cv. Tinaroo (Glycine). Macfarlane (1996) reported that the pasture resources for ruminant livestock production in the Solomon Islands could be categorized into open pastures, pastures under coconuts and pastures under trees.
The production systems in Vanuatu are:-
Estate plantation sector
Other plantations owned by the private sectors are Mon-beef Tech on the Island of Santo which supply beef solely to the abattoir in Santo; Din van Tan which owns one of the biggest beef cattle holdings, supplies beef mainly to its own SAEF cannery. Michelle (a French lady) owns a plantation that also supplies beef to her small abattoir which, in turn supplies beef to wholesalers and retailers. Another worth mentioning is the French Plantation known as Roche and Madam Coshe. These plantations contribute to the export market through their abattoirs and they have assisted to improve the economy of Vanuatu (Otto, 2001).
Cut-and-carry is an indicator of pressure on land for crops and the application of local laws to regulate the exploitation of communal and on-farm resources. The present trend of population growth and land ownership in the Pacific Islands has resulted in an increase in its use and competition for feed. This system gives lower production levels and even changes to lower production objectives (milk, traction, reproduction and growth) and in herd size and composition (fewer large ruminants and more small ruminants). The general rule in cut-and-carry is to give freshly cut forage equivalent to about 10 % of an animal’s body weight daily. Ideally half of the cut forage should be given in the morning and the rest in the evening so that the animal can make more efficient use of it and reduce waste.
The quality and the year-round availability of feed are good because farmers look for the best forage to harvest. However, the constraints are mainly availability of forage especially during adverse conditions and household labour, distance of feed from the farm, means of transport and access rights to feed on private and or communal or public land. Cut-and-carry is very common in Fiji, Samoa, Tonga, the Cook Islands, Vanuatu, the Solomon Islands and Papua New Guinea; the farmers involved are those with small farms, cultivating as shareholders, farmer labourers and landless households. The land these farmers have access to is often intensively cultivated, the households are poor and a major share of their income is derived from casual labour and/or employment. The livestock they keep are their main assets and savings.
Fiji – Feeding systems rely on tethering and enclosed grazing, with some cut-and-carry. There are no feedlots. Dairy cattle receive a lot of supplementary feed (Macfarlane 2000a).
PNG – Feeding systems are based on grazing. Some estates are interested in time controlled rotational grazing or cell grazing. Tethering is growing rapidly in mid-altitudes and areas of higher land use pressure where smallholders use forage along roadsides and around tree crops. It may be associated with cut and carry. Some estates feed copra meal, palm kernel cake and molasses with mineral supplementation (Macfarlane, 2000b).
Tonga – Cut and carry feeding of elephant grass, pasture, supplements such as copra meal, crop by-products for feeding, urea supplementation (Lee, 1999)
Samoa – Cut and carry is now practiced by farmers who tether their animals around Apia. Also Sunny Island Dairy farm at Lalom auga uses cut-and carry Napier and Guatemala grass (the latter on the wetter soils) to satisfy part of the feed requirements of the herd of 15 milking cows.
Vanuatu – Both smallholder and plantation graziers predominantly use free grazing. Tethering occurs occasionally but stall feeding is not practiced. The feeding system in both sectors is pasture based and no supplements or conserved feeds are used (Mullen, 1999).
Ruminants digest cellulosic substances and convert them to produce milk, meat, wool, hides for leather and draught power. A well managed pasture is therefore critical to the survival of ruminants and the products they provide. To obtain maximum profits from grazing, farmers must manage the land for high production and manage the animals to minimize forage waste and ensure that they are growing sufficiently. Grazing systems employ the basics of rational management to help producers accomplish their goals. Depending on what system farmers choose, they may improve pasture conditions, increase forage use, or enhance livestock production. Pasture-based livestock systems appeal to farmers seeking lower feed and labour costs and to consumers who want alternatives to grain-fed meat and dairy products. The choice of grazing system is the key to an economically viable pasture-based operation. Grazing systems vary widely in the degree of control which the farmer has in the management of grassland, but all are designed to help match the nutritional demands of animals to the forage supply. There are three main types of grazing system in the Pacific Island countries: (i) continuous grazing or set stocking, (ii) rotational or paddock grazing and (iii) strip grazing.
Continuous grazing or set stocking
Figures 9 – 13 show photographs of pasture for continuous grazing in some PICs. This results in selective grazing and under such grazing regime it is hard for nutritious and palatable legumes to survive.
This type of grazing frequently results in higher per-animal gains than other systems, so long as adequate forage is available to maintain high growth rates. Where continuous grazing is used the number of animals in the paddock must be adjusted from time to time to allow for seasonal pasture production. As animals grow, some animals have to be taken out of the grazing area to maintain a correct stocking rate. If pastures are overstocked, growth rates usually dwindle. Continuous grazing often results in poor forage utilization in the rainy season when re-growth is rapid. A high stocking rate should be used in the rainy season when forage production is high and decreased during the dry season. This system is of value on farms where pasture is plentiful and the farmer does not intend to increase stock numbers. In some countries such as Samoa and Vanuatu grazing cattle under coconut and on open pasture centre around continuous grazing.
Rotational or paddock grazing
Strip grazing with electric fencing involves giving animals a fresh allocation of pasture each day. It is usually organized within a paddock system or where there are no paddocks at all and the animals are controlled solely by the use of electric fences (Figures 25 -26). In the Pacific Island countries strip grazing systems are often employed where a farmer uses communal land with significant excess of forage when providing animals with access to a larger area would result in waste through trampling or spoiling by dung. The temporary fencing gives the farmer the versatility to strip graze. Generally the fence is moved daily and the distance it is moved is based upon the number of animals being grazed and the quality and quantity of pasture available. A back fence should used to stop animals from returning to land already grazed. Sheep and goats require three wires instead of a single wire.
Strip grazing has a number of benefits, such as:
If properly managed, constructed and serviced electrical fences can increase the efficiency and profitability of cattle, sheep, or goat enterprises through better management of animals and forage resources.
The bulk of cattle production occurs on open pastures in the Pacific Island countries (Figure 32); in well managed operations cattle are grazed at 1.5-3.0 AU/ha, depending on agro-ecological region and turn off slaughter weight cattle (280-300 kg carcass) at 24-36 months. Over the past 20 years an increasing number of commercial smallholder graziers have developed open improved pastures. For example in Vanuatu, the rapid increase in stockyard infrastructures on smallholder farms over the past 10 years has improved stock management and production per hectare from the best smallholder farms so that it is now close to some commercial farms.
The potential for animal production is one of the advantages of grazing livestock under plantation crops; they can be integrated with coconuts, oil palm, rubber, cocoa, and noni (Morinda citrifolia). Coconut and oil palm are significant and grazing under them is becoming increasingly important. In Fiji, cattle graze 27,000 ha under coconuts while sheep grazed puero (Pueraria phaseoloides) based pasture under coconuts on Taveuni. With the population of goats relatively constant and the development of sheep farming in Fiji, integration with tree crops is likely to increase (Macfarlane, 2000a). In Papua New Guinea cattle are integrated with approximately 100 km2 of coconuts (Macfarlane, 2000b), oil palm and rubber. In Vanuatu the preferred pasture plant under coconuts for cattle is buffel grass because it is extremely tolerant of high grazing pressure and the lower rainfall coastal environment where coconuts grow (Mullen and Shelton, 1996; Mullen, 1999). It is envisaged that in the Solomon Islands cattle will run under oil palm plantations as well as coconuts. In Samoa pasture-cattle-coconut systems are very common. Figures 27 – 30 contain photographs to illustrate crop/livestock systems in the PICs.
The main objectives of integration of animals with coconut and oil palm are:
The cattle industry in most of the Pacific Island countries is associated with coconut plantations. In Papua New Guinea cattle are integrated with 100 km2 of coconuts (Macfarlane, 1999) which could increase to 250 km2; the potential is 600 – 700 km2. There is a potential to expand cattle under coconuts in New Ireland to supply the Lihir gold mine, rising to 200 tons/meat/year.
Today nearly all smallholder and plantation graziers have at least part of their herds under coconuts. As copra prices continue to decline in real terms, the importance of cattle in the cattle-coconut farming system has increased. Daily liveweight gain of steers grazing under coconuts is below that of animals on open pastures due to the reduced quality of shaded herbage (Macfarlane 1993). Reduction in liveweight gains are exacerbated by dense plantings of coconuts (>150 palms/ha) on some smallholder farms. However, high quality veal is produced by specialist graziers who graze cows and calves under coconuts (Figures 28, 29 and 31). A unique quality of coconuts compared to most other plantation crops is that they can be intercropped on a semi-permanent basis. Unlike rubber and oil palm, the light environment under coconut is relatively constant and bright over the life of the crop which can be as long as 60 – 80 years (Shelton et al., 2002), although in the period 5-20 years light levels at ground level may be somewhat reduced (Reynolds, 1995).
Tropical pasture technology aims to improve animal production through the judicious use of inputs according to prevailing economic and social conditions (t'Mannetje, 1993). Nutritional research has demonstrated that very large increases in ruminant production can be achieved by small alterations to the feed base (Leng, 1993). In most tropical countries, including those in the South Pacific region, ruminant production is based on grazing pasture. Most tropical pastures are low in nutritive value due to their rapid growth and early lignification. Feed availability is more critical during the dry season.
To improve the nutrition of ruminant livestock it is recommended that cheap sources of protein should be used as supplements. Aregheore (2000a) suggested the inclusion of foliage of browse plants and multipurpose trees; the use of urea/mineral lick blocks to supplement grazing animals for correcting protein, energy and mineral deficiencies is highly advocated. In Fiji, the production of urea molasses blocks is common (Manueli and Mohammed, 2002).
There are several possibilities for improving forage production, and several options are open to smallholders. They can improve forage production by establishing:
Thus the reasons for improving forage production are to supplement the forage resources available with more and/or better quality feed for purposes such as:
This system advocates the adoption of cheap forage improvement based on legumes with minimum fertilizer use and the supplementation of low quality forage with the leaves of browses, legumes and multipurpose trees.
Animal production does not depend on pastures and forages alone. Crop residues and agro-industrial by-products make a substantial contribution in integrated crop-forage production systems. Aregheore (2000a) reported that they complement each other in ruminant nutrition and this is widely recognized by farmers. However, the feeding of livestock solely on poor quality forage, crop residues and agro-industrial by-products leads to low liveweight gains and low animal productivity. Inadequate nutrition of animals in the tropics is associated with delayed age at puberty or maturity; age at first conception and parturition; prolonged parturition interval, prolonged non-productive life and high mortality (Devendra and Li Pun, 1993). In the South Pacific region quantity and quality of forage, particularly in the dry season, are major constraints to livestock production from pastures. Therefore, there is the need to supplement fodder then. Strategic supplementation for energy, proteins, and minerals that might be deficient in low quality forage or crop residues offer an important means to ensure that animal performance is maintained during periods when feed shortage is imminent. Low quality forages can be improved in several ways. The use of foliage of browse plants and multipurpose trees is a cheap way of supplementing animals on poor pasture.
The use of foliage of forage legumes and multipurpose trees is underestimated but these can improve the quality and utilization of roughages. Several browses and multipurpose trees are used in the South Pacific region including: Leucaena leucocephala, Erythrina spp. (dadap), Calliandra calothyrsus, Sesbania grandiflora, Gliricidia sepium, Spondias mombin (Vi or Vie) breadfruit, bananas/plantain and mango. Advantages of using these forages especially in mixed farms in the humid tropics are as follow:-
Devendra (1990) reviewed the potential value of these forage and observed that, with ruminant livestock, the use of supplements consistently increased liveweight gain or milk production. In many instances the beneficial response was associated with reduced production costs of the forage supplements used. Legumes have been particularly advantageous and in a majority of situations stall-feeding or cut-and-carry systems are commoner than grazing. The leaves of these plants are cheap sources of protein, energy and sulphur for the rumen bacteria. They have great potential to be exploited for the benefit of ruminant livestock production.
6. Descriptive and analytical data on some
forages (grasses and browses)
Batiki grass (Ischaemum aristatum)
This is a creeping, stoloniferous, perennial with ascending culms and conspicuously red-coloured stolons rooting at hairy nodes (Figure 33). It is propagated by stem cuttings. Once established it spreads quickly. It is shade tolerant and therefore found in most coconut plantations in the Pacific Island countries. Batiki is very suitable for open pastures and performs well on acid soils at high altitudes. It is very competitive, therefore it is difficult to use in mixtures. Compared to most grasses it has low protein content (Aregheore, 2003).
Guinea grass (Panicum maximum)
Guinea is an erect tufted, perennial which can grow up to two metres if not grazed; there are many cultivars. Examples are Tall Guinea (a tall, robust variety that is well accepted by cattle) (Figure 34); Creeping Guinea (very well adapted for coconut plantations) and Common Guinea (not as high as Tall Guinea, but tall enough to interfere with coconut harvest). Guinea grass may be propagated by seed or vegetatively using splits. Seed propagation can be unreliable due to poor seed viability. Creeping Guinea is exceptionally shade tolerant and therefore suitable under plantations. Guinea grass can be used in open pastures where it could be combined with legumes in such a way that the legume can grow in the open spaces between bunches to prevent weed growth as well as fix nitrogen. It is a grass that cannot stand waterlogging, therefore a well-drained soil is required for its growth.
Signal grass (Brachiaria decumbens)
This is a coarse perennial with erect, ascending stems up to one metre high. The nodes are usually smooth but sometimes slightly hairy (Figure 35). It is propagated by stem cuttings or seeds. It is aggressive, smothers weeds easily and covers the ground rapidly. It could be used in grass/legume mixtures. It is shade tolerant, so can be recommended under coconuts and it produces good quality, palatable forage. It is well established on different soils but requires well-drained soil although it has been shown to be resistant to flooding.
Para grass (Brachiaria mutica)
Para is commonly used in rotational grazing and can be cut for green fodder or used for hay. It is a perennial that is widely distributed in the tropics and sub-tropics especially in areas with high rainfall. It is unproductive in the dry season because of its high water requirement. It is well suited to very wet, even waterlogged soils where it maintains a high dry matter content. It can be cut at intervals of 4-6 weeks and compares well in quality with most tropical fodders. Para grass combines well with creeping legumes, but is easily grazed out unless well-managed.
Nadi blue (Dichanthium caricosum).
Nadi blue is a tall robust perennial grass and has broad leaves which can be up to 40 cm long and 8-20 mm wide (Reynolds, 1995). It originated in tropical East and South Africa and grows well in areas with rainfall between 900 – 1,825 mm. Nadi blue spreads by short rhizomes. It combines well with legumes such as Sirato, Glycine and Greenleaf desmodium. It has a high digestibility and palatability and is usually established by seed in a well-prepared seedbed. It can also be established from cuttings or divided rootstocks. Nadi blue has been very effective in competing with Navua Sedge (Cyperus aromaticus) in low-lying (wet) areas in Fiji.
Setaria grass (Setaria sphacelata)
Setaria is a long-lived, caespitose perennial which generally forms dense tussocks and spreads by short rhizomes. Leaves can be up to 40 cm long and 8 – 20 mm wide, but considerable variations in the leaf width and plant height occur. It has a well-developed root system. The leaf blade is widely lanceolate, long acuminate, dense scabrous, and may have a brightly coloured midrib; leaf edges serrate. Leaf sheaths longer than the nodes; collar indistinct, ligule, short and thick. Inflorescence has a main stalk with shortened branches bearing spikes and bristles. Flower has two spikelets and the upper is bisexual (Ranacou, 1985).
Elephant or Napier grass (Pennisetum purpureum)
It is a tall deep-rooted perennial (Figure 36), widely found the Pacific Island countries and is more suited to cutting for fodder than grazing, but under rotational grazing a satisfactory stand can be maintained for many years. Elephant grass is normally established from stem cuttings that are planted similarly to sugar cane in rows of 60 – 90 cm apart. The yield of green forage depends on soil fertility and on how much fertilizer is applied. Compared to other tropical pasture grasses it has a high yield (120 tons per acre are not uncommon). Young leafy grass has low dry matter content (10-15 %).
Guatemala grass (Tripsacum laxum or T. andersonii)
An alternative grass for the dry season. It is a tall leafy perennial (Figure 37) and spreads by short stout rhizomes to form large clumps or stools (Whyte et al., 1959, Reynolds, 1995). The leaves are hairy and large. The grass is propagated by stem cuttings or pieces of root-stock (Reynolds, 1995). It is used as a cut-and-carry fodder because it is shallow rooted and can easily be uprooted by grazing stock. It is persistent in both dry and rainy season. In the dry season it is chopped with a manual chaff-cutter to about 8-10 cm and mixed with other feeds for ruminant livestock. It has a reasonable content of nutrients, especially protein, in both dry and rainy seasons. It is more persistent than elephant grass, but less productive and lower in nutritive value. It tolerates acidity.
Tables 2 – 3 present the proximate chemical composition and macro mineral contents of some common grasses found in the Pacific Island countries.
- indicates no data available; Source of data: Aregheore, E.M. (2004d)
Centro (Centrosema pubescens)
This is a perennial twinning and climbing legume with long, smooth stems which often root at the nodes. The trifoliate leaves are slightly hairy. Although centro roots at the nodes it is propagated by seeds which need to be inoculated with the right Rhizobium strain. Centro is slow to establish, however, once established it tolerates higher stocking rates than most legumes (VPIP, 1990). Centro mixes well with both creeping and tufted grasses and is regarded as the most persistent of the introduced legumes to the Pacific (Figure 38). It is well adapted to a wide range of soil but does not grow well on coral soils. It can tolerate heavy grazing better than puero but less than hetero (Pottier, 1983).
Hetero (Desmodium heterophyllum)
It is a small strongly stoloniferous plant with trifoliate leaves of which the central leaflet is the largest. This legume is usually propagated by cutting because the seeds are difficult to harvest. It spreads quickly with runners on a really wet soil which is the prerequisite for its successful establishment. It is adapted to a wide range of soils. It is a native legume in the Pacific (Figure 39) and it is well represented in open pasture and coconut areas. It may be shaded by tall grasses, however it mixes well with stoloniferous grasses and is very persistent under heavy grazing situations (Pottier, 1983).
Mimosa (Mimosa pudica)
Commonly called small mimosa or sensitive grass is a creeping plant with thorny stems (Figure 40)and many lobed leaves. It is very common in the Pacific. The leaves are sensitive and fold-up quickly when touched. Although it has proven to be able to produce liveweight gains, it is however, considered a weed and a volunteer pasture legume. It tolerates heavy grazing and does well with low growing stoloniferous grasses. It is not recommended for planting, but should be accepted where it grows. Small mimosa should be grazed back by continuous grazing rather than rotational grazing as cattle will eat the young tender shoots, but not the older woody thorny material (Pottier, 1983; Reynolds, 1995).
Puero (Pureraria phaseoloides)
Commonly called Puero or tropical kudzu
It is a perennial creeping legume, vigorously climbing or twining legume with large hairy leaves and hairy stem. The leaves are made up of three round large leaflets. Puero is cylindrical shaped but sometimes somewhat flattened, hairy and turns black in maturity. It can be established from cuttings or seed. It is a legume that is adapted to high rainfall tropical areas and is moderately drought tolerant because of its deep root system. It is fairly tolerant of waterlogging and shading. It also tolerates acid conditions and prefers heavy soils (Vanuatu Pasture Improvement Project (VPIP, 1990). It is commonly found on a wide range of soils. It shows seasonal variation in its palatability to cattle, being more palatable after flowering. It cannot tolerate heavy grazing, therefore it is advisable that farmers should be more cautious with early grazing as this may cause it to disappear from the pastures. Puero is the most important cover crop (Figure 41)for plantation crops such as coconuts, cocoa, rubber, citrus, oil palm and mango. It is best used in open pastures and it mixes well with improved grasses. It may be sown with a persistent legume such as centro (Pottier, 1983).
Siratro (Macroptilium atropurpureum)
Is a pioneer legume that is under-rated in the Pacific. Siratro along with leucaena and glycine is the best adapted to coastal soil fertility conditions. It is a deep rooted, creeping and twinning perennial with stems that root readily at the nodes (Figure 42). Leaves are trifoliate, dark green and slightly hairy with a characteristic lobe on one side of the leaf. It is not persistent at stocking rates in excess of 1.8 Animal unit (AU)/ha. It has proven more productive than legumes such as centro or verano stylo (VPIP, 1990). However, it is more susceptible to leaf and stem damage from fungus Rhizoctonia solani than other legumes and can be devastated during extended periods of high humidity. It combine well with a range of grasses and is more drought tolerant than glycine.
For details of other creeping and non-creeping legumes such as: Alysicarpus vaginalis, Calopogonium mucunoides, Desmodium heterophyllum, Desmodium canum, Desmodium intortum, Desmodium ovalifolium, Neonotonia wightii, Stylosanthes guianensis etc. refer to Reynolds (1995).
Calliandra (Calliandra calothyrsus)
Calliandra (Figure 43) has been introduced in Pacific Island countries but has acclimatized and is found growing luxuriantly wild or semi-cultivated in most countries where it is used as a hedge. It is a woody, perennial legume that is well adapted, productive and has some degree of resistance to pests and diseases. The high production potential and high protein content of Calliandra make it promising as a supplementary feed. However, owing to its high tannin content, its palatability is less than that of Leucaena and Gliricidia. Like most tree legumes it remains green throughout the year and produces a lot of leaf biomass. The leaves are used to supplement low quality roughage diets because of its potential as a high protein source (Aregheore, 2005a). The constraint to the feeding of Calliandra is its low digestibility in the rumen when it is dried or wilted. It has a high content of phenolic compounds that are responsible for the protection of the protein against degradation in the rumen by microflora. For highly productive dairy cows that need some by-pass prote in, Calliandra is a good dietary ingredient (Paterson et al., 1999).
The genus Erythrina (Figure 44) contains several species widely distributed throughout the tropics and subtropics. In the Pacific Island countries two are known, Erythrina indica and Erythrina variegeta var. orientale which occur throughout the sub-region and are generally called ‘dadap’. They are widely distributed in a wild or semi-cultivated state, especially as fencing and as hedges in compounds. It is a potentially valuable feed supplement (Aregheore, 2004a). Erythrina is high in crude protein (20.6 %), comparable with Leucaena and Gliricidia (Aregheore, 2004a). The season of the year and varietal differences affects its protein content. Aregheore, (2004b) reported a crude protein content of 32.6 %. Despite the high protein content, anti-nutritive factors in the form of soluble phenolic and condensed tannin compounds in the leaves may affect its full utilization in livestock nutrition. Another important anti-nutritional substance in foliage is the alkaloid betaerythroidine but some metabolism occurs in the rumen (Erythrina Production and Use, 1993). Erythrina spp. however, have high forage quality and could effectively serve as cheap protein supplements for low-quality diets during the dry season (Aregheore, 2004b, Aregheore and Pereira, 2004).
Gliricidia (Gliricidia sepium)
Gliricidia sepium (Figure 45) is a deep rooted, fast growing, medium sized leguminous tree, common in many tropical countries. It was introduced into Pacific Island country animal agro- forestry systems some years ago. The tree has no thorns and a smooth whitish-grey bark. Gliricidia is generally deciduous and grows in a wide range of climates and soil types. As it matures, crude protein levels decrease slightly while crude fibre increases. Palatability or acceptability of Gliricidia forage can be a problem. The presence of inhibiting substances such as coumarin and flavanol has been suggested to cause low palatability. Gliricidia also contains high tannins and total phenols. With ruminants an adjustment period is needed if they have not been fed Gliricidia from birth. Animals will lose weight for the first 4-6 weeks after the introduction of Gliricidia to their diets. Once animals are adjusted its feed value is well utilized for maintenance and production. However, farmers have developed various means to improve the intake of Gliricidia. Wilting, drying or sprinkling of salt or diluted molasses on leaves apparently hastens acceptance (Aregheore and Yahaya, 2002; and Aregheore and Pereira, 2004). Drying and wilting may influence chemical composition, digestibility and voluntary dry matter intake. However, palatability is increased when mixed wit h grass, straw or other roughages.
Leucaena (Leucaena leucocephala)
Leucaena leucocephala (Figure 46) is a shrub or tree which can grow up to 20 metres. The leaves are bipinnate, 15 – 20 cm long, with 4-10 pairs of pinnae, each with 5-20 but mostly 10-15 pairs of leaflets; leaflets 7-15 mm long and 2-4 mm wide. The plant is valued for its ability to withstand repeated defoliation, high yields of foliage and tolerance to low soil fertility and relatively low rainfall (Bogdan, 1977). It is remarkably tolerant to adverse moisture conditions, apparently because of its deep roots, and can grow at annual rainfalls of 500 to 5,000 mm; at low rainfall it responds well to irrigation. It is more tolerant of low soil phosphorus status than many other tropical legumes which may be due to the presence of endotrophic mycorrhizae in the roots (Possingham, et al. 1971). Leucaena is highly productive and palatable (Morris and Du Toit, 1998). It is one of the most widely used forage trees in agro-pastoral enterprises as it provides a number of other products apart from protein rich forage (Brewbaker et al., 1985) and serves as a source of energy and sulphur for rumen bacteria. Like Gliricidia it was introduced to Pacific Island country animal agro-forestry systems some years ago. Leucaena is one of the most productive fodders and is very popular among livestock farmers. Leucaena intake results in a notable improvement in the body condition of animals. Increased levels of Leucaena in the diets of both large and small ruminants have positive effect on forage intake and live weight gain. However, one problem with this tree is the defoliation caused by the psyllid (Heteropsylla cubana), although this was not as severe in the Pacific as in other areas such as S.E. Asia and psyllid-resistant varieties are now available (such as the cross between L. leucocephala and L. pallida - known as KX2 F1 hybrid).
The major problem in the utilization of leucaena by livestock is the presence of the non-toxic amino acid mimosine in the forage. Ingestion of large quantities of mimosine can lead to acute and chronic toxicosis, weight loss and death (Morris and Du Toit, 1998). The presence of DHP (3-hydroxyl-4(IH)-pyridone) a degradation product of mimosine, tends to depress rumen cellulotyic activity and cause rumen stasis (Jones 1994). Mimosine toxicity in leucaena diets can be limited by the introduction of mimosine degarding organisms into the rumen. Specialized rumen bacteria may degrade DHP further to harmless compounds. Where leucaena is fed to unadapted stock at rates of more than 30 % of diet, DHP may act as a potent goitrogen and result in hyperthyroidosm and death. However, it is possible to innoculate ruminants with DHP degrading organisms and thus overcome the toxic effects (Norton et al., 1994). Estimates indicate that cattle and goats fed with high levels of leucaena leaves plus fresh grasses have improved liveweight gains (Morris and Du Toit, 1998; Aregheore, 2004e).
Cassava leaves (Figure 47) are relished as a vegetable in human and livestock nutrition; leaf meal could be successfully used as a protein and minerals source ruminant nutrition. Available ingredients determine the level of cassava leaf meal inclusion in ruminant diets. Cassava leaf meal has an appreciable amount of metabolisable energy with a range of 6.65 - 7.95 MJ kg-1 (Hutagahung et al., 1974). At high dietary levels the meal has an unfavourable effect due to bulkiness, reduced energy intake and methionine deficiency. Although, cassava leaves have a great potential in human, monogastric and ruminant nutrition, their high fibre and cyanide content limits their use as a major protein source. Cassava leaves contain condensed tannins which may present some grounds for concern in ruminant nutrition. Tannin content in cassava leaves increases with maturity of the plant and varies between cultivars. Tannins have the ability to lower protein digestibility and amino acid availability by forming indigestible complexes with dietary proteins or by inactivation of proteolytic enzymes. Their high fibre content affects their digestibility. Processing is a key element in reducing cyanide (HCN) concentrations in leaves. The anti-nutritional and toxic components present in the leaves of cassava such as HCN and tannins can be removed or reduced to a tolerable level by wilting the fresh leaves and simple sun drying removes these components.
Traditionally sweet potato was grown for tubers and the foliage was considered as a waste and therefore under-utilised (Moat and Dryden, 1993). However, nowadays sweet potato is grown by smallholders as a dual-purpose crop. The vines are fed to livestock and the tubers used for human food. Dry matter production potential per hectare of some cultivars of sweet potato vines (Figure 48) can be as high as 4.3 to 6.0 tons/crop (Dominquez, 1992) and the forage (leaf, petiole and stem) accounts for approximately 64 % of fresh biomass. The forage contains 11 – 17 % crude protein and its digestibility is greater than 62 % (Aregheore, 2004c). It has been reported that as a supplement to low quality roughage, sweet potato vines increases intake and rate of liveweight gain of animals (Aregheore, 2004c). Sweet potato forage could be an important resource as an animal feed in the Pacific Island countries. The value of sweet potato is attributed to high yield, palatability and crude protein content. These characteristics coupled with high moisture content (Orodho et al., 1993) make it a suitable protein supplement for animals receiving low quality forage in the dry season.
This is a native browse plant (Figure 49), not yet used in ruminant diets. However, its leaves have medicinal value at the traditional level. Its green fruits are well appreciated by local people. In the Pacific Islands it grows to a full tree whereas, in other tropical countries especially in Africa, its size is small to medium. Its sticks are used as a staking material in yam barns. The leaves have long been recognized to be of nutritional value to small ruminants – goats and sheep hence smallholders harvest them and feed them to their animals as supplements to low quality roughages. The fresh leaves have an astringent taste which indicates the presence of saponins and tannins (Aregheore, 2004d).
Flemingia macrophylla (Figure 50) is a shrub of 0.6-2.4 m high; branches 3-angled; leaflets lanceolate to narrowly elliptical, acuminate, up to 30 cm long and 9 cm broad; racemes axillary, 5-15 cm long; bracts linear to lanceolate, 15-20 mm long; calyx-segments unequal, 9 mm long overall; corolla rosy-purple, the standard petal 9 mm long; pod 13 mm long (Adams, 1972). Leaves are stipulate; blades exstipulate, digitately 3-foliolate or 1-foliolate; leaflet blades gland-doted below. Inflorescences are densely spicate-racemose or paniculate, bracts foliaceous or dry, persistent or deciduous, bracteoles absent; calyx lobes sub equal or lowest longer; vexillary stamen free, remainder connate, anthers uniform; style glabrous. Pods are turgid, dehiscent, continuous within; and about 1.2 cm long. In the South Pacific it is found in American Samoa, Cook Islands, Fiji, Palau, Papua New Guinea, Samoa and Tonga. Flemingia appears to have some value as a dry season browse (Skerman 1977), although its digestibility is less than 40 %. Palatability of immature herbage is considerably better than that of older material. Crude protein values range between 14.5 to 18.3% (Asare, 1985). Flemingia has lower leaf nutrient levels than Leucaena and Gliricidia. Flemingia with Centrosema could be promising for mixing with grasses for temporary pastures on arable land also it could be used to support creeping legumes.
Moringa oleifera Lam (synonym: Moringa pterygosperma, Gaertner), (Figure 51) commonly referred to as drumstick tree' or 'horseradish tree' (the taste of the roots), is a member of the Moringaceae that grows throughout most of the tropics including many parts of Africa, Madagascar, India, Pakistan, Bangladesh and Afghanistan and in some Pacific Island countries such as Samoa, Fiji and the Solomon Islands. It is a multipurpose tree of significant economic importance with several industrial and medicinal uses. Moringa is a small tree (7-12 m high) with thick grey bark, fragrant white flowers and long green pods. The fruits, seeds, leaves and flowers are eaten as vegetables in some countries. The leaves are rich in carotene, iron and ascorbic acid and the pods in free leucine. The leaves are rich in protein and can be used as supplement to low quality forage (Aregheore, 2002b).
Mulberry (Morus alba)
Mulberry trees are found in most of the Pacific Islands and from time immemorial have played an active role in the traditional festivity of the inhabitants. Mulberry bark is used for the production of the popular Tapa cloth in the Pacific Islands. In some parts of the world the main use of the mulberry is as feed for the silkworm. Its wood is valuable and, depending on location, it is also appreciated for its fruit, eaten fresh, as juice or as preserves. The young leaves and stems are a delicious vegetable and infusions such as mulberry leaf tea have medicinal properties (Sanchez, 1999). Mulberries can be incorporated in intensive farming systems and used to feed sheep and goats in cut-and-carry systems. Mulberry has high quality forage which is palatable to both monogastric and ruminant livestock (Sanchez, 1999). Small ruminants eat fresh leaves and the young stems avidly, even if they have not been exposed to it before. Cattle consume the whole biomass if it is finely chopped. The nutrient composition of mulberry shows that it would be a formidable forage for monogastric and ruminant livestock in the Pacific Islands where it is found almost everywhere because of the “tapa” cloth production (Aregheore, 2004d).
It is a fast growing, shrub or short-lived tree that regenerates rapidly after lopping which grows to 4.5 - 6 m high (Figure 53) and is copiously branched, with pinnate leaves, pale yellow flowers, and slender, slightly twisted pods up to 25 cm long containing many seeds. The leaves and young branches are cut for fodder for cattle, goats and sheep. Sesbania contains the toxic constituent canavanine. Wilting leaves before they are fed to livestock could reduce this.
A better understanding of legumes and their nutritional composition is necessary so that feeding methods can be modified to avoid some debilitating effects associated with them. Most tree legumes contain anti-nutritive factors (ANFs) such as condensed and hydrolysable tannins, saponins, toxic amino acids (canavanine and mimosine), coumarin, flavanol, and total phenols; their presence causes low palatability and unacceptability to farm animals (Aregheore, 1999). Where such feeds are eaten ANFs interfere with nutrient bio-availability and consequently, utilization. However, over the years, precautions have been taken to reduce these potential limitations and improve the use of legumes in ruminant livestock feeding. There is now an wealth of information on ways of detoxification of such substances so as to reduce the incidence of toxicity in livestock. Some examples presently adopted at farm level are drying, wilting, soaking, spraying of leaves with chemicals e.g. polyethylene glycol (PEG) 4000 and the inclusion of highly fermentable carbohydrates in diets using the leaves of tree legumes. Plants that are tannin-rich should be fed at less than 25% of the diet dry matter to avoid detrimental effects such as reducing digestibility of fibre by inhibiting the activity of bacteria and fungi.
The proximate chemical composition and macro and micro mineral contents of foliage of some browse plants found in the Pacific Island countries is presented in Tables 4-6.
Leucaena generally has low levels of tannins which allow efficient utilization of the protein by assisting amino acids to bypass complete degradation in the rumen (Middleton et al. 1994). Ruminants need a special anaerobic bacteria, (Synergistes jonesii) to detoxify mimosine. Animals without the bacteria can only tolerate 30 % leucaena in their diet before growth is reduced, hair loss and thyroid enlargement occurs. This is the level that has given optimum growth rates in goats (Pacific Agroforestry, 1999). Animals without the bacteria can be infected with it by taking some rumen fluid from an animal with the bacteria and drenching them or adding the rumen fluid to their drinking water.
Most by-products are cheap, low energy feed ingredients and locally available. Below is a description of some agro-industrial by-products which are available in the PICs.
Cocoa is grown in Samoa, the Solomon Islands, Vanuatu and Papua New Guinea. Cocoa beans are the commercial products. Several by-products of value to livestock are generated during processing. Shells and dust are waste but the value of these fractions as a possible livestock feed has received very little attention in tropical countries; they are a good source of feed for ruminants. When fed to cows they increase the butterfat and vitamin D content of the milk. Cocoa beans and shells are high in the alkaloid, theobromine, the presence of which reduces their use in large quantities in compound rations. Theobromine has an unpleasant taste; palatability and toxicity problems usually occur when large quantities of the beans or shells are used in stock rations. Absolute drying removes to a large extent the theobromine and other alkaloids that are present in the shells and the beans. Cocoa pod, husk and cocoa seed shell (Figure 54) when dried and milled are suitable to meet the maintenance and perhaps part of the production rations of sheep, goats and cattle (Aregheore, 2002c). The husk is free of theobromine but high in fibre and this makes it a suitable source of bulk in ruminant diets.
Morinda citrifolia, also called noni, nonu or kura, great morinda or Indian mulberry is a member of the Rubiaceae and grows extensively throughout the South Pacific region as an important medicinal plant. Noni is a genus of about 80 species, mostly of tropical origin. Its traditional uses vary from one country to the other in the South Pacific. The juice from the fruit is regarded as having medicinal properties and most people in the Pacific Island countries drink it. The juice is high in vitamin C and there is a high demand for it as an alternative medicine for a host of illnesses. Its fruit is shaped like a potato with pineapple-like spots and turns from green to white as it ripens. It is the most used part of the plant but the seeds, roots, flowers, bark and leaves can be used medicinally. During extraction of juice from ripe noni fruits, large amounts of waste are generated which is discarded (Aregheore, 2005b). In both wet and dry state when noni juice extract waste (Figure 54) is offered on a cafeteria basis to livestock, they often reject it (Ken Newton, personal communication, 2002). The waste is the pericarp, pulp and seeds.
Coffee is grown in the South Pacific; its pulp represents a major agricultural waste which might be incorporated into animal feed. Pulp from wet processing forms 40 % of the weight of the fruit (Carlos et al., 1982). Attempts have been made to use coffee pulp as a feed for cattle, pigs and poultry, but with little success (Clifford and Ramirez-Martinez, 1991). Coffee pulp as an animal feed has a number of problems; it has a good amino acids profile (Morgan and Trinder, 1980). Fresh pulp has a crude protein content between 2.1 - 3.2 %, while dehydrated pulp has 11.2 - 12 % crude protein. If coffee pulp is used in excess of 20 % of rations, feed utilization and growth rates are impaired due to the presence of ill-defined anti-quality and toxic components. Various components, including caffeine, low molecular mass phenols and tannins have been blamed for the undesirable effects. Caffeine level and its effects depend on variety. In ruminants coffee pulp has a diuretic effect due to the caffeine and unavailable lignified protein so ruminant rations which contain more than 20 % coffee pulp result in low feed intake due to poor palatability and the toxic effects of caffeine, chlorogenic acids, tannins and high fibre. Tannins interfere with protein and dry matter digestibilities by inhibiting protease and other enzymes or by forming indigestible complexes with dietary protein. Ensiling improves the digestibility of the pulp for ruminants.
Copra cake remains (Figure 56) after the extraction of oil from the dried meat of coconut and is the most abundant and perhaps the cheapest protein and energy source in the South Pacific region (Ochetim, 1987; Aregheore, 2005c). Depending on the method of oil extraction the cake contains between 20 - 30 % protein, 1 - 7 % oil and about 7 - 10 % crude fibre (Creswell and Brooks, 1971). In the South Pacific, crude protein content ranges from 15.6 - 22 %. Dietary fibre and rancidity are major problems associated with the cake. Dietary fibres interfere with the absorption of other nutrients and in the macro-molecular form are anti-nutritional due to gel formation (hydrated polysaccharides). Residual oil in the cake has a tendency to become rancid, reducing appetite for feeds prepared with it. As a feed ingredient, it should not be more than 15 % in the diet (Thomas and Scott, 1962). Efficient drying is the only means by which rancidity (free fatty acids) can be overcome.
Desiccated coconut waste meal. Desiccated waste meal (DCWM) is obtained when fresh coconut flesh is crushed to extract coconut cream which is used for the production of oil for cooking, body cream and other products. It is readily available but is often discarded in both urban and rural areas. It is ideal for ruminants either wet or dry. In the wet form it does not keep long because of the development of rancidity and a foul smell. It is imperative to use it as soon as possible after processing or to dry it in the sun or by other cheap means (Aregheore and Tunabuna, 2000). If drying is not properly done an unpleasant flavour and odour result which affect intake and in some cases a total rejection of a concentrate diet compounded with it. There is need to dry it to minimize the development of free fatty acids that may develop due to residual oil. The protein is low in lysine and histidine. The meal is also high in fibre. These factors limit its use in the diets of monogastrics. In ruminants neither protein nor fibre content are limiting factors and DCWM provides an acceptable and very useful protein and energy supplement.
Palm kernel meal
Oil Palm Fronds (OPF) - Oil palm fronds are abundant waste fibrous material from oil palm plantations derived from the harvesting of oil palm fruit bunches and the pruning management; they are a source of forage in livestock-crop production systems (Dahlan, 1992a). OPF have been extensively evaluated in livestock feedings trials in Malaysia (Dahlan, 1992a, b), and although the use of oil palm fronds as ruminant feed is limited because of their low nitrogen content, fresh OPF could provide sufficient amounts of both metabolisable energy (ME) and protein for maintenance of pre-slaughter goats (Dahlan et al., 2000). Oil palm fronds contain high fibre and low protein, but moderate dry matter digestibility. Different techniques of processing and supplementation of the fronds to make them suitable for ruminants have been advocated. The addition of non-protein nitrogenous source and soluble carbohydrate can improve the nutrient quality, nutrient intake and digestibility. It has been observed that preserved oil palm fronds with urea or molasses increased the nutrient content of OPF. Ensiling and pelleting could also increase the digestion characteristics of OPF.
Palm Oil mill Effluents (POME) - Sludge and condensate effluents from palm oil mill could also be effectively prepared and used in the diets of lactating and animals for fattening.
They are by-products of flour mills; wheat bran or mill mix has wide acceptance in the diets of livestock. These are commercially available and extensively used in ruminant nutrition. Important by-products include maize bran, wheat bran and rice bran. They can be low or high in fibre depending on processing methods. These are usually cheap, low energy materials are used feed-millers to make cheap feeds or formulate low energy diets.
Rice bran, pollard and polishing
Agriculture in the South Pacific region is subsistence and crop-oriented, livestock are kept as a sideline against crop failure, consequently, the ruminant livestock industry is not as developed as it should be. With the increase in the demand for animal products, livestock production is now being embraced by farmers. There are many reasons for the relatively underdeveloped status of livestock in the region such as feed, social attitudes, lack of appropriate technologies, disease control, marketing, and poor extension services. The potential to increase and improve ruminant production requires the introduction of practical technologies in feeds for smallholders as the only means through which sustainability could be achieved, because smallholders hold much of the ruminant livestock.
Livestock are an integral component of the mixed farming systems that predominate in the Pacific island countries, therefore any introduced technologies should aim at achieving a balance to increase productivity, enhance wealth, while resource degradation is minimized. Grazing will avoid harvesting feed manually or mechanically, processing, storing it, and transporting it to animals. The livestock are moved to the forage during its peak production period. Farmers will manage the pasture as an important crop in itself and the animals provide a way to market it.
Grasses such as batiki, Guinea, signal and buffel are drought tolerant and could be used for pasture to provide biomass for an all-year round feeding. Legumes such as Centrosema, Stylosanthes and Siratro that are well established in the region could be in inter-cropping. Food-feed inter-cropping or mixed farming systems will make very efficient use of natural resources and use the synergies that exist between livestock and crops. Crop residues feed animals and manure fertilizes the soil. Since mixed farming systems generally have a negative nutrient balance, the transfer of nutrients from grazing land to cropland through animal manure is important. Crop rotations involving a grazed pasture phase can be highly efficient in generating nitrogen, whilst helping control crop diseases. This is practiced in Fiji and Vanuatu. Food-feed inter-cropping or mixed farming can add to soil biodiversity and animals are often the justification for agro-forestry inputs such as fodder trees (Vizard, 2000), and according to Vizard (2000) with the growth of human population and greater need for both crop and livestock production, the need for integrated systems will increase. Animal husbandry in this context must utilize crop, animal and urban by-products and residues efficiently, combined with weeds, grasses and any crop surplus that may be available (Vizard, 2000).
Some economic data
Feed is important for livestock production so the livestock sector is an integral part of agriculture. Questions that arise are, can domestic production be increased without consideration of feed and what are the implications of using local feeds for ruminants (Reddy and Sharma, 2002)? Information on the economic benefits of forages, crop residues and agro-industrial by-products as animal feeds are scant in the region. Reddy and Sharma (2002) looked at two types of livestock production in the Pacific: traditional and commercial. The traditional, small-scale, semi-subsistence production system, is cost-free because cattle, sheep and goats graze unmanaged pastures, while commercial, large-scale production systems use commercial feed (Table 9). If PICs were to increase domestic production of meat, more pasture will be needed but, in view of the contracting pastureland due to conversion to more profitable uses, there is a need for a substitute from either imports or an alternative domestic source.
Intensified livestock production requires high expenditure on feed and may be a potential cause of loss of foreign exchange for small Pacific Island nations. Substituting domestically available for imported feed can reduce this problem and help stimulate the whole economy. Reddy and Sharma (2002) suggested that there is a need for more work and research on how this could be achieved, bearing in mind the dietary requirements of livestock and cost-benefit factors related to domestic production vis-ŕ-vis importation of feed.
In the Solomon Islands the economic advantage of cattle under coconut plantations is reduced weeding costs, increased copra production and income from beef sales. Jonah (2004), in a study to analyse the costs and returns from beef cattle production and using 30 beef cattle farmers in Efate Island Vanuatu, reported that 40, 50 and 70 % of household income came from beef cattle on small, medium and large farms respectively. Signal grass and glycine dominate the pastures used by farmers. Average per farm annual returns from livestock were US$ 2,230 (small farms), US$ 4,877 (medium farms), and US$ 22,000 (large farms). Large farmers sell full grown mature cattle directly to butchers and abattoirs, whereas small and medium farmers sell young cattle to traders in the village, so they receive relatively low prices.
Aregheore and Tunabuna (2001), in a feeding trial used desiccated coconut waste meal (DCWM) at varying levels of 0, 38.5, 48.5 and 58.5 % with other feedstuffs in concentrate diets that were fed to goats for 56 days, reported that DCWM mixed well with other feedstuffs and goats accepted the diets without deleterious effects. The 38.5 % DCWM inclusion level was the best for the growing goats however the inclusion of DCWM at high levels did not significantly reduce cost/kg of the concentrate diet and liveweight gain (Table 10).
Rokomatu and Aregheore (2005) studying voluntary dry matter intake, growth and nutrient digestibility by Fiji Fantastic sheep fed a basal diet of Guinea grass alone or supplemented with either a concentrate mixture or crushed wheat grain observed that:- a cost comparison indicated that total supplement (kg) offered to sheep in groups B and C for 92 days was 319.1 and 129.7 kg, respectively, while the total cost and cost /kg of supplement for sheep in groups B and C were US$658.4 and US$185.5; US$2.0 and US$0.86, respectively. Cost analysis of the supplementation demonstrated that the concentrate mixture was expensive compared to wheat grain. However, the significant differences observed in the daily liveweight gain of group B sheep above other groups seems to justify the supplementation when sheep are fed a basal diet of native Guinea grass (Table 11).
Tamani (2004) investigated the effect of inclusion of molasses in concentrate supplements on milk yield and the effects of supplementary feeding on voluntary dry matter intake, liveweight gain, body condition score and apparent nutrient digestibility coefficients of cows grazing setaria pasture in Fiji. He reported that lactating dairy cows would require a source of readily fermented energy such as molasses in their diets. Economic data on production parameters - milk yield, fat corrected milk, body condition score and apparent nutrient digestibility coefficients, indicated that molasses levels in the range of 5 - 10 % are ideal, however 10 % was best and recommended for concentrate diets of lactating dairy cows on a basal diet of Setaria.
Supplementation of goats with 33% Leucaena and 66% Sesbania showed optimal digestible dry matter intakes (17.8 and 20.3 g/h/d respectively) and liveweight changes were 71 and 63 g/d respectively (Pacific Agroforestry, 1999). The digestibility of most tree legumes ranges from 40 – 65% with a crude protein percentage of 16 - 30% with leucaena identified as one of the highest quality giving the highest long-term growth rates in cattle.
Benefits and considerations of domestic production; a number of economic and social benefits could accrue to PICs with increased domestic production of livestock feed, including:
There are important issues to be addressed before endeavouring to significantly increase domestic production and a need to:
A number of local feed resources are available in the Pacific Islands whose potentials as animal feed are partially untapped (Aregheore, 2000a). Some are used at various capacities in intensive production systems while smallholders use them as supplementation to their animals. Some available and potential feedstuffs in the region that can be used in ruminant livestock have been highlighted (Naidu 1989; Aregheore, 2001a, b).Where large quantities are produced, transport cost often limits their potential users while farmers nearby fail to use them due to lack of knowledge (Moat, 2002).
Crops such as cassava, cocoyams, breadfruits, bananas/plantains, potatoes and yams are major traditional staple foods, with rice and maize in Fiji, Vanuatu and the Solomon Islands. When these crops are harvested and processed, residues and by-products remain. Crop residues are produced on-farm and therefore widely spread in farming communities. Examples of crop residues are peel and leaves from cassava, breadfruit, taro, bananas/plantain and yams; vines from sweet potatoes, banana pseudostems; straw and stovers from rice and maize; sugar cane tops. These residues are characteristically low in metabolisable energy and nitrogen which leads to low intake, but they are a key element in ruminant nutrition and can meet nutritional requirements of animals if properly processed. When residues from roots and tubers including bananas are properly processed they substitute in part for cereals and other carbohydrate sources in ruminant rations.
Generally, the cheapest and most available feed in the region for smallholders is pasture, so they rely heavily on it. Sustainable ruminant production depends on correct management of pasture and animals to provide profitable returns on investment in forage production. Farmers need adequate quantity and quality forage supply throughout the year for the least possible cost. Consequently, animal production in terms of growth, lactation and reproduction could only be achieved when the forage consumed is in excess of that required for maintenance; lactation needs are greater than for growth. The amount of forage eaten, therefore, depends on availability, physical and chemical composition and the nutrient requirements of the animal.
Intake is highly correlated with digestibility, but other factors are involved. A major physical factor that affects intake is the rate at which the material is broken down to a particle size small enough to pass out of the rumen. Legumes break down more easily than grasses and their intake is higher, even at the same digestibility. Differences also exist between parts of the same plant so leafiness is important. Most of our natural pastures, particularly in the dry season, are of poor quality and have a high content of less degradable materials such as cellulose, hemicellulose and lignin as well as a lower quantity of easily digested carbohydrates, sugars, pectin and fructrosans (Singh, 2001). When tropical pastures are spelled for dry season grazing most of the material becomes too fibrous and lignified; it further loses quality when there are brief showers since most of the soluble sugars in the leaf blades are dissolved. Animals will tend to lose weight even when enough forage is on the ground in the dry season. This calls for supplementation with crop residues and agro-industrial by-products or with browse.
In the dry season when animals have only low quality native grasses for grazing, the foliage of tree legumes and shrubs complements low quality forage/roughage and crop residues (Aregheore, 2000b). Examples of common tree legumes fed to ruminants in the region are Leucaena leucocephala, Gliricidia sepium, Sesbania grandiflora, Erythrina spp. and Calliandra calothyrsus. Such legumes have advantages during drought:
Pasture is the cheapest feed and will continue to play a significant role in ruminant nutrition in the Pacific Islands. The present trend is to match ruminant production with available feed, because resources within the region such as foliage of trees, grasses, crop residues and agro-industrial by-products can be used to counter the cost of imported feed. In the dry season, legumes have a proven record as palatable nutritious forage and can be used as supplements to poor quality feeds. Ruminants can utilize proteins from plants that have high fibre content. Figures 58– 63 contain photographs to illustrate their role and why pasture will continue to be used in ruminant nutrition in the PICs.
Forage legumes are abundant in the region; Gliricidia grows well and is used as live fence posts; fodder may be cut and dropped in the paddocks a day before animals are to graze. Wilting increases intake although there is some initial aversion to the consumption of Gliricidia but animals usually accept it after an adaptation period (Gliricidia Production and Use, 1989).
Calliandra is mostly fed green since drying reduces its quality to maintenance levels. During dry spells Calliandra accumulates tannins which lowers its quality. Best results are when Calliandra forms 20% of an animal’s diet and more then 30% can cause weight loss (Pacific Agroforestry, 1999). Legumes such as Erythrina (dadap or drala) have more then 40% of the crude protein soluble and 75% of the soluble nitrogen fraction is not true protein, which results in a fast release of nitrogen in the rumen. To efficiently use this nitrogen Erythrina fodder must be supplemented with a readily fermentable carbohydrate such as molasses.
For ruminant livestock, forages (grasses and legumes) are the cheapest source of feed. However, forage and other feed resources (crop residues and agro-industrial by-products) are often scare and sometimes unavailable to the smallholder. Livestock production is essentially a process of converting feed into product (Barnard, 1969), and the provision of the required balance of nutrients plays an important role in livestock growth and performance. Cost is an important factor influencing feed availability and performance of livestock. The leaves of most tree legumes are high in protein and are used to supplement livestock during the dry season period, but feeding of legumes is not without problems. Legumes can be grown as fodder banks (Figure 60) to be fed on a cut and carry system or animals allowed to browse them every alternate day for a limited period of 15-45 minutes (crash grazing). The limited period prevents damage to the plants and excessive defoliation. They serve as a source of fermentable N and of bypass protein.
During the dry season the role of the legume is to increase the efficiency of utilization of the basal diets of poor quality. They supply fermentable and bypass protein and have additional benefits because they contain carbohydrates, minerals and vitamins. They enhance the rumen ecosystem by increasing microbial growth, rate of fibre digestion and propionate production. The efficiency of utilization of metabolisable energy is higher for a legume than grass because legumes provide a better balance of nutrients for productive purposes. When legumes provide highly digestible carbohydrate it increases the digestibility of the basal diet.
The potentials of the available feed resources in the PICs (see photos below), if properly harnessed, can sustain the present ruminant livestock population. Ruminant physiological adaptation to the use of fibrous plant materials should be explored by nutritionists and appropriate diets formulated to meet requirements of grazing animals in year-round feeding systems.
[This paper was completed by the author in May/June 2005 and was edited by J.M. Suttie and S.G. Reynolds in June/July and September 2005].