Preparation of urea molasses blocks (UMB)
Poor quality roughages, e.g. cereal straws, poor quality hay, or dry-season forage that contains a lot of stem but not much leaf, can be deficient in crude protein (N). Insufficient N in the diet means that rumen microorganisms cannot make enough microbial protein for the maintenance or growth of ruminants. This can become critical, resulting in loss of condition and increased disease risk.
Urea and ruminant digestion
When fed as a part of the diet to ruminants, urea is converted to ammonia by the microflora in the rumen. Microorganisms in the rumen use ammonia to make microbial proteins as long as energy is available at the same time. Bacteria and protozoa are then digested by the animal. Urea therefore has a value that is partly equivalent to protein for ruminants. Molasses is a major by-product of the sugarcane industry. It is a source of energy and a widely available concentrated form of fermentable carbohydrate.
Molasses, urea and other ingredients can be used in the manufacture of molasses/urea feeds prepared as blocks. UMB are an excellent way of providing readily degradable protein and readily fermentable energy to ruminant animals, and they help increase the protein supply to the animal in situations where this may be limiting.
All the ruminants are nevertheless sensitive to a large quantity of urea which becomes toxic and intoxication can occur if a large amount of urea is ingested. Especially, goats are very fond of concentrates with urea and are therefore particularly sensitive to urea toxicity. So it is essential that the blocks are accurately made so that goats are not fed too much urea at one time. Also, an adaptation period of at least three weeks is required for the animal to utilize urea efficiently.
Ingredients for UMB
UMB can be made from a variety of components depending on their local availability, nutritive value, price, existing facilities for their use, and their desired influence on the quality of blocks. They can also include specific components:
Molasses provides fermentable substrate and various minerals and trace elements (but low amounts of phosphorous). Because of its pleasant taste and smell, it makes the block very attractive and palatable to animals. The degree Brix of the molasses should be as high as possible, and preferably higher than 85, to ensure solidification. (Degrees Brix is a hydrometer scale for sugar solutions graduated so that readings at a specified temperature represent percentages by weight of sugar in the solution, so 85° Brix is equivalent to 85 percent sugar).
Urea provides fermentable nitrogen, is the most important component of the block. With the increase of the microflora in the rumen, urea may increase the intake of straw and other low quality forages as well as their digestibility. The intake of urea must be limited to avoid toxicity problems but sufficient to maintain ammonia levels in the rumen consistently above 200 mg N/l for growth of microorganisms in the rumen and high rates of degradation of fibre.
It is important that urea and molasses are provided together to provide ammonia and energy at the same time – hence their combination in UMB.
The urea used in this formula is fertilizer grade, normally used as a nitrogen fertilizer in sugarcane plantations and rice fields. Since the urea is hygroscopic it is possible that during storage lumps may form in the sacks. In order to prevent excessive consumption of urea in too short a period, which may cause intoxication of the animals, it is necessary that all the lumps are crushed before introducing the urea into the mixture. This will guarantee a homogenous mixture of urea in the mass.
Wheat or rice bran
These serve a multiple purpose in the blocks. They provide some key nutrients including fat, protein and phosphorus. It also acts as an absorbent for the moisture contained in molasses and gives structure to the block. It may be replaced by other fibrous materials such as dry and fine bagasse (the residue from sugar cane processing) or groundnut hulls which are finely ground.
Other crop residues
Other crop residues can also be included in UMB. This depends on availability, and some crop residues and by-products will provide more nutrients than others.
These may be added where appropriate. Common salt is generally added because this is often deficient in the diet and it is cheap. Calcium is supplied by molasses and by the gelling agent, calcium oxide or cement (see below). Although phosphorus is deficient, there is no evidence that its addition is beneficial where animals are at below maintenance requirements when grazing on dry mature pastures or fed low-quality forage. Mineral requirements are reduced at maintenance or survival levels. Deficiencies will generally become a problem only when production is increased, particularly when a bypass protein supplement is given (proteins that are not degraded by rumen microorganisms and are digested in the intestines). In these cases phosphorus should be included in that supplement.
A gelling agent or binder is necessary in order to solidify the blocks. Various products have been tried successfully: magnesium oxide, bentonite, calcium oxide, calcium hydroxide and cement. The use of cement has raised questions about possible negative effects on animals. Research on the use of cement or its by-product, cement kiln dust, as a mineral supplement have not shown adverse effects at levels of 1 to 3 percent of the total diet dry matter. The USDA has restricted the use of cement kiln dust since it could cause a deposit of heavy metals in animal tissue.
Various chemicals or drugs for the control of parasites or for manipulation of rumen fermentation can be added to the molasses blocks which can be an excellent carrier for these products.
A leaflet produced by (KHAN and SIDDIKI 2004) includes the ingredients and instructions for a 10 kg block, as well as the following procedure for making 10 kg UMB in rural areas at least cost
- At first 3.9 kg. molasses is weighed and put in a large bowl.
- 500g. common salt and 1 kg of urea is added and admixture well manually.
- This mixture is kept for one night or at least 12 hours.
- After 12 hours, the mixture in the bowl is again mixed well by hand.
- Then wheat bran, rice polish, and lime, which were previously kept into separate bowls, are added with this mixture and also mixed well.
- Now, this mixture is placed in a 9 inch long, 5 inch wide and 5 inch height wooden mould, and then pressure is applied by wooden cover to give it block shape, block so prepared usually weighs 2.5 kg. (Click here to view an image of a simple wooden mould and Urea-Molasses Block).
- The block is now displaced from the mould and kept for 15 hours for hardening before ready for animal consumption.
- The mixture can be pressed in a bowl that results bowl-shaped blocks.
Distribution to the animals
For adult cattle or buffalo, about 0.5 kg of UMB can be given daily. For small ruminants, about 70– 80 g can be provided per animal per day (pers. comm. CIRAD).
Costs of UMB will be variable, depending on location and supply of the required ingredients. The document “Frequently asked questions on Urea-Molasses-Multinutrient Block Technology (UMMB)” by IAEA .http://www.iaea.org/programmes/nafa/d3/faq-ummb.pdf includes some economic comparisons as well as benefit:cost ratios from case studies.
KHAN, M.A.S. and CHOWDHURY, M.A.R. (2002) Urea Molasses Blocks to improve milk production and reproductive performance of cross-bred dairy cattle under smallholder farm condition in Bangladesh. In: Responding to the increasing global demand for animal products. Proceedings of an International Conference organized by the British Society of Animal Science, the American Society of Animal Science and the Mexican Society of Animal Science. Merida, Mexico, 12-15 November 2002.
KHAN, M.A.S. and SIDDIKI, S.R. (2004) Preparation of Urea Molasses Block (UMB) and it's use in livestock. [Leaflet] Forage Production and UMB Technology Project (NRI/DFID). Bangladesh Agricultural University, Mymensingh-2202.
VATTA, A.F. HARRISON, L.J.S. KRECEK, R.C. and PEARSON, R.A. (2004) Relative economic benefits of strategic anthelmintic treatment and urea-molasses block supplementation of Boer goats raised under extensive grazing conditions at Onderstepoort, Pretoria, South Africa. In: Smith, T., Godfrey, S.H., Buttery, P.J., Ssewannyana, E. and Owen, E., (Eds) (2005) Small stock in development. Proceedings of a workshop on enhancing the contribution of small livestock to the livelihoods of resource-poor communities. Hotel Brovad, Masaka, Uganda, 15–19 November 2004. Natural Resources International Ltd., Aylesford, Kent, UK. ISBN: 0-9546452-5-1.
Specific health and safety precautions
Urea in high levels is toxic to livestock. Do not feed urea at levels greater than 1% of a total ration (for example presented as grain and hay), or no more than 15 gram of urea per 50 kg live weight in a single feeding.
Do not handle urea without specialised equipment and facilities.
Urea bags have to be stored safely to keep them away from animals because ruminants relish urea. They are able to intake large quantities and thus become intoxicated. Goats are particularly fond of urea and so it is essential that the blocks are accurately made so that goats are not fed too much urea at one time.
Do not feed urea to non-ruminant livestock.
Contact details for DFID research project teams
To view table, click here.
Evidence of validation
To view table, click here
IAEA. Technology transfer: use of urea molasses multi-nutrient blocks in over 50 countries.http://www-naweb.iaea.org/nafa/aph/stories/2006-umm-blocks.html
RAJKOMAR, B. (1991) The molasses block technology in Mauritius and the African perspective. Livestock Research for Rural Development Volume 3, Number 3, December 1991. http://www.cipav.org.co/lrrd/lrrd3/3/maurit.htm
IAEA. Frequently asked questions on Urea-Molasses-Multinutrient Block Technology (UMMB). Harinder Makkar, Animal Production and Health Section, Joint FAO/IAEA Division, International Atomic Energy Agency, Vienna, Austria. http://www.iaea.org/programmes/nafa/d3/faq-ummb.pdf [Also available here].
Health and safety
The researchers, their institutions or this website cannot be held responsible for any damage resulting from the use of the materials or methods described here. The application or use of treatments, processes and technologies is the sole responsibility of the user.
This technology is an output from the Renewable Natural Resources Research strategy funded by the UK Department for International Development (DFID), for the benefit of developing countries. The views expressed are not necessarily those of DFID.
Technology selected and record compiled from original project documentation by Natural Resources International Ltd, with funding from DFID’s Central Research Department (Communications). Implementing and advising on this process were: Karen Wilkin and Tina Rowland (joint project leaders), Andy Frost, Vino Graffham, Jody Sunley, Liz McVeigh, RNRRS programme staff, FAO’s Research and Technology Development Service, FAO’s LEAD programme, DFID’s Central Research Department, Ken Campbell, Graham Farrell (Plant Clinic), Simon Eden-Green, Peter Golob, John Esser, Liz Betser (360º Responsibility). Validation domain reviewed by the Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Simon Eden-Green and Peter Golob. Uploading by Random X Solutions Ltd. For more information, please contact Karen Wilkin, NR International Ltd or Tina Rowland, Random X Solutions Ltd.
KHAN, M.A.S. and SIDDIKI, S.R. (2004). Preparation of Urea Molasses Block (UMB) and it's use in livestock. [Leaflet] Forage Production and UMB Technology Project (NRI/DFID). Bangladesh Agricultural University, Mymensingh-2202.