A.A. Adegbola, O.B. Smith and N.J. Okeudo
Department of Animal Science
Obafemi Awolowo University, Ile Ife, Nigeria
Five diets containing 0, 13, 25, 35 and 45% dried poultry manure (DPM) were formulated such that DPM replaced 0, 25, 50, 75 and 100% of the wheat offals and groundnut cake contained in the control diet 1. The diets were fed to 20 growing ewes in a 104 days growth study. Dry cassava peels and water were also provided ad libitum.
The intake of the animals fed the 0, 13, 25, 35 and 45% DPM diets were 87.1, 94.0, 88.6, 102.8 and 107.8 g/kg 0.75/day. The differences were not statistically significant. Also no statistical differences were observed in the growth rate of sheep which varied from 84.5g/head/day for sheep fed the 25% DPM diets to 100.6g/head/day for the animals on the 35% DPM diet. Efficiency of feed utilisation decreased from 8.7kg feed/kg gain to 10.5 as the level of manure in the diets increased from 0 to 45%. The growth performance of al the animals showed that sheep can be reared on diets containing poultry manure as the sole protein supplement, with dried cassava peels constituting 40 to 60% of the total diet. Sheep supplemented with poultry manure diets had higher intake of the dried cassava peel than sheep fed unsupplemented control diet.
In 1986, Nigeria produced 14.7 million tonnes of cassava (FAO, 1986) while the demand for this crop was put at 25 million tonnes for 1988. It is therefore safe to suggest that feeding cassava meal to livestock is not likely to be an attractive economic proposition. Cassava peel however, has been shown to form a constant part of household waste-product traditionally offered to sheep and goats in Southern Nigeria (Obioha, 1977). There are a large number of village-level, small-scale and large-scale "garri" processing factories which generated an estimated 2.9 million tonnes of cassava peel in Nigeria in 1986. Considerable research effort is being put into processing cassava peel for use by small ruminants at village level (Obioha, 1977; Adegbola and Asaolu, 1986). The bulk of this waste product produced at "garri" and starch processing factories will only be useful if the peel can be incorporated into livestock diet formulation. If such new feed packages can be developed, they may find a market with household owners of small ruminant stock as well as urban livestock owners of store-animals.
Compared to non-ruminants, very little work seem to have been reported on the utilisation of cassava peels by small ruminants. Walker (1951) reported feeding cassava peels to sheep and goats in Equatorial West Africa with poor response. Adebowale (1981) fed fermented cassava peels to sheep at 0, 20, 40 and 60% levels of inclusion to replace equivalent amounts of maize in the control diet. He recorded growth rates of 60.0, 38.3, 30.6 and 66.7 g/head/day and feed/gain ratios of 7.8, 10.9, 11.8 and 7.4 kg feed/kg gain respectively. He concluded that incorporating 20, 40 arid 60% cassava peels in the control diet increased economic returns by 15, 15 and 19% respectively. Fomunyan and Maffeja (1987) reported that sheep fed 0, 35 and 70% cassava peel-based diets complimented with elephant grass and using cottonseed cake as the protein source gained 45, 107 and 227 g/day. They concluded that liveweight gains of sheep increased with increasing levels of cassava peels intake and that the peels show promise as dry-season feed for sheep. In an earlier work Okorie, Obioha, Anyaekie and Ahamefule (1981) showed that poultry manure can replace groundnut cake in the diet of goats without any depression in growth rate and efficiency of feed utilisation. Given a good source of carbohydrates such as cassava peel, small ruminants ought to be able to make good use of the readily available N source as poultry manure. The objective of this study was to determine the response of sheep fed a basal diet of dried cassava peels supplemented with concentrates containing varying levels of hen-caged poultry manure as the main source of N with a view to developing acceptable simple feed compounds which can be made and sold at village production level.
Hen-caged manure was collected within two days of being voided by birds. The manure was sundried for two days by spreading to a thickness of about 2 cm on polythene sheets on a concrete base. Drying was terminated when the manure felt dry and gritty to touch with a dry matter content of 85-91%. The cassava peels were collected fresh from a "garri" processing plant, air-dried for 8 days on a concrete slab and sun-dried for one additional day to produce a dry matter content of 85-87%.
Five experimental diets were formulated so that poultry manure would replace 0. 25, 50, 75 and 100% of the conventional protein supplements (groundnut cake and wheat offals) contained in the control diet 1 (table 1).
Table 1: Comparison of supplemental diet fed to sheep
|
Ingredients (%) |
Levels of DPM in supplement feed (%) | ||||
|
|
0 |
13 |
25 |
35 |
45 |
|
Maize |
74.0 |
67.0 |
61.0 |
57.0 |
53.0 |
|
Poultry manure |
0.0 |
13.0 |
25.0 |
35.0 |
45.0 |
|
Wheat offals |
20.0 |
15.0 |
10.0 |
5.0 |
0.0 |
|
Groundnut cake |
4.0 |
3.0 |
2.0 |
1.0 |
0.0 |
|
Gone meal |
1.0 |
1.0 |
1.0 |
1.0 |
1.0 |
|
Vit/Min. premix* |
0.5 |
0.5 |
0.5 |
0.5 |
0.5 |
|
Common salt |
0.5 |
0.5 |
0.5 |
0.5 |
0.5 |
|
|
100.0 |
100.0 |
100.0 |
100.0 |
100.0 |
* Each kg of the vitamin mineral premix contains Vit. A., 640,000 I.U.,
Vit, D3, 120,000 I.U., Vit. E, 640 I.U., CU. 360mg, Se, 8mg, Mo, 60mg
Twenty growing ewes from a flock of WAD sheep, with an average weight of 14.3 ± 3.7kg were selected such that 4 animals were randomly alloted to each experimental diet. Each animal was treated as a replicate. Each animal was offered 55.0g of the experimental diet per kg metabolic size per day. Half of the daily ration was offered each animal at 9.00 hours and the remaining at 15.30 hours. Dried cassava peels and water were provided ad libitum. The orts from the cassava peels offered to each animal the previous day were removed at 7.00 hours and weighed, and about 30% more than the previous day's level of intake were offered at 8.00 hours every day.
The animals were housed individually in pens measuring 1.8 x 0.5m. An adaptation period of 14 days was allowed before data was collected for 90 days during which time the animals were weighed weekly. The weight of an animal at the end of a particular week was used to calculate the weight of the concentrate feed that will be offered to that particular animal the following week.
The chemical analyses for proximate components of the experimental diets of dried poultry manure and dried cassava peels were carried out using the methods outlined in AOAC (1975).
Data obtained on the growth rate, average dry matter intake of cassava peels alone, and of cassava peels plus the experimental feed, and the feed, as well as the efficiency of feed utilisation of the different animals were subjected to a two-way analyses of variance (Steel and Torrie, 1980).
Dried cassava peel and 75.4mg/kg content of HCN compared with 317.2 mg/kg for the fresh cassava peel (Table 2). The crude protein content of the dried peel was 4.2% compared with 1.2% for the wet peel. Sun-dried hen-caged manure contained a crude protein (CP) of 20.7% crude fibre of 10.7% and an ash content of 19.9% (Table 2).
Table 2: Proximate composition of poultry manure and peels used in the experiment (% of dry matter)
|
Feedstuff |
Crude Protein |
Crude Fibre |
Ether Extract |
Ash |
NFE |
HCN (mg/kg) |
|
Sundried hen-cage manure |
20.7 |
10.7 |
0.9 |
19.9 |
37.8 |
- |
|
Fresh cassava peel* |
1.2 |
2.3 |
0.4 |
1.1 |
23.0 |
317.2 |
|
Air-dried cassava peel** |
4.2 |
7.8 |
1.5 |
1.5 |
79.3 |
75.4 |
* Determined on the fresh sample with a dry matter content of 28%
** Air-dried for 8 days and sun-dried for one more day
The proximate composition of the experimental diets showed that the control diet contained a crude protein content of 12.3% compared with 14.4% CP contained in the diet supplemented with 45% DPH (Table 3). With the exception of the ash and energy levels, there were no significant differences in the proximate composition of the diets. Further, diets in which the main protein source was completely replaced with DPM had energy content of 3.6 kcal/g compared with 4.5 kcal/g for the control diet (Table 3).
Table 3: Proximate composition of supplemental diets fed to sheep (% of dry matter)
|
|
Levels of DPM | ||||
|
Chemical analyses |
0 |
13 |
25 |
35 |
45 |
|
Dry matter (%) |
87.3 |
87.4 |
87.6 |
87.7 |
87.9 |
|
Crude protein (%) |
12.3 |
12.9 |
13.7 |
14.1 |
14.4 |
|
Crude fibre (%) |
1.9 |
2.2 |
2.5 |
2.8 |
2.9 |
|
Ash (%) |
3.2 |
8.1 |
11.0 |
14.4 |
16.9 |
|
Ether extract (%) |
2.5 |
1.5 |
1.4 |
1.1 |
1.1 |
|
Nitrogen free extractives (%) |
68.3 |
62.8 |
59.0 |
55.3 |
52.6 |
|
Gross energy (Kcal/g dry matter |
4.5 |
4.1 |
4.1 |
3.9 |
3.6 |
Average dry matter intake of cassava peels by animals fed the control diet was 355.8g/day, while the intake by animals fed the 13, 25, 35 and 45% dry poultry manure (DPM) diets were 406.3, 371.0, 512.8 and 526.5g/day respectively (Table 4). Differences were however, not statistically significant. The average daily dry matter intake of 790.1g for the animals on the control diet increased generally to 952.3/head/day as the level of the manure in the experimental diets increased from 0 to 45% (Table 4). No statistical differences were observed in the growth rate of the animals fed the different diets. The fastest rate of growth rate of 107.8g/head/day were recorded for animals fed 45 DPM diet, while those on the 25% DPM diet grew the least gaining only 84.5g/head/day. The efficiency of feed conversion (kg feed gain) increased from 8.7/kg gain for animals fed the control diet to 10.5kg/kg gain for animals on the 45% DPM supplement diet. The differences were however not statistically significant.
Table 4: Response of West African dwarf sheep fed diets containing different levels of dried poultry manure (DPM) and cassava peels provided ad libitum
|
|
Levels of DPM in diet supplement (%) | ||||
|
|
0 |
13 |
25 |
35 |
45 |
|
Drymatter offer of experimental diet (g/kg metabolic weight/day) |
47.3 |
47.3 |
47.8 |
47.9 |
48.0 |
|
Average dry matter intake of cassava peels (g/kg metabolic weight/day) |
39.8 |
46.7 |
40.8 |
54.9 |
59.8 |
|
Average total dry matter intake (g/kg metabolic weight/day0 |
87.1 |
94.0 |
88.6 |
102.8 |
107.8 |
|
Average dry matter intake of cassava peels (g/head/day) |
355.8 |
406.3 |
371.0 |
512.8 |
526.5 |
|
Average dry matter offer of the experimental feed (g/head/day) |
434 |
412.6 |
424.0 |
445.6 |
426.8 |
|
Average total dry matter intake (g/head/day) |
790.1 |
818.9 |
795.0 |
958.4 |
952.3 |
|
Average growth rate (g/head/day) |
91.4 |
90.6 |
84.5 |
100.6 |
91.1 |
|
Efficiency of feed utilisation (kg feed/kg gain) |
8.7 |
9.0 |
9.4 |
9.5 |
10.5 |
All the animals grew fairly well and no statistical differences were observed in the growth rate of the animals fed the different diets. This observation is in agreement with the reports of Hadjipanayiotou (1984) who observed no differences in growth rate between growing heifers 'fattening kids' and fattening calves fed 30% DPM diets and the control animals fed soybean meal and cottonseed cake diets. El-Hag and Kurdi (1986) reported that animals consuming a 30% DPM diet performed better than those consuming a 30% cottonseed cake diet. Adu and Lakpini (1983) on the other hand observed that rams fed diets containing 0' 10' 20' 30 and 40% DPM diet recorded growth rates of 100, 83, 52, 41 and 32g/head/day respectively. It is very likely that the hay Adu and Lakpini (1983) used as the energy source for their animals were not as well utilised as the cassava peels were in this study. Further it was observed that sheep on 45% DPM diets had 55% of their total dry matter intake from dried cassava peels compared to 45% dried cassava peel intake for animals on the control diet. The higher intake of dried cassava peel by animals on DPM diets may be due to the fact that the 45% DPM diets had lower energy of 3.6 Kcal/g compared with 4.5 Kcal/g for the control diet and the animals had to take in larger quantities of the dried cassava peels to meet their energy needs.
Feeding up to 55% cassava peels as the main energy source of the animals in this study did not depress growth rate which averaged 90-100g/day for the entire experiment. Adebowale (1981) replaced maize with cassava peel and obtained a progressive depression on growth rate of animals. Fomunyan and Maffeja (1987) on the other hand observed improvements in growth rate, dry matter and crude protein digestibilities when cassava peels were used to replace elephant grass in the diets of sheep with cotton seed as the main source of N. The lack of agreements in these studies may be due to the fact that sheep utilise maize better than cassava peels, and the peels better than the elephant grass.
The efficiency of feed conversion figures ranged between 8.7 and 10.5 which is higher than the values (4.0 6.7) observed by Okorie et al (1981) but less than 19.8 reported by El-Hag and Kurdi (1986). The sheep used in this study and that of El-Hag and Kurdi (1986) had much higher average dry matter intakes than was reported by Okorie et al (1981) in their study. Also the different energy sources used to make up the energy requirements in the different studies may have affected the level of utilisation of ingested feed differently, and consequently have different effects on feed efficiency.
This study has shown that it may be worthwhile to investigate the feasibility of compounding a growers diet for sheep based on dried cassava peel and up to 45% DPM. The next phase in this study is designed to test the acceptability of preparing and using such a diet at a village production level.
It is suggested that this technology of feed compounding using 45% poultry manure can be transferred to a village in which households raising small ruminants are prevalent or where the village is near a commercial poultry unit generating waste. The feed package can also be produced and sold on the shelf by entrepreneurs with access to feed grains and dried poultry manure. Farmers who own or keep small ruminant stock with access to dried cassava peel should find such feed supplements adequate for their sheep production enterprises.
The authors wish to thank the International Development Research Centre, Ottawa, Canada for funding part of this study.
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