The effect of maize bran or maize bran mixed with sunflower cake on the performance of smallholder dairy cows in urban and peri-urban area in Morogoro, Tanzania
P S Mlay, A E Pereka, S T Balthazary, E C J Phiri, T Hvelplund*, M R Weisbjerg* and J Madsen**
Department of Physiology, Biochemistry, Pharmacology
and Toxicology, Sokoine University of Agriculture,
P. Box 3017,
Morogoro, Tanzania
panejo@yahoo.com
*
Department of Animal Science and Animal Health, The Royal
Veterinary and Agricultural University, Copenhagen,
Grønnegårdsvej 2, 1870 Frederiksberg, Denmark
**Department of Animal Nutrition and Physiology, Danish
Institute of Agricultural Sciences, Research Centre Foulum,
8830Tjele, Denmark
Abstract
A study was conducted to determine the effect of feeding milking cows a supplement of maize bran alone (MB) or maize bran mixed with sunflower meal (MBS) during the dry season. Eighteen smallholder farms in urban and peri-urban areas of Morogoro practising complete zero grazing with not less than two milking cows participated in the trial. Forty-eight cows were used with ranges of body weight 232-556 kg, previous milk yield 3-13 litres/day, body condition score 2.5-5, parity 2-5, and 3-6 months post calving. For each farm, both MBS and MB treatments were randomly distributed to the cows. Body weights and body condition scores were taken before, at 6th and 12th week of treatment. Daily milk production was recorded three weeks before, 12 weeks during and 3 weeks after the withdrawal of treatments. Milk samples were collected during the 12th week of treatment and analysed for butterfat (BF), crude protein (CP) and total solids (TS). The economic viability of the dairy enterprises in relation to supplementation was also assessed.
MBS fed cows had significantly higher (P<0.001) milk yield compared to MB fed cows. No differences were observed in milk composition parameters, body weights and body condition changes. The economic return for sunflower meal incorporation in MBS was found to be very high.
It is concluded that using sunflower meal mixed with maize bran was effective in increasing milk yield during the dry season and was economically profitable compared to maize bran alone.
Key words: Dairy cows, maize bran, milk yield, sunflower cake, supplementation
Introduction
Smallholder dairy production in urban and peri-urban areas is a common phenomenon in Tanzania as is the case in most tropical countries (Mlozi et al 92; Mosha 1991). Dairy production offers household income-generating and employment opportunities (Mlozi et al 1992; Mlay et al 2001). More importantly, the urban and peri-urban dairy industry supply urban dwellers with dairy products that are highly needed since rural based dairy production is very low (Anonymous 1994).
One of the major production constraints in the smallholder dairy sector in the tropics is the dwindling both in quantity and quality of the roughage during the dry season thereby leading to drastic reduction in animal productivity (Leng 1990; Plaizier et al 1999). In order to sustain modest production as well as maintaining body condition, it is important to provide additional sources of energy and protein during the dry season (Odham 1982; Preston and Leng 1987; Jelantik 2001).
Dairy farmers in Morogoro feed maize bran, which is mainly energy rich, to milking cows. However, rarely do they provide protein sources due to either lack of awareness of the importance of nitrogen supplementation to animals, or scarcity and high cost of protein supplements, or a combination of the these factors. In Morogoro, oilseed cakes from sunflower and cotton seeds are relatively cheaper than animal protein sources like fish, meat, bone and blood meals (Mlay et al 2001). Sunflower cake is widely available in Morogoro as most people grow sunflower seed crop for sale to the oil processing factory in Morogoro town as well as extracting oil for domestic use using the hand press (Hayman 1992; Shayo et al 1997; Temi 1999). However, the potential of sunflower meal as a protein supplement to improve ruminant productivity in urban and peri-urban areas of Morogoro has not been fully explored.
Therefore, it was the aim of this study to: (i) Investigate further the suitability of sunflower meal as a source of protein that is cheap, effective and acceptable by farmers in Morogoro. (ii) Find out the effect, if any, of added sunflower meal on milk yield, milk composition and body condition of cows during the dry season
Materials and methods
Study area
The study was carried out in Morogoro urban and peri-urban area at an altitude of 528m above sea level with an average rainfall of 800-1200 mm per annum. Heavy rains fall between April and May. The mean maximum and lowest temperatures are 32.4 and 14.8 oC respectively. Morogoro town is located at about 250 km West of Dar-es-Salaam along the Tanzania-Zambia highway. The study was carried out between November 1999 and March 2000. A total of 18 farms distributed in various wards in Morogoro (Table 1) with a total of 48 milking cows participated in the trial.
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Table 1 Distribution of farms and number of cows fed either maize bran-sunflower meal concentrate mixture (MBS) or maize bran alone (MB) |
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|
Ward |
No. of Farms |
Supplement |
|
|
Cows on MBS |
Cows on MB |
||
Bigwa |
1 |
2 |
2 |
|
Forest |
2 |
3 |
2 |
|
Kihonda |
3 |
4 |
3 |
|
Kichangani |
2 |
2 |
2 |
|
Kilakala |
3 |
5 |
3 |
|
Mazimbu |
2 |
3 |
2 |
|
Mbuyuni |
3 |
5 |
4 |
|
Mlimani |
2 |
3 |
3 |
|
Total |
18 |
27 |
21 |
Animals and treatments
The participating farmers owned at least two milking cows, kept under a zero grazing system. The selected cows were those with the following criteria: 2-6 months post calving, previous average yield of 3.0-13.0 litres per day, parity of 2-3, and body condition score 2.5-5.0. The type of animals kept by farmers in this study included various crosses between the local Tanzanian short horn zebu cattle and Boran with Holstein-Friesian, Ayrshire and Jersey.
Treatments were either maize bran alone (MB) with crude protein (CP) of 10.9% DM (control) or maize bran mixed with sunflower meal (MBS) with CP of 15% in DM. The composition of MBS (% DM basis) was: 31, 68 and 1 of sunflower meal, maize bran and mineral powder, respectively; and that of MB was 99 and 1 maize bran and mineral powder, respectively. The mineral powder (Cooper Kenya Limited, Nairobi Kenya) contained the following minerals with the % contribution of each given in brackets; NaCl (27.0), Ca (18.5), P (11.0), Mg (3.0), Fe (0.50), Cu (0.16), Mn (0.40), Zn (0.50), S (0.40), Co (0.02), I (0.02), Se (0.0015) Mo (0.0002) and Ca:P ratio of 1.68:1.
Each cow was given 4 kg/day (as fed basis) of the respective supplement with half the amount given during morning milking time (around 6-7am) and the other half during the evening milking time (5-6pm). For a given farm, treatments were equally distributed to the milking cows so that both MBS and MB treatments were present.
Bodyweight and condition scoring
Heart-girth measurement of the animals was taken before, at 6th and 12th week of treatment in order to predict the live weights. Concurrent measurements of body condition score were done by the method of Edmondson et al (1989) where 1 is severe under-condition and 5 severe over-condition.
Roughage intake
Once every week, one farm per ward was used in estimating forage intake (Table1). Weights and samples of forage offered were taken each morning and of refusals the next morning.
Feed analyses
Dry matter (DM) of samples was determined by hot oven drying at 105 oC for 24 hours. Neutral detergent fibre (NDF) was determined according to the method of Van Soest et al (1991). Mineral analysis including Ca, P, Na, K and Mg were determined using inductively coupled plasma spectrophotometer (AOAC 1990). In vitro organic matter digestibility was determined by the method of Tilley and Terry (1963). Nitrogen (N) contents were analysed by the Kjeldahl method (AOAC 1990) using a semi-automated N analyser (Kjeltec system 1002, Tecator AB, Hoganas, Sweden). Crude protein (CP) was derived from the N content by multiplying with a factor of 6.25.
Rumen degradability of dry matter (DM) and nitrogen (N) from MB and MBS were determined by the nylon bag technique (Ørskov and McDonald 1979; Madsen et al 1997) using ruminally fistulated mature crossbred heifers fed grass hay and 3kg/day of MBS. The incubation times were 0, 2, 4, 8, 16, 24, 48 and 72h. The residues in the bags were analysed for N by Kjeldahl method. Nitrogen degradabilities were fitted to the exponential equation p = a +b (1 + e-ct) where P =degradation at time t, a =the zero time intercept of the fitted curve, a +b = the asymptote of the curve at infinite time t and c = the degradation rate constant. Corrections for particle loss from the bag were made by the equation described by Weisbjerg et al (1990).
The Metabolisable energy of the supplements was determined by multiplying the calculated values of digestible energy (Hvelplund and Weisbjerg 1998) by a conversion factor of 0.82.
Milk yield and composition
Daily milk produced was recorded and weekly averages calculated. Yields were recorded for three weeks before imposing the treatments, for 12 weeks during treatment and three weeks post-treatment. Milk samples were taken in bottles (50 ml) in ice packed cool boxes in the 12th week of treatment. The samples were deep frozen in the lab and later analysed for milk butterfat (BF) percent by Gerber method while milk protein (CP) was calculated from nitrogen content from Kjeldahl method analysis (AOAC 1990) multiplied by a factor of 6.25. The percent total solids (TS) was determined by the reference method of oven drying at 105 oC in acid-washed sand for 12 hours. The solids not fat (SNF) were calculated as the difference between %TS and %BF (i.e. %TS -%BF).
Cost-benefit analysis
The production costs were computed from the major costs of feeds and labour charges. The cost-benefits of using sunflower meal was calculated based on the extra expense incurred when it was incorporated in the diet in relation to the revenue realised from sale of the extra milk obtained due to the supplements. No attempt was made to estimate the overall profitability of the dairy enterprises.
Statistical analyses
Analysis of variance was carried out using the SAS (1985) general linear model procedure with initial milk yield as a covariate with cow and farm as independent variables according to the model shown below.
Y = I + T+ F + M + e (Model 1)
Where: Y = Dependable variable
I = Intercept
T = Treatment (MB, MBS)
F = Farm
M = Mean initial yield for the 3 weeks pre-treatment
e = Random error
Means for milk yield during the 3 weeks prior and after treatment, body weight and condition scores were calculated using the above model but without the covariate statement i.e.
Y = I + T + F + e (Model 2)
Where each statement in the model is as explained in Model 1 above.
Results
Chemical composition and rumen degradability of the two supplements
The chemical composition of sunflower (S), maize bran (MB) and maize bran mixed with sunflower meal (MBS) used in this trial is shown in Table 2.
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Table 2 Chemical composition of sunflower meal (S), maize bran (MB) and maize bran mixed with sunflower meal (MBS) |
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|
Parameter |
Type of feed |
||
|
S |
MB |
MBS |
|
|
Dry matter, % |
94.2 |
91.5 |
92.2 |
|
Components, %DM basis |
|
|
|
|
Ash |
4.3 |
5.1 |
5.4 |
|
Organic matter |
95.7 |
94.9 |
94.6 |
|
Crude protein |
23.6 |
10.9 |
14.8 |
|
Ether extract |
4.5 |
10.7 |
9.2 |
|
Neutral detergent fibre |
59.1 |
31.9 |
38.0 |
|
Carbohydrates |
67.6 |
73.3 |
70.6 |
|
Potassium |
NA |
0.82 |
0.72 |
|
Calcium |
NA |
0.14 |
0.20 |
|
Magnesium |
NA |
0.32 |
0.29 |
|
Phosphorus |
NA |
0.76 |
0.72 |
|
Sodium |
NA |
0.23 |
0.22 |
|
IVOMD, % |
58.2 |
64.4 |
62.0 |
|
NA: not analysed; IVOMD: In vitro organic matter digestibility |
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There was slightly higher NDF content in MBS compared to MB due to higher NDF content of sunflower meal. MBS had higher CP and less ether extract (EE) compared to MB (14.8 Vs 10.9) and (9.2 Vs 10.7%), respectively.
Table 3 shows the rumen degradability constants and effective DM and N degradation of MB and MBS. Both supplements had high potential degradability of DM and N (83-90%). Effective N degradation at 2 and 5% h-1 passage rates was higher in MB compared to MBS.
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Table 3 Degradation constants and the effective degradation of dry matter (DM) and Nitrogen (N) in MB and MBS supplements. Values expressed as % |
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|
|
Degradation constants |
Washing loss, % DM |
Effective degradation |
|||||
|
a |
b |
a+b |
C (% h-1) |
2% h-1 |
5% h-1 |
|||
|
MBS |
DM |
33.3 |
50.5 |
83.8 |
3.02 |
44.3 |
58.8 |
47.5 |
|
MBS |
N |
56.3 |
29.3 |
85.7 |
6.76 |
55.2 |
63.7 |
54.1 |
|
MB |
DM |
36.4 |
49.5 |
85.9 |
5.37 |
34.3 |
66.9 |
54.2 |
|
MB |
N |
37.6 |
52.2 |
89.9 |
6.55 |
35.2 |
73.5 |
63.4 |
|
DM; dry matter, N; nitrogen |
||||||||
MB had higher energy while, MBS had a higher nitrogen contribution
(Table 4). Energy supplied from MB was slightly higher compared to MBS. The
daily amount of N escaping rumen degradation was
higher with MBS than MB.
|
Table 4. The energy and nitrogen contribution from supplements given during the on farm trial |
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|
Parameter |
Supplement |
|
|
MB |
MBS |
|
|
ME content, MJ/kg DM |
10.7 |
10.2 |
|
DM, % |
91.5 |
92.2 |
|
Amount given, kg as fed |
4.0 |
4.0 |
|
Amount given, kg DM |
3.7 |
3.7 |
|
Energy supply, MJ |
39.6 |
37.6 |
|
N content, % |
1.8 |
2.4 |
|
N supplied, g/day |
64.1 |
87.4 |
|
Effective N degradation, % |
73.5 |
63.4 |
|
Rumen degraded N, g/day |
47.1 |
55.4 |
|
Rumen undegradable N, g/day |
17.0 |
32.0 |
Milk yield and composition
Milk yield trends 3 weeks before, 12 weeks during and 3 weeks post treatment are portrayed in Figure 1 as raw means and differences in milk yield between MBS and MB. From an initial mean value of 0.7 litres/day in the pre-treatment period, the difference in milk yield between the two groups increased to 1.5 litres in the first week to 2.2 in the 12th week of treatment. Deduction of the mean difference in yield for the pre-treatment period from the differences in yield during the 12 weeks of treatment gave the extra yield due to MBS supplement. The extra yield increased from 0.84 litres/day in the first week to a maximum value (1.68 litres) in week 7 of treatment. There appeared to be a residual effect of MBS as the last three weeks post treatment showed extra daily milk yield of 1.28, 1.46 and 1.12 litres per week, respectively.
 |
Figure 1. Mean milk yield and the difference between MBS and MB supplements |
There was a higher (P<0.001) milk yield in cows fed MBS compared to MB for the whole treatment period and also for the three weeks post treatment (Table 5).
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Table 5 Least square means milk yield (litres/day) during the on farm feeding trial with maize bran mixed with sunflower meal (MBS) or maize bran alone (MB) |
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|
Time |
Supplements |
Difference |
P-Value |
|||
|
MBS |
MB |
|||||
|
Mean |
SE |
Mean |
SE |
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|
3 Weeks before |
7.2 |
0.44 |
6.3 |
0.52 |
0.9 |
**0.2 |
|
12 Weeks of treatment |
8.1 |
0.2 |
6.6 |
0.20 |
1.5 |
*0.001 |
|
3 Weeks after treatment |
7.2 |
0.43 |
5.1 |
0.51 |
2 |
**0.01 |
The composition of milk collected at the 12th week of treatment showed no differences between treatments (Table 6).
Table 6. Milk composition during the on farm feeding trial |
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Parameter |
Supplements |
*P-value |
|||
|
MBS |
MB |
||||
|
Lsmean |
SEM |
Lsmean |
SEM |
||
|
Butterfat, % |
4.01 |
0.187 |
3.84 |
0.208 |
0.5 |
|
Solids not fat, % |
9.01 |
0.210 |
9.03 |
0.234 |
1.0 |
|
Total solids, % |
13.02 |
0.254 |
12.86 |
0.283 |
0.7 |
|
Crude protein, % |
4.04 |
0.160 |
3.77 |
0.179 |
0.3 |
|
*Model 2 |
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Body weights and conditions scores
All the cows showed average improvements in live weight and body condition score during the 2 weeks of treatment, with no differences between supplements (Table 7).
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Table 7 Body weight and body condition scores for animals during the experimental period |
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|
|
Supplement |
*P-value |
|||
|
MBS |
MB |
||||
|
Mean |
SEM |
Mean |
SEM |
||
|
Body weight (BW), kg |
|
|
|
|
|
|
Initial BW |
381.9 |
13.71 |
358.1 |
15.93 |
0.3 |
|
BW at six weeks |
384.4 |
13.79 |
361.4 |
16.02 |
0.3 |
|
BW at 12 weeks |
387.1 |
13.71 |
363.2 |
15.93 |
0.3 |
|
BW change at 6 weeks |
2.40 |
0.656 |
3.4 |
0.763 |
0.3 |
|
BW change at 12 weeks |
5.15 |
1.272 |
5.10 |
1.478 |
0.6 |
|
Weight gain, kg/day |
|
|
|
|
|
|
First 6 weeks |
0.06 |
0.016 |
0.08 |
0.018 |
0.3 |
|
12 weeks of treatments |
0.07 |
0.030 |
0.06 |
0.035 |
1.0 |
|
Condition score (BCS) |
|
|
|
|
|
|
Initial BCS |
3.50 |
0.064 |
3.38 |
0.075 |
0.2 |
|
BCS at 6weeks |
3.52 |
0.062 |
3.39 |
0.072 |
0.2 |
|
BCS at 12 weeks |
3.56 |
0.059 |
3.41 |
0.069 |
0.3 |
|
Change in BCS at 6 weeks |
0.02 |
0.013 |
0.018 |
0.0148 |
|