Multinutrient blocks (MUB) as supplement for milking cows fed forages of low nutritive value in outh Vietnam

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

University of Agriculture and Forestry, Thu Duc, Ho Chi Minh City, Vietnam
*Centro para la Investigacion en Sistemas Sostenibles de Produccion Agropecuaria (CIPAV) AA20591 Cali, Colombia

Two experiments were carried out, at An Phuoc state farm and on private small farms, to determine animal response, farmer acceptance and the benefits of supplementing MUB to crossbred Holstein cows. On 3 smallholder farms, seven milking cows fed rice straw, native grasses and concentrates were supplemented with 1 kg MUB (5% urea) for 40 days. Milk yield, milk fat content before and after supplementation were: 7.17 kg/cow/day and 3.4% fat; and 8.17 kg/cow/day and 3.9% fat, respectively. On the State farm, 10 cows were divided into two groups: a control group fed poor quality grasses, crop by-products and concentrate as the basal diet, and an experimental group fed the basal diet plus 1 kg MUB (10% urea)/cow/day. The experiment lasted 140 days. Milk yield was significantly increased (P<0.001) by 17% by feeding MUB.

The basal diet of most of the cattle and buffaloes in Vietnam is based on crop residues and grazing on roadsides and on boundaries between crops. These diets are of poor quality and are imbalanced nutritionally. On eof the least cost methods for 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 are cheap, and easy to make on a small scale and are easy to store and handle.

The following trials were carried out to determine the benefits of MUB supplementation, animal responses, farmer acceptance, and on the suitability of available ingredients in the area to make the blocks.

Seven crossbred Holstein dairy cows in three households in Govap district 20 km from Ho Chi Minh City were used. The experiment was carried out in September and October, 1990. The blocks contained urea (5%), molasses (40%), cassava bran (25%), rice polishings (10%), lime (10%), bone meal (5%,) salt (5% ), all these ingredients being available in the area. Measurements were made of feed consumed, feed composition, milk yield 10 days before MUB supplementation and the yield between the 31st day - 40th day after supplementation began.

Trials were also made with different local ingredients in order to determine the composition that would produce the hardest block.

Table 1. Milk yield before and after MUB supplementation

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

T1	11.0	12.3	1.25	11.3
T2	11.74	12.79	1	8.5
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	0.92	15.9
C2	5.95	6.91	0.96	16.1

Mean	7.14	8.17	1.01	15.4
SD	3.08	3.29	0.31

Table 2: Milk composition

	-MUB	+MUB

Density	1.025	1.030
Milk fat (%)	3.40	3.95
Casein (%)	2.80	2.80

The milk yield of all the cows fed MUB was higher than before supplementation, although milk composition was not affected by treatment. All farmers were pleased with the results of MUB use, but complained about the price. The MUB price was relatively high because it was not the sugar cane harvesting season, and the price of molasses was high.

The cost of supplementation was less than the additional milk production giving a net profit to the farmer.

Table 3: Different compositions of MUB (in order of increasing hardness)

Ingredients	-----------------------------------à Increasing hardness

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

Cassava bran was better than groundnut husks as a binder in the blocks. It is planned to make the MUB with 10% urea in order to reduce the intake which in turn will lead to a reduction in costs.

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

Ten F1 crossbred Holstein x Friesian cows were randomly divided into two groups:

Table 4 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 5: Composition of feeds(%)

Feed	DM	CP	CF	Ash	EE	NFE

Concentrate	86.7	12.2	10.5	11.3	6.37	46.3
Native grasses	36.1	8.17	35.3	6.03	3.28	42.6
Guinea grass	38.6	4.06	36.6	5.53	2.96	47.3
Sugar cane tops	39.0	6.82	36.2	6.78	2.05	45.7
"A" Molasses	55.9	1.09	0	4.82	0	50.0
Cotton seed	90.3	24.0	18.2	4.86	5.96	37.2
Fish meal	54.3	19.3	0	27.2	7.81	0

The composition of the MUB was as follows: "A" molasses 35%, Urea 10%, Rice polishings 38%, Lime 10%, Salt 5%, Trace Mineral premix 2%. The ingredients were mixed by hand.

In the 1st month the cows in both groups received the same diet in order to measure the initial milk production. This was used as covariate to adjust the yields in the experimental period. The experimental period lasted 110 days, after a 20 day adaptation period. Measurements were made of milk production and milk composition.

Table 6: Effect of MUB on milk yields (kg/day) at An Phuoc State Farm

Cow	Initial		Experiment
No	Control	MUB	Control	MUB

1	5.1	5.04	4.99	5.95
2	6.04	6.02	5.97	6.74
3	6.48	6.30	6.51	7.54
4	6.14	6.12	6.16	7.02
5	7.82	7.88	7.65	8.33

Mean	6.32	6.27	6.26	7.12
Adjustedmean*			6.24	7.14
SEmean			±0.091 (P<.001)

Table 7. Analysis of variance for milk yield (Initial = covariate)

Source	DF	Seq SS	Adj SS	Adj MS	F	P

Initial	1	6.4034	6.5770	6.5770	159.72	0.000
Treatment	1	2.0226	2.0226	2.0226	49.12	0.000
Error	7	0.2883	0.2883	0.0412
Total	9	8.7142

There was a highly significant 17% increase in adjusted milk yield when the MUB was given (P<0.001).

Table 8: Effect of MUB on milk composition (%)

	Fat		Casein
Group	Initial	Final	Initial	Final

+MUB
Mean	3.90	3.84	2.92	2.78
SD	1.12	1.21	0.57	0.14


-MUB
Mean	4.56	4.26	2.76	3.00
SD	0.55	1.12	0.57	0.41

The improvements in milk production from supplementing imbalanced diets composed of low-nitrogen forages and concentrates with a molasses-urea block has been documented in many reports (Leng and Preston 1984; Kunju 1986; Sansoucy 1986; Sansoucy and Aarts 1986; Leng and Kunju 1989). The results of the present experiment corroborate these earlier findings.

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

Leng R A and Kunju G 1989 Supplementation practices for milking cattle and buffaloes in India. Report to National Dairy Development Board, Anand, India. pp31-40

Leng R A and Preston T R 1984 Nutritional strategies for the utilization of agro-industrial byprooducts by ruminants and extension of the principles and technologies to the small farmer in Asia. In: Proceedings 5th World Conference on Animal Production. Japanese Society of Zootechnical Science: Tokyo pp310-318

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

Sansoucy R 1986 The Sahel: Manufacture of molasses-urea blocks. World Animal Review 57:40-48

Sansoucy R and Aarts G 1986 Molasses-urea blocks as multinutrient supplements for ruminants in various conditions In: FAO Expert Consultation on Sugarcane as Feed (Editors: R Sansoucy G Aarts, R A Leng and T R Preston) FAO:Rome