K. M. Biwi
Ministry of Agriculture
Department of Livestock Development
P.O. Box 159, Zanzibar, Tanzania
Abstract
Introduction
Materials and methods
Results and discussion
Conclusion
References
Supplementation of concentrate and leucaena to dairy cattle fed on sodium hydroxide "dip"-treated and untreated maize stover was compared with an elephant grass-based diet in a latin square 3x3 change over design using 18 lactating dairy cows. Dry-matter intake, energy intake and milk production were studied.
The dry-matter intake of the test roughages and the ME intake from the total dry-matter intake of treated maize stover-based diet, untreated maize stover-based diet and elephant grass-based diet were 3.37, 3.11 and 4.92 kg DM/cow/day respectively, and 86.50, 75.40 and 81.34 kg MJME/cow/day, respectively. The dry-matter intake of the test roughages and ME intake were significantly different (P<0.01) between the treatments.
Actual milk yield and 4 percent FCM for TMS-based diet, MS-based diet and EG-based diet were 7.7, 7.6 and 7.7 kg/cow/day, respectively and 9.5, 8.8 and 9.3 kg/cow/day, respectively. The MS-based diet produced significantly low FCM yield (P<0.01); but yield of actual milk was not significantly different (P<0.05) between the treatments. Higher concentrate allowance in MS-based diet improved actual milk yield but not FCM.
Inadequate feeding during the dry season is a serious problem in Tanzania because in many areas grazing is the main form of cattle feeding. Judicious use of alternative feeds from crop residues can alleviate the problem of feed availability since straws and stovers are abundantly produced in the country (Kategile, 1982). However, the utilization of these crop residues is beset with inherent constraints of low protein, energy and mineral content which often cause inefficient use of the materials due to unacceptability by animals. Manipulation of feeding practices of these crop residues by moderate supplementation of protein, energy and minerals as well as chemical treatment can overcome these constraints and thus improve intake when fed to ruminants.
In this experiment, home-made concentrate and dried leucaena leaves were used to supplement treated and untreated maize stover fed to lactating dairy cattle for milk production, with elephant grass as a control roughage. Dry-matter intake, ME intake and milk production were measured.
Study area
This work was carried out at Sokoine University of Agriculture.
Roughages used
The roughages used were maize stover, elephant grass (Pennisetum purpureum) and leucaena (Leucaena leucocephala). The choice of maize stover was influenced by its abundance after the grain harvest and its potential as a dry season feed. The elephant grass was chosen because it is drought-resistant and grows naturally throughout the year in many areas along water courses. It is also a potential green forage for stall-feeding during the dry period. Leucaena flourishes well in coastal areas and grows naturally in many areas.
Procurement and preparation of the feeding materials
Maize stover was collected from the University Farm after the grain harvest and stored undershed before chopping in small pieces using a large hand knife. The sizes were in the range of 4-6 cm to facilitate easy mixing of leaves and stems. The chopped stover was divided into two portions, one for alkali treatment and other portion to be used untreated.
The alkali treatment method employed was the "dip" method developed and described by Sundstol (1981). The chopped maize stover was dipped in 1 per cent sodium hydroxide (NaOH) solution. The ratio of maize stover to solution was 1.15 (W/V). The untreated maize stover was soaked in plain water using the same ratio.
Elephant grass was collected from natural stands mostly along the river courses at the university premises. Vegetative parts were cut everyday and chopped into 4-8 cm to facilitate easy feeding.
Leucaena forage was collected and dried on concrete floor, and packed in bags.
The concentrate was made up of cassava flour, maize bran, cottonseed cake, urea, salt, Macklik supper and Vitamins A and D. The mixture was formulated to have approximately 17 percent crude protein.
Experimental design
The experiment was carried out in a 3x3 latin square change over design, with a set of six (3x3) latin squares (multiple classification including partition into within and between square variances). Eighteen mature cows of medium milk production were selected from the University farm. Three breeds Jersey, Ayrshire and Friesian were used.
There were three experimental periods denoted as P1, P2 and P3. Each period lasted for three weeks and was proceeded by a transitional period of two weeks. At the beginning of the experiment a longer period was required to adjust the animals to reasonable intake of the test roughages, particularly the untreated maize stover.
Feeding of the cows
The basal roughages of supplementary leucaena dried leaves was fed with concentrate at the stalls. Cows on sodium hydroxidetreated maize stover (TMS) and elephant grass (EG) received 0.6 kg concentrate for every 1 kg FCM after the first 4 kg of FCM, while those on untreated maize stover (MS) received 0.75 kg concentrate for each 1 kg FCM after the first 4 kg FCM.
The first feeding for the test roughages TMS, MS and EG commenced immediately after the feeding of concentrate and basal roughages in the morning, and the second feeding was after the evening milking. All the feeds were offered individually to each cow and the weights offered recorded. Refusal of test roughages were weighed the next morning for each individual cow, and daily intake was also recorded.
Measurements
The effects of the diets fed to the cows were measured in the following variables:
1. Dry-matter and energy intake
2. Milk yield and composition
3. 4% fat corrected milk
Data collection
The dry-matter intake of the test roughages were obtained by the difference between the dry-matter offered and that refused. Total dry-matter intake of the whole diet was recorded.
Morning and evening milk were recorded in kilogrammes and summed to make a total for a day's milk yield for each cow. A sample of milk in the morning and evening for two consecutive days per week-was taken and a subsample taken for chemical test. Milk fat content was analysed by the Gerber method (British Standard Institution B.S., 696, 1955). The 4 percent fat-corrected milk was calculated according to Gaines formula as described by Maynard et al (1979). Crude protein content was analysed by Kjeldahl method as outlined by A.O.A.C. (1965) (CP = %N x 6.38).
Statistical analysis
The analysis of variance for latin square design was carried out as described by Snedecor and Cochran 1967; with multiple classification including partition into within (w'n) and between (b'n) squares variance i.e. treatments b'n squares, columns w'n squares and rows w'n squares.
The new Duncan Multiple Range Test was used to compare the treatment means for the variables.
Feed intake
The mean dry-matter intake of the test roughages, total dry-matter intake and metabolisable energy intake by the lactating cows are presented in Table 1.
Table 1. Intake of dietary components, total dry-matter intake and ME intake.
|
Dietary components |
Treatments |
|||
|
NaOH "dip"-treated |
Untreated |
Elephant |
SED |
|
|
Test roughage (kg/cow/day) |
3.87a |
3.11b |
4 92c |
0.11 |
|
Total dry-matter intake (kg/cow/day) |
8.44a |
8.10b |
8.62acNS |
0.11 |
|
Total ME intake (e) (MJME/cow/day) |
86.50a |
75.49b |
81.34c |
2.44 |
(e) = ME = DE x 0.81 (MAFF, 19 75), DE = GE x Energy dig. Coefficient from sheep experiment.Means within a row with different letters are significantly different (P<0.01).
NS = not significant (P<0.05)
Mean dry-matter intake of the test roughages
The mean dry-matter intake of the elephant grass, sodium hydroxide "dip"-treated and untreated maize stovers and their levels of significance are shown in Table 1 and illustrated in Figure 1. The dry-matter intake of elephant grass was significantly higher (P<0.01) than that of treated and untreated maize stovers. The intake between the maize stovers also differed by 0.76 kg DM/cow/day, representing an increase of 24.44 per cent in favour of the sodium hydroxide "dip" treated maize stover. This difference was also significant (P<0.01) and falls within the range reported elsewhere (Greenhalgh et al, 1976; Kristensen, 1981). The intake of sodium hydroxide "dip" treated maize stover in this study was found to be higher than the level reported by Sundstol (1981). However, it was difficult to raise the intake above 4.5 kg DM/cow/day and the maximum arrived at was 4.23 kg DM/cow/day during the pre-experimental period. This confirms the suggestion by Owen (1981) that sodium hydroxide "dip"-treated maize stover can only play a role of supplement, replacer or partial replacer of the other roughages for lactating dairy cows .
Mean total dry-matter intake by lactating dairy cows
Cows had a higher total dry-matter intake of elephant grass-based diets (8.62 kg DM/cow/day) than the sodium hydroxide "dip"-treated maize stover (8.44 kg DM/cow/day) and untreated maize stover (8.10 kg DM/cow/day) based diets. The difference in total dry-matter intake between elephant grass and NaOH "dip"-treated maize stover based diets was not significant (P<0.05), but the differences between these diets and the untreated maize stover-based diet were significant (P<0.01).
The mean total dry-matter intake of elephant grass-based diet in this study was similar to the total dry-matte; intake reported by Combellas and Martinez (1982). These authors used elephant grass roughage with supplementation of 3 kg concentrate.
Metabolisable energy (ME) intake
Table 1 shows metabolisable energy (ME) intake of 86.50, 75.49 and 81.34 MJME/cow/day for treated maize stover, untreated maize stover and elephant grass-based diets, respectively. The ME intake of the sodium hydroxide "dip"-treated maize stover-based diet was significantly higher (P<0.01) than that of the untreated maize stover-based diet. Similarly the ME intake of the elephant grass-based diet was higher (P<0.05) than the untreated maize stover-based diet. Difference in ME intake between sodium hydroxide "dip"-treated maize stover and elephant grass-based diets were also significant (P<0.05).
This study indicated that the sodium hydroxide "dip" treated maize stover-based diet could supply ME better than fresh elephant grass-based diet.
Treatment effects of milk yield and 4% FCM
The mean daily actual milk yield and 4% FCM are presented in Table 2.
Table 2. Mean daily actual milk yield and 4% fat-corrected milk (FCM) as influenced by treatments.
|
Milk yield (kg/cow/day) |
Treatments |
|||
|
NaOH "dip"-treated maize stover |
Untreated maize stover |
Elephant grass |
SED |
|
|
Actual milk yield |
77a |
7.6b |
7.7a |
0.12NS |
|
4% fat-corrected milk |
9 5a |
8.8b |
9.3acNS |
0.18 |
NS = not significant (P<0.05).
Means within a row with different letters are significantly different (P<0.05).
Actual milk yield
The actual milk yields were 7.7, 7.6, 7.7 kg/cow/day for treated maize stover, untreated maize stover and elephant grass-based diets respectively, and the differences were non-significant (P<0.05).
There was a general decline in actual milk yield with advancing lactation, particularly with the sodium hydroxide "dip"-treated maize stover and untreated maize stover-based diets. The decline was however small from the first to second period than from the second to third period as illustrated in Figure 2. The fall in actual milk yield for the elephant grass-based diet was inconsistent. There was a decline in the second period and a sharp rise in the third period.
This trend was also reflected in the ME intake. The actual milk yield recorded in this study from the elephant grass-based diet was similar to the yield reported by Combellas and Martinez (1982).
4% fat-corrected milk (FCM)
The 4 percent fat-corrected milk yield was highest (9.5 kg/cow/day) with sodium hydroxide "dip"-treated maize stover-based diet than untreated maize stover (8.8 kg/cow/day) and elephant grass (9.3 kg/cow/day)-based diets. There was no significant difference in 4 percent fat-corrected milk yield between treated maize stover and elephant grass-based diets (P<0.05). However each of these two treatments produced significantly more 4 percent fat-corrected milk (P<0.1) than the untreated maize stover-based diet.
In this study it shows that sodium hydroxide ""dip"-treated maize stover was more efficiently utilized for milk production than elephant grass as less dry-matter consumed resulted in more FCM. Improved performance with alkali-treated roughages has also been reported in other studies (Greenhalgh et al , 1976) .
Fat and protein content in milk
Table 3 shows fat and protein content as influenced by treatments .
Table 3. Fat and protein content in milk.
|
Milk chemical composition (g/100g) |
Treatments |
|||
|
NaOH "dip"-treated maize stover |
Untreated maize stover |
Elephant grass |
SED |
|
|
Fat |
5.60a |
5.31b |
5.43ab NS |
0.10 |
|
Crude protein |
3.44a |
3.35a |
3.43a |
0.65NS |
NS = not significant (P<0.05) .
Means within a row with different letters are significantly different (P<0.05) .
Fat content
The mean fat content (g/100g) in milk ranged between 5.60-5.43g/100g. The sodium hydroxide "dip"--treated maize stover-based diet produced a higher milk fat content (P<0.05) than untreated maize stover. Similar findings were reported elsewhere (Greenhalgh et al, 1976; Kristensen, 1981). The higher fat content produced by the sodium hydroxide ""dip"-treated maize stover-based diet was a reflection of an improved crude fibre digestibility and hence the production of more acetic acid in the rumen.
Protein content
The mean protein contents were 3.44, 3.33, 3.34 g/100g for sodium hydroxide "dip"-treated maize stover, untreated maize stover and elephant grass-based diets, respectively. No significant differences were found between the treatments (P<0.05). The values obtained in this study are within the range of documented information (Campbell and Marshall, 1975).
Inherent constraints of low protein, energy and mineral availability in crop residues like maize stover cause inefficient use of these materials. Alkali treatment as well as supplementation of different nutrient could be useful in utilizing these crop residues as alternative feed during dry seasons for milk production. This study emphasises the usefulness of these materials.
AOAC (Association of Official Analytical Chemists). 1965. Official methods of analysis. (10th ed.). AOAC, Washington, D.C.
British Standard Institution. 1965. The Gerber method of fat analysis in milk and milk products. BS 696 1955. Part 2 revised. British Standard Institution, London.
Campbell, J.R. and Marshall, R.T. 1975. The science of providing milk for man. McGraw-Hill Book Company, New York, London. 801 pp.
Combellas, J. and Martinez, N. 1982. Intake and milk production in cows fed chopped elephant grass (Pennisetum purpureum) and concentrate. Tropical Animal Production 7: 57-60.
Greenhalgh, J.F.D.; Pirie, R. and Reid, G.W. 1976. Alkali treated barley straw in complete diets for lambs and dairy cows. Animal Production 22: 159 (Abstr).
Kategile, J.A. 1979. Performance of heifers fed on diets based on NaOH treated maize cobs and the effect of supplementary urea and source of carbohydrates. Animal Feed Science Technology 4:97-107.
Kategile, J.A. 1982. Utilization of low quality roughages with or without NaOH treatment. In: B. Kiflewahid, G.R. Potts and R.M. Drysdale (eds.), By-production utilization for animal production. Proceedings of Workshop on Applied Research held in Nairobi, Kenya, 26-30 September 1982. pp. 37-48.
Kristensen, V.F. 1981. Use of alkali treated straw in rations for dairy cows, beef cattle and buffaloes. In: J.A. Kategile, A.N. Said and F. Sundstol (eds.), Utilization of low quality roughages in Africa. A workshop held at Arusha, Tanzania, 18-22 January 1981. Lamport Gilbert Printers Ltd. Reading, England. pp. 91-106.
MAAF. 1975. Energy allowances and feeding for ruminants. Technical Bulletin 33. Her Majesty's Stationery Office, London.
Maynard, L.A.; Loosli, J.K.; Hintz, H.F. and Warner, R.G. 1979. Animal nutrition. 7th edition. Tata MacGraw-Hill Publishing Company Limited, New Delhi. pp. 602.
Owen, E. 1981. Use of alkali treated low quality roughage to sheep and goats. In: J.A. Kategile, A.N. Said and F. Sundstol (eds.), Utilization of low quality roughages in Africa. A workshop held in Arusha, Tanzania, 18-22 January 1981. Lamport Gilbert Printers Ltd., Reading, England. pp. 131-150.
Snedecor, G.W. and Cochran, W.G. 1967. Statistical methods. 6th edition. The Iowa State University Press, Ames, Iowa, U.S.A. 593 pp.
Sundstol, F. 1981. Methods for treatments of low quality roughages. In: J.A. Kategile, A.N. Said and F. Sundstol (eds.), Utilization of low quality roughages in Africa. A workshop held at Arusha, Tanzania, 18-22 January 1981. Lamport Gilbert Printers Ltd., Reading, England. pp. 61-80.
Urio, N.A. 1981. Alkali treatment of roughages and energy utilization of treated roughages fed to sheep and goats. Ph.D. thesis, University of Dar-es-Salaam, Tanzania.
