Use of Cassava as Animal Feed

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Blocks or cakes of urea-molasses as supplements for Sindhi x Yellow growing cattle fed rice straw and cut grass or cassava foliage

Ho Quang Do, Vo Van Son  and T R Preston*

College of Agriculture, Cantho University, Cantho, Vietnam
hqdo@ctu.edu.vn
* University of Tropical Agriculture, Phnom Penh, Cambodia
trpreston@email.com

Abstract

Nine growing cross-bred heifers (Sindhi X Yellow cattle) of 162 kg (162 ± 9 kg), receiving a basal diet of ad libitum rice straw were allocated to three treatments given as supplements. These were: a urea-molasses mixture (10% urea) prepared as a soft cake and offered at 500g/head/day plus fresh grass at 3 kg/100 kg liveweight; a urea-molasses mixture (10% urea) prepared as a hard block offered ad libitum plus fresh grass at 3 kg/100 kg liveweight; a urea-molasses mixture (10% urea) as a soft cake offered at 500 g/head/day plus fresh cassava foliage at 3 kg/100 kg liveweight.

Intake of rice straw and of total dry matter were highest (P=0.002) on  the combination of soft urea-molasses cake and cassava foliage supplements. The cattle ate all the soft cake that was offered (500 g/day) but those offered the hard block ate only  317g/day.  Growth rates were highest (P=0.002) with the soft cake and cassava foliage supplement (270 g/day) followed by the soft cake and grass  (190 g/day) and hard block and grass (160 g/day).

 Key words: Cattle, urea, blocks, cakes, feed intake, rice straw, growth

Introduction

Vietnam grows over 6 million ha of rice annually and it is estimated that this yields around 18 million tonnes of rice straw. This residue is the most abundant feed for ruminant animals in Vietnam, especially during the dry season. Many methods have been proposed for improving the nutritive value of rice straw, usually by some treatment involving the use of urea or ammonia (see review by Nguyen Trach 1998).  Incorporating urea in a hard block based on molasses and rice bran, with lime or cement as hardening agent, was proposed by Leng (1984) and popularised in many countries by the Feed Resources Group of FAO (Sansoucy 1986). Positive effects of this technology to improve use of rice straw by growing heifers were reported by Bui Xuan An et al (1992).  

Attempts to feed the hard block to swamp buffaloes in the Mekong delta were not successful as the animals would not consume them (Nguyen Van Thu et al 1993). Nguyen Phuc Tien and Preston (1998) observed the same phenomenon with swamp buffaloes exposed to one hour  of work daily driving a sugar cane crusher; by contrast, the same block was consumed avidly by native Yellow cattle on the same work schedule.  The solution to the intake problem, reported by Nguyen Van Thu et al (1993),  was to prepare the urea-rice bran-molasses mixture as a soft cake and, where necessary, to force-feed the mixture using a "bamboo pipe". 

There are few reports comparing the different methods of incorporating urea in rice straw diets and none comparing the hard "block" versus the soft "cake" (Nguyen Xuan Trach 1998).  The following experiment was designed to compare two methods of supplying the urea: comparing the hard "block" versus the soft "cake" and two forage supplements: ‘’Grass ‘’ versus ‘’ Cassava foliage’’
.

Material and methods

Location, animals and treatments

The trial was carried out on the Song Hau farm in Omon District, Cantho Province. Nine growing cross-bred (Sindhi x Yellow) heifers (initial weight 162 ± 9 kg), receiving a basal diet of ad libitum rice straw were allocated in a completely random design to three supplements:

·        Urea in a hard block + fresh grass

·        Urea in a soft cake + fresh grass

·        Urea in a soft cake + cassava foliage

Feeding system

The rice straw was purchased in Omon District, Cantho Provine. Fresh grass and fresh cassava foliage were purchased every day from farmers. The rice straw was offered ad libitum, fresh quantities being given morning and afternoon to ensure there was a residue of at least 0.5 kg.  The grass (mainly para grass, Bracchiaria decumbens) and foliage from cassava plants were given fresh in a single feed at a level of 3 kg/head/day.   The hard block was offered on ad libitum basis.  In the case of the soft cakes, one (250 g) was offered twice daily, in the  morning and afternoon. 

The soft cake was made by mixing first the urea, salt, coconut meal and rice bran. The molasses was then added, mixed and 1 kg of the mixture put into a box and pressed. For the hard block, the bone meal and cement were added to the rice bran, mixed together. The molasses was then added. A slurry was made of the lime, clay, salt and  water and this was then mixed with the dry ingredients.  The final mixture (lots of 2 kg) was pressed into a container and allowed to set in the shade for one week before being fed.

Measurements

The cattle were weighed on two consecutive two days at 15 day intervals.  Intakes of rice straw, grass and the soft cake were recorded every day. The hard block was weighed when first offered to the animals and again when it was almost fully consumed, after which it was replaced with a new block.  The rice straw, cassava foliage and grass were sampled every month and analysed for dry matter (48 hours in a forced air oven at 100 °C).

Statistical analysis

Liveweight gain for individual animals was estimated from the linear regression of liveweight on days in the trial. These data and those for feed intake were analysed by the ANOVA option of the Minitab software package (Version 12). The sources of variation were treatments and error.

Results and discussion

Feed intake

All the cake offered (500 g/head/day) was consumed while of the hard block, only 317 g/day was eaten. These findings are similar to those reported by Ho Quang Do (1999). Intake of rice straw was higher (P=0.04) for the supplements of soft cake versus hard block and for cassava foliage versus grass (P= 0.007).

Growth rate

Highest growth rate (P=0.002) was recorded on the combination of the soft cake and the cassava foliage (270 g/day), followed by the soft cake and grass (190 g/day) with poorest results on the hard block and grass (160 g/day). The advantages of the soft cake over the hard block confirm the earlier findings of Ho Quang Do et al (1999) and appear to reflect the higher intake of urea and other nutrients on the former. Fresh cassava foliage was shown by Ffoulkes and Preston (1978) to be comparable with soya bean meal as a source of bypass protein for cattle fattened on liquid molasses-urea as the basal diet. Similar rates of milk production in goats supplemented with either cottonseed cake or cassava leaf meal (Duong Van Liem et al 2000), support the conclusion that some of the protein in cassava foliage is able to “bypass” or “escape” the rumen fermentation.

Conclusions

Supplementing rice straw with a small amount of cassava foliage  and a soft cake containing 10% urea increased by 1.5  times the growth rate obtained on rice straw supplemented with a hard urea block and grass.

References

Bui Van Chinh 1991 Scientific information of AHRI, Number 5, Hanoi ( Vietnamese).

Bui Xuan An, Ngo Van Man and Luu Trong Hieu 1992 Molasses-urea block (MUB) and Acacia   mangium as supplements for crossbred heifers fed poor quality forages. Livestock Research for Rural Development. Volume 4, Number 2:   http://www.cipav.org.co/lrrd/lrrd4/2/an42.htm

 

Duong Thanh Liem, Ngo Van Man, and Nguyen Van Hao 2000 Cotton seed and cassava leaf meal as protein supplements for lactating goats, Seminar-Workshop Ho Chi Minh City, Vietnam, January 18-20 ^th , 2000.

 

Ffoulkes D and Preston T R 1978 Cassava or sweet potato forage as combined sources of protein and roughage in molasses based diets: effect of  supplementation with soybean meal. Tropical Animal Production   (3): 186-192

Ho Quang Do, Vo Van Son, Do Vo Anh Khoa and Nguyen Thi Kim Khang  1999  Urea supplementation of rice straw for Sindhi x Yellow cattle; sprayed in solution, as a soft cake or hard block.   Livestock Research for Rural Development.  Volume 11, Number 2:  http://www.cipav.org.co/lrrd/lrrd11/2/do112.htm

Leng R A 1984  The potential of solidified molasses-based blocks for the correction of multinutritional deficiencies in buffaloes and other ruminants fed low-quality agro-industrial byproducts. In: The Use of Nuclear Techniques to Improve Domestic Buffalo Production in Asia. IAEA: Vienna pp135-150.

Nguyen Phuc Tien and Preston T R 1998 Effect of work (driving sugar cane press) on intake of pressed sugar cane stalk and urea-treated rice straw by buffalo and cattle. Livestock Research for Rural Development. Volume 10, Number 1: http://www.cipav.org.co/lrrd/lrrd10/1/tien101.htm

Nguyen Van Thu, Nguyen Thi Kim Dong, Vo Ai Quac and Nguyen van Hon 1993 Effect of molasses-urea cake on performance of growing and working local buffaloes and cattle fed low nutritive value diets. Livestock Research for Rural Development. Volume 5, Number 1:  http://www.cipav.org.co/lrrd/lrrd5/1/thu51.htm

Nguyen Xuan Trach 1998 The need for improved utilisation of rice straw as feed for ruminants in Vietnam; An overview. Livestock Research for Rural Development. Volume 10, Number 2: http://www.cipav.org.co/lrrd/lrrd10/2/trach102.htm

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

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