Intensive animal feeding practices for optimum feed utilisation

A. Abate¹ B.H. Dzowela² and J.A. Kategile³

1. Department of Animal Production, University of Nairobi, P.O. Box 29053, Nairobi, Kenya.

2. International Centre for Research in Agroforestry (ICRAF), P.O. Box 8108, Causeway, Harare, Zimbabwe.

3. International Livestock Centre for Africa (ILCA), P.O. Box 3211, Harare, Zimbabwe.

Introduction
Intensive livestock production systems
Evolution of intensive smallholder feeding systems
Feed resources for intensive feeding
Animal responses to intensive feeding
Constraints to intensive feeding practices
References

Summary Decreasing farm size and the opportunity to market livestock products has promoted the development of intensive production systems in East and southern Africa. This paper reviews the characteristics of the common feed resources used in small-scale intensive farming systems in eastern and southern Africa. The data analysed show that reasonable responses are possible from growing heifers and lactating cows fed cultivated fodder Crop residues, on the other hand, need supplementation with concentrates or forage legumes to sustain animal production. Constraints to intensive feeding identified include shortages of land, feed and labour. It is suggested that economics will ultimately dictate the solution to the thee-way interaction between feed availability, intensive feeding systems and labour.

Introduction

Data from the Food and Agricultural Organization of the United Nations (FAO) indicate that the regional ruminant herd in East and southern Africa comprises 88 million cattle, 54 million goats, 46 million sheep and 7 million camels (FAO data covers the following countries: Angola, Botswana, Burundi, Ethiopia, Kenya, Lesotho, Madagascar, Malawi, Mauritius, Mozambique, Rwanda, Somalia, Swaziland, Tanzania, Uganda, Zambia and Zimbabwe).

The bulk of these animals utilise what FAO classifies as permanent pasture. Based on these data, permanent pasture occupies between 4% (Mauritius) and 73% (Botswana) of the total land area in the various countries. In the majority of the countries pastures occupy 23 to 60% of the land area. Virtually all the permanent pasture areas are not improved and therefore the ruminants depend on natural forages and browses which vary widely in quantity and quality through the year. Generally, ample herbaceous feed of good quality is available in the rainy season, while feed is inadequate in both quantity and quality during the dry season. As a result livestock productivity varies with the season. While technologies for improving natural pastures are available, they face serious constraints such as communal ownership and grazing in the traditional sector. Currently the traditional communal grazing system is under pressure. Human population is increasing, arable cropping is expanding and grazing areas are decreasing. Household farm size is also decreasing due to subdivision and individual user/ownership competition over the cultivated areas has become more pronounced.

As a response to this land pressure, farming systems that aim at maximising crop and animal production per unit area have evolved in several countries. There is a move towards utilisation of planted forages and the use of crop residues and purchased concentrates has increased. The focus of this paper is on the feeding practices that have evolved in intensive farming in some countries of eastern and southern Africa, with particular emphasis on dairy cattle. The objective is to suggest ways to optimise feed utilisation.

Intensive livestock production systems

The characteristics of intensive smallholder livestock production systems in East and southern Africa are:

· stall-feeding
· planted and sometimes irrigated pasture plots or rows for feeding ruminants
· au manure is spread on crop and pasture plots and
· crop residues, weeds etc are collected and fed and/or conserved for feeding.

All these operations are labour intensive. Livestock production thus competes with crops (food and cash) for labour land, fertiliser and recurrent funds for inputs. The adoption of technologies such as improved livestock breeds (e.g. dairy cattle for milk production) and improved feeding, disease control and management are crucial to promote both productivity and efficiency. While all components are important and must be in a package, feeding is the single most expensive item and therefore deserves particular attention.

High performance is usually achieved through the use of dependable feeding standards and by relating yields to the nutrient and energetic content of feeds fed. In sub-Saharan Africa this is largely not possible because:

· there is a wide range of unselected genera and species of forages available for feeding, but inedible herbaceous plants predominate in the over-used pasture

· the nutrient content and nutritive value of most feeds vary seasonally and

· dry matter (DM) intake of basal diets is usually inadequate.

These factors make it difficult to rationalise feeding based on stipulated standards. In the context of sub-Saharan Africa, therefore, intensive livestock production aims at achieving higher levels of DM intake through various vegetative and concentrate supplements to the basal diet. The practice is continent-wide and is gaining acceptance (e.g. Urio and Kategile, 1987; Olayiwole and Olorunju, 1987; Abate et al, 1990; Munthali et al, 1990; Morungu, 1991).

Intensive production in the dairy sector refers to systems that are based on zero-grazing and semi-zero-grazing. In semi-zero-grazing, cows are fed on natural and/or improved pastures by day and paddocked by night. They are given a variety of feeds, including forage crops, crop residues and concentrates. The typical small-scale farmer, however, practices zero-grazing or stall-feeding, which is the most intensive form of animal production. In Kenya and to a large extent in Tanzania and Malawi zero-grazing and semi-zero-grazing are associated with animals of high genetic potential such as Friesians, Ayrshires, Guernseys, Jerseys and/or their crosses with local zebus.

Farmers practicing stall-feeding are essentially commercial producers who keep from one to eight cattle. The importance of such farmers is apparent in Kenya, where about 80% of all grade dairy cattle are in the hands of these farmers (Abate, 1992). In this system, the cows are largely confined to sheds where they are fed and milked. Various types of feeds are brought in, including weeds, crop residues, roadside herbage, fodder from thinning and pruning of crops and purchased concentrates. The nutritional value and importance of the various types of feeds differ seasonally. Weeds and roadside herbage are important in the rainy season, while crop residues and planted forages are the major feeds in the dry seasons. Table 1 lists the most important feeds used in stall-feeding systems in Kenya, Tanzania and Malawi.

Unfortunately, data on quantities of forages and crop residues actually consumed are not available. While the list is impressive, reports from these countries indicate that feed supply is still a major constraint (Potter, 1987; Lwoga and Urio, 1987; Munthali and Dzowela, 1987). There is also a shortage of protein-rich feeds, such as cottonseed cake (Table 1).

Table 1. Annual dry-matter production of some fodders, crop residues and agro-industrial by-products used in intensive feeding systems in eastern and southern Africa.

Feed	Kenya¹	Tanzania²	Malawi³
Fodder (t/ha per year)
Napier grass	85-27.4*	-	21.9
Green maize	20-26	-	-
Casava tops	10-30	317	-
Sweet potato vines	14-6	-	-
Total crop residues (t/year)
Maize stover	7,500,000	3,509,500	2,710,400
Sorghum millet stover	676,000	3,227,000	65,400
Wheat straw	187,000	573,000	787
Rice	39,000	604,000	34,265
Total agro-industrial by-products (t/year)
Cottonseed cake	5,384	110,000	9,209
Sunflowerseed cake	8,062	3,700	-
Copra meal	5,128	3,900	-
Coffee pulp	33,000	11,300	-
Sisal pulp	41,000	300,000	-
Molasses		48,600	-

1 Said et al (1982); Wouters (1985); Abate (1988); Potter (1987); Abate et al (1987) Animal Production Division (1988).
2. Mngulwi (1983); Lwoga and Urio (1987).
3 Munthali and Dzowela (1987)
* Under farmers' management
(-) Not available

Evolution of intensive smallholder feeding systems

Generally the high population growth rate in sub-Saharan Africa has resulted in subdivision of land into small holdings to accommodate an increasing number of farmers. In countries such as Kenya it was government policy to resettle landless people on land that had previously been European-owned large-scale farms (Said, 1985). Land acquired through cooperatives was also usually subdivided to settle individual families. Moreover, traditional land tenure systems and inheritance norms meant that land continued to be subdivided amongst family members. This is the case in the densely populated areas of Kenya (Central Province), Tanzania (northern areas) and Malawi (south), where the area of agricultural land per capita is small and declining and is inadequate for the production of arable and cash crops as well as forage for grazing. Thus, despite being labour-intensive, stall-feeding, particularly of dairy animals, has evolved in these areas as a response to the lack of grazing land and the need to continue keeping livestock. As feed became more available through development of high-yielding fodder varieties, farmers were encouraged to adopt intensive feeding practices. Establishment of artificial insemination services meant that the presence of a bull was no longer a prerequisite to dairying. Improvements in the supply of foundation stock, veterinary services and marketing opportunities ensured sustainable growth of the enterprise. Later the introduction and development of feeding packages based on on-farm resources helped popularise stall-feeding.

Feed resources for intensive feeding

Efficient utilisation of forages requires knowledge of the composition and value of specific feeds as sources of protein, energy and minerals. Thereafter, the problem remains to decide which feed supplements to use to optimise the intake of basic components at minimal cost.

Napier or elephant grass (Pennisetum purpureum) is the most important fodder crop in the three reference countries, followed by Guatemala grass (Tripsacum fasciculatum) and Rhodes grass. Others are Kikuyu grass (Pennisetum clandestinum), Star grass (Cynodon spp) and Setaria. Results from research stations show that Napier grass can produce up to 35 t DM/ha per year (Ogwang and Mugerwa, 1976).

Table 2 shows the chemical compositions of Napier grass, Kikuyu grass, Rhodes grass, Star grass, Nandi setaria and sweet potato vines. These data should be viewed with caution as the forages were harvested at a stage of growth when their nutritional content was at its optimum. Abate and Abate (1991) reported that protein-rich Kikuyu grass is a useful addition to rations. However, in practice, it is probably cheaper to improve and maintain the productivity of grass plots through the incorporation of legumes.

Table 2. Nutritional characteristics of common grasses and fodders fed in intensive feeding systems in Kenya ¹

Forage	Regrowth stage (weeks)	Crude protein (g/kg DM)	Organic matter digestibility (%)	Metabolisable energy² (MJ/kg DM)
Kikuyu grass	8	191.0	67.0	9.4
Rhodes grass	6	77.0	60.1	8.2
Star grass	10	102.0	58.2	8.2
Nandi setaria	4	122.0	62.4	8.6
Napier grass	5	101.0	77.1	9.9
Sweet potato vines	-	146.0	65.5	8.0
Silverleaf desmodium	-	168.0	68.8	-

1. Modified from Said (1976).
2. Calculated by authors.
(-) Not determined

Experiments with grass/legume mixtures have demonstrated that legumes fix atmospheric nitrogen in the soil and thereafter the released nitrogen is utilised by the accompanying grass. However, smallholder dairy farmers have not been able to adopt the technology for a number of reasons, in particular because of the difficulties associated with establishing and managing such stands, especially when legumes are planted with vigorous grasses such as Napier and Guatemala. Mixing the grasses with legumes results in higher intakes of energy, protein and weight gains. Milk production levels are also recorded to be in excess of yields from feeding grass alone. In systems where fertilisers are not used, legumes have the potential to enhance soil fertility. A number of legumes have now been identified as suitable crops for increasing the quantity and quality of forage produced in smallholder farming systems. These include species of Desmodium, Macrotyloma and Trifolium. They are, however, not widely cultivated because of scarcity of land and competition from food crops, lack of seed and shortage of labour.

Fodder crops and browse/tree legumes

When deciding on the most suitable fodder or browse/tree legume to grow, a number of agronomic factors need to be considered in addition to nutritive value. These include:

· adaptation to local climatic and soil conditions
· ease of establishment and future propagation
· ease of harvesting and conservation and
· persistence and palatability.

In parts of eastern and central Africa, Napier grass is the basis of the diet in stall-feeding units, its high yield being the main reason for its popularity. Average yields in Kenya vary from about 8.5 to 27.4 t/ha per year under farmers management (Table 1). The variation in yield is mainly a result of differences in climate, soil moisture and fertility and management. Given similar growth conditions, Napier grass is more productive than other common pasture species such as Rhodes grass and it is comparable to other fodders such as green maize (see Abate et al, 1987). The crude-protein (CP) content under farmers' conditions is rather low at an average of about 7.4% (Wouters, 1985) but some reports show that Napier can contain as much as 16% crude protein in the DM when harvested at an early stage of growth (Ogwang and Mugerwa, 1976; Mureithi, personal communication). There are varietal differences in DM production of Napier grass which should be exploited by researchers for extension to farmers.

Table 3 gives information on the nutritional composition and degradability of common fodder crops offered to animals under intensive feeding in Kenya. They are variable in composition but, as already reported (Abate and Abate, 1991), feeding a combination of fodders has a balancing effect on the intake of critical nutrients such as protein and minerals. Apart from banana leaves, the fodders have moderate to high DM degradability. Kamande (1988) has reported that the major differences in DM disappearance of fodders are established significantly (P<0.05) during the first 36 hours of incubation.

Table 3. Nutritional composition and degradability of fodder fed in intensive feeding systems in Kenya.^1,2

Fodder	CP	NDF	Ash	DM degradability (%)
	g/kg DM
Guatemala grass	121.0	743.7	139.8	67.8
Pakistani hybrid	94.5	714.3	229.4	62.2
Bana grass (Pennisetum)	91.6	680.5	205.7	67.8
Green make chop	141.6	693.1	125.4	81.1
Fodder sorghum	173.4	653.5	132.4	78.9
Banana leaves	54.2	757.4	131.7	50.0
Sweet potato vines	205.3	426.3	179.3	77.8
Maize fodder*	78.3	587.1	-	70.5
Oat fodder	87.7	680.1	102.6	66.0
Cabbage*	154.4	258.1	98.4	97.1
Napier grass	89.5	705.9	132.7	62.9
Potatoes*	115.0	-	72.6	97.8
Banana stems	21.0	713.6	110.0
Kale	35.6	245.1	137.0	97.5

1. Modified from Kamande (1988).
2. Abate and Abate (1991).
(-) Not determined.
* Mean of two values.

The potential for use of tree legumes is in their ability to produce reasonable amounts of forage with high levels of CP. However, leguminous browse trees tend to have high levels of tannins and secondary metabolites that render nitrogen unfermentable in the rumen. Kapinga and Shayo (1990) have reported that browse plants are capable of producing up to 20 t DM/ha. Consequently, as a means of increasing the yields of DM and CP in smallholdings, efforts have been directed to introducing multipurpose trees such as Leucaena spp, Gliricidia spp and Calliandra spp in alley cropping systems and around homesteads in some parts of East and southern Africa. Onim et al (1991) have found Leucaena leucocephala the most compatible alley species to the Maseno 'double-cobber' variety of maize. Fodder trees and browse plants contain an average of about 26.0% CP and have digestibility values that are moderate to high. Their nutritive value may, however, be compromised by a deficiency of minerals and the presence of toxic and antinutritional substances. Fodder trees can persist perennially and are a valuable feed source, providing leaves, flowers and fruit particularly during the dry season. Forage trees such as L. leucocephala, Gliricidia septum and to some extent Sesbania sesban have proved successful species for dairy and small-stock feeding systems. Leaves, fruits and pods of Acacia spp have also served as useful feed supplements.

Food-crop residues

In Kenya, Tanzania and Malawi maize stover is the most abundant crop residue. Small-scale farmers usually feed it to their animals untreated. Depending on location, wheat, rice, barley and oat straws are also fed as the basal diet at zero-grazing units in Kenya (Said et al, 1982). As shown in Tables 4 and 5, variations in nutritive value exist within and between crop residues. Coffee pulp apart, the residues essentially consist of lignified structural carbohydrates that are low in minerals and are degraded slowly in the rumen. Such highly fibrous material results in higher proportions of carbohydrates escaping fermentation. Wheat straw is the least digestible at about 39% in vitro (Table 5) while some varieties of maize stover are about 56% digestible in vivo (Table 4). Except for banana leaves and coffee pulp, the residues contain less than 7% nitrogen. As a result, voluntary DM intake remains poor.

Table 4. Nutritive value of maize crop residues fed in intensive feeding systems in eastern Africa.

Maize residue	CP	NDF	Ash	DM degradability (%)	Source
	g/kg DM
Stover	23.1	741.0	121.0	50.3¹	Musimba (1981)
Stover	62.9	-	63.6	56.1²	Tubei (1981)
Stover	35.0	807.0	80.5	44.3¹	Biwi (1986)
Stover	53.9	815.0	82.7	80.0	Kamande (1968)
Stover	40.0	792.0	782	42.33	Kilongozi (1991)
Cobs	24.0	-	60.0	-	Urio (1981)
Cobs	22.0	-	33.6	55.0²	Tubei (1981)
Cobs	17.2	705.5	13.3	44.7²	Nangole (1982)

1. In vitro.
2. In vivo.
3. In sacco.
(-) Not determined.

Table 5. Nutritive value of cereal crop residues and other by-products used in intensive feeding systems in Kenya.

	CP	NDF	Ash	DM degradability (%)	Source
	g kg DM
Wheat straw	40.2	662.4	103.7	39.4¹	Musimba (1981)
Wheat straw	57.2	732.2	109.9	57.8²	Kamande (1988)
Rice straw	37.9	589.4	239.9	50.2¹	Musimba (1981)
Oat straw	33.0	-	78.0	51.13	Musimba (1981)
Banana straw	154.0	757.4	131.7	57.8²	Kamande(1988)
Pineapple waste	66.0	648.0	42.7	67.03	Methu, (unpublished data)
Coffe pulp	136.0	515.0	107.0	85.1²	Abate and Kiflewahid (1991)

1. In vitro.
2. In vivo.
3. In sacco.

Tubei (1981) fed sheep concentrate supplements to basal diets of crop residues and recorded intake and average daily gains respectively of 359 g and 79 g for maize cobs and 338 g and 62 g for maize stover. Urea treatment increased digestibility, intake and performance of ruminant animals fed crop residues under Kenyan conditions (Said, 1981) but the availability and cost of chemicals make treatment impractical for zero-grazing farmers. Supplementing with fermentable energy and nitrogen is instead a more attractive option. Total DM intake, digestibility and nitrogen retention were increased when lambs fed on maize stover were supplemented with legumes (Smith et al, 1990).

Monetary value of herbaceous feeds

In the majority of the pastoral and agro-pastoral systems in sub-Saharan Africa, herbage is regarded as free and without individual ownership. However, in areas of land shortage, scarcity of feed on-farm creates a demand and market value for this feed. The premium added therefore makes farmers more rational in its use. Issues such as economic returns and preferential feeding practices then become important: for example, milking cows and replacement heifers are preferred to bull calves for hand feeding.

There are many examples of herbaceous feeds that have gained commercial value in the densely populated areas of eastern and southern Africa. The feed groups include standing hay, crop residues and agro-industrial by-products. The introduction of dairy cattle in these areas has increased the commercial values of materials, with the trend likely to remain. In a number of eases in Kenya and Tanzania job opportunities have been created for non-livestock keepers, who collect and bundle the herbaceous materials for sale to livestock owners. There are also locations in Malawi and Tanzania where arable farmers are growing Leucaena leucocephala as a cash crop. The farmers harvest the leaves, sun-dry them and sell them to smallholder dairy farmers in both rural and pert-urban areas. Such entrepreneurial activities benefit both arable and livestock farmers.

Agro-industrial by-products

Feed sources originating from agro-industries include those providing easily fermentable energy, protein supplements and by-products of cereal milling, which are sources of both energy and protein. High-moisture products such as brewers' waste are bulky and require transport for effective. Their use is consequently limited to smallholders farming around urban centres, where most agro-industries are located. Table 6 shows the nutritional composition and degradability of agro-industrial by-products and commercial and home-made compounded concentrates given to animals in intensive feeding systems.

Table 6. Nutritional composition and degradability of concentrates fed in intensive feeding systems in Kenya. ^1,2

Concentrate	CP	NDF	Ash	DM degradability (%)
	g/kg DM
Cottonseed cake	311.0	207.0	59.0	67.4
Sunflowerseed cake	336.0	283.0	57.0	63.9
Wheat bran	172.0	134.0	79.0	69.6
Dairy meal	165.0	114.0	59.5	83.2
Crushed maize + dairy meal + wheat bran	164.3	152.2	61.3	77.7

1. Abate and Kiflewahid (1991).
2. Abate and Abate (1991).

Molasses is rapidly and entirely fermented in the rumen. It is usually fed in a liquid form mixed with fresh or dry forage. At other times it is used as a carrier for urea in molasses/urea blocks. Pineapple waste is equally rich in highly fermentable sugars. However, DM intake of fresh pineapple waste is usually low, with resultant low animal productivity (J.N. Methu, personal communication). It would appear that it is advisable to dry the material before feeding. Similarly, drying is essential for higher DM intakes of brewers' waste and coffee pulp.

Of the oilseed proteins, cottonseed and sunflowerseed cakes are the most commonly used supplements. High fibre levels are frequent in undecorticated forms of these cakes, which consequently have lower digestibility. Decorticated cottonseed cake is of good quality but has the disadvantage of low calcium content, which may lead to deficiency of calcium particularly in lactating cows. Wheat and maize brans are used widely as the energy portion of the ration. Their nutritive value varies with source but they are generally characterized by high levels of degradable energy. Brans are frequently fed singly but may also be combined with each other or with a commercially compounded feed such as dairy meal. The effectiveness of concentrates in promoting animal production under intensive feeding is doubtful because of the small quantities fed. In semi-zero-grazing and zero-grazing systems in Kenya, an average of about 0.8 kg DM of concentrate is fed a day to lactating cows (Abate and Abate, 1991). Apart from cost being sometimes prohibitive, the feeding of concentrates to dairy cows is inversely related to the distance from the supply centre (Stotz, 1979).

Non-protein nitrogen

The most widely used source of non-protein nitrogen (NPN) in ruminant rations is urea. Efficient utilisation of NPN requires matching of the rate of carbohydrate fermentation with the rate of ammonia release. Feeds containing sugars, such as molasses or starch, are used as carriers. It is similarly important to supplement diets containing NPN with minerals, especially sulphur. Feed-grade urea is available in the region relatively inexpensively but is not often used directly. Instead it is generally mixed with molasses, but farmers are not encouraged to use it with other ingredients on-farm due to the dangers of poisoning. As an alternative, ready prepared molasses/urea mixture (MUM) is available in some parts of Kenya and Tanzania.

Animal responses to intensive feeding

Quantitative data on the effects of intensive feeding on animal performance are scanty, particularly with respect to dairy cattle. However, the few experiments documented show that the potential exists for combining various feed resources to increase growth and milk production. Indeed, Abate and Kiflewahid (1992) have, on the basis of degradation characteristics, identified possible combinations of feeds for use in dairy rations.

Data presented in Table 7 show that the effect of Napier grass on the growth of purebred and Crossbred heifers is variable. When the quality of the Napier grass is medium to high (CP levels of about 12%) crossbred heifers initially weighing about 170 kg can grow at 400 g/day on fresh Napier grass fed ad libitum. Supplementing with about 1 kg of a maize grain concentrate produces a growth response of about 0.5 kg/day. Mature Napier grass containing 4% CP can meet only the maintenance requirements of crossbred heifers (KARI, 1985) (Table 7). To achieve weight gains of about 0.5 kg a day would require supplementation with about 3 kg of concentrate per animal a day (Table 7).

Table 7. Dry matter intake and performance of dairy animals fed Napier-grass-used diets in intensive feeding systems in Kenya.

Basal diet	Supplement	Total DM Intake (kg/day)	Animals	Growth rate g/day	Source
Napier grass-8 wk	None	3.0	Jersey heifers	361	Odhiambo (1974)
Napier grass-10 wk	None	3.4	Jersey heifers	409	Odhiambo (1974)
Napier grass-12 wk	None	3.2	Jersey heifers	348	Odhiambo (1974)
Napier grass	Pineapple waste	4.5	Ayrshire/Friesian steers	667	KARI (1990)
Napier grass	None	8.3*	Crossbred heifers	400	KARI (1983)
Napier grass	0.5 % BW	8.5*	Crossbred heifers	511	KARI (1983)
Napier grass	maize grain
Napier grass	None	5.0*	Crossbred heifers	10	KARI (1985)
Napier grass	1.3 kg maize flour	5.7*	Crossbred heifers	210	KARI (1985)
Napier grass	2.6 kg maize hour	6.5*	Crossbred heifers	480	KARI (1985)

* Calculated by authors.
BW = Brewers waste.

With lactating cows, DM intake of fresh Napier grass mixed with minerals is quite high, implying that the forage is acceptable to cattle. Ware-Austin (1963) noted that Napier grass is persistent, productive and capable of supporting milk production in Ayrshire and Jersey animals at a level higher than could be obtained from sown pastures.

In trials in Kenya, intake and milk production levels were comparable to those from green maize when Napier grass was supplemented with 2.0 kg of concentrate (Table 8). Friesian cows seemed to respond better to Napier grass feeding than did crossbreds. Though supplementing with 8.0 kg of concentrate increased milk production the practice would not be within the purchasing ability of the small-scale farmer. At any rate, supplementation should be carefully conducted to avoid replacing forage with concentrate.

Table 8. Dry matter intake and milk production by grade cows fed fodder-based diets in intensive feeding systems in Kenya.

Basal diet	Supplement	Total DM intake kg/day	Animals	Milk production (kg/day)	Source
Napier grass	None	13.9	Friesian	10.5	KARI (1984)
"	8.0 kg concentrate	18.2	Friesian	15.0	"
Napier grass	2.0 kg concentrate	11.6*	Crossbreds	7.1	KARI (1985)
Green maize	2.0 kg concentrate	12.0*	Crossbreds	8.1	"
Napier grass	0 kg Leucaena	7.8	Crossbreds	7.2	KARI (1990)
"	4.0 kg Leucaena	9.3	"	7.6	"
"	8.0 kg Leucaena	10.4	"	8.3	"
Early cut silage	2.0 kg concentrate	8.9	Crossbreds	11.7	Abate (1990)
"	4.0 kg concentrate	8.7	"	12.3	"

* Calculated by authors with DM of concentrate assumed to be 90%.

Another feed that has been fed to lactating cows under intensive conditions is ensiled maize (Abate, 1990). For small-scale farmers forage conservation through ensiling may be hampered by the difficulties associated with making good-quality silage. The answer may lie in intensifying feed production based on Napier grass. Examples of such intensification exist in the subhumid Kenyan and Tanzania coastal region. Here, copra cake and Leucaena leaf meal are used to supplement diets based on Napier grass (Table 9).

Table 9. Effect of Napier fodder supplementation¹ on DM intake, liveweight change and milk yield of lactating cows.

Treatments	Napier intake (kg/day)	Total intake (kg/day)	Intake per 100 kg metabolic wt (kg)	Milk yield (kg)	Body weight change (kg)
Napier fodder only	5.5	5.5	3.4	4.2	7.1
Napier + copra cake	5.6	6.8	2.9	5.2	6.1
Napier + Leucaena	5.8	7.0	3.4	5.2	7.6

1 Supplementation at the rate of 300 g/day for 56 days

Source: Adapted from Muinga R W. Thorpe W and Topps J H 1991. The lactational performance of Jersey cows given Napier fodder with and without protein concentrates in the semi humid tropics KARI/ILCA, P.O. Box 80147, Mombasa, Kenya

The performance of animals fed diets based on crop residues is shown in Table 10. It is apparent that, without supplementation, zebu bulls stall-fed maize stover can only maintain their weight. Gains are, however, possible when supplements are also fed and results seem better with forage legumes than with about the same amount of cereal bran. The possibility of attaining high weight gains from complete diets based on maize cobs is also shown (Table 10).

Table 10. Dry matter intake and performance of animals fad diets based on crop residues in intensive feeding systems in Africa.

Basal diet	Supplement	Total DM intake (kg/day)	Animals	Growth rate (g/day)	Source
Maize stover	None	4.2	Zebu bulls	8	Wegad and NDumbe (1987)
Maize stover	1 kg Leucaena hay	4.14		236
Maize stover	4 kg maize bran	8.3	Steers	360	Munthali (1987)
Maize stover	0.8 kg concentrate¹	2.9	Crossbreds	96	Kilongozi (1991)
Maize cobs²	None	5.1	Heifers	412	Kategile (1981)

1. DM of concentrate assumed to be 90%.
2. Complete diet.

Constraints to intensive feeding practices

There are practical problems associated with the feeding of forage in intensive production conditions. Shortage of forage is probably the first limiting factor. Decreasing quality, particularly towards the end of the growing season, imposes a limitation for high-yielding animals. Lack of information on suitable forage types and strains for given locations has contributed to the use of inappropriate strains and subsequently low forage yields.

It should be recognised that the growing of pure fodder crops is likely to receive less attention since the wishes of the farmers to meet their own immediate demand for food will far outweigh the need to address the feed requirements of their stock, particularly as land is further subdivided into smaller plots. In addition, competition from cash crops will preclude the diversion of land and labour to forage production.

There are insufficient of leguminous material for supplementing diets, and the levels at which legumes should be fed have not been established for different species. This is a particular problem with crop residues, which are usually deficient in at least one nutrient and cannot support animal production without adequate supplementation. Owing to their bulky nature, the majority of crop residues must be used at or close to where they are produced to reduce transport cost.

Supplementation with adequate amounts of concentrates is far from widespread. Some concentrates are purchased from distant places and this is a hindrance to their frequent use. It may also be necessary to limit export of such concentrates as molasses and protein cakes so as to make them more available to small-scale farmers. Shortage and high cost of labour for harvesting, carting and feeding large quantities of fresh material are also known to constrain intensive feeding of dairy animals.

The extension service in Kenya recommends the chopping of forage before feeding and this is largely accepted by farmers. The technology for particle size reduction has developed from use of the panga to hand- and motor-operated chaff cutters. The last of these reduces labour requirements but is probably used by few small-scale farmers since electricity is essential for its operation. The panga is the cheapest technology but the human energy expenditure involved makes retention of labour difficult. The three-way interaction of feed availability, feeding system and labour is complex and the solution will lie in the economics of the enterprise.

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