A.M. Nour, A.R. Abou Akkada, A.A. Nour and Awad Mabrouka
Department of Animal Production, Faculty of Agriculture
University of Alexandria, Alexandria, Egypt
Abstract
Introduction
Materials and methods
Results and discussion
References
Five groups of male lambs each of nine head Rahmany Barki were used to investigate the effect of different levels of corn stover (10, 30, 50, 70 and 90%) in pelleted diets on the growth performance and feed utilisation by lambs.
The results showed that voluntary feed intake, average daily gain and feed utilisation were significantly decreased by increasing the level of corn stover in the diet from 10 to 90%.
The digestibilities of DM, OM and CP were decreased by increasing the level of corn stover in the diet (with the exception of the diet containing 70% corn stover), however, crude fibre digestibility increased by increasing the level of corn stover.
The results recommended a pelleted diet containing 70% corn stover for growing lambs to achieve a good growth with lower cost of meat production. The cost of feed per one kg gain was 1.25, 1.12, 1.08, 0.91 and 5.88 LE for diets containing 10, 30, 50, 70 and 90% corn stover respectively.
There is a shortage of about 5-6 million tons of (TDN) which are required to secure better nutritional status of farm animals in Egypt.
On the other hand, the utilisation of the agro-industrial by-products (13-14 million tons DM/annum) can easily fulfil the present shortage in the amount of (TDN) needed to cover in animal feed requirements.
Corn (Zea mays L.) is grown (about 2 million feedans) in Egypt mainly for grain and it is the general farm practice to leave the ears on the stovers in the field until the grains are almost completely dry. The dry corn stover (about 4.3 million tons/annum), therefore is not suitable for animal feeding and is only used as fuel. It has been shown that corn stover can be successfully ensiled without any significant change in its nutritive value (Soliman et al, 1975 and 1977).
Shehata and Nour (1985) found that pelleting of rice straw with concentrates, molasses, urea and minerals can provide a suitable complete diet for use on large farms in Egypt. The main objective of this work was to study the effect of different levels of corn stover in pelleted diets on the digestibility of nutrients. Feed intake, growth performance and cost of meat production from sheep.
Corn stover constituted 10, 30, 50, 70 and 90% of complete pelleted diets, the compositions of which are shown in Table 1.
Forty five Barki lambs of about 26 kg each were allotted randomly to five groups each of nine head. Each group was fed on one of the five experimental diets ad lib. plus one kg fresh berseem per head daily/(213 g DM) at 9 a.m.; water was offered. Feed refusals were collected daily and weighed. The experiment lasted for 75 days, and the animals were weighted every two weeks before being fed or watered.
Table 1. Composition % of pelleted diets containing corn stover.
|
|
Diet |
||||
|
1 |
2 |
3 |
4 |
5 |
|
|
Per cent |
|||||
|
Corn stover |
10 |
30 |
50 |
70 |
90 |
|
Urea |
- |
0.25 |
0.5 |
1 |
1.5 |
|
Soyabean by-products |
20 |
20 |
20 |
20 |
- |
|
Wheat bran |
30 |
20 |
10 |
- |
- |
|
Milling by-products |
30 |
20 |
10 |
- |
- |
|
Molasses |
8 |
8 |
8 |
8 |
8 |
|
Calcium carbonate |
1.4 |
1.4 |
1.4 |
1.4 |
1.4 |
|
Salt |
0.5 |
0.5 |
0.5 |
0.5 |
0.5 |
|
Mineral mixture |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
Digestibility and N-balance trials were conducted during the test two weeks of the experiment on three animals from each group chosen randomly. Animals were fitted with nylon bags and harnesses for complete collection of faeces, and urine was collected daily in jars containing 5 ml concentrated HCl. Faeces were collected daily, mixed thoroughly, weighed and 10% of each day's collection was used for dry-matter determination. The samples collected over the period (7 days) were combined, ground, sod kept for chemical analysis.
The volume of urine was measured daily 8 a 10% portion of each urine collection was kept for determination of urinary nitrogen.
Analysis of diets, faeces and urine were carried out according to the methods of AOAC (1970).
The cost (LE/ton) of feed ingredients in the experimental diets is shown in Table 2.
Statistical analyses were conducted according to Snedecor sod Cochran (1967).
Table 2. Cost (LE/ton) of feed ingredients in the experimental
|
|
Diet |
||||
|
1 |
2 |
3 |
4 |
5 |
|
|
Corn stover |
- |
0.55 |
1.1 |
2.2 |
3.3 |
|
Urea |
50 |
50 |
50 |
50 |
- |
|
Soyabean by-products |
36 |
24 |
12 |
- |
- |
|
Wheat bran |
24 |
12 |
- |
- |
|
|
Milling by-products |
6.4 |
6.4 |
6.4 |
6.4 |
|
|
Molasses |
0.56 |
0.56 |
0.56 |
0.56 |
0.56 |
|
Calcium carbonate |
0.25 |
0.25 |
0.25 |
0.25 |
0.25 |
|
Salt |
0.50 |
0.50 |
0.50 |
0.25 |
0.25 |
|
Mineral mixture |
0.1 |
0.1 |
0.1 |
0.1 |
0.1 |
|
Total cost (LE/ton) |
132.70 |
115.26 |
97.81 |
80.66 |
37.76 |
1 LE = 0.44 US$
Chemical analysis of the corn stover and the 5 diets are shown in Table 3.
Digestibility determinations (Table 4) showed that the digestibilities of dry-matter (DMD), organic matter (OMD), crude protein (CPD) and nitrogen-free extract (NFED) were significant (P<.05); however, crude fiber digestibility (CFD) was significantly (P<0.01) increased by increasing the level (%) of corn stover in the diet. The digestibility coefficient of corn stover alone was CP, 36%; EE, 59%; CF, 67% increased and NFE, 60% and its nutritive value was: TDN 48.78% and DP, 1.8%, as reported by Badr (1960). Thus corn stover is a low quality feed, principally because of its high percentage of lignocellulose, low percentage of protein and the deficiency of readily available carbohydrates which limit microbial activity in the rumen.
Table 3. Chemical analyses (%) of corn stover and the tested diets.
|
|
Diet no. |
|||||
|
Corn stover |
1 |
2 |
3 |
4 |
5 |
|
|
Dry-matter |
85.2 |
91.13 |
89.34 |
90.57 |
91.02 |
91.02 |
|
Organic matter |
91.49 |
88.88 |
90.08 |
90.41 |
90.09 |
89.33 |
|
Crude protein |
5.4 |
11.33 |
11.18 |
11.03 |
11.59 |
9.27 |
|
Crude fiber |
33.2 |
15.45 |
17.90 |
18.05 |
25.87 |
28.31 |
|
Ether extract |
1.45 |
2.84 |
1.82 |
1.42 |
1.28 |
1.05 |
|
Ash |
8.51 |
11.12 |
9.92 |
9.59 |
9.19 |
10.67 |
|
Nitrogen-free extract |
51.7 |
59.26 |
59.28 |
59.91 |
51.35 |
50.73 |
The nutritive value of the tested diets (Table 4) was decreased by increasing the level of corn stover.
Dry-matter intake and liveweight changes of the lambs during the 75-day growth period are shown in Table 5. All lambs gained weight during the feeding experiment. Statistical analysis showed that the average total and daily gains were significantly influenced by increasing the level of corn stover in the diet. The body weight gains from diets containing 70 and 90% corn stover were significantly decreased (P<0.01). However, the differences between the diets containing 50 and 70% or 30 and 50 or 10 and 30% corn stover attained significance at 5% level (Table 5). The weight gain was very low with the diet containing 90% corn stover (Diet 5), providing nutrients sufficient virtually only for maintenance. The feed utilisation (feed/gain ratio) was greatly improved by increasing concentrates in the pelleted feed from 10 to 30%. These differences were highly significant (P<0.01), but that between the diets containing 30 and 50% was not significant.
Chemical analysis % of berseem
|
DM |
OM |
CP |
CF |
EE |
NFE |
|
88.04 |
87.31 |
17.49 |
26.92 |
2.46 |
40.43 |
Table 4. Feed intake (g/head/day), digestibility (%) and nutritive value (%) of different pelleted diets.
|
|
Diet |
|||||
|
1 |
2 |
3 |
4 |
5 |
||
|
Feed intake g/head/day |
1443 ± 297 |
1331 ± 107 |
1326 ± 76 |
1257 ± 52 |
1223 ± 26 |
|
|
Digestibility % |
||||||
|
|
Dry-matter |
64.01 ± 3.12 |
60.47 ± 3.78 |
54.49 ± 3.02 |
63.07 ± 3.86 |
50.25 ± 5.6 |
|
|
Organic matter |
65.22 ± 2.98 |
62.00 ± 3.19 |
55.72 ± 5.96 |
64.65 ± 3.58 |
51.81 ± 2.04 |
|
|
Crude protein |
55.66 ± 1.42 |
54.94 ± 2.58 |
53.27 ± 4.03 |
55.51 ± 2.41 |
47.83 ± 11.8 |
|
|
Crude fiber |
53.58 ± 10.26 |
49.36 ± 8.22 |
47.68 ± 4.76 |
63.34 ± 3.32 |
57.64 ± 4.43 |
|
|
Ether extract |
55.92 ± 8.1 |
59.76 ± 1.86 |
44.79 ± 6.-65 |
59.61 ± 1.77 |
54.49 ± 4.34 |
|
|
Nitrogen-free extract |
72.03 ± 0.62 |
67.00 ± 1.6 |
64.98 ± 1.03 |
63.34 ± 3.32 |
50.69 ± 4.41 |
|
Nutritive value % |
||||||
|
|
DCP |
6.81 ± 0.17 |
6.72 ± 0.33 |
6.43 ± 0.5 |
6.98 ± 0.27 |
5.1 ± 0.87 |
|
|
(TDN) |
60.59 ± 0.81 |
60.43 ± 3.98 |
54.22 ± 2.19 |
54.2 ± 1.52 |
48.32 ± 4.29 |
Table 5. Growth performance of the growing lambs fed on different diets containing corn stover.
|
|
Diet no. |
||||
|
1 |
2 |
3 |
4 |
5 |
|
|
No. of animals |
9 |
9 |
9 |
9 |
9 |
|
Initial weight (kg/head) |
26.44 ± 6.07 |
26.83 ± 6.27 |
25.89 ± 5.13 |
26.61 ± 5.10 |
27.11 ± 4.45 |
|
Final weight (kg/head) |
37.5 ± 7.13 |
36.39 ± 9.02 |
33.56 ± 8.73 |
32.83 ± 6.75 |
27.61 ± 4.06 |
|
Feeding period (days) |
75 |
75 |
75 |
75 |
75 |
|
Gain (kg) |
11.06 ± 2.22 |
9.56 ± 3.87 |
7.70 ± 4.56 |
6.89 ± 3.47 |
0.5 |
|
Average daily gain (g/head/day) |
147 ± 30 |
127 ± 50 |
102 ± 60 |
92 ± 46 |
6.0 ± 13 |
|
Average feed intake * (g/head/day) |
1387 |
1231 |
1123 |
1041 |
935 |
|
Feed gain ratio |
9.44 |
9.69 |
11.01 |
11.31 |
155.83 |
|
Cost of one kg gain from feed (LE/kg) |
1.25 |
1.12 |
1.08 |
0.91 |
5.88 |
* Feed intake from the pelleted diets plus 212 gm dry matter from berseem in fresh form daily.
It is relevant to note in this context that for the maintenance of adult ruminant, the characteristics desirable in the feed are:
(1) crude protein level which is above 6-7%.(2) dry-matter digestibility of about 50-55% and DMI of the order of 1.7% of the body weight.
Preston and Leng (1984) showed the following nutritional factors merit attention in order of priority:
(1) fermentable energy
(2) fermentable nitrogen
(3) micronutrients (especially S. P and B vitamins)
(4) roughages (for adequate rumen function)
(5) by-pass protein, and
(6) by-pass energy.
To overcome the nutritional constraints of corn stover, supplementation with concentrates (energy, protein minerals etc.) and green fodder were tried in order to find suitable combinations that are both acceptable and beneficial to the growth of lambs.
The foregoing data indicate that increasing the level of concentrate from 10 to 30% in the diet was sufficient to provide enough nutrients to increase the weight gain of the animals from just above maintenance (6 g/head/day) when fed on Diet 5 to a moderate level of growth (96 g/head/day) when fed on Diet 4. More increase in the average daily gain was achieved by increasing the level of concentrates. However, the rates of increase in weight gain were lower than that obtained by adding 30% concentrates.
El Shinnawy and Abou Raya (1983) reported that pelleting mixtures including maize stalks seemed to increase the feeding value of the mixture to an extent greater than would be calculated from the individual ingredients. Pelleting mixtures results in a satisfactory intake when directly fed to lambs, and the increased feed density and more efficient packing capacity reduces transporting expenses.
Table 2 shows that the diet containing 90% corn stover was cheap (37.76 LE/ton), and that containing 10% corn stover was the most expensive (132.7 LE/ton). However, the cost of production of 1 kg gain from the tested feeds (Table 5) showed that the most economical mixture was that containing 70% corn stover (0.91 LE/kg).
Thus the present results indicate that the pelleted diet containing 70% corn stover is a suitable diet for feeding growing lambs in Egypt.
AOAC (Association of Official Analytical Chemists). 1970. Official methods of analysis. AOAC, Washington, D.C.
Badr, M.F. 1960. Corn stover. Its chemical composition and nutritive value in livestock ration. Alex. J. Agric. Res. 7(1): 15-24.
Devendra, C. 1985. Forage supplements: Potential value in feeding systems based on crop residues and agro-industrial by-products in south east Asia. Proceedings of the International Workshop held in Khon Kaen, Thailand, November 29 - December 2, 1984. pp. 221-248.
El-Shinnawy, M.M. and Abou Raya, A.K. 1983. Unconventional feeds. Min. of Agr. Cen. Admin. for Anim. Prod, Arab Republic of Egypt.
Preston, T.R. and Leng, R.A. 1984. Supplementation of diets based on fibrous residues and by-products. In: F. Sundstol and E. Owen (eds), Straw and other fibrous byproducts as feed. Elsevier Press, Amsterdam. pp. 373-913.
Shehata, M.N. and Nour, A.M. 1986. Rice straw in complete pelleted diets for sheep. In: T.R. Preston and M.Y. Nuwanyakapa (eds), Towards optimal feeding of agricultural byproducts to livestock in Africa. Proceedings of a workshop held at the University of Alexandria, Egypt, October 1985. ILCA, Addis Ababa, Ethiopia. pp. 79-86.
Snedecor, G.W. and Cochran, W.H. 1967. Statistical methods. 6th edition. Iowa State Univ. Press, Ames, Iowa, U.S.A.
Soliman, S.M.; Abou Akkada, A.R. and Naga, Habib, M.M. 1975. The use of corn fodder, its silage and corn stover as an animal feed. III. A composition between the digestibility and protein biological value of the three products. Alex. J. Agric. Res. 23(1): 21.
Soliman, S.M.; El-Shazly, K. and Abou Akkada, A.R. 1977. Some aspects of the use of corn stover silage in animal feeding. Alex. J. Agric. Res. 25(3): 423-428.
