A.K. Tuah
Department of Animal Science, University of Science and Technology, Kumasi, Ghana
Abstract
Introduction
Agricultural by-product feed resources available in Ghana
Acknowledgements
References
Sheep constitute a significant proportion of the ruminant livestock population in Ghana. There is a growing interest in the raising of sheep in backyards among urban dwellers, but their major problems is the availability of feed as their animals are not allowed to roam and graze freely as is done in the village.
The agricultural by-product feeds available in Ghana include cereal and legume straws, corncob, cocoapod husk, coffee pulp and peels of yams, cocoyams, plantains and cassava. The nutritional problems encountered in the utilisation of these by-products, the treatments needed to improve their nutritional values and the economics of feeding to sheep have been discussed. The other major problems associated with the use of these by-products are bulking, transportation, storage and processing.
In the villages, in the southern parts of the country, it is suggested that grazing animals should be supplemented with peels. In the villages in the northern parts of the country, the feeding of cereal and legume straws should be encouraged. In the cities it is suggested that commercial feed mills should prepare diets from these by-products for sale. There is also the need to improve the growth rate and feed conversion efficiencies of the local breeds of sheep if they are to be raised intensively in the towns and cities.
Sheep constitute about 42.67%, on numerical basis, of the ruminant livestock population in Ghana (Veterinary Services Department, Min. of Agric., Ghana, unpublished data). The rate of increase in the population of sheep is reported to be higher than that of any other species of ruminant livestock in the country (3.4% for sheep 1.2% for goats and 1% for cattle, (Veterinary Services Department, Min. of Agric., Ghana, unpublished data). Apart from being a source of meat, sheep are also the choice animals for sacrifices to gods and stools and for appeasing elders when they are offended by their juniors.
There is at present a growing interest in raising sheep in backyards by urban dwellers. The major problems of these backyard farmers is availability of feed. Unlike the backyard poultry farmers in the towns and cities, the backyard sheep farmers have no access to commercially-prepared feeds since no feedmill prepares sheep feeds for sale. They have to buy cut grasses and household offals such as cassava peels to feed in confinement these animals as the municipal authorities do not permit free roaming of sheep as is done in the villages.
Since the costs of sheep feeds prepared from concentrates such as cereal grains will be very prohibitive, attempts are being made by some researchers in the country to formulate sheep rations based mainly on agricultural and industrial by-products.
The aim of this paper is to discuss some of the prospects for and problems encountered in attempting to use agricultural by-products in rations for sheep in Ghana.
Some of the agro-industrial by-product feed resources available in Ghana and their nutritive values are shown in Table 1. The industrial by-products are: wheatbran, dried brewers (spent grains from the breweries), oilseed cakes, copra, cottonseed cake and palmkernel); pito mash (spent grains from the brewing of local beer, pito) and maize bran. These by-products are used greatly in the rations of non-ruminants. The oilseed cakes are produced in the rations of ruminants, as there is not enough for making rations for non-ruminants.
The agricultural by-products which could be used in the rations of sheep are rice-bran, sun-dried poultry manure, coffee pulp, cocoapod husk, peels of cassava, plantain, cocoyam and yam, cereal and legume straws and corncobs.
With the cereal and legume straws and corncobs, the major limitations are their low digestibilities due to lignification of their cell walls which form the bulk of the materials. Apart from cowpea straws (for crude protein), they are also low in crude protein, water and most likely some essential minerals. The straws are also deficient in Vitamin A.
El-Naga (1987) reported of improvement in nutritional value of straws with supplementation of minerals, vitamins and nitrogen. El-Naga (1986) also obtained improvement in intake of straws with hydration. It is also believed that cereal straws are more efficiently utilised when supplemented with green forages (Mbatya et al, 1983). The actual constituents in green forages which help to improve the utilisation of cereal straws are not known. These cereal straws also respond to alkali treatment. Since sodium hydroxide is an expensive product in Ghana, lee (an affluent from the manufacture of soap) or woodash solution could be used to treat these straws as has been shown in Table 1 for corn stover. Varietal differences in digestibilities exist in cereal and legume straws (Tuah et al, 1988) and good quality straws could be used for feeding.
Table 1: Nutritive values of some agro-industrial by-products which could be used in sheep rations in Ghana
|
By-product |
DM% |
% Crude Protein (DM basis) |
IVDMD* Untreated |
IVDMD 5% NaOH treated |
IVDMD Lee treated |
IVDMD 10% wood ash solution treated |
|
Cassava peels |
27.9 |
5.71 |
62.95 |
|
|
|
|
Plantain peels (Apentu) |
19.8 |
10.64 |
76.03 |
|
|
|
|
Yam peels (White) |
17.70 |
11.21 |
61.58 |
|
|
|
|
Rice straw ITA 230 |
93.40 |
4.36 |
46.78 |
65.82 |
|
|
|
Corn stover (Dobidi) |
92.74 |
5.04 |
51.13 |
62.03 |
75.38 |
63.25 |
|
Cowpea straw TVX 1948 | ||||||
|
OIF variety |
90.58 |
13.31 |
54.18 |
|
|
|
|
Cocopod husk |
89.50 |
7.60 |
41.37 |
41.56 |
|
|
|
Coffee pulp |
90.56 |
8.8 |
33.07 |
33.72 |
|
|
|
Sun dried poultry - manure |
91.66 |
14.77 |
|
|
|
|
|
Copra cake |
90.90 |
22.80 |
|
|
|
|
|
Cottonseed cake |
91.42 |
35.43 |
|
|
|
|
|
Maize bran |
86.86 |
12.73 |
|
|
|
|
|
Rice bran |
91.96 |
7.47 |
68.27 |
72.96 |
|
|
|
Wheat bran |
86.50 |
17.77 |
|
|
|
|
|
Dried brewers spent grain |
93.37 |
18.29 |
|
|
|
|
|
Corncob |
93.27 |
3.20 |
35.60 |
68-90 |
|
|
|
Palmkernel cake (sun dried) |
91.1 |
16.91 |
|
|
|
|
|
Cocoyam peels |
17.62 |
9.56 |
|
|
|
|
* IVDMD = In vitro dry matter digestibility
Coffee pulp has low in vitro dry matter digestibility and does not respond to alkali treatment (Tuah and Ørskov, 1987; Table 1). It is high in lignin (about 27%) (Tuah and Ørskov, 1987). It contains about 5% condensed tannins. It, however, has the advantage of stimulating appetite in sheep (Tuah et al, 1985).
Cocoapod husk has to be dried quickly; otherwise it grows mouldy and loses all the digestible carbohydrates. At present it is dried electrically. The energy cost of obtaining one metric tonne of dried cocoapod husk is about 400 litres of oil (Gibb, 1975). The efficiency of using solar driers should be tested and if successful they can be adopted for use by small-scale farmers and the state owned large cocoa plantations.
The peels of yams, plantains and cassava (and perhaps cocoyam for which no figures are available) are more digestible than the straws, corncob, coffee pulp and cocoapod husk (Table 1). They are most likely low in lignin. The cyanide content of the local varieties of cassava peels are not high but if there is the need to reduce it further, this can be achieved by fermenting the material before drying (Osei and Duodu, 1988). The crude protein contents of these peels, apart from cassava, are high and compare with that of tropical grasses (8% for grass hay, Akinsoyinu and Adeloye, 1987).
Poultry manure has to be dried before it can be stored for any appreciable length of time. When using poultry manure, copper toxicity and urinary calculi (in males) may occur. On the University of Science and Technology livestock farm, however, even layer manure has been fed to sheep for about seven months without any problems. The Djallonke breed of sheep may not be very sensitive to these disorders.
Corncob has low in vitro dry-matter digestibility but it responds to alkali treatment. It is bulked in the villages after shelling of corn.
Feed intake, performance and feed costs of production using some agro-industrial by-products and grass in sheep diets in Ghana.
Tables 2 and 3 contain feed intake, performance and feed costs of production of animals fed various diets containing some agro-industrial by-products, maize and dried grass. These trials were conducted on the livestock farm of the Department of Animal Science, University of Science and Technology (UST) Kumasi, Ghana.
In experiment 1 (Table 3) the costs of kilogram gain were ¢870.25 and ¢512.05 for diets containing 60% and 45% cocoapod husk respectively. For the diet containing 66% dried grass the cost per kilogram gain was ¢942.48.
In experiment 2 (Table 3) the cost per kilogram gain ranged from ¢437.12 to ¢555.34. There was no maize in any of the diets and the rations were formulated to contain mainly agricultural by-products.
These figures demonstrate clearly the advantages agricultural by-products have over dried grass. In fact in the city of Accra, 1kg DM of cut grass costs ¢133.3. If feed conversion efficiency (FCE) is about 20kg feed/kg gain as was for the diet containing 66% dried grass (Table 2) then the cost per kilogram gain would be ¢2666.6. If FCE is about 10kg feed/kg gain then the cost per kilogram gain would be ¢1333.3.
The FCE is however, most likely more than 10kg feed/kg gain. It is at least about 15kg feed/kg gain and the cost of kg gain would be ¢1999.5. Akinsoyinu and Adeloye (1987) in Nigeria obtained a FCE value of 14.61kg feed/kg when they fed a diet consisting of 66.6% grass hay and 26.6% maize to Djallonke sheep. If diets based mainly on agricultural by-products are cheaper than cut grass (which people buy in large quantities in Accra) why are agricultural by-products not being used in diets for sheep in the urban areas? The market exists for the sale of these feeds.
Problems associated with the utilisation of agricultural by-products in sheep diets in Ghana
Apart from the nutritional problems discussed earlier when discussing the types of agricultural by-products available in the country, there are other problems. The first of these is perhaps the lack of interest on the part of feedmillers to produce sheep diets as most of the by-products are not found in the cities where the commercial feedmills are located.
The cereal straws, apart from rice, are scattered on the farms after harvesting the grains. They have to be bulked and transported to the villages and stores. There are no machines in the villages to process those straws for incorporation in diets for ruminants. There are no sources of non-protein nitrogen to be added to the straws as all the poultry farms in the country are located near the big towns and cities and no urea is imported. Cocoa pod husk, as indicated earlier, ought to be dried quickly to retain its digestible carbohydrates and it is found on the cocoa farms where animals are not allowed for fear of damage to trees and fruits. Transporting the fresh husk to the villages for drying is almost impossible.
US$1 = Cedi 250 (but fluctuates); ¢ = Cedi
Table 2: Ration composition, growth rates, cost per kg feed (as is basis), feed conversion efficiency (F.C.E) and cost per kg gain of animals fed diets containing different levels of cocoa pod husk and dried grass.
|
Ingredients |
1 |
2 |
3 |
4 |
5 |
|
Cocoapod husk |
- |
15.0 |
30.0 |
45.0 |
60.0 |
|
Dried grass (Panicum maximum) |
66.0 |
49.25 |
33.25 |
20.0 |
6.0 |
|
Corn |
7.25 |
14.0 |
19.0 |
21.25 |
25.25 |
|
Dried browers-spent grains |
25.0 |
20.0 |
16.0 |
12.0 |
7.0 |
|
Bone meal |
1.0 |
1.0 |
1.0 |
1.0 |
1.0 |
|
Sodium chloride |
0.5 |
9.5 |
0.5 |
0.5 |
0.5 |
|
Trace mineral-vitamin premix |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
|
Cost/kg of feed (Cedis *, as-is basis) |
39.60 |
38.88 |
37.72 |
36.29 |
35.29 |
|
Daily gain in weight (g) |
22.42 |
35.51 |
43.55 |
46.65 |
20.72 |
|
Cost/kg gain (cedis) |
942.48 |
654.35 |
574.85 |
512.05 |
870.25 |
|
Kg feed/kg gain (F.C.E as-is basis) |
23.80 |
16.83 |
15.24 |
14.11 |
24.66 |
*232 Cedis = 1 US$
Table 3: Ration composition, growth rates, cost per kg feed (as-in basis), feed conversion efficiency (F.C.E) and cost per kg gain of animals fed diets containing different levels of cocoa pod husk and sodium hydroxide-treated corncob.
|
Ingrediets |
Diets | ||||
|
|
1 |
2 |
3 |
4 |
5 |
|
Cocoapod husk |
- |
20.0 |
40.0 |
60.0 |
80.0 |
|
Sodium hydroxide treated corn cob (10%) |
65.4 |
49.4 |
32.0 |
16.0 |
- |
|
Sun-dried poultry manure |
19.0 |
15.0 |
12.4 |
8.0 |
3.4 |
|
Wheat bran |
15.0 |
15.0 |
15.0 |
15.0 |
15.0 |
|
Common salt |
0.5 |
0.5 |
0.5 |
0.5 |
0.5 |
|
Dicalcium phosphate |
- |
- |
- |
0.4 |
1.0 |
|
Trace mineral-vitamin premix |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
|
Cost/kg of feed (as-is basis; cedis) |
31.34 |
29.94 |
28.05 |
26.88 |
25.81 |
|
Daily gain in weight (9) |
31.15 |
45.21 |
40.69 |
28.98 |
26.70 |
|
Kg feed/kg gain (F.C.E. as-is basis) |
17.72 |
14.60 |
16.56 |
19.71 |
20.25 |
|
Cost/kg gain (cedis) |
555.34 |
437.12 |
464.51 |
529.80 |
522.65 |
Villages: In the southern parts of the country especially in the forest belt the dry season is not very severe and animals rarely lose weight. Sheep and goats are also allowed to graze freely in the villages and they are not kept intensively. They are housed only in the night.
The farms where crops are grown are also far away from the villages and the people keep animals only as a "hobby" as they are basically food and cash crop farmers. They are not motivated to spend time and money on these animals as they are not their main sources of income. They may therefore not be interested in transporting agricultural by-products from their farms to feed animals but they may be interested in transporting them to the villages for sale. It is suggested that the animals are fed with fresh peels of cassava, yams, cocoyam and plantains every morning before the animals are allowed to go out to graze or in the evenings when they are brought into their barns for the night.
These people eat these foodstuffs every day and there will be no problem obtaining the peels. Where a neighbour has no animals, his/her peels could be collected by another fellow for feeding to his/her animals.
In the northern parts of the country the dry season is more severe and lasts a longer period of time than in the forest belt. The people also have great interest in raising animals as the animals contribute greatly to their incomes. Their farms are also not very far away from the villages. The farmers could be motivated to feed agricultural by-products from their own farms but will not be prepared to buy feeds from commercial feedmillers. They will be prepared to transport the straws to the villages.
The straws could be treated with wood ash solutions to improve their nutritional value. The use of green crops as supplements could be undertaken if drought-tolerant leguminous trees and shrubs such as Acacia sp. are planted.
It may also be necessary to provide simple machines (similar to corn mills found in some villages in the country) for shredding straws before feeding to animals. Legume straws which have higher nitrogen contents than cereal straws should be incorporated in the diets.
The Extension Services Department of the Ministry of Agriculture should be strengthened to advise farmers on the proper treatments and feeding of straws and other agricultural by-products.
In the cities, peels of cassava, plantain, cocoyam and yams could be bought from the chop bars and the garri factories by commercial feedmills. These have to be washed to reduce soil contamination before drying in the sun. They would then be ground and incorporated in diets. Poultry manure could be collected from the poultry farms, sun-dried and later used. Dried cocoapod husk could be bought from the large estate cocoa plantations and also from small-scale cocoa farmers. Cereal and legume straws, and corncobs could be bought from large scale farmers and also from small-scale farmers if they are willing to transport them to the villages. Already, rice straw is baled by some large-scale farmers for sale. These cereal straws and corncobs could be treated with wood-ash solutions and dried. The formulations of the diets, should be based on results of experiments conducted in the research institutions.
Dried brewers-spent grains, wheat bran, maize bran and rice bran could be bought to be used in the diets.
Feeds prepared with these ingredients could then be sold to backyard farmers in the urban areas.
There is also the need to improve the performance of sheep kept in the backyards in the urban areas. The local breed, the Djallonke, has a very slow growth rate (about 20-50g/day). Under village conditions, since no expenditure is incurred in their feeding, this slow growth rate may not pose a great problem. In the urban areas since people are going to invest in housing and feeds, it is necessary to increase the productivity of the animals. If a crossbreeding programme is to be instituted, then the breed selected should have the good attributes which the Djallonke has (high fertility, high prolificacy, and big gut size) in addition to having fast growth rate and high feed conversion efficiency.
The author is grateful to Ms. Cecilia Turkson for typing the script. Mr. S.Y, Annor is thanked for his assistance, and Mr. S.S. Yambillah is acknowledged for the chemical analysis of the feedstuffs. The Cocoa Research Institute of Ghana and the International Atomic Energy Agency (IAEA), Vienna, supported the research and they are acknowledged.
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Gibb, J.A.C. 1975. Energy costs and crop drying. Span 18(1): 31.
Mbatya, P.B.A., Kay, M. and Smart R.I. 1983. Methods of improving the utilisation of cereal straw by ruminants. 1. Supplements of urea, molasses and grass and treatment with sodium hydroxide. Anim. Feed. Sci. Technol. 8: 221-227.
Osei, S.A. and Duodu, S. 1988. Effect of fermented cassava peel meal on the performance of broillers. Brit. Poult. Sci. 29: 671-675.
Tuah, A.K., Boye-Doe, N. and Safo-Kantanka, O. 1988. Studies of the nutritive value of straws of six varieties of cowpea (Vigna unguiculata L. Walp.) and straws of two varieties of maize (Zea mays) grown in the Ashanti forest belt of Ghana. Submitted. Biological Wastes.
Tuah, A.K., Dzoagbe, S. and Adomako, D. 1985. Evaluation of cocoapod husk as feed ingredient for sheep in Ghana. Proceedings of the 9th International Cocoa Research Conference, 12-18th Feb. 1984, Lome, Togo, pp. 505-510
Tuah, A.K. and Øorskov E.R. 1987. A study on the degradation of untreated, ammonia-treated, sodium hydroxide-treated and water-soaked corncob and cocoapod husk in the rumen using the nylon bag technique. paper presented at the ARNAB Workshop held in Bamenda, Cameroon, 20-27 October, 1987.
