Multi-nutrient blocks (MUB) as supplement for milking cows fed forages of low nutritive value in south Vietnam

Multi-nutrient blocks (MUB) as supplement for milking cows fed forages of low nutritive value in south Vietnam

* University of Agriculture and Forestry, Thu Duc, Hochi Minh City, Vietnam
** Convenio Interinstitucional para la Producción Agropecuaria en el Valle del rio Cauca (CIPAV) AA 7482, Cali, Colombia.

Two experiments were carried out at An Phuoc state farm and on private small farms to determine animal response, farmer acceptance and benefits of supplementing MUB to crossbred Holstein cows.

On 3 small farms, seven milking cows fed rice straw, native grasses and concentrate were supplemented with 1 kg MUB (5% urea) during 40 days. Milk yield and milk fat content (before and after supplementation) were 7.17 kg/d, 3.4% and 8.17 kg/d and 3.9% respectively.

Ten cows were divided in two groups: control fed low quality grass and crop by-products and concentrate (as basal diet); experiment group fed basal diet plus 1 kg MUB (10%urea)/d. The experiment lasted 140 days. Milk yield, adjusted by covariance for yield prior to starting the trial was (kg/d): 6.257 and 7.203 (SEmean ±0.069) for the control and MUB supplemented animals.

KEY WORDS: Urea-molasses blocks, crossbred cattle, crop residues, milk yield, milk composition.

The basal diet of most of the cattle and buffaloes in Vietnam is based on crop residues and grazing lands, roadside grasses or boundaries between crops. These diets are poor and imbalanced in nutritional value.

The least cost method of improving the nutritive value of crop residues (rice straw, cane tops and bagasse) is by providing free access to multinutritional blocks (MUB), rich in urea and minerals (Preston and Leng 1987). MUB is cheap and easy to make on a small scale or in factories. These blocks are also very easy to handle. It is necessary to carry out experiments on the benefit of MUB supplementation, animal responses, farmer acceptance and proportion of available ingredients in the area to make adequate blocks.

Experiment 1: effects of supplementing mub on the milk yield of crossbred holstein cows on small farms.

Seven crossbred Holstein dairy cows on three farms in the Govap district, 20 km from HoChiMinh city. The experiment was carried out in September and October, 1990. Blocks were made of different composition using available ingredients to find the hardest block. The final composition chosen was urea 5%, molasses 40%, cassava bran 25%, rice polishing 10%, lime 10%, bone meal 5%, salt 5%. All these ingredients are available in the area.

Measurements were made of feed intake, feed composition, the milk yield during 10 days before MUB supplementation and the yield from 31st day 40th day after supplementation.

Table 1: Details of animals used in experiment 1.

Cow	Holstein/Zebu	Lactation	Lactating month

T1	1/2	2	3
T2	1/2	2	3
T3	1/2	2	3
U1	3/4	1	6
U2	1/2	1	6
C1	1/2	1	4
C2	1/2	1	4

Table 2: Milk yield before and after MUB supplementation

	Milk yield (kg/d)		Difference
Cow	-MUB	+MUB	(kg/d)	(%)

T1	11.04	12.29	1.25	11.3
T2	11.74	12.79	1.05	8.9
T3	8.25	9.79	1.54	18.7
U1	2.91	3.36	0.45	15.5
U2	4.35	5.29	0.94	21.6
C1	5.78	6.76	0.98	16.9
C2	5.95	6.91	0.96	16.1

Mean	7.15	8.17	1.02	15.6
SE	±1.16	±1.24	±0.12

Table 4: Different compositions of blocks studied (1-->6, order of increasing hardness)

Ingredients	1	2	3	4	5	6

Molasses	40	40	40	40	40	40
Urea	5	5	5	5	5	5
Salt	5	5	5	5	5	5
Bone meal	5	5	5	5	5	5
Lime	10	10	10	10	10	15
Cassava bran	0	10	35	25	35	25
Rice polishing	0	0	0	10	0	5
Groundnut husk	35	25	0	0	0	0

The block is now being made with 10% urea to reduce the amount of block to be fed daily and thus improve the profitability.

Experiment 2: effects of supplementing mub on the milk production of crossbred holstein-friesian dairy cattle at an phuoc state farm.

The experiment was carried out at An Phuoc farm at the end of the rainy season. Ten F1 Crossbred Holstein/Zebu cows were randomly divided in two groups:

In the 1st month the cows of both the control and experimental group received the same diet in order to measure the initial milk production, which was to be the covariate in the statistical analysis. The experiment then lasted a further 110 days when the two groups received the basal diet with or without access to the MUB. The first 20 days of this period were considered as a period of adaptation.

Table 5: Basal diet (kg/cow/day)

	Initial	1-30d	31-60d	61-90d

Concentrate	3.2	3.3	4.3	4.3
Native grasses	9.3	9.5	10.7	7.3
Guinea grass	10.5	10.3	10.8	5.7
Sugar cane tops	0	0	0	13.4
Molasses	0.7	0.7	0.7	0.7
Cotton seed meal	1.5	1.5	0	0
Fish meal	0.16	0.17	0	0

Table 6: Composition of feed (%)

Feed	DM	CP	CF	Ash	EE	NFE

Concentrate	86.70	12.23	10.52	11.29	6.37	46.31
Native grasses	36.14	8.17	35.28	6.03	3.28	42.59
Guinea grass	38.65	4.06	36.64	5.53	2.96	47.34
Sugar cane tops	39.00	6.82	36.17	6.78	2.05	45.69
"A" Molasses*	55.90	1.09	0	4.82	0	50.00
Cotton seed meal	90.25	24.04	18.16	4.86	5.96	37.23
Fish meal	54.27	19.27	0	27.19	7.81	0

* In the artisan production of sugar in Vietnam, the concentrated cane juice is centrifuged producing an "A" sugar and an "A" molasses, which is richer in sugar than final molasses, as produced in the industrial process.

The composition of MUB was: "A" molasses 35%, Urea 10%, Rice polishing 38%, Lime 10%, Salt 5%, Trace Mineral premix 2%. The blocks were made by hand.

Table 7: Milk yield of each cow at An Phuoc (kg/cow/d)

Cow	Initial		Cow	Experiment
No:	Ctrl	MUB	No:	Ctrl	MUB

1	5.1	5.04	6	4.99	5.95
2	6.04	6.02	7	5.97	6.74
3	6.48	6.3	8	6.51	7.54
4	6.14	6.12	9	6.16	7.02
5	7.82	7.88	10	7.65	8.33

Mean:	6.316	6.272		6.256	7.116

There was no significant difference between the two groups in initial milk production. There was a highly significant effect (P=0.007) of MUB on milk yield during the experimental period. The mean values, adjusted by covariance for yield prior to the experiment, were 6.26 and 7.20 kg/day for control and MUB treatments respectively.

Table 9: Unadjusted means for milk composition (%) in the experiment at An Phuoc State Farm

	Control		MUB
	Initial	Final	Initial	Final

Fat	4.56	4.26	3.90	3.84
Casein	2.76	3.00	2.92	2.78

There was no effect of MUB treatment on milk fat content (P=0.93). Economic profit: The price of MUB is 0.10 US$/kg; and milk is 0.20 US$/kg. The advantage from giving MUB was 0.72 US$/cow/day.

Milk yield was increased both on the commercial farms and on the State Farm when the basal diet was supplemented with the urea- molasses blocks. The response was approximately 1 kg of milk per kg of MUB. These results are similar to those reported by Kunju (1986), following introduction of a molasses-urea block into the diet of lactating buffaloes in villages in India.

All farmers had a good opinion about the MUB supplement but complained about the price. The MUB price was high during the trial (US$0.10/kg) because at that time the sugar cane harvest had finished so the price of molasses was high (US$0.12/kg). During the sugar cane harvest the price of molasses falls to 0.07US$/kg. Even so the price of supplementation (US$0.12/day) was less than the value of the increase in milk yield of about 1 kg (1 kg milk = US$0.20/day).

Kunju P J G 1986 Urea molasses block lick: a feed supplement for ruminants. In: Rice straw and related feeds in ruminant rations (Editors: M N M Ibrahim and J B Schiere) Proceedings International Workshop, Kandy:Sri Lanka pp261-274

Preston T R and Leng R A 1987 Matching Ruminant Production Systems with Available Resources in the Tropics and Subtropics. PENAMBUL Books Ltd: Armidale NSW, Australia

Table 3: Milk composition (%)

	-MUB	+MUB

Density	1.025	1.030
Milk fat	3.40	3.95
Casein	2.80	2.80

Table 8: Analysis of covariance for effect of MUB on milk yield, using milk yield prior to experiment (c) as the covariate

Source	DF	ADJ SS	MS	F	P

Covariates	1	5.8632	5.8632	38.27	0.000
MUB	1	2.2052	2.2052	14.39	0.007
Error	7	1.0725	0.1532
Total	9	8.4256


Covariate	Coeff	Stdev	t-value	P
(c)	0.8489	0.137	6.186	0.000


Adjusted means(kg/d):	-MUB 6.257	+MUB 7.203	SEmean ±0.069

Table 10: Analysis of covariance for effects of MUB on milk fat content (milk fat in initial period = 'c')

Source	DF	ADJ SS	MS	F	P

Covariates	1	4.406	4.406	3.32	0.111
MUB	1	0.012	0.012	0.01	0.926
Error	7	9.278	1.325
Total	9	14.125


Covariate	Coeff	Stdev	t-value	P
‘c’	0.7491	0.411	1.823	0.111


Adjusted means:	-MUB 4.01%		+MUB 4.09%

Table 11: Analysis of covariance for effects of MUB on casein content of milk (casein content in initial period = C3)

Source	DF	ADJ SS	MS	F	P

Covariates	1	0.0508	0.0508	0.39	0.553
MUB	1	0.1410	0.1410	1.08	0.334
Error	7	0.9172	0.1310
Total	9	1.0890


Covariate	Coeff	Stdev	t-value	P
C3	0.1234	0.198	0.6228	0.553


Adjusted means:	-MUB 3.01%		+MUB 2.77%